VertexDescriptionInputs BuildVertexDescriptionInputs(Attributes input)
{
VertexDescriptionInputs output;
ZERO_INITIALIZE(VertexDescriptionInputs, output);
$VertexDescriptionInputs.ObjectSpaceNormal: output.ObjectSpaceNormal = input.normalOS;
$VertexDescriptionInputs.WorldSpaceNormal: output.WorldSpaceNormal = TransformObjectToWorldNormal(input.normalOS);
$VertexDescriptionInputs.ViewSpaceNormal: output.ViewSpaceNormal = TransformWorldToViewDir(output.WorldSpaceNormal);
$VertexDescriptionInputs.TangentSpaceNormal: output.TangentSpaceNormal = float3(0.0f, 0.0f, 1.0f);
$VertexDescriptionInputs.ObjectSpaceTangent: output.ObjectSpaceTangent = input.tangentOS.xyz;
$VertexDescriptionInputs.WorldSpaceTangent: output.WorldSpaceTangent = TransformObjectToWorldDir(input.tangentOS.xyz);
$VertexDescriptionInputs.ViewSpaceTangent: output.ViewSpaceTangent = TransformWorldToViewDir(output.WorldSpaceTangent);
$VertexDescriptionInputs.TangentSpaceTangent: output.TangentSpaceTangent = float3(1.0f, 0.0f, 0.0f);
$VertexDescriptionInputs.ObjectSpaceBiTangent: output.ObjectSpaceBiTangent = normalize(cross(input.normalOS, input.tangentOS.xyz) * (input.tangentOS.w > 0.0f ? 1.0f : -1.0f) * GetOddNegativeScale());
$VertexDescriptionInputs.WorldSpaceBiTangent: output.WorldSpaceBiTangent = TransformObjectToWorldDir(output.ObjectSpaceBiTangent);
$VertexDescriptionInputs.ViewSpaceBiTangent: output.ViewSpaceBiTangent = TransformWorldToViewDir(output.WorldSpaceBiTangent);
$VertexDescriptionInputs.TangentSpaceBiTangent: output.TangentSpaceBiTangent = float3(0.0f, 1.0f, 0.0f);
$VertexDescriptionInputs.ObjectSpacePosition: output.ObjectSpacePosition = input.positionOS;
$VertexDescriptionInputs.WorldSpacePosition: output.WorldSpacePosition = TransformObjectToWorld(input.positionOS);
$VertexDescriptionInputs.ViewSpacePosition: output.ViewSpacePosition = TransformWorldToView(output.WorldSpacePosition);
$VertexDescriptionInputs.TangentSpacePosition: output.TangentSpacePosition = float3(0.0f, 0.0f, 0.0f);
$VertexDescriptionInputs.AbsoluteWorldSpacePosition: output.AbsoluteWorldSpacePosition = GetAbsolutePositionWS(TransformObjectToWorld(input.positionOS));
$VertexDescriptionInputs.ObjectSpacePositionPredisplacement: output.ObjectSpacePositionPredisplacement = input.positionOS;
$VertexDescriptionInputs.WorldSpacePositionPredisplacement: output.WorldSpacePositionPredisplacement = TransformObjectToWorld(input.positionOS);
$VertexDescriptionInputs.ViewSpacePositionPredisplacement: output.ViewSpacePositionPredisplacement = TransformWorldToView(output.WorldSpacePosition);
$VertexDescriptionInputs.TangentSpacePositionPredisplacement: output.TangentSpacePositionPredisplacement = float3(0.0f, 0.0f, 0.0f);
$VertexDescriptionInputs.AbsoluteWorldSpacePositionPredisplacement: output.AbsoluteWorldSpacePositionPredisplacement = GetAbsolutePositionWS(TransformObjectToWorld(input.positionOS));
$VertexDescriptionInputs.WorldSpaceViewDirection: output.WorldSpaceViewDirection = GetWorldSpaceNormalizeViewDir(output.WorldSpacePosition);
$VertexDescriptionInputs.ObjectSpaceViewDirection: output.ObjectSpaceViewDirection = TransformWorldToObjectDir(output.WorldSpaceViewDirection);
$VertexDescriptionInputs.ViewSpaceViewDirection: output.ViewSpaceViewDirection = TransformWorldToViewDir(output.WorldSpaceViewDirection);
$VertexDescriptionInputs.TangentSpaceViewDirection: float3x3 tangentSpaceTransform = float3x3(output.WorldSpaceTangent,output.WorldSpaceBiTangent,output.WorldSpaceNormal);
$VertexDescriptionInputs.TangentSpaceViewDirection: output.TangentSpaceViewDirection = TransformWorldToTangent(output.WorldSpaceViewDirection, tangentSpaceTransform);
$VertexDescriptionInputs.ScreenPosition: output.ScreenPosition = ComputeScreenPos(TransformWorldToHClip(output.WorldSpacePosition), _ProjectionParams.x);
$VertexDescriptionInputs.NDCPosition: output.NDCPosition = output.ScreenPosition.xy / output.ScreenPosition.w;
$VertexDescriptionInputs.PixelPosition: output.PixelPosition = float2(output.NDCPosition.x, 1.0f - output.NDCPosition.y) * _ScreenParams.xy;
$VertexDescriptionInputs.uv0: output.uv0 = input.uv0;
$VertexDescriptionInputs.uv1: output.uv1 = input.uv1;
$VertexDescriptionInputs.uv2: output.uv2 = input.uv2;
$VertexDescriptionInputs.uv3: output.uv3 = input.uv3;
$VertexDescriptionInputs.VertexColor: output.VertexColor = input.color;
$VertexDescriptionInputs.TimeParameters: output.TimeParameters = _TimeParameters.xyz;
$VertexDescriptionInputs.BoneWeights: output.BoneWeights = input.weights;
$VertexDescriptionInputs.BoneIndices: output.BoneIndices = input.indices;
$VertexDescriptionInputs.VertexID: output.VertexID = input.vertexID;
return output;
}
void TerrainVaryingGeneration(inout Attributes input, inout Varyings output)
{
float4 positionOS = float4(input.positionOS, 1.0);
#if defined(VARYINGS_NEED_TEXCOORD0) && defined(ATTRIBUTES_NEED_NORMAL)
TerrainInstancing(positionOS, input.normalOS, input.uv0.xy);
#elif defined(VARYINGS_NEED_TEXCOORD0)
float3 normal = float3(0, 0, 0);
TerrainInstancing(positionOS, normal, input.uv0.xy);
#elif defined(ATTRIBUTES_NEED_NORMAL)
TerrainInstancing(positionOS, input.normalOS);
#else
TerrainInstancing(positionOS);
#endif
input.positionOS = positionOS.xyz;
#if defined(VARYINGS_NEED_TEXCOORD0) && defined(UNIVERSAL_TERRAIN_SPLAT01)
output.uvSplat01.xy = TRANSFORM_TEX(input.uv0, _Splat0);
output.uvSplat01.zw = TRANSFORM_TEX(input.uv0, _Splat1);
#endif
#if defined(VARYINGS_NEED_TEXCOORD0) && defined(UNIVERSAL_TERRAIN_SPLAT23)
output.uvSplat23.xy = TRANSFORM_TEX(input.uv0, _Splat2);
output.uvSplat23.zw = TRANSFORM_TEX(input.uv0, _Splat3);
#endif
}
float4 ConstructTerrainTangent(float3 normal, float3 positiveZ)
{
// Consider a flat terrain. It should have tangent be (1, 0, 0) and bitangent be (0, 0, 1) as the UV of the terrain grid mesh is a scale of the world XZ position.
// In CreateTangentToWorld function (in SpaceTransform.hlsl), it is cross(normal, tangent) * sgn for the bitangent vector.
// It is not true in a left-handed coordinate system for the terrain bitangent, if we provide 1 as the tangent.w. It would produce (0, 0, -1) instead of (0, 0, 1).
// Also terrain's tangent calculation was wrong in a left handed system because cross((0,0,1), terrainNormalOS) points to the wrong direction as negative X.
// Therefore all the 4 xyzw components of the tangent needs to be flipped to correct the tangent frame.
// (See TerrainLitData.hlsl - GetSurfaceAndBuiltinData)
float3 tangent = cross(normal, positiveZ);
return float4(tangent, -1);
}