public static IEnumerable <VFXExpression> SampleEdgeAttribute(VFXExpression source, VFXExpression index, VFXExpression lerp, IEnumerable <VertexAttribute> vertexAttributes)
{
bool skinnedMesh = source.valueType == UnityEngine.VFX.VFXValueType.SkinnedMeshRenderer;
var mesh = !skinnedMesh ? source : new VFXExpressionMeshFromSkinnedMeshRenderer(source);
var meshIndexFormat = new VFXExpressionMeshIndexFormat(mesh);
var oneInt = VFXOperatorUtility.OneExpression[UnityEngine.VFX.VFXValueType.Int32];
var oneUint = VFXOperatorUtility.OneExpression[UnityEngine.VFX.VFXValueType.Uint32];
var threeUint = VFXOperatorUtility.ThreeExpression[UnityEngine.VFX.VFXValueType.Uint32];
var nextIndex = index + oneUint;
//Loop triangle
var loop = VFXOperatorUtility.Modulo(nextIndex, threeUint);
var predicat = new VFXExpressionCondition(UnityEngine.VFX.VFXValueType.Uint32, VFXCondition.NotEqual, loop, VFXOperatorUtility.ZeroExpression[UnityEngine.VFX.VFXValueType.Uint32]);
nextIndex = new VFXExpressionBranch(predicat, nextIndex, nextIndex - threeUint);
var sampledIndex_A = new VFXExpressionSampleIndex(mesh, index, meshIndexFormat);
var sampledIndex_B = new VFXExpressionSampleIndex(mesh, nextIndex, meshIndexFormat);
var sampling_A = SampleVertexAttribute(source, sampledIndex_A, vertexAttributes).ToArray();
var sampling_B = SampleVertexAttribute(source, sampledIndex_B, vertexAttributes).ToArray();
for (int i = 0; i < vertexAttributes.Count(); ++i)
{
var outputValueType = sampling_A[i].valueType;
var s = VFXOperatorUtility.CastFloat(lerp, outputValueType);
yield return(VFXOperatorUtility.Lerp(sampling_A[i], sampling_B[i], s));
}
}
protected override sealed VFXExpression[] BuildExpression(VFXExpression[] inputExpression)
{
var mesh = inputExpression[0].valueType == VFXValueType.Mesh ? inputExpression[0] : new VFXExpressionMeshFromSkinnedMeshRenderer(inputExpression[0]);
var indexFormat = new VFXExpressionMeshIndexFormat(mesh);
var indexCount = new VFXExpressionMeshIndexCount(mesh);
var index = VFXOperatorUtility.ApplyAddressingMode(inputExpression[1], indexCount, VFXOperatorUtility.SequentialAddressingMode.Wrap);
var sampledIndex = new VFXExpressionSampleIndex(mesh, index, indexFormat);
return(new[] { sampledIndex });
}
public static IEnumerable <VFXExpression> SampleTriangleAttribute(VFXExpression source, VFXExpression triangleIndex, VFXExpression coord, SurfaceCoordinates coordMode, IEnumerable <VertexAttribute> vertexAttributes)
{
bool skinnedMesh = source.valueType == UnityEngine.VFX.VFXValueType.SkinnedMeshRenderer;
var mesh = !skinnedMesh ? source : new VFXExpressionMeshFromSkinnedMeshRenderer(source);
var meshIndexCount = new VFXExpressionMeshIndexCount(mesh);
var meshIndexFormat = new VFXExpressionMeshIndexFormat(mesh);
var threeUint = VFXOperatorUtility.ThreeExpression[UnityEngine.VFX.VFXValueType.Uint32];
var baseIndex = triangleIndex * threeUint;
var sampledIndex_A = new VFXExpressionSampleIndex(mesh, baseIndex, meshIndexFormat);
var sampledIndex_B = new VFXExpressionSampleIndex(mesh, baseIndex + VFXValue.Constant <uint>(1u), meshIndexFormat);
var sampledIndex_C = new VFXExpressionSampleIndex(mesh, baseIndex + VFXValue.Constant <uint>(2u), meshIndexFormat);
var allInputValues = new List <VFXExpression>();
var sampling_A = SampleVertexAttribute(source, sampledIndex_A, vertexAttributes).ToArray();
var sampling_B = SampleVertexAttribute(source, sampledIndex_B, vertexAttributes).ToArray();
var sampling_C = SampleVertexAttribute(source, sampledIndex_C, vertexAttributes).ToArray();
VFXExpression barycentricCoordinates = null;
var one = VFXOperatorUtility.OneExpression[UnityEngine.VFX.VFXValueType.Float];
if (coordMode == SurfaceCoordinates.Barycentric)
{
var barycentricCoordinateInput = coord;
barycentricCoordinates = new VFXExpressionCombine(barycentricCoordinateInput.x, barycentricCoordinateInput.y, one - barycentricCoordinateInput.x - barycentricCoordinateInput.y);
}
else if (coordMode == SurfaceCoordinates.Uniform)
{
//https://hal.archives-ouvertes.fr/hal-02073696v2/document
var input = coord;
var half2 = VFXOperatorUtility.HalfExpression[UnityEngine.VFX.VFXValueType.Float2];
var zero = VFXOperatorUtility.ZeroExpression[UnityEngine.VFX.VFXValueType.Float];
var t = input * half2;
var offset = t.y - t.x;
var pred = new VFXExpressionCondition(UnityEngine.VFX.VFXValueType.Float, VFXCondition.Greater, offset, zero);
var t2 = new VFXExpressionBranch(pred, t.y + offset, t.y);
var t1 = new VFXExpressionBranch(pred, t.x, t.x - offset);
var t3 = one - t2 - t1;
barycentricCoordinates = new VFXExpressionCombine(t1, t2, t3);
/* Possible variant See http://inis.jinr.ru/sl/vol1/CMC/Graphics_Gems_1,ed_A.Glassner.pdf (p24) uniform distribution from two numbers in triangle generating barycentric coordinate
* var input = VFXOperatorUtility.Saturate(inputExpression[2]);
* var s = input.x;
* var t = VFXOperatorUtility.Sqrt(input.y);
* var a = one - t;
* var b = (one - s) * t;
* var c = s * t;
* barycentricCoordinates = new VFXExpressionCombine(a, b, c);
*/
}
else
{
throw new InvalidOperationException("No supported surfaceCoordinates : " + coord);
}
for (int i = 0; i < vertexAttributes.Count(); ++i)
{
var outputValueType = sampling_A[i].valueType;
var barycentricCoordinateX = VFXOperatorUtility.CastFloat(barycentricCoordinates.x, outputValueType);
var barycentricCoordinateY = VFXOperatorUtility.CastFloat(barycentricCoordinates.y, outputValueType);
var barycentricCoordinateZ = VFXOperatorUtility.CastFloat(barycentricCoordinates.z, outputValueType);
var r = sampling_A[i] * barycentricCoordinateX + sampling_B[i] * barycentricCoordinateY + sampling_C[i] * barycentricCoordinateZ;
yield return(r);
}
}
