OpenSubdiv/opensubdiv/osd/mtlPatchGregory.metal

#line 0 "osd/mtlPatchGregory.metal"

//
//   Copyright 2013 Pixar
//
//   Licensed under the Apache License, Version 2.0 (the "Apache License")
//   with the following modification; you may not use this file except in
//   compliance with the Apache License and the following modification to it:
//   Section 6. Trademarks. is deleted and replaced with:
//
//   6. Trademarks. This License does not grant permission to use the trade
//      names, trademarks, service marks, or product names of the Licensor
//      and its affiliates, except as required to comply with Section 4(c) of
//      the License and to reproduce the content of the NOTICE file.
//
//   You may obtain a copy of the Apache License at
//
//       http://www.apache.org/licenses/LICENSE-2.0
//
//   Unless required by applicable law or agreed to in writing, software
//   distributed under the Apache License with the above modification is
//   distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
//   KIND, either express or implied. See the Apache License for the specific
//   language governing permissions and limitations under the Apache License.
//

//----------------------------------------------------------
// Patches.Gregory.Hull
//----------------------------------------------------------

void OsdComputePerVertex(
	float4 position,
    threadgroup OsdPerVertexGregory& hullVertex,
    int vertexId,
    float4x4 modelViewProjectionMatrix,
    OsdPatchParamBufferSet osdBuffers
    )
{
	OsdComputePerVertexGregory(vertexId, position.xyz, hullVertex, osdBuffers);

#if OSD_ENABLE_PATCH_CULL
    float4 clipPos = mul(modelViewProjectionMatrix, position);    
    short3 clip0 = short3(clipPos.x < clipPos.w,                    
    clipPos.y < clipPos.w,                    
    clipPos.z < clipPos.w);                   
    short3 clip1 = short3(clipPos.x > -clipPos.w,                   
    clipPos.y > -clipPos.w,                   
    clipPos.z > -clipPos.w);                  
    hullVertex.clipFlag = short3(clip0) + 2*short3(clip1);
#endif
}

//----------------------------------------------------------
// Patches.Gregory.Factors
//----------------------------------------------------------

void OsdComputePerPatchFactors(
	int3 patchParam,
	float tessLevel,
	unsigned patchID,
	float4x4 projectionMatrix,
	float4x4 modelViewMatrix,
	OsdPatchParamBufferSet osdBuffer,
	threadgroup PatchVertexType* patchVertices,
	device MTLQuadTessellationFactorsHalf& quadFactors
	)
{
    float4 tessLevelOuter = float4(0,0,0,0);
    float2 tessLevelInner = float2(0,0);

	OsdGetTessLevels(
 		tessLevel, 
 		projectionMatrix, 
 		modelViewMatrix,
		patchVertices[0].P, 
		patchVertices[3].P, 
		patchVertices[2].P, 
		patchVertices[1].P,
		patchParam, 
		tessLevelOuter, 
		tessLevelInner
		);

    quadFactors.edgeTessellationFactor[0] = tessLevelOuter[0];
    quadFactors.edgeTessellationFactor[1] = tessLevelOuter[1];
    quadFactors.edgeTessellationFactor[2] = tessLevelOuter[2];
    quadFactors.edgeTessellationFactor[3] = tessLevelOuter[3];
    quadFactors.insideTessellationFactor[0] = tessLevelInner[0];
    quadFactors.insideTessellationFactor[1] = tessLevelInner[1];
}

//----------------------------------------------------------
// Patches.Gregory.Vertex
//----------------------------------------------------------

void OsdComputePerPatchVertex(
	int3 patchParam, 
	unsigned ID, 
	unsigned PrimitiveID, 
	unsigned ControlID,
	threadgroup PatchVertexType* patchVertices,
	OsdPatchParamBufferSet osdBuffers
	)
{
	OsdComputePerPatchVertexGregory(
		patchParam,
		ID,
		PrimitiveID,
		patchVertices,
		osdBuffers.perPatchVertexBuffer[ControlID],
		osdBuffers);
}

//----------------------------------------------------------
// Patches.Gregory.Domain
//----------------------------------------------------------

template<typename PerPatchVertexGregory>
OsdPatchVertex ds_gregory_patches(
                     PerPatchVertexGregory patch,
                     int3 patchParam,
                     float2 UV
                    )
{
    OsdPatchVertex output;
    
    float3 P = float3(0,0,0), dPu = float3(0,0,0), dPv = float3(0,0,0);
    float3 N = float3(0,0,0), dNu = float3(0,0,0), dNv = float3(0,0,0);
    
    float3 cv[20];
    cv[0] = patch[0].P;
    cv[1] = patch[0].Ep;
    cv[2] = patch[0].Em;
    cv[3] = patch[0].Fp;
    cv[4] = patch[0].Fm;
    
    cv[5] = patch[1].P;
    cv[6] = patch[1].Ep;
    cv[7] = patch[1].Em;
    cv[8] = patch[1].Fp;
    cv[9] = patch[1].Fm;
    
    cv[10] = patch[2].P;
    cv[11] = patch[2].Ep;
    cv[12] = patch[2].Em;
    cv[13] = patch[2].Fp;
    cv[14] = patch[2].Fm;
    
    cv[15] = patch[3].P;
    cv[16] = patch[3].Ep;
    cv[17] = patch[3].Em;
    cv[18] = patch[3].Fp;
    cv[19] = patch[3].Fm;
    
    OsdEvalPatchGregory(patchParam, UV, cv, P, dPu, dPv, N, dNu, dNv);
    
    // all code below here is client code
    output.position = P;
    output.normal = N;
    output.tangent = dPu;
    output.bitangent = dPv;
#if OSD_COMPUTE_NORMAL_DERIVATIVES
    output.Nu = dNu;
    output.Nv = dNv;
#endif

    output.patchCoord = OsdInterpolatePatchCoord(UV, patchParam);
    
    return output;
}

#if USE_STAGE_IN
template<typename PerPatchVertexGregoryBasis>
#endif
OsdPatchVertex OsdComputePatch(
	float tessLevel,
	float2 domainCoord,
	unsigned patchID,
#if USE_STAGE_IN
	PerPatchVertexGregoryBasis osdPatch
#else
    OsdVertexBufferSet osdBuffers
#endif
	)
{
	return ds_gregory_patches(
#if USE_STAGE_IN
		osdPatch.cv,
		osdPatch.patchParam,
#else
        osdBuffers.perPatchVertexBuffer + patchID * VERTEX_CONTROL_POINTS_PER_PATCH,
        osdBuffers.patchParamBuffer[patchID],
#endif
		domainCoord);
}