Files
Fishing2/Assets/Obi/Scripts/Common/Backends/Burst/Collisions/BurstTriangleMesh.cs
2026-01-22 22:08:21 +08:00

220 lines
10 KiB
C#

#if (OBI_BURST && OBI_MATHEMATICS && OBI_COLLECTIONS)
using Unity.Burst;
using Unity.Collections;
using Unity.Jobs;
using Unity.Mathematics;
namespace Obi
{
public struct BurstTriangleMesh : BurstLocalOptimization.IDistanceFunction
{
public BurstColliderShape shape;
public BurstAffineTransform colliderToSolver;
public BurstMath.CachedTri tri;
public void Evaluate(float4 point, float4 radii, quaternion orientation, ref BurstLocalOptimization.SurfacePoint projectedPoint)
{
point = colliderToSolver.InverseTransformPointUnscaled(point);
if (shape.is2D)
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 static JobHandle GenerateContacts(ObiColliderWorld world,
BurstSolverImpl solver,
NativeList<Oni.ContactPair> contactPairs,
NativeQueue<BurstContact> contactQueue,
NativeArray<int> contactOffsetsPerType,
float deltaTime,
JobHandle inputDeps)
{
int pairCount = contactOffsetsPerType[(int)Oni.ShapeType.TriangleMesh + 1] - contactOffsetsPerType[(int)Oni.ShapeType.TriangleMesh];
if (pairCount == 0) return inputDeps;
var job = new GenerateTriangleMeshContactsJob
{
contactPairs = contactPairs,
positions = solver.positions,
orientations = solver.orientations,
velocities = solver.velocities,
invMasses = solver.invMasses,
radii = solver.principalRadii,
simplices = solver.simplices,
simplexCounts = solver.simplexCounts,
simplexBounds = solver.simplexBounds,
transforms = world.colliderTransforms.AsNativeArray<BurstAffineTransform>(),
shapes = world.colliderShapes.AsNativeArray<BurstColliderShape>(),
rigidbodies = world.rigidbodies.AsNativeArray<BurstRigidbody>(),
triangleMeshHeaders = world.triangleMeshContainer.headers.AsNativeArray<TriangleMeshHeader>(),
bihNodes = world.triangleMeshContainer.bihNodes.AsNativeArray<BIHNode>(),
triangles = world.triangleMeshContainer.triangles.AsNativeArray<Triangle>(),
vertices = world.triangleMeshContainer.vertices.AsNativeArray<float3>(),
contactsQueue = contactQueue.AsParallelWriter(),
solverToWorld = solver.inertialFrame,
worldToSolver = solver.worldToSolver,
deltaTime = deltaTime,
parameters = solver.abstraction.parameters,
firstPair = contactOffsetsPerType[(int)Oni.ShapeType.TriangleMesh]
};
inputDeps = job.Schedule(pairCount, 1, inputDeps);
return inputDeps;
}
}
[BurstCompile]
struct GenerateTriangleMeshContactsJob : IJobParallelFor
{
[ReadOnly] public NativeList<Oni.ContactPair> contactPairs;
// particle arrays:
[ReadOnly] public NativeArray<float4> velocities;
[ReadOnly] public NativeArray<float4> positions;
[ReadOnly] public NativeArray<quaternion> orientations;
[ReadOnly] public NativeArray<float> invMasses;
[ReadOnly] public NativeArray<float4> radii;
// simplex arrays:
[ReadOnly] public NativeArray<int> simplices;
[ReadOnly] public SimplexCounts simplexCounts;
[ReadOnly] public NativeArray<BurstAabb> simplexBounds;
// collider arrays:
[ReadOnly] public NativeArray<BurstAffineTransform> transforms;
[ReadOnly] public NativeArray<BurstColliderShape> shapes;
[ReadOnly] public NativeArray<BurstRigidbody> rigidbodies;
// triangle mesh data:
[ReadOnly] public NativeArray<TriangleMeshHeader> triangleMeshHeaders;
[ReadOnly] public NativeArray<BIHNode> bihNodes;
[ReadOnly] public NativeArray<Triangle> triangles;
[ReadOnly] public NativeArray<float3> vertices;
[WriteOnly]
[NativeDisableParallelForRestriction]
public NativeQueue<BurstContact>.ParallelWriter contactsQueue;
// auxiliar data:
[ReadOnly] public int firstPair;
[ReadOnly] public BurstInertialFrame solverToWorld;
[ReadOnly] public BurstAffineTransform worldToSolver;
[ReadOnly] public float deltaTime;
[ReadOnly] public Oni.SolverParameters parameters;
public void Execute(int i)
{
int simplexIndex = contactPairs[firstPair + i].bodyA;
int colliderIndex = contactPairs[firstPair + i].bodyB;
var shape = shapes[colliderIndex];
if (shape.dataIndex < 0)
return;
int rigidbodyIndex = shape.rigidbodyIndex;
var header = triangleMeshHeaders[shape.dataIndex];
int simplexStart = simplexCounts.GetSimplexStartAndSize(simplexIndex, out int simplexSize);
var simplexBound = simplexBounds[simplexIndex];
BurstAffineTransform colliderToSolver = worldToSolver * transforms[colliderIndex];
// invert a full matrix here to accurately represent collider bounds scale.
var solverToCollider = math.inverse(float4x4.TRS(colliderToSolver.translation.xyz, colliderToSolver.rotation, colliderToSolver.scale.xyz));
var simplexBoundsCS = simplexBound.Transformed(solverToCollider);
float4 marginCS = new float4((shape.contactOffset + parameters.collisionMargin) / colliderToSolver.scale.xyz, 0);
BurstTriangleMesh triangleMeshShape = new BurstTriangleMesh()
{
colliderToSolver = colliderToSolver,
shape = shape
};
NativeQueue<int> queue = new NativeQueue<int>(Allocator.Temp);
queue.Enqueue(0);
while (!queue.IsEmpty())
{
int nodeIndex = queue.Dequeue();
var node = bihNodes[header.firstNode + nodeIndex];
// leaf node:
if (node.firstChild < 0)
{
// 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, marginCS);
if (triangleBounds.IntersectsAabb(simplexBoundsCS, shape.is2D))
{
float4 simplexBary = BurstMath.BarycenterForSimplexOfSize(simplexSize);
triangleMeshShape.tri.Cache(v1 * colliderToSolver.scale, v2 * colliderToSolver.scale, v3 * colliderToSolver.scale);
var colliderPoint = BurstLocalOptimization.Optimize(ref triangleMeshShape, positions, orientations, radii, simplices, simplexStart, simplexSize,
ref simplexBary, out float4 simplexPoint, parameters.surfaceCollisionIterations, parameters.surfaceCollisionTolerance);
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 * deltaTime + dAB <= simplexRadius + shape.contactOffset + parameters.collisionMargin)
{
contactsQueue.Enqueue(new BurstContact()
{
bodyA = simplexIndex,
bodyB = colliderIndex,
pointA = simplexBary,
pointB = colliderPoint.point,
normal = colliderPoint.normal * triangleMeshShape.shape.sign
});
}
}
}
}
else // check min and/or max children:
{
// visit min node:
if (simplexBoundsCS.min[node.axis] <= node.min)
queue.Enqueue(node.firstChild);
// visit max node:
if (simplexBoundsCS.max[node.axis] >= node.max)
queue.Enqueue(node.firstChild + 1);
}
}
}
}
}
#endif