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[Renderers/SDL2] Added rounded corner borders and fixed other issues (#…
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…258)
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@TimothyHoytBSME
TimothyHoytBSME authored Feb 13, 2025
1 parent d9e02ab commit eb55396
Showing 1 changed file with 189 additions and 31 deletions.
220 changes: 189 additions & 31 deletions renderers/SDL2/clay_renderer_SDL2.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,10 @@
#include <SDL_image.h>
#include <stdio.h>

#ifndef M_PI
#define M_PI 3.14159
#endif

#define CLAY_COLOR_TO_SDL_COLOR_ARGS(color) color.r, color.g, color.b, color.a

typedef struct
Expand Down Expand Up @@ -48,8 +52,8 @@ static void SDL_RenderFillRoundedRect(SDL_Renderer* renderer, const SDL_FRect re

int indexCount = 0, vertexCount = 0;

const float minRadius = SDL_min(rect.w, rect.h) / 2.0f;
const float clampedRadius = SDL_min(cornerRadius, minRadius);
const float maxRadius = SDL_min(rect.w, rect.h) / 2.0f;
const float clampedRadius = SDL_min(cornerRadius, maxRadius);

const int numCircleSegments = SDL_max(NUM_CIRCLE_SEGMENTS, (int)clampedRadius * 0.5f);

Expand Down Expand Up @@ -141,6 +145,121 @@ static void SDL_RenderFillRoundedRect(SDL_Renderer* renderer, const SDL_FRect re
SDL_RenderGeometry(renderer, NULL, vertices, vertexCount, indices, indexCount);
}

//all rendering is performed by a single SDL call, using twi sets of arcing triangles, inner and outer, that fit together; along with two tringles to fill the end gaps.
void SDL_RenderCornerBorder(SDL_Renderer *renderer, Clay_BoundingBox* boundingBox, Clay_BorderRenderData* config, int cornerIndex, Clay_Color _color){
/////////////////////////////////
//The arc is constructed of outer triangles and inner triangles (if needed).
//First three vertices are first outer triangle's vertices
//Each two vertices after that are the inner-middle and second-outer vertex of
//each outer triangle after the first, because there first-outer vertex is equal to the
//second-outer vertex of the previous triangle. Indices set accordingly.
//The final two vertices are the missing vertices for the first and last inner triangles (if needed)
//Everything is in clockwise order (CW).
/////////////////////////////////
const SDL_Color color = (SDL_Color) {
.r = (Uint8)_color.r,
.g = (Uint8)_color.g,
.b = (Uint8)_color.b,
.a = (Uint8)_color.a,
};

float centerX, centerY, outerRadius, clampedRadius, startAngle, borderWidth;
const float maxRadius = SDL_min(boundingBox->width, boundingBox->height) / 2.0f;

SDL_Vertex vertices[512];
int indices[512];
int indexCount = 0, vertexCount = 0;

switch (cornerIndex) {
case(0):
startAngle = M_PI;
outerRadius = SDL_min(config->cornerRadius.topLeft, maxRadius);
centerX = boundingBox->x + outerRadius;
centerY = boundingBox->y + outerRadius;
borderWidth = config->width.top;
break;
case(1):
startAngle = 3*M_PI/2;
outerRadius = SDL_min(config->cornerRadius.topRight, maxRadius);
centerX = boundingBox->x + boundingBox->width - outerRadius;
centerY = boundingBox->y + outerRadius;
borderWidth = config->width.top;
break;
case(2):
startAngle = 0;
outerRadius = SDL_min(config->cornerRadius.bottomRight, maxRadius);
centerX = boundingBox->x + boundingBox->width - outerRadius;
centerY = boundingBox->y + boundingBox->height - outerRadius;
borderWidth = config->width.bottom;
break;
case(3):
startAngle = M_PI/2;
outerRadius = SDL_min(config->cornerRadius.bottomLeft, maxRadius);
centerX = boundingBox->x + outerRadius;
centerY = boundingBox->y + boundingBox->height - outerRadius;
borderWidth = config->width.bottom;
break;
default: break;
}

const float innerRadius = outerRadius - borderWidth;
const int minNumOuterTriangles = NUM_CIRCLE_SEGMENTS;
const int numOuterTriangles = SDL_max(minNumOuterTriangles, ceilf(outerRadius * 0.5f));
const float angleStep = M_PI / (2.0*(float)numOuterTriangles);

//outer triangles, in CW order
for (int i = 0; i < numOuterTriangles; i++) {
float angle1 = startAngle + i*angleStep; //first-outer vertex angle
float angle2 = startAngle + ((float)i + 0.5) * angleStep; //inner-middle vertex angle
float angle3 = startAngle + (i+1)*angleStep; // second-outer vertex angle

if( i == 0){ //first outer triangle
vertices[vertexCount++] = (SDL_Vertex){ {centerX + SDL_cosf(angle1) * outerRadius, centerY + SDL_sinf(angle1) * outerRadius}, color, {0, 0} }; //vertex index = 0
}
indices[indexCount++] = vertexCount - 1; //will be second-outer vertex of last outer triangle if not first outer triangle.

vertices[vertexCount++] = (innerRadius > 0)?
(SDL_Vertex){ {centerX + SDL_cosf(angle2) * (innerRadius), centerY + SDL_sinf(angle2) * (innerRadius)}, color, {0, 0}}:
(SDL_Vertex){ {centerX, centerY }, color, {0, 0}};
indices[indexCount++] = vertexCount - 1;

vertices[vertexCount++] = (SDL_Vertex){ {centerX + SDL_cosf(angle3) * outerRadius, centerY + SDL_sinf(angle3) * outerRadius}, color, {0, 0} };
indices[indexCount++] = vertexCount - 1;
}

if(innerRadius > 0){
// inner triangles in CW order (except the first and last)
for (int i = 0; i < numOuterTriangles - 1; i++){ //skip the last outer triangle
if(i==0){ //first outer triangle -> second inner triangle
indices[indexCount++] = 1; //inner-middle vertex of first outer triangle
indices[indexCount++] = 2; //second-outer vertex of first outer triangle
indices[indexCount++] = 3; //innder-middle vertex of second-outer triangle
}else{
int baseIndex = 3; //skip first outer triangle
indices[indexCount++] = baseIndex + (i-1)*2; // inner-middle vertex of current outer triangle
indices[indexCount++] = baseIndex + (i-1)*2 + 1; // second-outer vertex of current outer triangle
indices[indexCount++] = baseIndex + (i-1)*2 + 2; // inner-middle vertex of next outer triangle
}
}

float endAngle = startAngle + M_PI/2.0;

//last inner triangle
indices[indexCount++] = vertexCount - 2; //inner-middle vertex of last outer triangle
indices[indexCount++] = vertexCount - 1; //second-outer vertex of last outer triangle
vertices[vertexCount++] = (SDL_Vertex){ {centerX + SDL_cosf(endAngle) * innerRadius, centerY + SDL_sinf(endAngle) * innerRadius}, color, {0, 0} }; //missing vertex
indices[indexCount++] = vertexCount - 1;

// //first inner triangle
indices[indexCount++] = 0; //first-outer vertex of first outer triangle
indices[indexCount++] = 1; //inner-middle vertex of first outer triangle
vertices[vertexCount++] = (SDL_Vertex){ {centerX + SDL_cosf(startAngle) * innerRadius, centerY + SDL_sinf(startAngle) * innerRadius}, color, {0, 0} }; //missing vertex
indices[indexCount++] = vertexCount - 1;
}

SDL_RenderGeometry(renderer, NULL, vertices, vertexCount, indices, indexCount);
}

SDL_Rect currentClippingRectangle;

static void Clay_SDL2_Render(SDL_Renderer *renderer, Clay_RenderCommandArray renderCommands, SDL2_Font *fonts)
Expand Down Expand Up @@ -228,35 +347,74 @@ static void Clay_SDL2_Render(SDL_Renderer *renderer, Clay_RenderCommandArray ren
}
case CLAY_RENDER_COMMAND_TYPE_BORDER: {
Clay_BorderRenderData *config = &renderCommand->renderData.border;

if (config->width.left > 0) {
SDL_SetRenderDrawColor(renderer, CLAY_COLOR_TO_SDL_COLOR_ARGS(config->color));
SDL_FRect rect = { boundingBox.x, boundingBox.y + config->cornerRadius.topLeft, config->width.left, boundingBox.height - config->cornerRadius.topLeft - config->cornerRadius.bottomLeft };
SDL_RenderFillRectF(renderer, &rect);
}

if (config->width.right > 0) {
SDL_SetRenderDrawColor(renderer, CLAY_COLOR_TO_SDL_COLOR_ARGS(config->color));
SDL_FRect rect = { boundingBox.x + boundingBox.width - config->width.right, boundingBox.y + config->cornerRadius.topRight, config->width.right, boundingBox.height - config->cornerRadius.topRight - config->cornerRadius.bottomRight };
SDL_RenderFillRectF(renderer, &rect);
}

if (config->width.right > 0) {
SDL_SetRenderDrawColor(renderer, CLAY_COLOR_TO_SDL_COLOR_ARGS(config->color));
SDL_FRect rect = { boundingBox.x + boundingBox.width - config->width.right, boundingBox.y + config->cornerRadius.topRight, config->width.right, boundingBox.height - config->cornerRadius.topRight - config->cornerRadius.bottomRight };
SDL_RenderFillRectF(renderer, &rect);
}

if (config->width.top > 0) {
SDL_SetRenderDrawColor(renderer, CLAY_COLOR_TO_SDL_COLOR_ARGS(config->color));
SDL_FRect rect = { boundingBox.x + config->cornerRadius.topLeft, boundingBox.y, boundingBox.width - config->cornerRadius.topLeft - config->cornerRadius.topRight, config->width.top };
SDL_RenderFillRectF(renderer, &rect);
}

if (config->width.bottom > 0) {
SDL_SetRenderDrawColor(renderer, CLAY_COLOR_TO_SDL_COLOR_ARGS(config->color));
SDL_FRect rect = { boundingBox.x + config->cornerRadius.bottomLeft, boundingBox.y + boundingBox.height - config->width.bottom, boundingBox.width - config->cornerRadius.bottomLeft - config->cornerRadius.bottomRight, config->width.bottom };
SDL_RenderFillRectF(renderer, &rect);
SDL_SetRenderDrawColor(renderer, CLAY_COLOR_TO_SDL_COLOR_ARGS(config->color));

if(boundingBox.width > 0 & boundingBox.height > 0){
const float maxRadius = SDL_min(boundingBox.width, boundingBox.height) / 2.0f;

if (config->width.left > 0) {
const float clampedRadiusTop = SDL_min((float)config->cornerRadius.topLeft, maxRadius);
const float clampedRadiusBottom = SDL_min((float)config->cornerRadius.bottomLeft, maxRadius);
SDL_FRect rect = {
boundingBox.x,
boundingBox.y + clampedRadiusTop,
(float)config->width.left,
(float)boundingBox.height - clampedRadiusTop - clampedRadiusBottom
};
SDL_RenderFillRectF(renderer, &rect);
}

if (config->width.right > 0) {
const float clampedRadiusTop = SDL_min((float)config->cornerRadius.topRight, maxRadius);
const float clampedRadiusBottom = SDL_min((float)config->cornerRadius.bottomRight, maxRadius);
SDL_FRect rect = {
boundingBox.x + boundingBox.width - config->width.right,
boundingBox.y + clampedRadiusTop,
(float)config->width.right,
(float)boundingBox.height - clampedRadiusTop - clampedRadiusBottom
};
SDL_RenderFillRectF(renderer, &rect);
}

if (config->width.top > 0) {
const float clampedRadiusLeft = SDL_min((float)config->cornerRadius.topLeft, maxRadius);
const float clampedRadiusRight = SDL_min((float)config->cornerRadius.topRight, maxRadius);
SDL_FRect rect = {
boundingBox.x + clampedRadiusLeft,
boundingBox.y,
boundingBox.width - clampedRadiusLeft - clampedRadiusRight,
(float)config->width.top };
SDL_RenderFillRectF(renderer, &rect);
}

if (config->width.bottom > 0) {
const float clampedRadiusLeft = SDL_min((float)config->cornerRadius.bottomLeft, maxRadius);
const float clampedRadiusRight = SDL_min((float)config->cornerRadius.bottomRight, maxRadius);
SDL_FRect rect = {
boundingBox.x + clampedRadiusLeft,
boundingBox.y + boundingBox.height - config->width.bottom,
boundingBox.width - clampedRadiusLeft - clampedRadiusRight,
(float)config->width.bottom
};
SDL_RenderFillRectF(renderer, &rect);
}

//corner index: 0->3 topLeft -> CW -> bottonLeft
if (config->width.top > 0 & config->cornerRadius.topLeft > 0) {
SDL_RenderCornerBorder(renderer, &boundingBox, config, 0, config->color);
}

if (config->width.top > 0 & config->cornerRadius.topRight> 0) {
SDL_RenderCornerBorder(renderer, &boundingBox, config, 1, config->color);
}

if (config->width.bottom > 0 & config->cornerRadius.bottomLeft > 0) {
SDL_RenderCornerBorder(renderer, &boundingBox, config, 2, config->color);
}

if (config->width.bottom > 0 & config->cornerRadius.bottomLeft > 0) {
SDL_RenderCornerBorder(renderer, &boundingBox, config, 3, config->color);
}
}

break;
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