#define SAMPLE_LAYER_NORMALMAP_AG(textureName, samplerName, coord, scale) SampleLayerNormalAG(TEXTURE2D_PARAM(textureName, samplerName), coord, layerTexCoord.weights, scale)
#define SAMPLE_LAYER_NORMALMAP_RGB(textureName, samplerName, coord, scale) SampleLayerNormalRGB(TEXTURE2D_PARAM(textureName, samplerName), coord, layerTexCoord.weights, scale)
// This function apply per pixel displacement mapping algorithm
// It will determine offset for uv coordinate to apply.
// Note that we also need to affect ligthmaps uv, so FragInputs will be modfy too
// This function return current sampled heights (up to 4) + height at intersection
void ApplyDisplacement(FragInputs input, inout LayerTexCoord layerTexCoord)
{
#if defined(_HEIGHTMAP) && defined(_PER_PIXEL_DISPLACEMENT)
// ref: https://www.gamedev.net/resources/_/technical/graphics-programming-and-theory/a-closer-look-at-parallax-occlusion-mapping-r3262
float3 viewDirTS = TransformWorldToTangent(V, input.tangentToWorld);
// Change the number of samples per ray depending on the viewing angle for the surface.
// Oblique angles require smaller step sizes to achieve more accurate precision for computing displacement.
int numSteps = (int)lerp(_PPPMaxSamples, _PPPMinSamples, viewDirTS.z);
// View vector is from the point to the camera, but we want to raymarch from camera to point, so reverse the sign
// The length of viewDirTS vector determines the furthest amount of displacement:
// float parallaxLimit = -length(viewDirTS.xy) / viewDirTS.z;
// float2 parallaxDir = normalize(Out.viewDirTS.xy);
// float2 parallaxMaxOffsetTS = parallaxDir * parallaxLimit;
// Above code simplify to
float2 parallaxMaxOffsetTS = (viewDirTS.xy / -viewDirTS.z) /* * _POMHeightMapScale.x */;
float2 texOffsetPerStep = stepSize * parallaxMaxOffsetTS;
#ifdef _LAYER_COUNT
ParallaxOcclusionMappingLayer0(layerTexCoord, numSteps, texOffsetPerStep);
ParallaxOcclusionMappingLayer1(layerTexCoord, numSteps, texOffsetPerStep);
ParallaxOcclusionMappingLayer2(layerTexCoord, numSteps, texOffsetPerStep);
ParallaxOcclusionMappingLayer3(layerTexCoord, numSteps, texOffsetPerStep);
#else
ParallaxOcclusionMappingLayer(layerTexCoord, numSteps, texOffsetPerStep);
#endif
// TODO: We are supposed to modify lightmaps coordinate (fetch in GetBuiltin), but this isn't the same uv mapping, so can't apply the offset here...
// Let's assume it will be "fine" as indirect diffuse is often low frequency
#endif
}
#ifndef LAYERED_LIT_SHADER
#define LAYER_INDEX 0
positionWS, normalWS, isTriplanar, layerTexCoord);
}
void ApplyPerPixelDisplacement(FragInputs input, float3 V, inout LayerTexCoord layerTexCoord)
{
#if defined(_HEIGHTMAP) && defined(_PER_PIXEL_DISPLACEMENT)
// ref: https://www.gamedev.net/resources/_/technical/graphics-programming-and-theory/a-closer-look-at-parallax-occlusion-mapping-r3262
float3 viewDirTS = TransformWorldToTangent(V, input.tangentToWorld);
// Change the number of samples per ray depending on the viewing angle for the surface.
// Oblique angles require smaller step sizes to achieve more accurate precision for computing displacement.
// int numSteps = (int)lerp(_PPPMaxSamples, _PPPMinSamples, viewDirTS.z);
int numSteps = (int)lerp(15, 15, viewDirTS.z);
ParallaxOcclusionMappingLayer(layerTexCoord, numSteps, viewDirTS);
// TODO: We are supposed to modify lightmaps coordinate (fetch in GetBuiltin), but this isn't the same uv mapping, so can't apply the offset here...
// Let's assume it will be "fine" as indirect diffuse is often low frequency
#endif
}
void GetSurfaceAndBuiltinData(FragInputs input, float3 V, inout PositionInputs posInput, out SurfaceData surfaceData, out BuiltinData builtinData)
{
LayerTexCoord layerTexCoord;
ApplyDisplacement(input, layerTexCoord);
ApplyPerPixel Displacement(input, V , layerTexCoord);
float depthOffset = 0.0;
#ifdef _DEPTHOFFSET_ON
positionWS, normalWS, isTriplanar, layerTexCoord);
}
void ApplyPerPixelDisplacement(FragInputs input, float3 V, inout LayerTexCoord layerTexCoord)
{
#if defined(_HEIGHTMAP) && defined(_PER_PIXEL_DISPLACEMENT)
float3 viewDirTS = TransformWorldToTangent(V, input.tangentToWorld);
int numSteps = (int)lerp(15, 15, viewDirTS.z);
ParallaxOcclusionMappingLayer0(layerTexCoord, numSteps, viewDirTS);
ParallaxOcclusionMappingLayer1(layerTexCoord, numSteps, viewDirTS);
ParallaxOcclusionMappingLayer2(layerTexCoord, numSteps, viewDirTS);
ParallaxOcclusionMappingLayer3(layerTexCoord, numSteps, viewDirTS);
#endif
}
void GetSurfaceAndBuiltinData(FragInputs input, float3 V, inout PositionInputs posInput, out SurfaceData surfaceData, out BuiltinData builtinData)
{
LayerTexCoord layerTexCoord;
ApplyDisplacement(input, layerTexCoord);
ApplyPerPixelDisplacement(input, V, layerTexCoord);
float height0 = SampleHeightmap0(LayerTexCoord layerTexCoord);
float height1 = SampleHeightmap1(LayerTexCoord layerTexCoord);
sebastienlagarde
8 年前