public void Execute(int i)
{
int simplexStart = simplexCounts.GetSimplexStartAndSize(i, out int simplexSize);
var bounds = new BurstAabb(float.MaxValue, float.MinValue);
for (int j = 0; j < simplexSize; ++j)
{
int p = simplices[simplexStart + j];
// Find this particle's stick distance:
int m = particleMaterialIndices[p];
float stickDistance = m >= 0 ? collisionMaterials[m].stickDistance : 0;
// Expand simplex bounds, using both the particle's original position and its velocity:
bounds.EncapsulateParticle(positions[p], positions[p] + velocities[p] * continuousCollisionDetection * dt,
math.max(radii[p].x + stickDistance, fluidRadii[p] * 0.5f) + collisionMargin);
}
simplexBounds[i] = bounds;
}
public void Execute(int i)
{
var cell = particleGrid.usedCells[i];
BurstAabb cellBounds = new BurstAabb(float.MaxValue, float.MinValue);
// here we calculate cell bounds that enclose both the predicted position and the original position of all its particles,
// for accurate continuous collision detection.
for (int p = 0; p < cell.Length; ++p)
{
int pIndex = cell[p];
// get collision material stick distance:
float stickDistance = 0;
int materialIndex = particleMaterialIndices[pIndex];
if (materialIndex >= 0)
{
stickDistance = collisionMaterials[materialIndex].stickDistance;
}
cellBounds.EncapsulateParticle(positions[pIndex],
positions[pIndex] + velocities[pIndex] * deltaTime,
radii[pIndex].x + stickDistance);
}
// transform the cell bounds to world space:
cellBounds.Transform(solverToWorld);
// get all colliders overlapped by the cell bounds, in all grid levels:
NativeList <int> candidates = new NativeList <int>(Allocator.Temp);
for (int l = 0; l < gridLevels.Length; ++l)
{
GetCandidatesForBoundsAtLevel(candidates, cellBounds, gridLevels[l], is2D);
}
if (candidates.Length > 0)
{
// make sure each candidate collider only shows up once in the array:
NativeArray <int> uniqueCandidates = candidates.AsArray();
uniqueCandidates.Sort();
int uniqueCount = uniqueCandidates.Unique();
// iterate over candidate colliders, generating contacts for each one
for (int c = 0; c < uniqueCount; ++c)
{
int colliderIndex = uniqueCandidates[c];
BurstColliderShape shape = shapes[colliderIndex];
BurstAabb colliderBounds = bounds[colliderIndex];
BurstAffineTransform colliderToSolver = worldToSolver * transforms[colliderIndex];
// transform collider bounds to solver space:
colliderBounds.Transform(worldToSolver);
// iterate over all particles in the cell:
for (int p = 0; p < cell.Length; ++p)
{
int particleIndex = cell[p];
// skip this pair if particle and collider have the same phase:
if (shape.phase == (phases[particleIndex] & (int)Oni.ParticleFlags.GroupMask))
{
continue;
}
// get collision material stick distance:
float stickDistance = 0;
int materialIndex = particleMaterialIndices[particleIndex];
if (materialIndex >= 0)
{
stickDistance = collisionMaterials[materialIndex].stickDistance;
}
// inflate collider bounds by particle's bounds:
BurstAabb inflatedColliderBounds = colliderBounds;
inflatedColliderBounds.Expand(radii[particleIndex].x * 1.2f + stickDistance);
float4 invDir = math.rcp(velocities[particleIndex] * deltaTime);
// We check particle trajectory ray vs inflated collider aabb
// instead of checking particle vs collider aabbs directly, as this reduces
// the amount of contacts generated for fast moving particles.
if (inflatedColliderBounds.IntersectsRay(positions[particleIndex], invDir, shape.is2D != 0))
{
// generate contacts for the collider:
GenerateContacts(shape.type,
particleIndex, colliderIndex,
positions[particleIndex], orientations[particleIndex], velocities[particleIndex], radii[particleIndex],
colliderToSolver, shape, contactsQueue, deltaTime);
}
}
}
}
}
