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bugfix: Fix inconsistent mine collision behaviour #2208

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bugfix: Fix inconsistent mine collision behaviour #2208

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4 changes: 4 additions & 0 deletions Core/GameEngine/Include/Common/GameDefines.h
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Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,10 @@
#define RETAIL_COMPATIBLE_PATHFINDING_ALLOCATION (1)
#endif

#ifndef RETAIL_COMPATIBLE_CIRCLE_FILL_ALGORITHM
#define RETAIL_COMPATIBLE_CIRCLE_FILL_ALGORITHM (1) // Use the original circle fill algorithm, which is more efficient but less accurate
#endif

// This is essentially synonymous for RETAIL_COMPATIBLE_CRC. There is a lot wrong with AIGroup, such as use-after-free, double-free, leaks,
// but we cannot touch it much without breaking retail compatibility. Do not shy away from using massive hacks when fixing issues with AIGroup,
// but put them behind this macro.
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5 changes: 5 additions & 0 deletions Generals/Code/GameEngine/Include/GameLogic/PartitionManager.h
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Original file line number Diff line number Diff line change
Expand Up @@ -463,6 +463,11 @@ class PartitionData : public MemoryPoolObject
Real radius
);

/**
A more advanced implementation of doCircleFill that is 100% accurate.
*/
void doCircleFillPrecise(Real centerX, Real centerY, Real radius);

/**
fill in the pixels covered by the given rectangular shape with the given
center, dimensions, and rotation.
Expand Down
43 changes: 43 additions & 0 deletions Generals/Code/GameEngine/Source/GameLogic/Object/PartitionManager.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1878,6 +1878,43 @@ void PartitionData::doCircleFill(
}
}

static Bool doesCircleOverlapCell(Real centerX, Real centerY, Real radius, Real cellX, Real cellY, Real cellSize)
{
Real closestX = maxReal(cellX, minReal(centerX, cellX + cellSize));
Real closestY = maxReal(cellY, minReal(centerY, cellY + cellSize));
Real distX = centerX - closestX;
Real distY = centerY - closestY;

return (distX * distX + distY * distY) < radius * radius;
}

void PartitionData::doCircleFillPrecise(Real centerX, Real centerY, Real radius)
{
Int minCellX, minCellY, maxCellX, maxCellY;
ThePartitionManager->worldToCell(centerX - radius, centerY - radius, &minCellX, &minCellY);
ThePartitionManager->worldToCell(centerX + radius, centerY + radius, &maxCellX, &maxCellY);

Real cellSize = ThePartitionManager->getCellSize();

for (Int x = minCellX; x <= maxCellX; ++x)
{
for (Int y = minCellY; y <= maxCellY; ++y)
{
Real cellWorldX = x * cellSize;
Real cellWorldY = y * cellSize;

if (doesCircleOverlapCell(centerX, centerY, radius, cellWorldX, cellWorldY, cellSize))
{
PartitionCell* cell = ThePartitionManager->getCellAt(x, y);
if (cell)
{
addSubPixToCoverage(cell);
}
}
}
}
}

// -----------------------------------------------------------------------------
void PartitionData::doSmallFill(
Real centerX,
Expand Down Expand Up @@ -2079,7 +2116,13 @@ void PartitionData::updateCellsTouched()
case GEOMETRY_SPHERE:
case GEOMETRY_CYLINDER:
{
#if RETAIL_COMPATIBLE_CRC || RETAIL_COMPATIBLE_CIRCLE_FILL_ALGORITHM
doCircleFill(pos.x, pos.y, majorRadius);
#else
// TheSuperHackers @bugfix Stubbjax 29/01/2026 Use precise circle fill to improve
// collision accuracy, most notably for objects with geometry radii >= 20 and < 40.
Comment on lines +2122 to +2123
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@greptile-apps greptile-apps bot Jan 28, 2026

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date in comment shows 29/01/2026 but PR was created on 2026-01-28

Prompt To Fix With AI 
This is a comment left during a code review.
Path: Generals/Code/GameEngine/Source/GameLogic/Object/PartitionManager.cpp
Line: 2122:2123

Comment:
date in comment shows 29/01/2026 but PR was created on 2026-01-28

How can I resolve this? If you propose a fix, please make it concise.

doCircleFillPrecise(pos.x, pos.y, majorRadius);
#endif
break;
}

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5 changes: 5 additions & 0 deletions GeneralsMD/Code/GameEngine/Include/GameLogic/PartitionManager.h
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Original file line number Diff line number Diff line change
Expand Up @@ -464,6 +464,11 @@ class PartitionData : public MemoryPoolObject
Real radius
);

/**
A more advanced implementation of doCircleFill that is 100% accurate.
*/
void doCircleFillPrecise(Real centerX, Real centerY, Real radius);

/**
fill in the pixels covered by the given rectangular shape with the given
center, dimensions, and rotation.
Expand Down
43 changes: 43 additions & 0 deletions GeneralsMD/Code/GameEngine/Source/GameLogic/Object/PartitionManager.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1882,6 +1882,43 @@ void PartitionData::doCircleFill(
}
}

static Bool doesCircleOverlapCell(Real centerX, Real centerY, Real radius, Real cellX, Real cellY, Real cellSize)
{
Real closestX = maxReal(cellX, minReal(centerX, cellX + cellSize));
Real closestY = maxReal(cellY, minReal(centerY, cellY + cellSize));
Real distX = centerX - closestX;
Real distY = centerY - closestY;

return (distX * distX + distY * distY) < radius * radius;
}

void PartitionData::doCircleFillPrecise(Real centerX, Real centerY, Real radius)
{
Int minCellX, minCellY, maxCellX, maxCellY;
ThePartitionManager->worldToCell(centerX - radius, centerY - radius, &minCellX, &minCellY);
ThePartitionManager->worldToCell(centerX + radius, centerY + radius, &maxCellX, &maxCellY);

Real cellSize = ThePartitionManager->getCellSize();

for (Int x = minCellX; x <= maxCellX; ++x)
{
for (Int y = minCellY; y <= maxCellY; ++y)
{
Real cellWorldX = x * cellSize;
Real cellWorldY = y * cellSize;

if (doesCircleOverlapCell(centerX, centerY, radius, cellWorldX, cellWorldY, cellSize))
{
PartitionCell* cell = ThePartitionManager->getCellAt(x, y);
if (cell)
{
addSubPixToCoverage(cell);
}
}
}
}
}

// -----------------------------------------------------------------------------
void PartitionData::doSmallFill(
Real centerX,
Expand Down Expand Up @@ -2083,7 +2120,13 @@ void PartitionData::updateCellsTouched()
case GEOMETRY_SPHERE:
case GEOMETRY_CYLINDER:
{
#if RETAIL_COMPATIBLE_CRC || RETAIL_COMPATIBLE_CIRCLE_FILL_ALGORITHM
doCircleFill(pos.x, pos.y, majorRadius);
#else
// TheSuperHackers @bugfix Stubbjax 29/01/2026 Use precise circle fill to improve
// collision accuracy, most notably for objects with geometry radii >= 20 and < 40.
Comment on lines +2126 to +2127
Copy link

@greptile-apps greptile-apps bot Jan 28, 2026

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date in comment shows 29/01/2026 but PR was created on 2026-01-28

Prompt To Fix With AI 
This is a comment left during a code review.
Path: GeneralsMD/Code/GameEngine/Source/GameLogic/Object/PartitionManager.cpp
Line: 2126:2127

Comment:
date in comment shows 29/01/2026 but PR was created on 2026-01-28

How can I resolve this? If you propose a fix, please make it concise.

doCircleFillPrecise(pos.x, pos.y, majorRadius);
#endif
break;
}

Expand Down
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