Files
HauntedBloodlines/Assets/Obi/Scripts/Common/Backends/Burst/Collisions/BurstTriangleMesh.cs
2025-05-29 22:31:40 +03:00

149 lines
7.2 KiB
C#

#if (OBI_BURST && OBI_MATHEMATICS && OBI_COLLECTIONS)
using Unity.Collections;
using Unity.Mathematics;
namespace Obi
{
public struct BurstTriangleMesh : BurstLocalOptimization.IDistanceFunction, IBurstCollider
{
public BurstColliderShape shape;
public BurstAffineTransform colliderToSolver;
public BurstAffineTransform solverToWorld;
public TriangleMeshHeader header;
public NativeArray<BIHNode> bihNodes;
public NativeArray<Triangle> triangles;
public NativeArray<float3> vertices;
public float dt;
public float collisionMargin;
private BurstMath.CachedTri tri;
public void Evaluate(float4 point, float4 radii, quaternion orientation, ref BurstLocalOptimization.SurfacePoint projectedPoint)
{
point = colliderToSolver.InverseTransformPointUnscaled(point);
if (shape.is2D != 0)
point[2] = 0;
float4 nearestPoint = BurstMath.NearestPointOnTri(tri, point, out float4 bary);
float4 normal = math.normalizesafe(point - nearestPoint);
projectedPoint.point = colliderToSolver.TransformPointUnscaled(nearestPoint + normal * shape.contactOffset);
projectedPoint.normal = colliderToSolver.TransformDirection(normal);
}
public void Contacts(int colliderIndex,
int rigidbodyIndex,
NativeArray<BurstRigidbody> rigidbodies,
NativeArray<float4> positions,
NativeArray<quaternion> orientations,
NativeArray<float4> velocities,
NativeArray<float4> radii,
NativeArray<int> simplices,
in BurstAabb simplexBounds,
int simplexIndex,
int simplexStart,
int simplexSize,
NativeQueue<BurstContact>.ParallelWriter contacts,
int optimizationIterations,
float optimizationTolerance)
{
BIHTraverse(colliderIndex, rigidbodyIndex, simplexIndex, simplexStart, simplexSize,
rigidbodies, positions, orientations, velocities, radii, simplices, in simplexBounds, 0, contacts, optimizationIterations, optimizationTolerance);
}
private void BIHTraverse(int colliderIndex,
int rigidbodyIndex,
int simplexIndex,
int simplexStart,
int simplexSize,
NativeArray<BurstRigidbody> rigidbodies,
NativeArray<float4> positions,
NativeArray<quaternion> orientations,
NativeArray<float4> velocities,
NativeArray<float4> radii,
NativeArray<int> simplices,
in BurstAabb simplexBounds,
int nodeIndex,
NativeQueue<BurstContact>.ParallelWriter contacts,
int optimizationIterations,
float optimizationTolerance)
{
var node = bihNodes[header.firstNode + nodeIndex];
if (node.firstChild >= 0)
{
// visit min node:
if (simplexBounds.min[node.axis] <= node.min)
BIHTraverse(colliderIndex, rigidbodyIndex, simplexIndex, simplexStart, simplexSize,
rigidbodies, positions, orientations, velocities, radii, simplices, in simplexBounds,
node.firstChild, contacts, optimizationIterations, optimizationTolerance);
// visit max node:
if (simplexBounds.max[node.axis] >= node.max)
BIHTraverse(colliderIndex, rigidbodyIndex, simplexIndex, simplexStart, simplexSize,
rigidbodies, positions, orientations, velocities, radii, simplices, in simplexBounds,
node.firstChild + 1, contacts, optimizationIterations, optimizationTolerance);
}
else
{
// check for contact against all triangles:
for (int dataOffset = node.start; dataOffset < node.start + node.count; ++dataOffset)
{
Triangle t = triangles[header.firstTriangle + dataOffset];
float4 v1 = new float4(vertices[header.firstVertex + t.i1], 0);
float4 v2 = new float4(vertices[header.firstVertex + t.i2], 0);
float4 v3 = new float4(vertices[header.firstVertex + t.i3], 0);
BurstAabb triangleBounds = new BurstAabb(v1, v2, v3, shape.contactOffset + collisionMargin);
if (triangleBounds.IntersectsAabb(simplexBounds, shape.is2D != 0))
{
float4 simplexBary = BurstMath.BarycenterForSimplexOfSize(simplexSize);
tri.Cache(v1 * colliderToSolver.scale, v2 * colliderToSolver.scale, v3 * colliderToSolver.scale);
var colliderPoint = BurstLocalOptimization.Optimize<BurstTriangleMesh>(ref this, positions, orientations, radii, simplices, simplexStart, simplexSize,
ref simplexBary, out float4 simplexPoint, optimizationIterations, optimizationTolerance);
float4 velocity = float4.zero;
float simplexRadius = 0;
for (int j = 0; j < simplexSize; ++j)
{
int particleIndex = simplices[simplexStart + j];
simplexRadius += radii[particleIndex].x * simplexBary[j];
velocity += velocities[particleIndex] * simplexBary[j];
}
float4 rbVelocity = float4.zero;
if (rigidbodyIndex >= 0)
rbVelocity = BurstMath.GetRigidbodyVelocityAtPoint(rigidbodyIndex, colliderPoint.point, rigidbodies, solverToWorld);
float dAB = math.dot(simplexPoint - colliderPoint.point, colliderPoint.normal);
float vel = math.dot(velocity - rbVelocity, colliderPoint.normal);
if (vel * dt + dAB <= simplexRadius + shape.contactOffset + collisionMargin)
{
contacts.Enqueue(new BurstContact()
{
bodyA = simplexIndex,
bodyB = colliderIndex,
pointA = simplexBary,
pointB = colliderPoint.point,
normal = colliderPoint.normal,
});
}
}
}
}
}
}
}
#endif