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VertexDescriptionInputs AttributesMeshToVertexDescriptionInputs(AttributesMesh 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.xyz, 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).xyz);
$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).xyz);
$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; // Note: in case of animation this will be overwrite (allow to handle motion vector)
$VertexDescriptionInputs.BoneWeights: output.BoneWeights = input.weights;
$VertexDescriptionInputs.BoneIndices: output.BoneIndices = input.indices;
$VertexDescriptionInputs.VertexID: output.VertexID = input.vertexID;
return output;
}
VertexDescription GetVertexDescription(AttributesMesh input, float3 timeParameters)
{
// build graph inputs
VertexDescriptionInputs vertexDescriptionInputs = AttributesMeshToVertexDescriptionInputs(input);
// Override time parameters with used one (This is required to correctly handle motion vector for vertex animation based on time)
$VertexDescriptionInputs.TimeParameters: vertexDescriptionInputs.TimeParameters = timeParameters;
VertexDescription vertexDescription = VertexDescriptionFunction(vertexDescriptionInputs);
return vertexDescription;
}
// Vertex height displacement
#ifdef HAVE_MESH_MODIFICATION
UNITY_INSTANCING_BUFFER_START(Terrain)
UNITY_DEFINE_INSTANCED_PROP(float4, _TerrainPatchInstanceData) // float4(xBase, yBase, skipScale, ~)
UNITY_INSTANCING_BUFFER_END(Terrain)
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);
}
AttributesMesh ApplyMeshModification(AttributesMesh input, float3 timeParameters
#ifdef USE_CUSTOMINTERP_SUBSTRUCT
, inout VaryingsMeshToPS varyings
#endif
)
{
#ifdef UNITY_INSTANCING_ENABLED
float2 patchVertex = input.positionOS.xy;
float4 instanceData = UNITY_ACCESS_INSTANCED_PROP(Terrain, _TerrainPatchInstanceData);
float2 sampleCoords = (patchVertex.xy + instanceData.xy) * instanceData.z; // (xy + float2(xBase,yBase)) * skipScale
float height = UnpackHeightmap(_TerrainHeightmapTexture.Load(int3(sampleCoords, 0)));
input.positionOS.xz = sampleCoords * _TerrainHeightmapScale.xz;
input.positionOS.y = height * _TerrainHeightmapScale.y;
#if defined(ATTRIBUTES_NEED_NORMAL) && !defined(ENABLE_TERRAIN_PERPIXEL_NORMAL)
input.normalOS = _TerrainNormalmapTexture.Load(int3(sampleCoords.xy, 0)).rgb * 2.0 - 1.0;
#endif
#ifdef ATTRIBUTES_NEED_TEXCOORD0
#ifdef ENABLE_TERRAIN_PERPIXEL_NORMAL
input.uv0.xy = sampleCoords;
#else
input.uv0.xy = sampleCoords * _TerrainHeightmapRecipSize.zw;
#endif
#endif
#endif
VertexDescription vertexDescription = GetVertexDescription(input, timeParameters);
// copy graph output to the results
$VertexDescription.Position: input.positionOS = vertexDescription.Position;
$VertexDescription.Normal: input.normalOS = vertexDescription.Normal;
$VertexDescription.uv0: input.uv0 = vertexDescription.uv0;
return input;
}
#endif // HAVE_MESH_MODIFICATION
FragInputs BuildFragInputs(VaryingsMeshToPS input)
{
FragInputs output;
ZERO_INITIALIZE(FragInputs, output);
// Init to some default value to make the computer quiet (else it output 'divide by zero' warning even if value is not used).
// TODO: this is a really poor workaround, but the variable is used in a bunch of places
// to compute normals which are then passed on elsewhere to compute other values...
output.tangentToWorld = k_identity3x3;
output.positionSS = input.positionCS; // input.positionCS is SV_Position
#ifdef ENABLE_TERRAIN_PERPIXEL_NORMAL
// it will be reconstructed in fragment stage
$FragInputs.tangentToWorld: float3x3 tangentToWorld = k_identity3x3;
#else
$FragInputs.tangentToWorld: float3 normalWS = input.normalWS;
$FragInputs.tangentToWorld: float3 normalOS = TransformWorldToObjectNormal(normalWS);
$FragInputs.tangentToWorld: float4 tangentOS = ConstructTerrainTangent(normalOS, float3(0.0, 0.0, 1.0));
$FragInputs.tangentToWorld: float4 tangentWS = float4(TransformObjectToWorldNormal(tangentOS.xyz), 0.0);
$FragInputs.tangentToWorld: float3x3 tangentToWorld = BuildTangentToWorld(tangentWS, normalWS);
#endif
$FragInputs.positionRWS: output.positionRWS = input.positionRWS;
$FragInputs.positionPixel: output.positionPixel = input.positionCS.xy; // NOTE: this is not actually in clip space, it is the VPOS pixel coordinate value
$FragInputs.positionPredisplacementRWS: output.positionPredisplacementRWS = input.positionPredisplacementRWS;
$FragInputs.tangentToWorld: output.tangentToWorld = tangentToWorld;
$FragInputs.texCoord0: output.texCoord0 = input.texCoord0;
$FragInputs.color: output.color = input.color;
// splice point to copy custom interpolator fields from varyings to frag inputs
$splice(CustomInterpolatorVaryingsToFragInputs)
return output;
}
// existing HDRP code uses the combined function to go directly from packed to frag inputs
FragInputs UnpackVaryingsMeshToFragInputs(PackedVaryingsMeshToPS input)
{
UNITY_SETUP_INSTANCE_ID(input);
VaryingsMeshToPS unpacked = UnpackVaryingsMeshToPS(input);
return BuildFragInputs(unpacked);
}