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float3 GetVertexDisplacement(float3 positionWS, float3 normalWS, float2 texCoord0, float2 texCoord1, float2 texCoord2, float2 texCoord3, float4 vertexColor, float3 objectScale)
{
// This call will work for both LayeredLit and Lit shader
LayerTexCoord layerTexCoord;
ZERO_INITIALIZE(LayerTexCoord, layerTexCoord);
GetLayerTexCoord(texCoord0, texCoord1, texCoord2, texCoord3, positionWS, normalWS, layerTexCoord);
// TODO: do this algorithm for lod fetching as lod not available in vertex/domain shader
// http://www.sebastiansylvan.com/post/the-problem-with-tessellation-in-directx-11/
float lod = 0.0;
float height = ComputePerVertexDisplacement(layerTexCoord, vertexColor, lod);
float3 displ = height * normalWS;
// Applying scaling of the object if requested
displ *= objectScale;
return displ;
}
void ApplyVertexModification(AttributesMesh input, float3 normalWS, float3 objectScale, inout float3 positionWS)
{
// If tessellation is enabled we apply displacement map after tessellation
#if defined(_VERTEX_DISPLACEMENT) && !defined(TESSELLATION_ON)
positionWS += GetVertexDisplacement(positionWS, normalWS,
#ifdef ATTRIBUTES_NEED_TEXCOORD0
input.uv0,
#else
float2(0.0, 0.0),
#endif
#ifdef ATTRIBUTES_NEED_TEXCOORD1
input.uv1,
#else
float2(0.0, 0.0),
#endif
#ifdef ATTRIBUTES_NEED_TEXCOORD2
input.uv2,
#else
float2(0.0, 0.0),
#endif
#ifdef ATTRIBUTES_NEED_TEXCOORD3
input.uv3,
#else
float2(0.0, 0.0),
#endif
#ifdef ATTRIBUTES_NEED_COLOR
input.color,
#else
float4(0.0, 0.0, 0.0, 0.0),
#endif
objectScale);
#endif
#ifdef _VERTEX_WIND
float3 rootWP = mul(GetObjectToWorldMatrix(), float4(0, 0, 0, 1)).xyz;
ApplyWindDisplacement(positionWS, normalWS, rootWP, _Stiffness, _Drag, _ShiverDrag, _ShiverDirectionality, _InitialBend, input.color.a, _Time);
#endif
}
#ifdef TESSELLATION_ON
float4 GetTessellationFactors(float3 p0, float3 p1, float3 p2, float3 n0, float3 n1, float3 n2)
{
float maxDisplacement = GetMaxDisplacement();
// For tessellation we want to process tessellation factor always from the point of view of the camera (to be consistent and avoid Z-fight).
// For the culling part however we want to use the current view (shadow view).
// Thus the following code play with both.
#if defined(SHADERPASS) && (SHADERPASS != SHADERPASS_SHADOWS)
bool frustumCulledCurrentView = WorldViewFrustumCull(p0, p1, p2, maxDisplacement, (float4[4])_FrustumPlanes); // _FrustumPlanes are primary camera planes
bool frustumCulledMainView = false;
#else
bool frustumCulledCurrentView = WorldViewFrustumCull(p0, p1, p2, maxDisplacement, (float4[4])unity_CameraWorldClipPlanes); // unity_CameraWorldClipPlanes is set by legacy Unity in case of shadow and contain shadow view plan
// In the case of shadow, we don't want to tessellate anything that is not seen by the main view frustum. It can result in minor popping of tessellation into a shadow but we can't afford it anyway.
bool frustumCulledMainView = WorldViewFrustumCull(p0, p1, p2, maxDisplacement, (float4[4])_FrustumPlanes);
#endif
bool faceCull = false;
#ifndef _DOUBLESIDED_ON
// TODO: Handle inverse culling (for mirror)!
if (_TessellationBackFaceCullEpsilon > -0.99) // Is backface culling enabled ?
{
faceCull = BackFaceCullTriangle(p0, p1, p2, _TessellationBackFaceCullEpsilon, GetCurrentViewPosition()); // Use shadow view
}
#endif
if (frustumCulledCurrentView || faceCull)
{
// Settings factor to 0 will kill the triangle
return float4(0.0, 0.0, 0.0, 0.0);
}
// See comment above:
// During shadow passes, we decide that anything outside the main view frustum should not be tessellated.
if (frustumCulledMainView)
{
return float4(1.0, 1.0, 1.0, 1.0);
}
// We use the parameters of the primary (scene view) camera in order
// to have identical tessellation levels for both the scene view and
// shadow views. Otherwise, depth comparisons become meaningless!
float3 tessFactor = float3(1.0, 1.0, 1.0);
// Adaptive screen space tessellation
if (_TessellationFactorTriangleSize > 0.0)
{
// return a value between 0 and 1
tessFactor *= GetScreenSpaceTessFactor( p0, p1, p2, _ViewProjMatrix, _ScreenSize, _TessellationFactorTriangleSize); // Use primary camera view
}
// Distance based tessellation
if (_TessellationFactorMaxDistance > 0.0)
{
float3 distFactor = GetDistanceBasedTessFactor(p0, p1, p2, GetPrimaryCameraPosition(), _TessellationFactorMinDistance, _TessellationFactorMaxDistance); // Use primary camera view
// We square the disance factor as it allow a better percptual descrease of vertex density.
tessFactor *= distFactor * distFactor;
}
tessFactor *= _TessellationFactor;
// TessFactor below 1.0 have no effect. At 0 it kill the triangle, so clamp it to 1.0
tessFactor.xyz = float3(max(1.0, tessFactor.x), max(1.0, tessFactor.y), max(1.0, tessFactor.z));
return CalcTriEdgeTessFactors(tessFactor);
}
// tessellationFactors
// x - 1->2 edge
// y - 2->0 edge
// z - 0->1 edge
// w - inside tessellation factor
void ApplyTessellationModification(VaryingsMeshToDS input, float3 normalWS, float3 objectScale, inout float3 positionWS)
{
#if defined(_VERTEX_DISPLACEMENT)
positionWS += GetVertexDisplacement(positionWS, normalWS,
#ifdef VARYINGS_DS_NEED_TEXCOORD0
input.texCoord0,
#else
float2(0.0, 0.0),
#endif
#ifdef VARYINGS_DS_NEED_TEXCOORD1
input.texCoord1,
#else
float2(0.0, 0.0),
#endif
#ifdef VARYINGS_DS_NEED_TEXCOORD2
input.texCoord2,
#else
float2(0.0, 0.0),
#endif
#ifdef VARYINGS_DS_NEED_TEXCOORD3
input.texCoord3,
#else
float2(0.0, 0.0),
#endif
#ifdef VARYINGS_DS_NEED_COLOR
input.color,
#else
float4(0.0, 0.0, 0.0, 0.0),
#endif
objectScale);
#endif // _VERTEX_DISPLACEMENT
}
#endif // #ifdef TESSELLATION_ON