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⚡ Optimize AABB and Circle intersection calculations #142

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Merged
johnstrand merged 2 commits into from
Aug 21, 2026
Merged

⚡ Optimize AABB and Circle intersection calculations #142

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⚡ Optimize AABB and Circle intersection calculations
google-labs-jules[bot] Aug 21, 2026
c62b71e
Merge branch 'master' into perf/optimize-aabb-circle-intersects-11788…
johnstrand Aug 21, 2026
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33 changes: 6 additions & 27 deletions src/GameUtils/Types/Geometry/AABB.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -150,42 +150,19 @@ public bool Intersects(Polygon2D polygon)
{
if (!Intersects(polygon.BoundingBox)) return false;

// 1. Fast bounds check: compute polygon bounds on the fly
if (polygon.Vertices.Length > 0)
{
var pMinX = polygon.Vertices[0].X;
var pMaxX = polygon.Vertices[0].X;
var pMinY = polygon.Vertices[0].Y;
var pMaxY = polygon.Vertices[0].Y;

for (int i = 1; i < polygon.Vertices.Length; i++)
{
var v = polygon.Vertices[i];
if (v.X < pMinX) pMinX = v.X;
if (v.X > pMaxX) pMaxX = v.X;
if (v.Y < pMinY) pMinY = v.Y;
if (v.Y > pMaxY) pMaxY = v.Y;
}

if (pMinX > Max.X || pMaxX < Min.X || pMinY > Max.Y || pMaxY < Min.Y)
{
return false;
}
}

// 2. Check if any polygon vertex is inside the AABB
// 1. Check if any polygon vertex is inside the AABB
foreach (var v in polygon.Vertices)
{
if (Contains(v)) return true;
}

// 3. Check if any polygon edge intersects the AABB
// 2. Check if any polygon edge intersects the AABB
foreach (var e in polygon.Edges)
{
if (Intersects(e)) return true;
}

// 4. Check if the AABB is completely inside the polygon
// 3. Check if the AABB is completely inside the polygon
return polygon.Contains(Center);
}
#pragma warning restore S3267
Expand Down Expand Up @@ -213,7 +190,9 @@ public bool Intersects(Vector2 start, Vector2 end)
/// </summary>
public bool Intersects(Vector2 center, float radius)
{
return Intersects(new Circle(center, radius));
var closest = Vector2.Clamp(center, Min, Max);
var distance = Vector2.DistanceSquared(center, closest);
return distance <= radius * radius;
}

/// <summary>
Expand Down
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