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107 行
3.6 KiB
107 行
3.6 KiB
float4 TessellationEdge(float3 p0, float3 p1, float3 p2, float3 n0, float3 n1, float3 n2)
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{
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float maxDisplacement = ADD_ZERO_IDX(_HeightAmplitude);
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#ifdef _LAYER_COUNT
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maxDisplacement = max(maxDisplacement, _HeightAmplitude1);
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#if _LAYER_COUNT >= 3
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maxDisplacement = max(maxDisplacement, _HeightAmplitude2);
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#endif
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#if _LAYER_COUNT >= 4
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maxDisplacement = max(maxDisplacement, _HeightAmplitude3);
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#endif
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#endif
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bool frustumCulled = WorldViewFrustumCull(p0, p1, p2, maxDisplacement, (float4[4])unity_CameraWorldClipPlanes);
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bool faceCull = false;
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#if !(defined(_DOUBLESIDED) || defined(_DOUBLESIDED_LIGHTING_FLIP) || defined(_DOUBLESIDED_LIGHTING_MIRROR))
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// TODO: Handle inverse culling (for mirror)!
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if (_TessellationBackFaceCullEpsilon > -0.99) // Is backface culling enabled ?
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{
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faceCull = BackFaceCullTriangle(p0, p1, p2, _TessellationBackFaceCullEpsilon, _WorldSpaceCameraPos);
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}
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#endif
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if (frustumCulled || faceCull)
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{
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// Settings factor to 0 will kill the triangle
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return float4(0.0, 0.0, 0.0, 0.0);
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}
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float3 tessFactor = float3(1.0, 1.0, 1.0);
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// Aaptive screen space tessellation
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if (_TessellationFactorTriangleSize > 0.0)
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{
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// return a value between 0 and 1
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tessFactor *= GetScreenSpaceTessFactor( p0, p1, p2, GetWorldToHClipMatrix(), _ScreenParams, _TessellationFactorTriangleSize);
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}
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// Distance based tessellation
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if (_TessellationFactorMaxDistance > 0.0)
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{
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tessFactor *= GetDistanceBasedTessFactor(p0, p1, p2, _WorldSpaceCameraPos, _TessellationFactorMinDistance, _TessellationFactorMaxDistance);
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}
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tessFactor *= _TessellationFactor;
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// TessFactor below 1.0 have no effect. At 0 it kill the triangle, so clamp it to 1.0
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tessFactor.xyz = float3(max(1.0, tessFactor.x), max(1.0, tessFactor.y), max(1.0, tessFactor.z));
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return CalcTriEdgeTessFactors(tessFactor);
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}
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float3 GetDisplacement(VaryingsMeshToDS input)
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{
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// This call will work for both LayeredLit and Lit shader
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LayerTexCoord layerTexCoord;
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GetLayerTexCoord(
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#ifdef VARYINGS_DS_NEED_TEXCOORD0
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input.texCoord0,
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#else
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float2(0.0, 0.0),
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#endif
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#ifdef VARYINGS_DS_NEED_TEXCOORD1
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input.texCoord1,
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#else
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float2(0.0, 0.0),
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#endif
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#ifdef VARYINGS_DS_NEED_TEXCOORD2
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input.texCoord2,
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#else
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float2(0.0, 0.0),
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#endif
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#ifdef VARYINGS_DS_NEED_TEXCOORD3
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input.texCoord3,
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#else
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float2(0.0, 0.0),
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#endif
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input.positionWS,
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#ifdef VARYINGS_DS_NEED_NORMAL
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input.normalWS,
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#else
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float3(0.0, 0.0, 1.0),
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#endif
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layerTexCoord);
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// TODO: For now just use Layer0, but we are suppose to apply the same heightmap blending than in the pixel shader
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#ifdef _HEIGHTMAP
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// TODO test mip lod to reduce texture cache miss
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// TODO: Move to camera relative and change distance to length
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//float dist = distance(input.positionWS, cameraPosWS);
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// No ddx/ddy to calculate LOD, use camera distance instead
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//float fadeDist = _TessellationFactorMaxDistance - _TessellationFactorMinDistance;
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//float heightMapLod = saturate((dist - _TessellationFactorMinDistance) / min(fadeDist, 0.01)) * 6; // 6 is an arbitrary number here
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float heightMapLod = 0.0;
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float height = (SAMPLE_LAYER_TEXTURE2D_LOD(ADD_ZERO_IDX(_HeightMap), ADD_ZERO_IDX(sampler_HeightMap), ADD_ZERO_IDX(layerTexCoord.base), heightMapLod).r - ADD_ZERO_IDX(_HeightCenter)) * ADD_ZERO_IDX(_HeightAmplitude);
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#else
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float height = 0.0;
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#endif
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#ifdef VARYINGS_DS_NEED_NORMAL
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return height * input.normalWS;
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#else
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return float3(0.0, 0.0, 0.0);
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#endif
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}
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