67 lines
3.0 KiB
HLSL
67 lines
3.0 KiB
HLSL
#define TESSELLATION_INTERPOLATE_BARY(name, bary) output.name = input0.name * bary.x + input1.name * bary.y + input2.name * bary.z
|
|
|
|
// p0, p1, p2 triangle world position
|
|
// p0, p1, p2 triangle world vertex normal
|
|
real3 PhongTessellation(real3 positionWS, real3 p0, real3 p1, real3 p2, real3 n0, real3 n1, real3 n2, real3 baryCoords, real shape)
|
|
{
|
|
real3 c0 = ProjectPointOnPlane(positionWS, p0, n0);
|
|
real3 c1 = ProjectPointOnPlane(positionWS, p1, n1);
|
|
real3 c2 = ProjectPointOnPlane(positionWS, p2, n2);
|
|
|
|
real3 phongPositionWS = baryCoords.x * c0 + baryCoords.y * c1 + baryCoords.z * c2;
|
|
|
|
return lerp(positionWS, phongPositionWS, shape);
|
|
}
|
|
|
|
// Reference: http://twvideo01.ubm-us.net/o1/vault/gdc10/slides/Bilodeau_Bill_Direct3D11TutorialTessellation.pdf
|
|
|
|
// Compute both screen and distance based adaptation - return factor between 0 and 1
|
|
real3 GetScreenSpaceTessFactor(real3 p0, real3 p1, real3 p2, real4x4 viewProjectionMatrix, real4 screenSize, real triangleSize)
|
|
{
|
|
// Get screen space adaptive scale factor
|
|
real2 edgeScreenPosition0 = ComputeNormalizedDeviceCoordinates(p0, viewProjectionMatrix) * screenSize.xy;
|
|
real2 edgeScreenPosition1 = ComputeNormalizedDeviceCoordinates(p1, viewProjectionMatrix) * screenSize.xy;
|
|
real2 edgeScreenPosition2 = ComputeNormalizedDeviceCoordinates(p2, viewProjectionMatrix) * screenSize.xy;
|
|
|
|
real EdgeScale = 1.0 / triangleSize; // Edge size in reality, but name is simpler
|
|
real3 tessFactor;
|
|
tessFactor.x = saturate(distance(edgeScreenPosition1, edgeScreenPosition2) * EdgeScale);
|
|
tessFactor.y = saturate(distance(edgeScreenPosition0, edgeScreenPosition2) * EdgeScale);
|
|
tessFactor.z = saturate(distance(edgeScreenPosition0, edgeScreenPosition1) * EdgeScale);
|
|
|
|
return tessFactor;
|
|
}
|
|
|
|
real3 GetDistanceBasedTessFactor(real3 p0, real3 p1, real3 p2, real3 cameraPosWS, real tessMinDist, real tessMaxDist)
|
|
{
|
|
real3 edgePosition0 = 0.5 * (p1 + p2);
|
|
real3 edgePosition1 = 0.5 * (p0 + p2);
|
|
real3 edgePosition2 = 0.5 * (p0 + p1);
|
|
|
|
// In case camera-relative rendering is enabled, 'cameraPosWS' is statically known to be 0,
|
|
// so the compiler will be able to optimize distance() to length().
|
|
real dist0 = distance(edgePosition0, cameraPosWS);
|
|
real dist1 = distance(edgePosition1, cameraPosWS);
|
|
real dist2 = distance(edgePosition2, cameraPosWS);
|
|
|
|
// The saturate will handle the produced NaN in case min == max
|
|
real fadeDist = tessMaxDist - tessMinDist;
|
|
real3 tessFactor;
|
|
tessFactor.x = saturate(1.0 - (dist0 - tessMinDist) / fadeDist);
|
|
tessFactor.y = saturate(1.0 - (dist1 - tessMinDist) / fadeDist);
|
|
tessFactor.z = saturate(1.0 - (dist2 - tessMinDist) / fadeDist);
|
|
|
|
return tessFactor;
|
|
}
|
|
|
|
real4 CalcTriTessFactorsFromEdgeTessFactors(real3 triVertexFactors)
|
|
{
|
|
real4 tess;
|
|
tess.x = triVertexFactors.x;
|
|
tess.y = triVertexFactors.y;
|
|
tess.z = triVertexFactors.z;
|
|
tess.w = (triVertexFactors.x + triVertexFactors.y + triVertexFactors.z) / 3.0;
|
|
|
|
return tess;
|
|
}
|