collision.c

#include "quakedef.h"
#include "polygon.h"

#define COLLISION_EDGEDIR_DOT_EPSILON (0.999f)
#define COLLISION_EDGECROSS_MINLENGTH2 (1.0f / 4194304.0f)
#define COLLISION_SNAPSCALE (32.0f)
#define COLLISION_SNAP (1.0f / COLLISION_SNAPSCALE)
#define COLLISION_SNAP2 (2.0f / COLLISION_SNAPSCALE)
#define COLLISION_PLANE_DIST_EPSILON (2.0f / COLLISION_SNAPSCALE)

cvar_t collision_impactnudge = {0, "collision_impactnudge", "0.03125", "how much to back off from the impact"};
cvar_t collision_extendmovelength = {0, "collision_extendmovelength", "16", "internal bias on trace length to ensure detection of collisions within the collision_impactnudge distance so that short moves do not degrade across frames (this does not alter the final trace length)"};
cvar_t collision_extendtraceboxlength = {0, "collision_extendtraceboxlength", "1", "internal bias for tracebox() qc builtin to account for collision_impactnudge (this does not alter the final trace length)"};
cvar_t collision_extendtracelinelength = {0, "collision_extendtracelinelength", "1", "internal bias for traceline() qc builtin to account for collision_impactnudge (this does not alter the final trace length)"};
cvar_t collision_debug_tracelineasbox = {0, "collision_debug_tracelineasbox", "0", "workaround for any bugs in Collision_TraceLineBrushFloat by using Collision_TraceBrushBrushFloat"};
cvar_t collision_cache = {0, "collision_cache", "1", "store results of collision traces for next frame to reuse if possible (optimization)"};
//cvar_t collision_triangle_neighborsides = {0, "collision_triangle_neighborsides", "1", "override automatic side generation if triangle has neighbors with face planes that form a convex edge (perfect solution, but can not work for all edges)"};
cvar_t collision_triangle_bevelsides = {0, "collision_triangle_bevelsides", "0", "generate sloped edge planes on triangles - if 0, see axialedgeplanes"};
cvar_t collision_triangle_axialsides = {0, "collision_triangle_axialsides", "1", "generate axially-aligned edge planes on triangles - otherwise use perpendicular edge planes"};

mempool_t *collision_mempool;

void Collision_Init (void)
{
	Cvar_RegisterVariable(&collision_impactnudge);
	Cvar_RegisterVariable(&collision_extendmovelength);
	Cvar_RegisterVariable(&collision_extendtracelinelength);
	Cvar_RegisterVariable(&collision_extendtraceboxlength);
	Cvar_RegisterVariable(&collision_debug_tracelineasbox);
	Cvar_RegisterVariable(&collision_cache);
//	Cvar_RegisterVariable(&collision_triangle_neighborsides);
	Cvar_RegisterVariable(&collision_triangle_bevelsides);
	Cvar_RegisterVariable(&collision_triangle_axialsides);
	collision_mempool = Mem_AllocPool("collision cache", 0, NULL);
	Collision_Cache_Init(collision_mempool);
}














static void Collision_PrintBrushAsQHull(colbrushf_t *brush, const char *name)
{
	int i;
	Con_Printf("3 %s\n%i\n", name, brush->numpoints);
	for (i = 0;i < brush->numpoints;i++)
		Con_Printf("%f %f %f\n", brush->points[i].v[0], brush->points[i].v[1], brush->points[i].v[2]);
	// FIXME: optimize!
	Con_Printf("4\n%i\n", brush->numplanes);
	for (i = 0;i < brush->numplanes;i++)
		Con_Printf("%f %f %f %f\n", brush->planes[i].normal[0], brush->planes[i].normal[1], brush->planes[i].normal[2], brush->planes[i].dist);
}

static void Collision_ValidateBrush(colbrushf_t *brush)
{
	int j, k, pointsoffplanes, pointonplanes, pointswithinsufficientplanes, printbrush;
	float d;
	printbrush = false;
	if (!brush->numpoints)
	{
		Con_Print("Collision_ValidateBrush: brush with no points!\n");
		printbrush = true;
	}
#if 0
	// it's ok for a brush to have one point and no planes...
	if (brush->numplanes == 0 && brush->numpoints != 1)
	{
		Con_Print("Collision_ValidateBrush: brush with no planes and more than one point!\n");
		printbrush = true;
	}
#endif
	if (brush->numplanes)
	{
		pointsoffplanes = 0;
		pointswithinsufficientplanes = 0;
		for (k = 0;k < brush->numplanes;k++)
			if (DotProduct(brush->planes[k].normal, brush->planes[k].normal) < 0.0001f)
				Con_Printf("Collision_ValidateBrush: plane #%i (%f %f %f %f) is degenerate\n", k, brush->planes[k].normal[0], brush->planes[k].normal[1], brush->planes[k].normal[2], brush->planes[k].dist);
		for (j = 0;j < brush->numpoints;j++)
		{
			pointonplanes = 0;
			for (k = 0;k < brush->numplanes;k++)
			{
				d = DotProduct(brush->points[j].v, brush->planes[k].normal) - brush->planes[k].dist;
				if (d > COLLISION_PLANE_DIST_EPSILON)
				{
					Con_Printf("Collision_ValidateBrush: point #%i (%f %f %f) infront of plane #%i (%f %f %f %f)\n", j, brush->points[j].v[0], brush->points[j].v[1], brush->points[j].v[2], k, brush->planes[k].normal[0], brush->planes[k].normal[1], brush->planes[k].normal[2], brush->planes[k].dist);
					printbrush = true;
				}
				if (fabs(d) > COLLISION_PLANE_DIST_EPSILON)
					pointsoffplanes++;
				else
					pointonplanes++;
			}
			if (pointonplanes < 3)
				pointswithinsufficientplanes++;
		}
		if (pointswithinsufficientplanes)
		{
			Con_Print("Collision_ValidateBrush: some points have insufficient planes, every point must be on at least 3 planes to form a corner.\n");
			printbrush = true;
		}
		if (pointsoffplanes == 0) // all points are on all planes
		{
			Con_Print("Collision_ValidateBrush: all points lie on all planes (degenerate, no brush volume!)\n");
			printbrush = true;
		}
	}
	if (printbrush)
		Collision_PrintBrushAsQHull(brush, "unnamed");
}

static float nearestplanedist_float(const float *normal, const colpointf_t *points, int numpoints)
{
	float dist, bestdist;
	if (!numpoints)
		return 0;
	bestdist = DotProduct(points->v, normal);
	points++;
	while(--numpoints)
	{
		dist = DotProduct(points->v, normal);
		bestdist = min(bestdist, dist);
		points++;
	}
	return bestdist;
}

static float furthestplanedist_float(const float *normal, const colpointf_t *points, int numpoints)
{
	float dist, bestdist;
	if (!numpoints)
		return 0;
	bestdist = DotProduct(points->v, normal);
	points++;
	while(--numpoints)
	{
		dist = DotProduct(points->v, normal);
		bestdist = max(bestdist, dist);
		points++;
	}
	return bestdist;
}

static void Collision_CalcEdgeDirsForPolygonBrushFloat(colbrushf_t *brush)
{
	int i, j;
	for (i = 0, j = brush->numpoints - 1;i < brush->numpoints;j = i, i++)
		VectorSubtract(brush->points[i].v, brush->points[j].v, brush->edgedirs[j].v);
}

colbrushf_t *Collision_NewBrushFromPlanes(mempool_t *mempool, int numoriginalplanes, const colplanef_t *originalplanes, int supercontents, int q3surfaceflags, const texture_t *texture, int hasaabbplanes)
{
	// TODO: planesbuf could be replaced by a remapping table
	int j, k, l, m, w, xyzflags;
	int numpointsbuf = 0, maxpointsbuf = 256, numedgedirsbuf = 0, maxedgedirsbuf = 256, numplanesbuf = 0, maxplanesbuf = 256, numelementsbuf = 0, maxelementsbuf = 256;
	int isaabb = true;
	double maxdist;
	colbrushf_t *brush;
	colpointf_t pointsbuf[256];
	colpointf_t edgedirsbuf[256];
	colplanef_t planesbuf[256];
	int elementsbuf[1024];
	int polypointbuf[256];
	int pmaxpoints = 64;
	int pnumpoints;
	double p[2][3*64];
#if 0
	// enable these if debugging to avoid seeing garbage in unused data-
	memset(pointsbuf, 0, sizeof(pointsbuf));
	memset(edgedirsbuf, 0, sizeof(edgedirsbuf));
	memset(planesbuf, 0, sizeof(planesbuf));
	memset(elementsbuf, 0, sizeof(elementsbuf));
	memset(polypointbuf, 0, sizeof(polypointbuf));
	memset(p, 0, sizeof(p));
#endif

	// check if there are too many planes and skip the brush
	if (numoriginalplanes >= maxplanesbuf)
	{
		Con_DPrint("Collision_NewBrushFromPlanes: failed to build collision brush: too many planes for buffer\n");
		return NULL;
	}

	// figure out how large a bounding box we need to properly compute this brush
	maxdist = 0;
	for (j = 0;j < numoriginalplanes;j++)
		maxdist = max(maxdist, fabs(originalplanes[j].dist));
	// now make it large enough to enclose the entire brush, and round it off to a reasonable multiple of 1024
	maxdist = floor(maxdist * (4.0 / 1024.0) + 2) * 1024.0;
	// construct a collision brush (points, planes, and renderable mesh) from
	// a set of planes, this also optimizes out any unnecessary planes (ones
	// whose polygon is clipped away by the other planes)
	for (j = 0;j < numoriginalplanes;j++)
	{
		// add the new plane
		VectorCopy(originalplanes[j].normal, planesbuf[numplanesbuf].normal);
		planesbuf[numplanesbuf].dist = originalplanes[j].dist;
		planesbuf[numplanesbuf].q3surfaceflags = originalplanes[j].q3surfaceflags;
		planesbuf[numplanesbuf].texture = originalplanes[j].texture;
		numplanesbuf++;

		// create a large polygon from the plane
		w = 0;
		PolygonD_QuadForPlane(p[w], originalplanes[j].normal[0], originalplanes[j].normal[1], originalplanes[j].normal[2], originalplanes[j].dist, maxdist);
		pnumpoints = 4;
		// clip it by all other planes
		for (k = 0;k < numoriginalplanes && pnumpoints >= 3 && pnumpoints <= pmaxpoints;k++)
		{
			// skip the plane this polygon
			// (nothing happens if it is processed, this is just an optimization)
			if (k != j)
			{
				// we want to keep the inside of the brush plane so we flip
				// the cutting plane
				PolygonD_Divide(pnumpoints, p[w], -originalplanes[k].normal[0], -originalplanes[k].normal[1], -originalplanes[k].normal[2], -originalplanes[k].dist, COLLISION_PLANE_DIST_EPSILON, pmaxpoints, p[!w], &pnumpoints, 0, NULL, NULL, NULL);
				w = !w;
			}
		}

		// if nothing is left, skip it
		if (pnumpoints < 3)
		{
			//Con_DPrintf("Collision_NewBrushFromPlanes: warning: polygon for plane %f %f %f %f clipped away\n", originalplanes[j].normal[0], originalplanes[j].normal[1], originalplanes[j].normal[2], originalplanes[j].dist);
			continue;
		}

		for (k = 0;k < pnumpoints;k++)
		{
			int l, m;
			m = 0;
			for (l = 0;l < numoriginalplanes;l++)
				if (fabs(DotProduct(&p[w][k*3], originalplanes[l].normal) - originalplanes[l].dist) < COLLISION_PLANE_DIST_EPSILON)
					m++;
			if (m < 3)
				break;
		}
		if (k < pnumpoints)
		{
			Con_DPrintf("Collision_NewBrushFromPlanes: warning: polygon point does not lie on at least 3 planes\n");
			//return NULL;
		}

		// check if there are too many polygon vertices for buffer
		if (pnumpoints > pmaxpoints)
		{
			Con_DPrint("Collision_NewBrushFromPlanes: failed to build collision brush: too many points for buffer\n");
			return NULL;
		}

		// check if there are too many triangle elements for buffer
		if (numelementsbuf + (pnumpoints - 2) * 3 > maxelementsbuf)
		{
			Con_DPrint("Collision_NewBrushFromPlanes: failed to build collision brush: too many triangle elements for buffer\n");
			return NULL;
		}

		// add the unique points for this polygon
		for (k = 0;k < pnumpoints;k++)
		{
			float v[3];
			// downgrade to float precision before comparing
			VectorCopy(&p[w][k*3], v);

			// check if there is already a matching point (no duplicates)
			for (m = 0;m < numpointsbuf;m++)
				if (VectorDistance2(v, pointsbuf[m].v) < COLLISION_SNAP2)
					break;

			// if there is no match, add a new one
			if (m == numpointsbuf)
			{
				// check if there are too many and skip the brush
				if (numpointsbuf >= maxpointsbuf)
				{
					Con_DPrint("Collision_NewBrushFromPlanes: failed to build collision brush: too many points for buffer\n");
					return NULL;
				}
				// add the new one
				VectorCopy(&p[w][k*3], pointsbuf[numpointsbuf].v);
				numpointsbuf++;
			}

			// store the index into a buffer
			polypointbuf[k] = m;
		}

		// add the triangles for the polygon
		// (this particular code makes a triangle fan)
		for (k = 0;k < pnumpoints - 2;k++)
		{
			elementsbuf[numelementsbuf++] = polypointbuf[0];
			elementsbuf[numelementsbuf++] = polypointbuf[k + 1];
			elementsbuf[numelementsbuf++] = polypointbuf[k + 2];
		}

		// add the unique edgedirs for this polygon
		for (k = 0, l = pnumpoints-1;k < pnumpoints;l = k, k++)
		{
			float dir[3];
			// downgrade to float precision before comparing
			VectorSubtract(&p[w][k*3], &p[w][l*3], dir);
			VectorNormalize(dir);

			// check if there is already a matching edgedir (no duplicates)
			for (m = 0;m < numedgedirsbuf;m++)
				if (DotProduct(dir, edgedirsbuf[m].v) >= COLLISION_EDGEDIR_DOT_EPSILON)
					break;
			// skip this if there is
			if (m < numedgedirsbuf)
				continue;

			// try again with negated edgedir
			VectorNegate(dir, dir);
			// check if there is already a matching edgedir (no duplicates)
			for (m = 0;m < numedgedirsbuf;m++)
				if (DotProduct(dir, edgedirsbuf[m].v) >= COLLISION_EDGEDIR_DOT_EPSILON)
					break;
			// if there is no match, add a new one
			if (m == numedgedirsbuf)
			{
				// check if there are too many and skip the brush
				if (numedgedirsbuf >= maxedgedirsbuf)
				{
					Con_DPrint("Collision_NewBrushFromPlanes: failed to build collision brush: too many edgedirs for buffer\n");
					return NULL;
				}
				// add the new one
				VectorCopy(dir, edgedirsbuf[numedgedirsbuf].v);
				numedgedirsbuf++;
			}
		}

		// if any normal is not purely axial, it's not an axis-aligned box
		if (isaabb && (originalplanes[j].normal[0] == 0) + (originalplanes[j].normal[1] == 0) + (originalplanes[j].normal[2] == 0) < 2)
			isaabb = false;
	}

	// if nothing is left, there's nothing to allocate
	if (numplanesbuf < 4)
	{
		Con_DPrintf("Collision_NewBrushFromPlanes: failed to build collision brush: %i triangles, %i planes (input was %i planes), %i vertices\n", numelementsbuf / 3, numplanesbuf, numoriginalplanes, numpointsbuf);
		return NULL;
	}

	// if no triangles or points could be constructed, then this routine failed but the brush is not discarded
	if (numelementsbuf < 12 || numpointsbuf < 4)
		Con_DPrintf("Collision_NewBrushFromPlanes: unable to rebuild triangles/points for collision brush: %i triangles, %i planes (input was %i planes), %i vertices\n", numelementsbuf / 3, numplanesbuf, numoriginalplanes, numpointsbuf);

	// validate plane distances
	for (j = 0;j < numplanesbuf;j++)
	{
		float d = furthestplanedist_float(planesbuf[j].normal, pointsbuf, numpointsbuf);
		if (fabs(planesbuf[j].dist - d) > COLLISION_PLANE_DIST_EPSILON)
			Con_DPrintf("plane %f %f %f %f mismatches dist %f\n", planesbuf[j].normal[0], planesbuf[j].normal[1], planesbuf[j].normal[2], planesbuf[j].dist, d);
	}

	// allocate the brush and copy to it
	brush = (colbrushf_t *)Mem_Alloc(mempool, sizeof(colbrushf_t) + sizeof(colpointf_t) * numpointsbuf + sizeof(colpointf_t) * numedgedirsbuf + sizeof(colplanef_t) * numplanesbuf + sizeof(int) * numelementsbuf);
	brush->isaabb = isaabb;
	brush->hasaabbplanes = hasaabbplanes;
	brush->supercontents = supercontents;
	brush->numplanes = numplanesbuf;
	brush->numedgedirs = numedgedirsbuf;
	brush->numpoints = numpointsbuf;
	brush->numtriangles = numelementsbuf / 3;
	brush->planes = (colplanef_t *)(brush + 1);
	brush->points = (colpointf_t *)(brush->planes + brush->numplanes);
	brush->edgedirs = (colpointf_t *)(brush->points + brush->numpoints);
	brush->elements = (int *)(brush->points + brush->numpoints);
	brush->q3surfaceflags = q3surfaceflags;
	brush->texture = texture;
	for (j = 0;j < brush->numpoints;j++)
	{
		brush->points[j].v[0] = pointsbuf[j].v[0];
		brush->points[j].v[1] = pointsbuf[j].v[1];
		brush->points[j].v[2] = pointsbuf[j].v[2];
	}
	for (j = 0;j < brush->numedgedirs;j++)
	{
		brush->edgedirs[j].v[0] = edgedirsbuf[j].v[0];
		brush->edgedirs[j].v[1] = edgedirsbuf[j].v[1];
		brush->edgedirs[j].v[2] = edgedirsbuf[j].v[2];
	}
	for (j = 0;j < brush->numplanes;j++)
	{
		brush->planes[j].normal[0] = planesbuf[j].normal[0];
		brush->planes[j].normal[1] = planesbuf[j].normal[1];
		brush->planes[j].normal[2] = planesbuf[j].normal[2];
		brush->planes[j].dist = planesbuf[j].dist;
		brush->planes[j].q3surfaceflags = planesbuf[j].q3surfaceflags;
		brush->planes[j].texture = planesbuf[j].texture;
	}
	for (j = 0;j < brush->numtriangles * 3;j++)
		brush->elements[j] = elementsbuf[j];

	xyzflags = 0;
	VectorClear(brush->mins);
	VectorClear(brush->maxs);
	for (j = 0;j < min(6, numoriginalplanes);j++)
	{
		     if (originalplanes[j].normal[0] ==  1) {xyzflags |=  1;brush->maxs[0] =  originalplanes[j].dist;}
		else if (originalplanes[j].normal[0] == -1) {xyzflags |=  2;brush->mins[0] = -originalplanes[j].dist;}
		else if (originalplanes[j].normal[1] ==  1) {xyzflags |=  4;brush->maxs[1] =  originalplanes[j].dist;}
		else if (originalplanes[j].normal[1] == -1) {xyzflags |=  8;brush->mins[1] = -originalplanes[j].dist;}
		else if (originalplanes[j].normal[2] ==  1) {xyzflags |= 16;brush->maxs[2] =  originalplanes[j].dist;}
		else if (originalplanes[j].normal[2] == -1) {xyzflags |= 32;brush->mins[2] = -originalplanes[j].dist;}
	}
	// if not all xyzflags were set, then this is not a brush from q3map/q3map2, and needs reconstruction of the bounding box
	// (this case works for any brush with valid points, but sometimes brushes are not reconstructed properly and hence the points are not valid, so this is reserved as a fallback case)
	if (xyzflags != 63)
	{
		VectorCopy(brush->points[0].v, brush->mins);
		VectorCopy(brush->points[0].v, brush->maxs);
		for (j = 1;j < brush->numpoints;j++)
		{
			brush->mins[0] = min(brush->mins[0], brush->points[j].v[0]);
			brush->mins[1] = min(brush->mins[1], brush->points[j].v[1]);
			brush->mins[2] = min(brush->mins[2], brush->points[j].v[2]);
			brush->maxs[0] = max(brush->maxs[0], brush->points[j].v[0]);
			brush->maxs[1] = max(brush->maxs[1], brush->points[j].v[1]);
			brush->maxs[2] = max(brush->maxs[2], brush->points[j].v[2]);
		}
	}
	brush->mins[0] -= 1;
	brush->mins[1] -= 1;
	brush->mins[2] -= 1;
	brush->maxs[0] += 1;
	brush->maxs[1] += 1;
	brush->maxs[2] += 1;
	Collision_ValidateBrush(brush);
	return brush;
}



void Collision_CalcPlanesForTriangleBrushFloat(colbrushf_t *brush)
{
	int i;
	float edge0[3], edge1[3], edge2[3];
	colpointf_t *p;

	TriangleNormal(brush->points[0].v, brush->points[1].v, brush->points[2].v, brush->planes[0].normal);
	if (DotProduct(brush->planes[0].normal, brush->planes[0].normal) < 0.0001f)
	{
		// there's no point in processing a degenerate triangle (GIGO - Garbage In, Garbage Out)
		// note that some of these exist in q3bsp bspline patches
		brush->numplanes = 0;
		return;
	}

	// there are 5 planes (front, back, sides) and 3 edges
	brush->numplanes = 5;
	brush->numedgedirs = 3;
	VectorNormalize(brush->planes[0].normal);
	brush->planes[0].dist = DotProduct(brush->points->v, brush->planes[0].normal);
	VectorNegate(brush->planes[0].normal, brush->planes[1].normal);
	brush->planes[1].dist = -brush->planes[0].dist;
	// edge directions are easy to calculate
	VectorSubtract(brush->points[2].v, brush->points[0].v, edge0);
	VectorSubtract(brush->points[0].v, brush->points[1].v, edge1);
	VectorSubtract(brush->points[1].v, brush->points[2].v, edge2);
	VectorCopy(edge0, brush->edgedirs[0].v);
	VectorCopy(edge1, brush->edgedirs[1].v);
	VectorCopy(edge2, brush->edgedirs[2].v);
	// now select an algorithm to generate the side planes
	if (collision_triangle_bevelsides.integer)
	{
		// use 45 degree slopes at the edges of the triangle to make a sinking trace error turn into "riding up" the slope rather than getting stuck
		CrossProduct(edge0, brush->planes->normal, brush->planes[2].normal);
		CrossProduct(edge1, brush->planes->normal, brush->planes[3].normal);
		CrossProduct(edge2, brush->planes->normal, brush->planes[4].normal);
		VectorNormalize(brush->planes[2].normal);
		VectorNormalize(brush->planes[3].normal);
		VectorNormalize(brush->planes[4].normal);
		VectorAdd(brush->planes[2].normal, brush->planes[0].normal, brush->planes[2].normal);
		VectorAdd(brush->planes[3].normal, brush->planes[0].normal, brush->planes[3].normal);
		VectorAdd(brush->planes[4].normal, brush->planes[0].normal, brush->planes[4].normal);
		VectorNormalize(brush->planes[2].normal);
		VectorNormalize(brush->planes[3].normal);
		VectorNormalize(brush->planes[4].normal);
	}
	else if (collision_triangle_axialsides.integer)
	{
		float projectionnormal[3], projectionedge0[3], projectionedge1[3], projectionedge2[3];
		int i, best;
		float dist, bestdist;
		bestdist = fabs(brush->planes[0].normal[0]);
		best = 0;
		for (i = 1;i < 3;i++)
		{
			dist = fabs(brush->planes[0].normal[i]);
			if (bestdist < dist)
			{
				bestdist = dist;
				best = i;
			}
		}
		VectorClear(projectionnormal);
		if (brush->planes[0].normal[best] < 0)
			projectionnormal[best] = -1;
		else
			projectionnormal[best] = 1;
		VectorCopy(edge0, projectionedge0);
		VectorCopy(edge1, projectionedge1);
		VectorCopy(edge2, projectionedge2);
		projectionedge0[best] = 0;
		projectionedge1[best] = 0;
		projectionedge2[best] = 0;
		CrossProduct(projectionedge0, projectionnormal, brush->planes[2].normal);
		CrossProduct(projectionedge1, projectionnormal, brush->planes[3].normal);
		CrossProduct(projectionedge2, projectionnormal, brush->planes[4].normal);
		VectorNormalize(brush->planes[2].normal);
		VectorNormalize(brush->planes[3].normal);
		VectorNormalize(brush->planes[4].normal);
	}
	else
	{
		CrossProduct(edge0, brush->planes->normal, brush->planes[2].normal);
		CrossProduct(edge1, brush->planes->normal, brush->planes[3].normal);
		CrossProduct(edge2, brush->planes->normal, brush->planes[4].normal);
		VectorNormalize(brush->planes[2].normal);
		VectorNormalize(brush->planes[3].normal);
		VectorNormalize(brush->planes[4].normal);
	}
	brush->planes[2].dist = DotProduct(brush->points[2].v, brush->planes[2].normal);
	brush->planes[3].dist = DotProduct(brush->points[0].v, brush->planes[3].normal);
	brush->planes[4].dist = DotProduct(brush->points[1].v, brush->planes[4].normal);

	if (developer_extra.integer)
	{
		// validity check - will be disabled later
		Collision_ValidateBrush(brush);
		for (i = 0;i < brush->numplanes;i++)
		{
			int j;
			for (j = 0, p = brush->points;j < brush->numpoints;j++, p++)
				if (DotProduct(p->v, brush->planes[i].normal) > brush->planes[i].dist + COLLISION_PLANE_DIST_EPSILON)
					Con_DPrintf("Error in brush plane generation, plane %i\n", i);
		}
	}
}

colbrushf_t *Collision_AllocBrushFromPermanentPolygonFloat(mempool_t *mempool, int numpoints, float *points, int supercontents, int q3surfaceflags, const texture_t *texture)
{
	colbrushf_t *brush;
	brush = (colbrushf_t *)Mem_Alloc(mempool, sizeof(colbrushf_t) + sizeof(colplanef_t) * (numpoints + 2) + sizeof(colpointf_t) * numpoints);
	brush->isaabb = false;
	brush->hasaabbplanes = false;
	brush->supercontents = supercontents;
	brush->numpoints = numpoints;
	brush->numedgedirs = numpoints;
	brush->numplanes = numpoints + 2;
	brush->planes = (colplanef_t *)(brush + 1);
	brush->points = (colpointf_t *)points;
	brush->edgedirs = (colpointf_t *)(brush->planes + brush->numplanes);
	brush->q3surfaceflags = q3surfaceflags;
	brush->texture = texture;
	Sys_Error("Collision_AllocBrushFromPermanentPolygonFloat: FIXME: this code needs to be updated to generate a mesh...");
	return brush;
}

// NOTE: start and end of each brush pair must have same numplanes/numpoints
void Collision_TraceBrushBrushFloat(trace_t *trace, const colbrushf_t *trace_start, const colbrushf_t *trace_end, const colbrushf_t *other_start, const colbrushf_t *other_end)
{
	int nplane, nplane2, nedge1, nedge2, hitq3surfaceflags = 0;
	int tracenumedgedirs = trace_start->numedgedirs;
	//int othernumedgedirs = other_start->numedgedirs;
	int tracenumpoints = trace_start->numpoints;
	int othernumpoints = other_start->numpoints;
	int numplanes1 = other_start->numplanes;
	int numplanes2 = numplanes1 + trace_start->numplanes;
	int numplanes3 = numplanes2 + trace_start->numedgedirs * other_start->numedgedirs * 2;
	vec_t enterfrac = -1, leavefrac = 1, startdist, enddist, ie, f, imove, enterfrac2 = -1;
	vec4_t startplane;
	vec4_t endplane;
	vec4_t newimpactplane;
	const texture_t *hittexture = NULL;
	vec_t startdepth = 1;
	vec3_t startdepthnormal;

	VectorClear(startdepthnormal);
	Vector4Clear(newimpactplane);

	// fast case for AABB vs compiled brushes (which begin with AABB planes and also have precomputed bevels for AABB collisions)
	if (trace_start->isaabb && other_start->hasaabbplanes)
		numplanes3 = numplanes2 = numplanes1;

	// Separating Axis Theorem:
	// if a supporting vector (plane normal) can be found that separates two
	// objects, they are not colliding.
	//
	// Minkowski Sum:
	// reduce the size of one object to a point while enlarging the other to
	// represent the space that point can not occupy.
	//
	// try every plane we can construct between the two brushes and measure
	// the distance between them.
	for (nplane = 0;nplane < numplanes3;nplane++)
	{
		if (nplane < numplanes1)
		{
			nplane2 = nplane;
			VectorCopy(other_start->planes[nplane2].normal, startplane);
			VectorCopy(other_end->planes[nplane2].normal, endplane);
		}
		else if (nplane < numplanes2)
		{
			nplane2 = nplane - numplanes1;
			VectorCopy(trace_start->planes[nplane2].normal, startplane);
			VectorCopy(trace_end->planes[nplane2].normal, endplane);
		}
		else
		{
			// pick an edgedir from each brush and cross them
			nplane2 = nplane - numplanes2;
			nedge1 = nplane2 >> 1;
			nedge2 = nedge1 / tracenumedgedirs;
			nedge1 -= nedge2 * tracenumedgedirs;
			if (nplane2 & 1)
			{
				CrossProduct(trace_start->edgedirs[nedge1].v, other_start->edgedirs[nedge2].v, startplane);
				CrossProduct(trace_end->edgedirs[nedge1].v, other_end->edgedirs[nedge2].v, endplane);
			}
			else
			{
				CrossProduct(other_start->edgedirs[nedge2].v, trace_start->edgedirs[nedge1].v, startplane);
				CrossProduct(other_end->edgedirs[nedge2].v, trace_end->edgedirs[nedge1].v, endplane);
			}
			if (VectorLength2(startplane) < COLLISION_EDGECROSS_MINLENGTH2 || VectorLength2(endplane) < COLLISION_EDGECROSS_MINLENGTH2)
				continue; // degenerate crossproducts
			VectorNormalize(startplane);
			VectorNormalize(endplane);
		}
		startplane[3] = furthestplanedist_float(startplane, other_start->points, othernumpoints);
		endplane[3] = furthestplanedist_float(startplane, other_end->points, othernumpoints);
		startdist = nearestplanedist_float(startplane, trace_start->points, tracenumpoints) - startplane[3];
		enddist = nearestplanedist_float(endplane, trace_end->points, tracenumpoints) - endplane[3];
		//Con_Printf("%c%i: startdist = %f, enddist = %f, startdist / (startdist - enddist) = %f\n", nplane2 != nplane ? 'b' : 'a', nplane2, startdist, enddist, startdist / (startdist - enddist));

		// aside from collisions, this is also used for error correction
		if (startdist <= 0.0f && nplane < numplanes1 && (startdepth < startdist || startdepth == 1))
		{
			startdepth = startdist;
			VectorCopy(startplane, startdepthnormal);
		}

		if (startdist > enddist)
		{
			// moving into brush
			if (enddist > 0.0f)
				return;
			if (startdist >= 0)
			{
				// enter
				imove = 1 / (startdist - enddist);
				f = startdist * imove;
				// check if this will reduce the collision time range
				if (enterfrac < f)
				{
					// reduced collision time range
					enterfrac = f;
					// if the collision time range is now empty, no collision
					if (enterfrac > leavefrac)
						return;
					// calculate the nudged fraction and impact normal we'll
					// need if we accept this collision later
					enterfrac2 = (startdist - collision_impactnudge.value) * imove;
					// if the collision would be further away than the trace's
					// existing collision data, we don't care about this
					// collision
					if (enterfrac2 >= trace->fraction)
						return;
					ie = 1.0f - enterfrac;
					newimpactplane[0] = startplane[0] * ie + endplane[0] * enterfrac;
					newimpactplane[1] = startplane[1] * ie + endplane[1] * enterfrac;
					newimpactplane[2] = startplane[2] * ie + endplane[2] * enterfrac;
					newimpactplane[3] = startplane[3] * ie + endplane[3] * enterfrac;
					if (nplane < numplanes1)
					{
						// use the plane from other
						nplane2 = nplane;
						hitq3surfaceflags = other_start->planes[nplane2].q3surfaceflags;
						hittexture = other_start->planes[nplane2].texture;
					}
					else if (nplane < numplanes2)
					{
						// use the plane from trace
						nplane2 = nplane - numplanes1;
						hitq3surfaceflags = trace_start->planes[nplane2].q3surfaceflags;
						hittexture = trace_start->planes[nplane2].texture;
					}
					else
					{
						hitq3surfaceflags = other_start->q3surfaceflags;
						hittexture = other_start->texture;
					}
				}
			}
		}
		else
		{
			// moving out of brush
			if (startdist >= 0)
				return;
			if (enddist > 0)
			{
				// leave
				f = startdist / (startdist - enddist);
				// check if this will reduce the collision time range
				if (leavefrac > f)
				{
					// reduced collision time range
					leavefrac = f;
					// if the collision time range is now empty, no collision
					if (enterfrac > leavefrac)
						return;
				}
			}
		}
	}

	// at this point we know the trace overlaps the brush because it was not
	// rejected at any point in the loop above

	// see if the trace started outside the brush or not
	if (enterfrac > -1)
	{
		// started outside, and overlaps, therefore there is a collision here
		// store out the impact information
		if (trace->hitsupercontentsmask & other_start->supercontents)
		{
			trace->hitsupercontents = other_start->supercontents;
			trace->hitq3surfaceflags = hitq3surfaceflags;
			trace->hittexture = hittexture;
			trace->fraction = bound(0, enterfrac2, 1);
			VectorCopy(newimpactplane, trace->plane.normal);
			trace->plane.dist = newimpactplane[3];
		}
	}
	else
	{
		// started inside, update startsolid and friends
		trace->startsupercontents |= other_start->supercontents;
		if (trace->hitsupercontentsmask & other_start->supercontents)
		{
			trace->startsolid = true;
			if (leavefrac < 1)
				trace->allsolid = true;
			VectorCopy(newimpactplane, trace->plane.normal);
			trace->plane.dist = newimpactplane[3];
			if (trace->startdepth > startdepth)
			{
				trace->startdepth = startdepth;
				VectorCopy(startdepthnormal, trace->startdepthnormal);
			}
		}
	}
}

// NOTE: start and end of each brush pair must have same numplanes/numpoints
void Collision_TraceLineBrushFloat(trace_t *trace, const vec3_t linestart, const vec3_t lineend, const colbrushf_t *other_start, const colbrushf_t *other_end)
{
	int nplane, hitq3surfaceflags = 0;
	int numplanes = other_start->numplanes;
	vec_t enterfrac = -1, leavefrac = 1, startdist, enddist, ie, f, imove, enterfrac2 = -1;
	vec4_t startplane;
	vec4_t endplane;
	vec4_t newimpactplane;
	const texture_t *hittexture = NULL;
	vec_t startdepth = 1;
	vec3_t startdepthnormal;

	if (collision_debug_tracelineasbox.integer)
	{
		colboxbrushf_t thisbrush_start, thisbrush_end;
		Collision_BrushForBox(&thisbrush_start, linestart, linestart, 0, 0, NULL);
		Collision_BrushForBox(&thisbrush_end, lineend, lineend, 0, 0, NULL);
		Collision_TraceBrushBrushFloat(trace, &thisbrush_start.brush, &thisbrush_end.brush, other_start, other_end);
		return;
	}

	VectorClear(startdepthnormal);
	Vector4Clear(newimpactplane);

	// Separating Axis Theorem:
	// if a supporting vector (plane normal) can be found that separates two
	// objects, they are not colliding.
	//
	// Minkowski Sum:
	// reduce the size of one object to a point while enlarging the other to
	// represent the space that point can not occupy.
	//
	// try every plane we can construct between the two brushes and measure
	// the distance between them.
	for (nplane = 0;nplane < numplanes;nplane++)
	{
		VectorCopy(other_start->planes[nplane].normal, startplane);
		startplane[3] = other_start->planes[nplane].dist;
		VectorCopy(other_end->planes[nplane].normal, endplane);
		endplane[3] = other_end->planes[nplane].dist;
		startdist = DotProduct(linestart, startplane) - startplane[3];
		enddist = DotProduct(lineend, endplane) - endplane[3];
		//Con_Printf("%c%i: startdist = %f, enddist = %f, startdist / (startdist - enddist) = %f\n", nplane2 != nplane ? 'b' : 'a', nplane2, startdist, enddist, startdist / (startdist - enddist));

		// aside from collisions, this is also used for error correction
		if (startdist <= 0.0f && (startdepth < startdist || startdepth == 1))
		{
			startdepth = startdist;
			VectorCopy(startplane, startdepthnormal);
		}

		if (startdist > enddist)
		{
			// moving into brush
			if (enddist > 0.0f)
				return;
			if (startdist > 0)
			{
				// enter
				imove = 1 / (startdist - enddist);
				f = startdist * imove;
				// check if this will reduce the collision time range
				if (enterfrac < f)
				{
					// reduced collision time range
					enterfrac = f;
					// if the collision time range is now empty, no collision
					if (enterfrac > leavefrac)
						return;
					// calculate the nudged fraction and impact normal we'll
					// need if we accept this collision later
					enterfrac2 = (startdist - collision_impactnudge.value) * imove;
					// if the collision would be further away than the trace's
					// existing collision data, we don't care about this
					// collision
					if (enterfrac2 >= trace->fraction)
						return;
					ie = 1.0f - enterfrac;
					newimpactplane[0] = startplane[0] * ie + endplane[0] * enterfrac;
					newimpactplane[1] = startplane[1] * ie + endplane[1] * enterfrac;
					newimpactplane[2] = startplane[2] * ie + endplane[2] * enterfrac;
					newimpactplane[3] = startplane[3] * ie + endplane[3] * enterfrac;
					hitq3surfaceflags = other_start->planes[nplane].q3surfaceflags;
					hittexture = other_start->planes[nplane].texture;
				}
			}
		}
		else
		{
			// moving out of brush
			if (startdist > 0)
				return;
			if (enddist > 0)
			{
				// leave
				f = startdist / (startdist - enddist);
				// check if this will reduce the collision time range
				if (leavefrac > f)
				{
					// reduced collision time range
					leavefrac = f;
					// if the collision time range is now empty, no collision
					if (enterfrac > leavefrac)
						return;
				}
			}
		}
	}

	// at this point we know the trace overlaps the brush because it was not
	// rejected at any point in the loop above

	// see if the trace started outside the brush or not
	if (enterfrac > -1)
	{
		// started outside, and overlaps, therefore there is a collision here
		// store out the impact information
		if (trace->hitsupercontentsmask & other_start->supercontents)
		{
			trace->hitsupercontents = other_start->supercontents;
			trace->hitq3surfaceflags = hitq3surfaceflags;
			trace->hittexture = hittexture;
			trace->fraction = bound(0, enterfrac2, 1);
			VectorCopy(newimpactplane, trace->plane.normal);
			trace->plane.dist = newimpactplane[3];
		}
	}
	else
	{
		// started inside, update startsolid and friends
		trace->startsupercontents |= other_start->supercontents;
		if (trace->hitsupercontentsmask & other_start->supercontents)
		{
			trace->startsolid = true;
			if (leavefrac < 1)
				trace->allsolid = true;
			VectorCopy(newimpactplane, trace->plane.normal);
			trace->plane.dist = newimpactplane[3];
			if (trace->startdepth > startdepth)
			{
				trace->startdepth = startdepth;
				VectorCopy(startdepthnormal, trace->startdepthnormal);
			}
		}
	}
}

qboolean Collision_PointInsideBrushFloat(const vec3_t point, const colbrushf_t *brush)
{
	int nplane;
	const colplanef_t *plane;

	if (!BoxesOverlap(point, point, brush->mins, brush->maxs))
		return false;
	for (nplane = 0, plane = brush->planes;nplane < brush->numplanes;nplane++, plane++)
		if (DotProduct(plane->normal, point) > plane->dist)
			return false;
	return true;
}

void Collision_TracePointBrushFloat(trace_t *trace, const vec3_t point, const colbrushf_t *thatbrush)
{
	if (!Collision_PointInsideBrushFloat(point, thatbrush))
		return;

	trace->startsupercontents |= thatbrush->supercontents;
	if (trace->hitsupercontentsmask & thatbrush->supercontents)
	{
		trace->startsolid = true;
		trace->allsolid = true;
	}
}

static void Collision_SnapCopyPoints(int numpoints, const colpointf_t *in, colpointf_t *out, float fractionprecision, float invfractionprecision)
{
	int i;
	for (i = 0;i < numpoints;i++)
	{
		out[i].v[0] = floor(in[i].v[0] * fractionprecision + 0.5f) * invfractionprecision;
		out[i].v[1] = floor(in[i].v[1] * fractionprecision + 0.5f) * invfractionprecision;
		out[i].v[2] = floor(in[i].v[2] * fractionprecision + 0.5f) * invfractionprecision;
	}
}

void Collision_TraceBrushTriangleMeshFloat(trace_t *trace, const colbrushf_t *thisbrush_start, const colbrushf_t *thisbrush_end, int numtriangles, const int *element3i, const float *vertex3f, int stride, float *bbox6f, int supercontents, int q3surfaceflags, const texture_t *texture, const vec3_t segmentmins, const vec3_t segmentmaxs)
{
	int i;
	colpointf_t points[3];
	colpointf_t edgedirs[3];
	colplanef_t planes[5];
	colbrushf_t brush;
	memset(&brush, 0, sizeof(brush));
	brush.isaabb = false;
	brush.hasaabbplanes = false;
	brush.numpoints = 3;
	brush.numedgedirs = 3;
	brush.numplanes = 5;
	brush.points = points;
	brush.edgedirs = edgedirs;
	brush.planes = planes;
	brush.supercontents = supercontents;
	brush.q3surfaceflags = q3surfaceflags;
	brush.texture = texture;
	for (i = 0;i < brush.numplanes;i++)
	{
		brush.planes[i].q3surfaceflags = q3surfaceflags;
		brush.planes[i].texture = texture;
	}
	if(stride > 0)
	{
		int k, cnt, tri;
		cnt = (numtriangles + stride - 1) / stride;
		for(i = 0; i < cnt; ++i)
		{
			if(BoxesOverlap(bbox6f + i * 6, bbox6f + i * 6 + 3, segmentmins, segmentmaxs))
			{
				for(k = 0; k < stride; ++k)
				{
					tri = i * stride + k;
					if(tri >= numtriangles)
						break;
					VectorCopy(vertex3f + element3i[tri * 3 + 0] * 3, points[0].v);
					VectorCopy(vertex3f + element3i[tri * 3 + 1] * 3, points[1].v);
					VectorCopy(vertex3f + element3i[tri * 3 + 2] * 3, points[2].v);
					Collision_SnapCopyPoints(brush.numpoints, points, points, COLLISION_SNAPSCALE, COLLISION_SNAP);
					Collision_CalcEdgeDirsForPolygonBrushFloat(&brush);
					Collision_CalcPlanesForTriangleBrushFloat(&brush);
					//Collision_PrintBrushAsQHull(&brush, "brush");
					Collision_TraceBrushBrushFloat(trace, thisbrush_start, thisbrush_end, &brush, &brush);
				}
			}
		}
	}
	else if(stride == 0)
	{
		for (i = 0;i < numtriangles;i++, element3i += 3)
		{
			if (TriangleBBoxOverlapsBox(vertex3f + element3i[0]*3, vertex3f + element3i[1]*3, vertex3f + element3i[2]*3, segmentmins, segmentmaxs))
			{
				VectorCopy(vertex3f + element3i[0] * 3, points[0].v);
				VectorCopy(vertex3f + element3i[1] * 3, points[1].v);
				VectorCopy(vertex3f + element3i[2] * 3, points[2].v);
				Collision_SnapCopyPoints(brush.numpoints, points, points, COLLISION_SNAPSCALE, COLLISION_SNAP);
				Collision_CalcEdgeDirsForPolygonBrushFloat(&brush);
				Collision_CalcPlanesForTriangleBrushFloat(&brush);
				//Collision_PrintBrushAsQHull(&brush, "brush");
				Collision_TraceBrushBrushFloat(trace, thisbrush_start, thisbrush_end, &brush, &brush);
			}
		}
	}
	else
	{
		for (i = 0;i < numtriangles;i++, element3i += 3)
		{
			VectorCopy(vertex3f + element3i[0] * 3, points[0].v);
			VectorCopy(vertex3f + element3i[1] * 3, points[1].v);
			VectorCopy(vertex3f + element3i[2] * 3, points[2].v);
			Collision_SnapCopyPoints(brush.numpoints, points, points, COLLISION_SNAPSCALE, COLLISION_SNAP);
			Collision_CalcEdgeDirsForPolygonBrushFloat(&brush);
			Collision_CalcPlanesForTriangleBrushFloat(&brush);
			//Collision_PrintBrushAsQHull(&brush, "brush");
			Collision_TraceBrushBrushFloat(trace, thisbrush_start, thisbrush_end, &brush, &brush);
		}
	}
}

void Collision_TraceLineTriangleMeshFloat(trace_t *trace, const vec3_t linestart, const vec3_t lineend, int numtriangles, const int *element3i, const float *vertex3f, int stride, float *bbox6f, int supercontents, int q3surfaceflags, const texture_t *texture, const vec3_t segmentmins, const vec3_t segmentmaxs)
{
	int i;
	// FIXME: snap vertices?
	if(stride > 0)
	{
		int k, cnt, tri;
		cnt = (numtriangles + stride - 1) / stride;
		for(i = 0; i < cnt; ++i)
		{
			if(BoxesOverlap(bbox6f + i * 6, bbox6f + i * 6 + 3, segmentmins, segmentmaxs))
			{
				for(k = 0; k < stride; ++k)
				{
					tri = i * stride + k;
					if(tri >= numtriangles)
						break;
					Collision_TraceLineTriangleFloat(trace, linestart, lineend, vertex3f + element3i[tri * 3 + 0] * 3, vertex3f + element3i[tri * 3 + 1] * 3, vertex3f + element3i[tri * 3 + 2] * 3, supercontents, q3surfaceflags, texture);
				}
			}
		}
	}
	else
	{
		for (i = 0;i < numtriangles;i++, element3i += 3)
			Collision_TraceLineTriangleFloat(trace, linestart, lineend, vertex3f + element3i[0] * 3, vertex3f + element3i[1] * 3, vertex3f + element3i[2] * 3, supercontents, q3surfaceflags, texture);
	}
}

void Collision_TraceBrushTriangleFloat(trace_t *trace, const colbrushf_t *thisbrush_start, const colbrushf_t *thisbrush_end, const float *v0, const float *v1, const float *v2, int supercontents, int q3surfaceflags, const texture_t *texture)
{
	int i;
	colpointf_t points[3];
	colpointf_t edgedirs[3];
	colplanef_t planes[5];
	colbrushf_t brush;
	memset(&brush, 0, sizeof(brush));
	brush.isaabb = false;
	brush.hasaabbplanes = false;
	brush.numpoints = 3;
	brush.numedgedirs = 3;
	brush.numplanes = 5;
	brush.points = points;
	brush.edgedirs = edgedirs;
	brush.planes = planes;
	brush.supercontents = supercontents;
	brush.q3surfaceflags = q3surfaceflags;
	brush.texture = texture;
	for (i = 0;i < brush.numplanes;i++)
	{
		brush.planes[i].q3surfaceflags = q3surfaceflags;
		brush.planes[i].texture = texture;
	}
	VectorCopy(v0, points[0].v);
	VectorCopy(v1, points[1].v);
	VectorCopy(v2, points[2].v);
	Collision_SnapCopyPoints(brush.numpoints, points, points, COLLISION_SNAPSCALE, COLLISION_SNAP);
	Collision_CalcEdgeDirsForPolygonBrushFloat(&brush);
	Collision_CalcPlanesForTriangleBrushFloat(&brush);
	//Collision_PrintBrushAsQHull(&brush, "brush");
	Collision_TraceBrushBrushFloat(trace, thisbrush_start, thisbrush_end, &brush, &brush);
}

void Collision_BrushForBox(colboxbrushf_t *boxbrush, const vec3_t mins, const vec3_t maxs, int supercontents, int q3surfaceflags, const texture_t *texture)
{
	int i;
	memset(boxbrush, 0, sizeof(*boxbrush));
	boxbrush->brush.isaabb = true;
	boxbrush->brush.hasaabbplanes = true;
	boxbrush->brush.points = boxbrush->points;
	boxbrush->brush.edgedirs = boxbrush->edgedirs;
	boxbrush->brush.planes = boxbrush->planes;
	boxbrush->brush.supercontents = supercontents;
	boxbrush->brush.q3surfaceflags = q3surfaceflags;
	boxbrush->brush.texture = texture;
	if (VectorCompare(mins, maxs))
	{
		// point brush
		boxbrush->brush.numpoints = 1;
		boxbrush->brush.numedgedirs = 0;
		boxbrush->brush.numplanes = 0;
		VectorCopy(mins, boxbrush->brush.points[0].v);
	}
	else
	{
		boxbrush->brush.numpoints = 8;
		boxbrush->brush.numedgedirs = 3;
		boxbrush->brush.numplanes = 6;
		// there are 8 points on a box
		// there are 3 edgedirs on a box (both signs are tested in collision)
		// there are 6 planes on a box
		VectorSet(boxbrush->brush.points[0].v, mins[0], mins[1], mins[2]);
		VectorSet(boxbrush->brush.points[1].v, maxs[0], mins[1], mins[2]);
		VectorSet(boxbrush->brush.points[2].v, mins[0], maxs[1], mins[2]);
		VectorSet(boxbrush->brush.points[3].v, maxs[0], maxs[1], mins[2]);
		VectorSet(boxbrush->brush.points[4].v, mins[0], mins[1], maxs[2]);
		VectorSet(boxbrush->brush.points[5].v, maxs[0], mins[1], maxs[2]);
		VectorSet(boxbrush->brush.points[6].v, mins[0], maxs[1], maxs[2]);
		VectorSet(boxbrush->brush.points[7].v, maxs[0], maxs[1], maxs[2]);
		VectorSet(boxbrush->brush.edgedirs[0].v, 1, 0, 0);
		VectorSet(boxbrush->brush.edgedirs[1].v, 0, 1, 0);
		VectorSet(boxbrush->brush.edgedirs[2].v, 0, 0, 1);
		VectorSet(boxbrush->brush.planes[0].normal, -1,  0,  0);boxbrush->brush.planes[0].dist = -mins[0];
		VectorSet(boxbrush->brush.planes[1].normal,  1,  0,  0);boxbrush->brush.planes[1].dist =  maxs[0];
		VectorSet(boxbrush->brush.planes[2].normal,  0, -1,  0);boxbrush->brush.planes[2].dist = -mins[1];
		VectorSet(boxbrush->brush.planes[3].normal,  0,  1,  0);boxbrush->brush.planes[3].dist =  maxs[1];
		VectorSet(boxbrush->brush.planes[4].normal,  0,  0, -1);boxbrush->brush.planes[4].dist = -mins[2];
		VectorSet(boxbrush->brush.planes[5].normal,  0,  0,  1);boxbrush->brush.planes[5].dist =  maxs[2];
		for (i = 0;i < 6;i++)
		{
			boxbrush->brush.planes[i].q3surfaceflags = q3surfaceflags;
			boxbrush->brush.planes[i].texture = texture;
		}
	}
	boxbrush->brush.supercontents = supercontents;
	boxbrush->brush.q3surfaceflags = q3surfaceflags;
	boxbrush->brush.texture = texture;
	VectorSet(boxbrush->brush.mins, mins[0] - 1, mins[1] - 1, mins[2] - 1);
	VectorSet(boxbrush->brush.maxs, maxs[0] + 1, maxs[1] + 1, maxs[2] + 1);
	//Collision_ValidateBrush(&boxbrush->brush);
}

//pseudocode for detecting line/sphere overlap without calculating an impact point
//linesphereorigin = sphereorigin - linestart;linediff = lineend - linestart;linespherefrac = DotProduct(linesphereorigin, linediff) / DotProduct(linediff, linediff);return VectorLength2(linesphereorigin - bound(0, linespherefrac, 1) * linediff) >= sphereradius*sphereradius;

// LordHavoc: currently unused, but tested
// note: this can be used for tracing a moving sphere vs a stationary sphere,
// by simply adding the moving sphere's radius to the sphereradius parameter,
// all the results are correct (impactpoint, impactnormal, and fraction)
float Collision_ClipTrace_Line_Sphere(double *linestart, double *lineend, double *sphereorigin, double sphereradius, double *impactpoint, double *impactnormal)
{
	double dir[3], scale, v[3], deviationdist2, impactdist, linelength;
	// make sure the impactpoint and impactnormal are valid even if there is
	// no collision
	VectorCopy(lineend, impactpoint);
	VectorClear(impactnormal);
	// calculate line direction
	VectorSubtract(lineend, linestart, dir);
	// normalize direction
	linelength = VectorLength(dir);
	if (linelength)
	{
		scale = 1.0 / linelength;
		VectorScale(dir, scale, dir);
	}
	// this dotproduct calculates the distance along the line at which the
	// sphere origin is (nearest point to the sphere origin on the line)
	impactdist = DotProduct(sphereorigin, dir) - DotProduct(linestart, dir);
	// calculate point on line at that distance, and subtract the
	// sphereorigin from it, so we have a vector to measure for the distance
	// of the line from the sphereorigin (deviation, how off-center it is)
	VectorMA(linestart, impactdist, dir, v);
	VectorSubtract(v, sphereorigin, v);
	deviationdist2 = sphereradius * sphereradius - VectorLength2(v);
	// if squared offset length is outside the squared sphere radius, miss
	if (deviationdist2 < 0)
		return 1; // miss (off to the side)
	// nudge back to find the correct impact distance
	impactdist -= sqrt(deviationdist2);
	if (impactdist >= linelength)
		return 1; // miss (not close enough)
	if (impactdist < 0)
		return 1; // miss (linestart is past or inside sphere)
	// calculate new impactpoint
	VectorMA(linestart, impactdist, dir, impactpoint);
	// calculate impactnormal (surface normal at point of impact)
	VectorSubtract(impactpoint, sphereorigin, impactnormal);
	// normalize impactnormal
	VectorNormalize(impactnormal);
	// return fraction of movement distance
	return impactdist / linelength;
}

void Collision_TraceLineTriangleFloat(trace_t *trace, const vec3_t linestart, const vec3_t lineend, const float *point0, const float *point1, const float *point2, int supercontents, int q3surfaceflags, const texture_t *texture)
{
	float d1, d2, d, f, f2, impact[3], edgenormal[3], faceplanenormal[3], faceplanedist, faceplanenormallength2, edge01[3], edge21[3], edge02[3];

	// this function executes:
	// 32 ops when line starts behind triangle
	// 38 ops when line ends infront of triangle
	// 43 ops when line fraction is already closer than this triangle
	// 72 ops when line is outside edge 01
	// 92 ops when line is outside edge 21
	// 115 ops when line is outside edge 02
	// 123 ops when line impacts triangle and updates trace results

	// this code is designed for clockwise triangles, conversion to
	// counterclockwise would require swapping some things around...
	// it is easier to simply swap the point0 and point2 parameters to this
	// function when calling it than it is to rewire the internals.

	// calculate the faceplanenormal of the triangle, this represents the front side
	// 15 ops
	VectorSubtract(point0, point1, edge01);
	VectorSubtract(point2, point1, edge21);
	CrossProduct(edge01, edge21, faceplanenormal);
	// there's no point in processing a degenerate triangle (GIGO - Garbage In, Garbage Out)
	// 6 ops
	faceplanenormallength2 = DotProduct(faceplanenormal, faceplanenormal);
	if (faceplanenormallength2 < 0.0001f)
		return;
	// calculate the distance
	// 5 ops
	faceplanedist = DotProduct(point0, faceplanenormal);

	// if start point is on the back side there is no collision
	// (we don't care about traces going through the triangle the wrong way)

	// calculate the start distance
	// 6 ops
	d1 = DotProduct(faceplanenormal, linestart);
	if (d1 <= faceplanedist)
		return;

	// calculate the end distance
	// 6 ops
	d2 = DotProduct(faceplanenormal, lineend);
	// if both are in front, there is no collision
	if (d2 >= faceplanedist)
		return;

	// from here on we know d1 is >= 0 and d2 is < 0
	// this means the line starts infront and ends behind, passing through it

	// calculate the recipricol of the distance delta,
	// so we can use it multiple times cheaply (instead of division)
	// 2 ops
	d = 1.0f / (d1 - d2);
	// calculate the impact fraction by taking the start distance (> 0)
	// and subtracting the face plane distance (this is the distance of the
	// triangle along that same normal)
	// then multiply by the recipricol distance delta
	// 4 ops
	f = (d1 - faceplanedist) * d;
	f2  = f - collision_impactnudge.value * d;
	// skip out if this impact is further away than previous ones
	// 1 ops
	if (f2 >= trace->fraction)
		return;
	// calculate the perfect impact point for classification of insidedness
	// 9 ops
	impact[0] = linestart[0] + f * (lineend[0] - linestart[0]);
	impact[1] = linestart[1] + f * (lineend[1] - linestart[1]);
	impact[2] = linestart[2] + f * (lineend[2] - linestart[2]);

	// calculate the edge normal and reject if impact is outside triangle
	// (an edge normal faces away from the triangle, to get the desired normal
	//  a crossproduct with the faceplanenormal is used, and because of the way
	// the insidedness comparison is written it does not need to be normalized)

	// first use the two edges from the triangle plane math
	// the other edge only gets calculated if the point survives that long

	// 20 ops
	CrossProduct(edge01, faceplanenormal, edgenormal);
	if (DotProduct(impact, edgenormal) > DotProduct(point1, edgenormal))
		return;

	// 20 ops
	CrossProduct(faceplanenormal, edge21, edgenormal);
	if (DotProduct(impact, edgenormal) > DotProduct(point2, edgenormal))
		return;

	// 23 ops
	VectorSubtract(point0, point2, edge02);
	CrossProduct(faceplanenormal, edge02, edgenormal);
	if (DotProduct(impact, edgenormal) > DotProduct(point0, edgenormal))
		return;

	// 8 ops (rare)

	// store the new trace fraction
	trace->fraction = f2;

	// store the new trace plane (because collisions only happen from
	// the front this is always simply the triangle normal, never flipped)
	d = 1.0 / sqrt(faceplanenormallength2);
	VectorScale(faceplanenormal, d, trace->plane.normal);
	trace->plane.dist = faceplanedist * d;

	trace->hitsupercontents = supercontents;
	trace->hitq3surfaceflags = q3surfaceflags;
	trace->hittexture = texture;
}

void Collision_BoundingBoxOfBrushTraceSegment(const colbrushf_t *start, const colbrushf_t *end, vec3_t mins, vec3_t maxs, float startfrac, float endfrac)
{
	int i;
	colpointf_t *ps, *pe;
	float tempstart[3], tempend[3];
	VectorLerp(start->points[0].v, startfrac, end->points[0].v, mins);
	VectorCopy(mins, maxs);
	for (i = 0, ps = start->points, pe = end->points;i < start->numpoints;i++, ps++, pe++)
	{
		VectorLerp(ps->v, startfrac, pe->v, tempstart);
		VectorLerp(ps->v, endfrac, pe->v, tempend);
		mins[0] = min(mins[0], min(tempstart[0], tempend[0]));
		mins[1] = min(mins[1], min(tempstart[1], tempend[1]));
		mins[2] = min(mins[2], min(tempstart[2], tempend[2]));
		maxs[0] = min(maxs[0], min(tempstart[0], tempend[0]));
		maxs[1] = min(maxs[1], min(tempstart[1], tempend[1]));
		maxs[2] = min(maxs[2], min(tempstart[2], tempend[2]));
	}
	mins[0] -= 1;
	mins[1] -= 1;
	mins[2] -= 1;
	maxs[0] += 1;
	maxs[1] += 1;
	maxs[2] += 1;
}

//===========================================

static void Collision_TranslateBrush(const vec3_t shift, colbrushf_t *brush)
{
	int i;
	// now we can transform the data
	for(i = 0; i < brush->numplanes; ++i)
	{
		brush->planes[i].dist += DotProduct(shift, brush->planes[i].normal);
	}
	for(i = 0; i < brush->numpoints; ++i)
	{
		VectorAdd(brush->points[i].v, shift, brush->points[i].v);
	}
	VectorAdd(brush->mins, shift, brush->mins);
	VectorAdd(brush->maxs, shift, brush->maxs);
}

static void Collision_TransformBrush(const matrix4x4_t *matrix, colbrushf_t *brush)
{
	int i;
	vec3_t v;
	// we're breaking any AABB properties here...
	brush->isaabb = false;
	brush->hasaabbplanes = false;
	// now we can transform the data
	for(i = 0; i < brush->numplanes; ++i)
	{
		Matrix4x4_TransformPositivePlane(matrix, brush->planes[i].normal[0], brush->planes[i].normal[1], brush->planes[i].normal[2], brush->planes[i].dist, brush->planes[i].normal);
	}
	for(i = 0; i < brush->numedgedirs; ++i)
	{
		Matrix4x4_Transform(matrix, brush->edgedirs[i].v, v);
		VectorCopy(v, brush->edgedirs[i].v);
	}
	for(i = 0; i < brush->numpoints; ++i)
	{
		Matrix4x4_Transform(matrix, brush->points[i].v, v);
		VectorCopy(v, brush->points[i].v);
	}
	VectorCopy(brush->points[0].v, brush->mins);
	VectorCopy(brush->points[0].v, brush->maxs);
	for(i = 1; i < brush->numpoints; ++i)
	{
		if(brush->points[i].v[0] < brush->mins[0]) brush->mins[0] = brush->points[i].v[0];
		if(brush->points[i].v[1] < brush->mins[1]) brush->mins[1] = brush->points[i].v[1];
		if(brush->points[i].v[2] < brush->mins[2]) brush->mins[2] = brush->points[i].v[2];
		if(brush->points[i].v[0] > brush->maxs[0]) brush->maxs[0] = brush->points[i].v[0];
		if(brush->points[i].v[1] > brush->maxs[1]) brush->maxs[1] = brush->points[i].v[1];
		if(brush->points[i].v[2] > brush->maxs[2]) brush->maxs[2] = brush->points[i].v[2];
	}
}

typedef struct collision_cachedtrace_parameters_s
{
	dp_model_t *model;
	vec3_t end;
	vec3_t start;
	int hitsupercontentsmask;
	matrix4x4_t matrix;
}
collision_cachedtrace_parameters_t;

typedef struct collision_cachedtrace_s
{
	qboolean valid;
	collision_cachedtrace_parameters_t p;
	trace_t result;
}
collision_cachedtrace_t;

static mempool_t *collision_cachedtrace_mempool;
static collision_cachedtrace_t *collision_cachedtrace_array;
static int collision_cachedtrace_firstfree;
static int collision_cachedtrace_lastused;
static int collision_cachedtrace_max;
static int collision_cachedtrace_sequence;
static int collision_cachedtrace_hashsize;
static int *collision_cachedtrace_hash;
static unsigned int *collision_cachedtrace_arrayfullhashindex;
static unsigned int *collision_cachedtrace_arrayhashindex;
static unsigned int *collision_cachedtrace_arraynext;
static unsigned char *collision_cachedtrace_arrayused;
static qboolean collision_cachedtrace_rebuildhash;

void Collision_Cache_Reset(qboolean resetlimits)
{
	if (collision_cachedtrace_hash)
		Mem_Free(collision_cachedtrace_hash);
	if (collision_cachedtrace_array)
		Mem_Free(collision_cachedtrace_array);
	if (collision_cachedtrace_arrayfullhashindex)
		Mem_Free(collision_cachedtrace_arrayfullhashindex);
	if (collision_cachedtrace_arrayhashindex)
		Mem_Free(collision_cachedtrace_arrayhashindex);
	if (collision_cachedtrace_arraynext)
		Mem_Free(collision_cachedtrace_arraynext);
	if (collision_cachedtrace_arrayused)
		Mem_Free(collision_cachedtrace_arrayused);
	if (resetlimits || !collision_cachedtrace_max)
		collision_cachedtrace_max = collision_cache.integer ? 128 : 1;
	collision_cachedtrace_firstfree = 1;
	collision_cachedtrace_lastused = 0;
	collision_cachedtrace_hashsize = collision_cachedtrace_max;
	collision_cachedtrace_array = (collision_cachedtrace_t *)Mem_Alloc(collision_cachedtrace_mempool, collision_cachedtrace_max * sizeof(collision_cachedtrace_t));
	collision_cachedtrace_hash = (int *)Mem_Alloc(collision_cachedtrace_mempool, collision_cachedtrace_hashsize * sizeof(int));
	collision_cachedtrace_arrayfullhashindex = (unsigned int *)Mem_Alloc(collision_cachedtrace_mempool, collision_cachedtrace_max * sizeof(unsigned int));
	collision_cachedtrace_arrayhashindex = (unsigned int *)Mem_Alloc(collision_cachedtrace_mempool, collision_cachedtrace_max * sizeof(unsigned int));
	collision_cachedtrace_arraynext = (unsigned int *)Mem_Alloc(collision_cachedtrace_mempool, collision_cachedtrace_max * sizeof(unsigned int));
	collision_cachedtrace_arrayused = (unsigned char *)Mem_Alloc(collision_cachedtrace_mempool, collision_cachedtrace_max * sizeof(unsigned char));
	collision_cachedtrace_sequence = 1;
	collision_cachedtrace_rebuildhash = false;
}

void Collision_Cache_Init(mempool_t *mempool)
{
	collision_cachedtrace_mempool = mempool;
	Collision_Cache_Reset(true);
}

static void Collision_Cache_RebuildHash(void)
{
	int index;
	int range = collision_cachedtrace_lastused + 1;
	int sequence = collision_cachedtrace_sequence;
	int firstfree = collision_cachedtrace_max;
	int lastused = 0;
	int *hash = collision_cachedtrace_hash;
	unsigned int hashindex;
	unsigned int *arrayhashindex = collision_cachedtrace_arrayhashindex;
	unsigned int *arraynext = collision_cachedtrace_arraynext;
	collision_cachedtrace_rebuildhash = false;
	memset(collision_cachedtrace_hash, 0, collision_cachedtrace_hashsize * sizeof(int));
	for (index = 1;index < range;index++)
	{
		if (collision_cachedtrace_arrayused[index] == sequence)
		{
			hashindex = arrayhashindex[index];
			arraynext[index] = hash[hashindex];
			hash[hashindex] = index;
			lastused = index;
		}
		else
		{
			if (firstfree > index)
				firstfree = index;
			collision_cachedtrace_arrayused[index] = 0;
		}
	}
	collision_cachedtrace_firstfree = firstfree;
	collision_cachedtrace_lastused = lastused;
}

void Collision_Cache_NewFrame(void)
{
	if (collision_cache.integer)
	{
		if (collision_cachedtrace_max < 128)
			Collision_Cache_Reset(true);
	}
	else
	{
		if (collision_cachedtrace_max > 1)
			Collision_Cache_Reset(true);
	}
	// rebuild hash if sequence would overflow byte, otherwise increment
	if (collision_cachedtrace_sequence == 255)
	{
		Collision_Cache_RebuildHash();
		collision_cachedtrace_sequence = 1;
	}
	else
	{
		collision_cachedtrace_rebuildhash = true;
		collision_cachedtrace_sequence++;
	}
}

static unsigned int Collision_Cache_HashIndexForArray(unsigned int *array, unsigned int size)
{
	unsigned int i;
	unsigned int hashindex = 0;
	// this is a super-cheesy checksum, designed only for speed
	for (i = 0;i < size;i++)
		hashindex += array[i] * (1 + i);
	return hashindex;
}

static collision_cachedtrace_t *Collision_Cache_Lookup(dp_model_t *model, const matrix4x4_t *matrix, const matrix4x4_t *inversematrix, const vec3_t start, const vec3_t end, int hitsupercontentsmask)
{
	int hashindex = 0;
	unsigned int fullhashindex;
	int index = 0;
	int range;
	int sequence = collision_cachedtrace_sequence;
	int *hash = collision_cachedtrace_hash;
	unsigned int *arrayfullhashindex = collision_cachedtrace_arrayfullhashindex;
	unsigned int *arraynext = collision_cachedtrace_arraynext;
	collision_cachedtrace_t *cached = collision_cachedtrace_array + index;
	collision_cachedtrace_parameters_t params;
	// all non-cached traces use the same index
	if (!collision_cache.integer)
		r_refdef.stats[r_stat_photoncache_traced]++;
	else
	{
		// cached trace lookup
		memset(&params, 0, sizeof(params));
		params.model = model;
		VectorCopy(start, params.start);
		VectorCopy(end,   params.end);
		params.hitsupercontentsmask = hitsupercontentsmask;
		params.matrix = *matrix;
		fullhashindex = Collision_Cache_HashIndexForArray((unsigned int *)&params, sizeof(params) / sizeof(unsigned int));
		hashindex = (int)(fullhashindex % (unsigned int)collision_cachedtrace_hashsize);
		for (index = hash[hashindex];index;index = arraynext[index])
		{
			if (arrayfullhashindex[index] != fullhashindex)
				continue;
			cached = collision_cachedtrace_array + index;
			//if (memcmp(&cached->p, &params, sizeof(params)))
			if (cached->p.model != params.model
			 || cached->p.end[0] != params.end[0]
			 || cached->p.end[1] != params.end[1]
			 || cached->p.end[2] != params.end[2]
			 || cached->p.start[0] != params.start[0]
			 || cached->p.start[1] != params.start[1]
			 || cached->p.start[2] != params.start[2]
			 || cached->p.hitsupercontentsmask != params.hitsupercontentsmask
			 || cached->p.matrix.m[0][0] != params.matrix.m[0][0]
			 || cached->p.matrix.m[0][1] != params.matrix.m[0][1]
			 || cached->p.matrix.m[0][2] != params.matrix.m[0][2]
			 || cached->p.matrix.m[0][3] != params.matrix.m[0][3]
			 || cached->p.matrix.m[1][0] != params.matrix.m[1][0]
			 || cached->p.matrix.m[1][1] != params.matrix.m[1][1]
			 || cached->p.matrix.m[1][2] != params.matrix.m[1][2]
			 || cached->p.matrix.m[1][3] != params.matrix.m[1][3]
			 || cached->p.matrix.m[2][0] != params.matrix.m[2][0]
			 || cached->p.matrix.m[2][1] != params.matrix.m[2][1]
			 || cached->p.matrix.m[2][2] != params.matrix.m[2][2]
			 || cached->p.matrix.m[2][3] != params.matrix.m[2][3]
			 || cached->p.matrix.m[3][0] != params.matrix.m[3][0]
			 || cached->p.matrix.m[3][1] != params.matrix.m[3][1]
			 || cached->p.matrix.m[3][2] != params.matrix.m[3][2]
			 || cached->p.matrix.m[3][3] != params.matrix.m[3][3]
			)
				continue;
			// found a matching trace in the cache
			r_refdef.stats[r_stat_photoncache_cached]++;
			cached->valid = true;
			collision_cachedtrace_arrayused[index] = collision_cachedtrace_sequence;
			return cached;
		}
		r_refdef.stats[r_stat_photoncache_traced]++;
		// find an unused cache entry
		for (index = collision_cachedtrace_firstfree, range = collision_cachedtrace_max;index < range;index++)
			if (collision_cachedtrace_arrayused[index] == 0)
				break;
		if (index == range)
		{
			// all claimed, but probably some are stale...
			for (index = 1, range = collision_cachedtrace_max;index < range;index++)
				if (collision_cachedtrace_arrayused[index] != sequence)
					break;
			if (index < range)
			{
				// found a stale one, rebuild the hash
				Collision_Cache_RebuildHash();
			}
			else
			{
				// we need to grow the cache
				collision_cachedtrace_max *= 2;
				Collision_Cache_Reset(false);
				index = 1;
			}
		}
		// link the new cache entry into the hash bucket
		collision_cachedtrace_firstfree = index + 1;
		if (collision_cachedtrace_lastused < index)
			collision_cachedtrace_lastused = index;
		cached = collision_cachedtrace_array + index;
		collision_cachedtrace_arraynext[index] = collision_cachedtrace_hash[hashindex];
		collision_cachedtrace_hash[hashindex] = index;
		collision_cachedtrace_arrayhashindex[index] = hashindex;
		cached->valid = false;
		cached->p = params;
		collision_cachedtrace_arrayfullhashindex[index] = fullhashindex;
		collision_cachedtrace_arrayused[index] = collision_cachedtrace_sequence;
	}
	return cached;
}

void Collision_Cache_ClipLineToGenericEntitySurfaces(trace_t *trace, dp_model_t *model, matrix4x4_t *matrix, matrix4x4_t *inversematrix, const vec3_t start, const vec3_t end, int hitsupercontentsmask)
{
	collision_cachedtrace_t *cached = Collision_Cache_Lookup(model, matrix, inversematrix, start, end, hitsupercontentsmask);
	if (cached->valid)
	{
		*trace = cached->result;
		return;
	}

	Collision_ClipLineToGenericEntity(trace, model, NULL, NULL, vec3_origin, vec3_origin, 0, matrix, inversematrix, start, end, hitsupercontentsmask, collision_extendmovelength.value, true);

	cached->result = *trace;
}

void Collision_Cache_ClipLineToWorldSurfaces(trace_t *trace, dp_model_t *model, const vec3_t start, const vec3_t end, int hitsupercontents)
{
	collision_cachedtrace_t *cached = Collision_Cache_Lookup(model, &identitymatrix, &identitymatrix, start, end, hitsupercontents);
	if (cached->valid)
	{
		*trace = cached->result;
		return;
	}

	Collision_ClipLineToWorld(trace, model, start, end, hitsupercontents, collision_extendmovelength.value, true);

	cached->result = *trace;
}

typedef struct extendtraceinfo_s
{
	trace_t *trace;
	float realstart[3];
	float realend[3];
	float realdelta[3];
	float extendstart[3];
	float extendend[3];
	float extenddelta[3];
	float reallength;
	float extendlength;
	float scaletoextend;
	float extend;
}
extendtraceinfo_t;

static void Collision_ClipExtendPrepare(extendtraceinfo_t *extendtraceinfo, trace_t *trace, const vec3_t tstart, const vec3_t tend, float textend)
{
	memset(trace, 0, sizeof(*trace));
	trace->fraction = 1;

	extendtraceinfo->trace = trace;
	VectorCopy(tstart, extendtraceinfo->realstart);
	VectorCopy(tend, extendtraceinfo->realend);
	VectorSubtract(extendtraceinfo->realend, extendtraceinfo->realstart, extendtraceinfo->realdelta);
	VectorCopy(extendtraceinfo->realstart, extendtraceinfo->extendstart);
	VectorCopy(extendtraceinfo->realend, extendtraceinfo->extendend);
	VectorCopy(extendtraceinfo->realdelta, extendtraceinfo->extenddelta);
	extendtraceinfo->reallength = VectorLength(extendtraceinfo->realdelta);
	extendtraceinfo->extendlength = extendtraceinfo->reallength;
	extendtraceinfo->scaletoextend = 1.0f;
	extendtraceinfo->extend = textend;

	// make the trace longer according to the extend parameter
	if (extendtraceinfo->reallength && extendtraceinfo->extend)
	{
		extendtraceinfo->extendlength = extendtraceinfo->reallength + extendtraceinfo->extend;
		extendtraceinfo->scaletoextend = extendtraceinfo->extendlength / extendtraceinfo->reallength;
		VectorMA(extendtraceinfo->realstart, extendtraceinfo->scaletoextend, extendtraceinfo->realdelta, extendtraceinfo->extendend);
		VectorSubtract(extendtraceinfo->extendend, extendtraceinfo->extendstart, extendtraceinfo->extenddelta);
	}
}

static void Collision_ClipExtendFinish(extendtraceinfo_t *extendtraceinfo)
{
	trace_t *trace = extendtraceinfo->trace;

	if (trace->fraction != 1.0f)
	{
		// undo the extended trace length
		trace->fraction *= extendtraceinfo->scaletoextend;

		// if the extended trace hit something that the unextended trace did not hit (even considering the collision_impactnudge), then we have to clear the hit information
		if (trace->fraction > 1.0f)
		{
			// note that ent may refer to either startsolid or fraction<1, we can't restore the startsolid ent unfortunately
 			trace->ent = NULL;
			trace->hitq3surfaceflags = 0;
			trace->hitsupercontents = 0;
			trace->hittexture = NULL;
			VectorClear(trace->plane.normal);
			trace->plane.dist = 0.0f;
		}
	}

	// clamp things
	trace->fraction = bound(0, trace->fraction, 1);

	// calculate the end position
	VectorMA(extendtraceinfo->realstart, trace->fraction, extendtraceinfo->realdelta, trace->endpos);
}

void Collision_ClipToGenericEntity(trace_t *trace, dp_model_t *model, const frameblend_t *frameblend, const skeleton_t *skeleton, const vec3_t bodymins, const vec3_t bodymaxs, int bodysupercontents, matrix4x4_t *matrix, matrix4x4_t *inversematrix, const vec3_t tstart, const vec3_t mins, const vec3_t maxs, const vec3_t tend, int hitsupercontentsmask, float extend)
{
	vec3_t starttransformed, endtransformed;
	extendtraceinfo_t extendtraceinfo;
	Collision_ClipExtendPrepare(&extendtraceinfo, trace, tstart, tend, extend);

	Matrix4x4_Transform(inversematrix, extendtraceinfo.extendstart, starttransformed);
	Matrix4x4_Transform(inversematrix, extendtraceinfo.extendend, endtransformed);
#if COLLISIONPARANOID >= 3
	Con_Printf("trans(%f %f %f -> %f %f %f, %f %f %f -> %f %f %f)", extendtraceinfo.extendstart[0], extendtraceinfo.extendstart[1], extendtraceinfo.extendstart[2], starttransformed[0], starttransformed[1], starttransformed[2], extendtraceinfo.extendend[0], extendtraceinfo.extendend[1], extendtraceinfo.extendend[2], endtransformed[0], endtransformed[1], endtransformed[2]);
#endif

	if (model && model->TraceBox)
	{
		if(model->TraceBrush && (inversematrix->m[0][1] || inversematrix->m[0][2] || inversematrix->m[1][0] || inversematrix->m[1][2] || inversematrix->m[2][0] || inversematrix->m[2][1]))
		{
			// we get here if TraceBrush exists, AND we have a rotation component (SOLID_BSP case)
			// using starttransformed, endtransformed is WRONG in this case!
			// should rather build a brush and trace using it
			colboxbrushf_t thisbrush_start, thisbrush_end;
			Collision_BrushForBox(&thisbrush_start, mins, maxs, 0, 0, NULL);
			Collision_BrushForBox(&thisbrush_end, mins, maxs, 0, 0, NULL);
			Collision_TranslateBrush(extendtraceinfo.extendstart, &thisbrush_start.brush);
			Collision_TranslateBrush(extendtraceinfo.extendend, &thisbrush_end.brush);
			Collision_TransformBrush(inversematrix, &thisbrush_start.brush);
			Collision_TransformBrush(inversematrix, &thisbrush_end.brush);
			//Collision_TranslateBrush(starttransformed, &thisbrush_start.brush);
			//Collision_TranslateBrush(endtransformed, &thisbrush_end.brush);
			model->TraceBrush(model, frameblend, skeleton, trace, &thisbrush_start.brush, &thisbrush_end.brush, hitsupercontentsmask);
		}
		else // this is only approximate if rotated, quite useless
			model->TraceBox(model, frameblend, skeleton, trace, starttransformed, mins, maxs, endtransformed, hitsupercontentsmask);
	}
	else // and this requires that the transformation matrix doesn't have angles components, like SV_TraceBox ensures; FIXME may get called if a model is SOLID_BSP but has no TraceBox function
		Collision_ClipTrace_Box(trace, bodymins, bodymaxs, starttransformed, mins, maxs, endtransformed, hitsupercontentsmask, bodysupercontents, 0, NULL);

	Collision_ClipExtendFinish(&extendtraceinfo);

	// transform plane
	// NOTE: this relies on plane.dist being directly after plane.normal
	Matrix4x4_TransformPositivePlane(matrix, trace->plane.normal[0], trace->plane.normal[1], trace->plane.normal[2], trace->plane.dist, trace->plane.normal);
}

void Collision_ClipToWorld(trace_t *trace, dp_model_t *model, const vec3_t tstart, const vec3_t mins, const vec3_t maxs, const vec3_t tend, int hitsupercontents, float extend)
{
	extendtraceinfo_t extendtraceinfo;
	Collision_ClipExtendPrepare(&extendtraceinfo, trace, tstart, tend, extend);
	// ->TraceBox: TraceBrush not needed here, as worldmodel is never rotated
	if (model && model->TraceBox)
		model->TraceBox(model, NULL, NULL, trace, extendtraceinfo.extendstart, mins, maxs, extendtraceinfo.extendend, hitsupercontents);
	Collision_ClipExtendFinish(&extendtraceinfo);
}

void Collision_ClipLineToGenericEntity(trace_t *trace, dp_model_t *model, const frameblend_t *frameblend, const skeleton_t *skeleton, const vec3_t bodymins, const vec3_t bodymaxs, int bodysupercontents, matrix4x4_t *matrix, matrix4x4_t *inversematrix, const vec3_t tstart, const vec3_t tend, int hitsupercontentsmask, float extend, qboolean hitsurfaces)
{
	vec3_t starttransformed, endtransformed;
	extendtraceinfo_t extendtraceinfo;
	Collision_ClipExtendPrepare(&extendtraceinfo, trace, tstart, tend, extend);

	Matrix4x4_Transform(inversematrix, extendtraceinfo.extendstart, starttransformed);
	Matrix4x4_Transform(inversematrix, extendtraceinfo.extendend, endtransformed);
#if COLLISIONPARANOID >= 3
	Con_Printf("trans(%f %f %f -> %f %f %f, %f %f %f -> %f %f %f)", extendtraceinfo.extendstart[0], extendtraceinfo.extendstart[1], extendtraceinfo.extendstart[2], starttransformed[0], starttransformed[1], starttransformed[2], extendtraceinfo.extendend[0], extendtraceinfo.extendend[1], extendtraceinfo.extendend[2], endtransformed[0], endtransformed[1], endtransformed[2]);
#endif

	if (model && model->TraceLineAgainstSurfaces && hitsurfaces)
		model->TraceLineAgainstSurfaces(model, frameblend, skeleton, trace, starttransformed, endtransformed, hitsupercontentsmask);
	else if (model && model->TraceLine)
		model->TraceLine(model, frameblend, skeleton, trace, starttransformed, endtransformed, hitsupercontentsmask);
	else
		Collision_ClipTrace_Box(trace, bodymins, bodymaxs, starttransformed, vec3_origin, vec3_origin, endtransformed, hitsupercontentsmask, bodysupercontents, 0, NULL);

	Collision_ClipExtendFinish(&extendtraceinfo);

	// transform plane
	// NOTE: this relies on plane.dist being directly after plane.normal
	Matrix4x4_TransformPositivePlane(matrix, trace->plane.normal[0], trace->plane.normal[1], trace->plane.normal[2], trace->plane.dist, trace->plane.normal);
}

void Collision_ClipLineToWorld(trace_t *trace, dp_model_t *model, const vec3_t tstart, const vec3_t tend, int hitsupercontents, float extend, qboolean hitsurfaces)
{
	extendtraceinfo_t extendtraceinfo;
	Collision_ClipExtendPrepare(&extendtraceinfo, trace, tstart, tend, extend);

	if (model && model->TraceLineAgainstSurfaces && hitsurfaces)
		model->TraceLineAgainstSurfaces(model, NULL, NULL, trace, extendtraceinfo.extendstart, extendtraceinfo.extendend, hitsupercontents);
	else if (model && model->TraceLine)
		model->TraceLine(model, NULL, NULL, trace, extendtraceinfo.extendstart, extendtraceinfo.extendend, hitsupercontents);

	Collision_ClipExtendFinish(&extendtraceinfo);
}

void Collision_ClipPointToGenericEntity(trace_t *trace, dp_model_t *model, const frameblend_t *frameblend, const skeleton_t *skeleton, const vec3_t bodymins, const vec3_t bodymaxs, int bodysupercontents, matrix4x4_t *matrix, matrix4x4_t *inversematrix, const vec3_t start, int hitsupercontentsmask)
{
	float starttransformed[3];
	memset(trace, 0, sizeof(*trace));
	trace->fraction = 1;

	Matrix4x4_Transform(inversematrix, start, starttransformed);
#if COLLISIONPARANOID >= 3
	Con_Printf("trans(%f %f %f -> %f %f %f)", start[0], start[1], start[2], starttransformed[0], starttransformed[1], starttransformed[2]);
#endif

	if (model && model->TracePoint)
		model->TracePoint(model, NULL, NULL, trace, starttransformed, hitsupercontentsmask);
	else
		Collision_ClipTrace_Point(trace, bodymins, bodymaxs, starttransformed, hitsupercontentsmask, bodysupercontents, 0, NULL);

	VectorCopy(start, trace->endpos);
	// transform plane
	// NOTE: this relies on plane.dist being directly after plane.normal
	Matrix4x4_TransformPositivePlane(matrix, trace->plane.normal[0], trace->plane.normal[1], trace->plane.normal[2], trace->plane.dist, trace->plane.normal);
}

void Collision_ClipPointToWorld(trace_t *trace, dp_model_t *model, const vec3_t start, int hitsupercontents)
{
	memset(trace, 0, sizeof(*trace));
	trace->fraction = 1;
	if (model && model->TracePoint)
		model->TracePoint(model, NULL, NULL, trace, start, hitsupercontents);
	VectorCopy(start, trace->endpos);
}

void Collision_CombineTraces(trace_t *cliptrace, const trace_t *trace, void *touch, qboolean isbmodel)
{
	// take the 'best' answers from the new trace and combine with existing data
	if (trace->allsolid)
		cliptrace->allsolid = true;
	if (trace->startsolid)
	{
		if (isbmodel)
			cliptrace->bmodelstartsolid = true;
		cliptrace->startsolid = true;
		if (cliptrace->fraction == 1)
			cliptrace->ent = touch;
		if (cliptrace->startdepth > trace->startdepth)
		{
			cliptrace->startdepth = trace->startdepth;
			VectorCopy(trace->startdepthnormal, cliptrace->startdepthnormal);
		}
	}
	// don't set this except on the world, because it can easily confuse
	// monsters underwater if there's a bmodel involved in the trace
	// (inopen && inwater is how they check water visibility)
	//if (trace->inopen)
	//	cliptrace->inopen = true;
	if (trace->inwater)
		cliptrace->inwater = true;
	if ((trace->fraction < cliptrace->fraction) && (VectorLength2(trace->plane.normal) > 0))
	{
		cliptrace->fraction = trace->fraction;
		VectorCopy(trace->endpos, cliptrace->endpos);
		cliptrace->plane = trace->plane;
		cliptrace->ent = touch;
		cliptrace->hitsupercontents = trace->hitsupercontents;
		cliptrace->hitq3surfaceflags = trace->hitq3surfaceflags;
		cliptrace->hittexture = trace->hittexture;
	}
	cliptrace->startsupercontents |= trace->startsupercontents;
}