Files
Fishing2/Assets/Obi/Scripts/Common/Backends/Burst/Collisions/BurstHeightField.cs
2025-11-10 00:08:26 +08:00

273 lines
13 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 BurstHeightField : BurstLocalOptimization.IDistanceFunction
{
public BurstColliderShape shape;
public BurstAffineTransform colliderToSolver;
public BurstMath.CachedTri tri;
public float4 triNormal;
public HeightFieldHeader header;
public NativeArray<float> heightFieldSamples;
public void Evaluate(float4 point, float4 radii, quaternion orientation, ref BurstLocalOptimization.SurfacePoint projectedPoint)
{
point = colliderToSolver.InverseTransformPoint(point);
float4 nearestPoint = BurstMath.NearestPointOnTri(tri, point, out _);
float4 normal = math.normalizesafe(point - nearestPoint);
// flip the contact normal if it points below ground: (doesn't work with holes)
//BurstMath.OneSidedNormal(triNormal, ref normal);
projectedPoint.point = colliderToSolver.TransformPoint(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.Heightmap + 1] - contactOffsetsPerType[(int)Oni.ShapeType.Heightmap];
if (pairCount == 0) return inputDeps;
var job = new GenerateHeightFieldContactsJob
{
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>(),
heightFieldHeaders = world.heightFieldContainer.headers.AsNativeArray<HeightFieldHeader>(),
heightFieldSamples = world.heightFieldContainer.samples.AsNativeArray<float>(),
contactsQueue = contactQueue.AsParallelWriter(),
solverToWorld = solver.inertialFrame,
worldToSolver = solver.worldToSolver,
deltaTime = deltaTime,
parameters = solver.abstraction.parameters,
firstPair = contactOffsetsPerType[(int)Oni.ShapeType.Heightmap]
};
inputDeps = job.Schedule(pairCount, 1, inputDeps);
return inputDeps;
}
}
[BurstCompile]
struct GenerateHeightFieldContactsJob : 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;
// height field data:
[ReadOnly] public NativeArray<HeightFieldHeader> heightFieldHeaders;
[ReadOnly] public NativeArray<float> heightFieldSamples;
[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;
var header = heightFieldHeaders[shape.dataIndex];
int rigidbodyIndex = shapes[colliderIndex].rigidbodyIndex;
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);
BurstHeightField triangleMeshShape = new BurstHeightField()
{
colliderToSolver = colliderToSolver,
shape = shapes[colliderIndex],
header = heightFieldHeaders[shapes[colliderIndex].dataIndex],
heightFieldSamples = heightFieldSamples
};
float4 triNormal = float4.zero;
var co = new BurstContact { bodyA = simplexIndex, bodyB = colliderIndex };
int resolutionU = (int)shape.center.x;
int resolutionV = (int)shape.center.y;
// calculate terrain cell size:
float cellWidth = shape.size.x / (resolutionU - 1);
float cellHeight = shape.size.z / (resolutionV - 1);
// calculate particle bounds min/max cells:
int2 min = new int2((int)math.floor(simplexBoundsCS.min[0] / cellWidth), (int)math.floor(simplexBoundsCS.min[2] / cellHeight));
int2 max = new int2((int)math.floor(simplexBoundsCS.max[0] / cellWidth), (int)math.floor(simplexBoundsCS.max[2] / cellHeight));
for (int su = min[0]; su <= max[0]; ++su)
{
if (su >= 0 && su < resolutionU - 1)
{
for (int sv = min[1]; sv <= max[1]; ++sv)
{
if (sv >= 0 && sv < resolutionV - 1)
{
// calculate neighbor sample indices:
int csu1 = math.clamp(su + 1, 0, resolutionU - 1);
int csv1 = math.clamp(sv + 1, 0, resolutionV - 1);
// sample heights:
float h1 = heightFieldSamples[header.firstSample + sv * resolutionU + su] * shape.size.y;
float h2 = heightFieldSamples[header.firstSample + sv * resolutionU + csu1] * shape.size.y;
float h3 = heightFieldSamples[header.firstSample + csv1 * resolutionU + su] * shape.size.y;
float h4 = heightFieldSamples[header.firstSample + csv1 * resolutionU + csu1] * shape.size.y;
if (h1 < 0) continue;
h1 = math.abs(h1);
h2 = math.abs(h2);
h3 = math.abs(h3);
h4 = math.abs(h4);
float min_x = su * shape.size.x / (resolutionU - 1);
float max_x = csu1 * shape.size.x / (resolutionU - 1);
float min_z = sv * shape.size.z / (resolutionV - 1);
float max_z = csv1 * shape.size.z / (resolutionV - 1);
float4 convexPoint;
float4 simplexBary = BurstMath.BarycenterForSimplexOfSize(simplexSize);
// ------contact against the first triangle------:
float4 v1 = new float4(min_x, h3, max_z, 0);
float4 v2 = new float4(max_x, h4, max_z, 0);
float4 v3 = new float4(min_x, h1, min_z, 0);
triangleMeshShape.tri.Cache(v1, v2, v3);
triNormal.xyz = math.normalizesafe(math.cross((v2 - v1).xyz, (v3 - v1).xyz));
var colliderPoint = BurstLocalOptimization.Optimize(ref triangleMeshShape, positions, orientations, radii, simplices, simplexStart, simplexSize,
ref simplexBary, out convexPoint, 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(convexPoint - colliderPoint.point, colliderPoint.normal);
float vel = math.dot(velocity - rbVelocity, colliderPoint.normal);
if (vel * deltaTime + dAB <= simplexRadius + shape.contactOffset + parameters.collisionMargin)
{
co.pointB = colliderPoint.point;
co.normal = colliderPoint.normal * triangleMeshShape.shape.sign;
co.pointA = simplexBary;
contactsQueue.Enqueue(co);
}
// ------contact against the second triangle------:
v1 = new float4(min_x, h1, min_z, 0);
v2 = new float4(max_x, h4, max_z, 0);
v3 = new float4(max_x, h2, min_z, 0);
triangleMeshShape.tri.Cache(v1, v2, v3);
triNormal.xyz = math.normalizesafe(math.cross((v2 - v1).xyz, (v3 - v1).xyz));
colliderPoint = BurstLocalOptimization.Optimize(ref triangleMeshShape, positions, orientations, radii, simplices, simplexStart, simplexSize,
ref simplexBary, out convexPoint, parameters.surfaceCollisionIterations, parameters.surfaceCollisionTolerance);
velocity = float4.zero;
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];
}
rbVelocity = float4.zero;
if (rigidbodyIndex >= 0)
rbVelocity = BurstMath.GetRigidbodyVelocityAtPoint(rigidbodyIndex, colliderPoint.point, rigidbodies, solverToWorld);
dAB = math.dot(convexPoint - colliderPoint.point, colliderPoint.normal);
vel = math.dot(velocity - rbVelocity, colliderPoint.normal);
if (vel * deltaTime + dAB <= simplexRadius + shape.contactOffset + parameters.collisionMargin)
{
co.pointB = colliderPoint.point;
co.normal = colliderPoint.normal * triangleMeshShape.shape.sign;
co.pointA = simplexBary;
contactsQueue.Enqueue(co);
}
}
}
}
}
}
}
}
#endif