private static void SampleKernel(GpuShapeInfo shape, GpuSpaceInfo space, Matrix transformation, float maxDistance, bool revert)
{
var start = space.Bounds.Length * (blockIdx.x * blockDim.x + threadIdx.x) / blockDim.x / gridDim.x;
var end = space.Bounds.Length * (blockIdx.x * blockDim.x + threadIdx.x + 1) / blockDim.x / gridDim.x;
var inversedTransformation = transformation.Inverse();
for (int voxelIndex = start; voxelIndex < end; voxelIndex++)
{
var voxel = space.Voxels.Get(voxelIndex);
var spaceCoordinates = space.Bounds.At(voxelIndex);
var spacePosition = spaceCoordinates.AsVertex();
var shapePosition = transformation * spacePosition;
var shapeCoordinates = DiscreteCoordinates.Floor(shapePosition);
for (int partIndex = 0; partIndex < 8; partIndex++)
{
var partCoordinates = shapeCoordinates.Move(partIndex % 2, (partIndex >> 1) % 2, (partIndex >> 2) % 2);
var warpedPartCoordinates = shape.Bounds.Warp(partCoordinates);
ref var cell = ref shape.Voxels[shape.Bounds.Index(warpedPartCoordinates)];
var distance = Vector.Between(warpedPartCoordinates.AsVertex(), cell.NearestIntersection).Length;
var normal = Vector.Between(
spacePosition,
inversedTransformation * (shapePosition + cell.Normal)
).Normalize() * (revert ? -1 : 1);
var weight = DeviceFunction.Max(0f, 1f - distance / maxDistance);
var factor =
(1 - DeviceFunction.Abs(partCoordinates.X - shapePosition.X)) *
(1 - DeviceFunction.Abs(partCoordinates.Y - shapePosition.Y)) *
(1 - DeviceFunction.Abs(partCoordinates.Z - shapePosition.Z));
voxel.Weight += weight * factor;
voxel.Normal += normal * factor * weight;
}
space.Voxels.Set(voxelIndex, voxel);
}
public static void Sample(GpuShapeInfo shape, GpuSpaceInfo space, Matrix transformation, float maxDistance, bool revert)
{
Gpu.Default.Launch(SampleKernel, _lunchParams, shape, space, transformation, maxDistance, revert);
Gpu.Default.Synchronize();
}
