forked from bartvdbraak/blender
414 lines
13 KiB
C
414 lines
13 KiB
C
/*
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* Adapted from code Copyright 2009-2010 NVIDIA Corporation
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* Modifications Copyright 2011, Blender Foundation.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/* Triangle Primitive
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*
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* Basic triangle with 3 vertices is used to represent mesh surfaces. For BVH
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* ray intersection we use a precomputed triangle storage to accelerate
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* intersection at the cost of more memory usage */
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CCL_NAMESPACE_BEGIN
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/* Refine triangle intersection to more precise hit point. For rays that travel
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* far the precision is often not so good, this reintersects the primitive from
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* a closer distance. */
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ccl_device_inline float3 triangle_refine(KernelGlobals *kg, ShaderData *sd, const Intersection *isect, const Ray *ray)
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{
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float3 P = ray->P;
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float3 D = ray->D;
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float t = isect->t;
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#ifdef __INTERSECTION_REFINE__
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if(isect->object != OBJECT_NONE) {
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#ifdef __OBJECT_MOTION__
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Transform tfm = sd->ob_itfm;
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#else
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Transform tfm = object_fetch_transform(kg, isect->object, OBJECT_INVERSE_TRANSFORM);
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#endif
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P = transform_point(&tfm, P);
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D = transform_direction(&tfm, D*t);
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D = normalize_len(D, &t);
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}
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P = P + D*t;
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float4 v00 = kernel_tex_fetch(__tri_woop, isect->prim*TRI_NODE_SIZE+0);
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float Oz = v00.w - P.x*v00.x - P.y*v00.y - P.z*v00.z;
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float invDz = 1.0f/(D.x*v00.x + D.y*v00.y + D.z*v00.z);
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float rt = Oz * invDz;
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P = P + D*rt;
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if(isect->object != OBJECT_NONE) {
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#ifdef __OBJECT_MOTION__
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Transform tfm = sd->ob_tfm;
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#else
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Transform tfm = object_fetch_transform(kg, isect->object, OBJECT_TRANSFORM);
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#endif
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P = transform_point(&tfm, P);
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}
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return P;
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#else
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return P + D*t;
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#endif
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}
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/* same as above, except that isect->t is assumed to be in object space for instancing */
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ccl_device_inline float3 triangle_refine_subsurface(KernelGlobals *kg, ShaderData *sd, const Intersection *isect, const Ray *ray)
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{
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float3 P = ray->P;
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float3 D = ray->D;
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float t = isect->t;
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#ifdef __INTERSECTION_REFINE__
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if(isect->object != OBJECT_NONE) {
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#ifdef __OBJECT_MOTION__
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Transform tfm = sd->ob_itfm;
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#else
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Transform tfm = object_fetch_transform(kg, isect->object, OBJECT_INVERSE_TRANSFORM);
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#endif
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P = transform_point(&tfm, P);
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D = transform_direction(&tfm, D);
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D = normalize(D);
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}
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P = P + D*t;
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float4 v00 = kernel_tex_fetch(__tri_woop, isect->prim*TRI_NODE_SIZE+0);
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float Oz = v00.w - P.x*v00.x - P.y*v00.y - P.z*v00.z;
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float invDz = 1.0f/(D.x*v00.x + D.y*v00.y + D.z*v00.z);
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float rt = Oz * invDz;
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P = P + D*rt;
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if(isect->object != OBJECT_NONE) {
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#ifdef __OBJECT_MOTION__
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Transform tfm = sd->ob_tfm;
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#else
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Transform tfm = object_fetch_transform(kg, isect->object, OBJECT_TRANSFORM);
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#endif
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P = transform_point(&tfm, P);
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}
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return P;
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#else
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return P + D*t;
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#endif
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}
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/* normal on triangle */
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ccl_device_inline float3 triangle_normal(KernelGlobals *kg, ShaderData *sd)
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{
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/* load triangle vertices */
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float4 tri_vindex = kernel_tex_fetch(__tri_vindex, sd->prim);
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float3 v0 = float4_to_float3(kernel_tex_fetch(__tri_verts, __float_as_int(tri_vindex.x)));
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float3 v1 = float4_to_float3(kernel_tex_fetch(__tri_verts, __float_as_int(tri_vindex.y)));
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float3 v2 = float4_to_float3(kernel_tex_fetch(__tri_verts, __float_as_int(tri_vindex.z)));
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/* return normal */
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if(sd->flag & SD_NEGATIVE_SCALE_APPLIED)
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return normalize(cross(v2 - v0, v1 - v0));
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else
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return normalize(cross(v1 - v0, v2 - v0));
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}
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/* point and normal on triangle */
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ccl_device_inline void triangle_point_normal(KernelGlobals *kg, int object, int prim, float u, float v, float3 *P, float3 *Ng, int *shader)
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{
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/* load triangle vertices */
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float4 tri_vindex = kernel_tex_fetch(__tri_vindex, prim);
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float3 v0 = float4_to_float3(kernel_tex_fetch(__tri_verts, __float_as_int(tri_vindex.x)));
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float3 v1 = float4_to_float3(kernel_tex_fetch(__tri_verts, __float_as_int(tri_vindex.y)));
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float3 v2 = float4_to_float3(kernel_tex_fetch(__tri_verts, __float_as_int(tri_vindex.z)));
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/* compute point */
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float t = 1.0f - u - v;
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*P = (u*v0 + v*v1 + t*v2);
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/* get object flags, instance-aware */
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int object_flag = kernel_tex_fetch(__object_flag, object >= 0 ? object : ~object);
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/* compute normal */
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if(object_flag & SD_NEGATIVE_SCALE_APPLIED)
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*Ng = normalize(cross(v2 - v0, v1 - v0));
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else
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*Ng = normalize(cross(v1 - v0, v2 - v0));
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/* shader`*/
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*shader = kernel_tex_fetch(__tri_shader, prim);
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}
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/* Triangle vertex locations */
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ccl_device_inline void triangle_vertices(KernelGlobals *kg, int prim, float3 P[3])
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{
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float4 tri_vindex = kernel_tex_fetch(__tri_vindex, prim);
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P[0] = float4_to_float3(kernel_tex_fetch(__tri_verts, __float_as_int(tri_vindex.x)));
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P[1] = float4_to_float3(kernel_tex_fetch(__tri_verts, __float_as_int(tri_vindex.y)));
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P[2] = float4_to_float3(kernel_tex_fetch(__tri_verts, __float_as_int(tri_vindex.z)));
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}
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/* Interpolate smooth vertex normal from vertices */
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ccl_device_inline float3 triangle_smooth_normal(KernelGlobals *kg, int prim, float u, float v)
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{
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/* load triangle vertices */
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float4 tri_vindex = kernel_tex_fetch(__tri_vindex, prim);
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float3 n0 = float4_to_float3(kernel_tex_fetch(__tri_vnormal, __float_as_int(tri_vindex.x)));
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float3 n1 = float4_to_float3(kernel_tex_fetch(__tri_vnormal, __float_as_int(tri_vindex.y)));
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float3 n2 = float4_to_float3(kernel_tex_fetch(__tri_vnormal, __float_as_int(tri_vindex.z)));
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return normalize((1.0f - u - v)*n2 + u*n0 + v*n1);
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}
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/* Ray differentials on triangle */
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ccl_device_inline void triangle_dPdudv(KernelGlobals *kg, int prim, float3 *dPdu, float3 *dPdv)
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{
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/* fetch triangle vertex coordinates */
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float4 tri_vindex = kernel_tex_fetch(__tri_vindex, prim);
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float3 p0 = float4_to_float3(kernel_tex_fetch(__tri_verts, __float_as_int(tri_vindex.x)));
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float3 p1 = float4_to_float3(kernel_tex_fetch(__tri_verts, __float_as_int(tri_vindex.y)));
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float3 p2 = float4_to_float3(kernel_tex_fetch(__tri_verts, __float_as_int(tri_vindex.z)));
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/* compute derivatives of P w.r.t. uv */
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*dPdu = (p0 - p2);
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*dPdv = (p1 - p2);
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}
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/* Reading attributes on various triangle elements */
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ccl_device float triangle_attribute_float(KernelGlobals *kg, const ShaderData *sd, AttributeElement elem, int offset, float *dx, float *dy)
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{
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if(elem == ATTR_ELEMENT_FACE) {
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if(dx) *dx = 0.0f;
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if(dy) *dy = 0.0f;
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return kernel_tex_fetch(__attributes_float, offset + sd->prim);
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}
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else if(elem == ATTR_ELEMENT_VERTEX || elem == ATTR_ELEMENT_VERTEX_MOTION) {
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float4 tri_vindex = kernel_tex_fetch(__tri_vindex, sd->prim);
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float f0 = kernel_tex_fetch(__attributes_float, offset + __float_as_int(tri_vindex.x));
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float f1 = kernel_tex_fetch(__attributes_float, offset + __float_as_int(tri_vindex.y));
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float f2 = kernel_tex_fetch(__attributes_float, offset + __float_as_int(tri_vindex.z));
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#ifdef __RAY_DIFFERENTIALS__
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if(dx) *dx = sd->du.dx*f0 + sd->dv.dx*f1 - (sd->du.dx + sd->dv.dx)*f2;
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if(dy) *dy = sd->du.dy*f0 + sd->dv.dy*f1 - (sd->du.dy + sd->dv.dy)*f2;
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#endif
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return sd->u*f0 + sd->v*f1 + (1.0f - sd->u - sd->v)*f2;
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}
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else if(elem == ATTR_ELEMENT_CORNER) {
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int tri = offset + sd->prim*3;
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float f0 = kernel_tex_fetch(__attributes_float, tri + 0);
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float f1 = kernel_tex_fetch(__attributes_float, tri + 1);
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float f2 = kernel_tex_fetch(__attributes_float, tri + 2);
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#ifdef __RAY_DIFFERENTIALS__
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if(dx) *dx = sd->du.dx*f0 + sd->dv.dx*f1 - (sd->du.dx + sd->dv.dx)*f2;
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if(dy) *dy = sd->du.dy*f0 + sd->dv.dy*f1 - (sd->du.dy + sd->dv.dy)*f2;
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#endif
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return sd->u*f0 + sd->v*f1 + (1.0f - sd->u - sd->v)*f2;
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}
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else {
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if(dx) *dx = 0.0f;
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if(dy) *dy = 0.0f;
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return 0.0f;
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}
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}
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ccl_device float3 triangle_attribute_float3(KernelGlobals *kg, const ShaderData *sd, AttributeElement elem, int offset, float3 *dx, float3 *dy)
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{
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if(elem == ATTR_ELEMENT_FACE) {
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if(dx) *dx = make_float3(0.0f, 0.0f, 0.0f);
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if(dy) *dy = make_float3(0.0f, 0.0f, 0.0f);
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return float4_to_float3(kernel_tex_fetch(__attributes_float3, offset + sd->prim));
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}
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else if(elem == ATTR_ELEMENT_VERTEX || elem == ATTR_ELEMENT_VERTEX_MOTION) {
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float4 tri_vindex = kernel_tex_fetch(__tri_vindex, sd->prim);
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float3 f0 = float4_to_float3(kernel_tex_fetch(__attributes_float3, offset + __float_as_int(tri_vindex.x)));
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float3 f1 = float4_to_float3(kernel_tex_fetch(__attributes_float3, offset + __float_as_int(tri_vindex.y)));
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float3 f2 = float4_to_float3(kernel_tex_fetch(__attributes_float3, offset + __float_as_int(tri_vindex.z)));
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#ifdef __RAY_DIFFERENTIALS__
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if(dx) *dx = sd->du.dx*f0 + sd->dv.dx*f1 - (sd->du.dx + sd->dv.dx)*f2;
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if(dy) *dy = sd->du.dy*f0 + sd->dv.dy*f1 - (sd->du.dy + sd->dv.dy)*f2;
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#endif
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return sd->u*f0 + sd->v*f1 + (1.0f - sd->u - sd->v)*f2;
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}
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else if(elem == ATTR_ELEMENT_CORNER || elem == ATTR_ELEMENT_CORNER_BYTE) {
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int tri = offset + sd->prim*3;
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float3 f0, f1, f2;
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if(elem == ATTR_ELEMENT_CORNER) {
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f0 = float4_to_float3(kernel_tex_fetch(__attributes_float3, tri + 0));
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f1 = float4_to_float3(kernel_tex_fetch(__attributes_float3, tri + 1));
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f2 = float4_to_float3(kernel_tex_fetch(__attributes_float3, tri + 2));
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}
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else {
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f0 = color_byte_to_float(kernel_tex_fetch(__attributes_uchar4, tri + 0));
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f1 = color_byte_to_float(kernel_tex_fetch(__attributes_uchar4, tri + 1));
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f2 = color_byte_to_float(kernel_tex_fetch(__attributes_uchar4, tri + 2));
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}
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#ifdef __RAY_DIFFERENTIALS__
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if(dx) *dx = sd->du.dx*f0 + sd->dv.dx*f1 - (sd->du.dx + sd->dv.dx)*f2;
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if(dy) *dy = sd->du.dy*f0 + sd->dv.dy*f1 - (sd->du.dy + sd->dv.dy)*f2;
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#endif
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return sd->u*f0 + sd->v*f1 + (1.0f - sd->u - sd->v)*f2;
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}
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else {
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if(dx) *dx = make_float3(0.0f, 0.0f, 0.0f);
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if(dy) *dy = make_float3(0.0f, 0.0f, 0.0f);
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return make_float3(0.0f, 0.0f, 0.0f);
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}
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}
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/* Ray-Triangle intersection for BVH traversal
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*
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* Based on Sven Woop's algorithm with precomputed triangle storage */
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ccl_device_inline bool triangle_intersect(KernelGlobals *kg, Intersection *isect,
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float3 P, float3 dir, uint visibility, int object, int triAddr)
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{
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/* compute and check intersection t-value */
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float4 v00 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+0);
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float4 v11 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+1);
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float Oz = v00.w - P.x*v00.x - P.y*v00.y - P.z*v00.z;
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float invDz = 1.0f/(dir.x*v00.x + dir.y*v00.y + dir.z*v00.z);
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float t = Oz * invDz;
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if(t > 0.0f && t < isect->t) {
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/* compute and check barycentric u */
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float Ox = v11.w + P.x*v11.x + P.y*v11.y + P.z*v11.z;
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float Dx = dir.x*v11.x + dir.y*v11.y + dir.z*v11.z;
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float u = Ox + t*Dx;
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if(u >= 0.0f) {
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/* compute and check barycentric v */
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float4 v22 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+2);
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float Oy = v22.w + P.x*v22.x + P.y*v22.y + P.z*v22.z;
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float Dy = dir.x*v22.x + dir.y*v22.y + dir.z*v22.z;
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float v = Oy + t*Dy;
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if(v >= 0.0f && u + v <= 1.0f) {
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#ifdef __VISIBILITY_FLAG__
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/* visibility flag test. we do it here under the assumption
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* that most triangles are culled by node flags */
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if(kernel_tex_fetch(__prim_visibility, triAddr) & visibility)
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#endif
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{
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/* record intersection */
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isect->t = t;
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isect->u = u;
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isect->v = v;
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isect->prim = triAddr;
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isect->object = object;
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isect->type = PRIMITIVE_TRIANGLE;
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return true;
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}
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}
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}
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}
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return false;
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}
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/* Special ray intersection routines for subsurface scattering. In that case we
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* only want to intersect with primitives in the same object, and if case of
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* multiple hits we pick a single random primitive as the intersection point. */
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#ifdef __SUBSURFACE__
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ccl_device_inline void triangle_intersect_subsurface(KernelGlobals *kg, Intersection *isect_array,
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float3 P, float3 dir, int object, int triAddr, float tmax, uint *num_hits, uint *lcg_state, int max_hits)
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{
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/* compute and check intersection t-value */
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float4 v00 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+0);
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float4 v11 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+1);
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float Oz = v00.w - P.x*v00.x - P.y*v00.y - P.z*v00.z;
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float invDz = 1.0f/(dir.x*v00.x + dir.y*v00.y + dir.z*v00.z);
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float t = Oz * invDz;
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if(t > 0.0f && t < tmax) {
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/* compute and check barycentric u */
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float Ox = v11.w + P.x*v11.x + P.y*v11.y + P.z*v11.z;
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float Dx = dir.x*v11.x + dir.y*v11.y + dir.z*v11.z;
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float u = Ox + t*Dx;
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if(u >= 0.0f) {
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/* compute and check barycentric v */
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float4 v22 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+2);
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float Oy = v22.w + P.x*v22.x + P.y*v22.y + P.z*v22.z;
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float Dy = dir.x*v22.x + dir.y*v22.y + dir.z*v22.z;
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float v = Oy + t*Dy;
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if(v >= 0.0f && u + v <= 1.0f) {
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(*num_hits)++;
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int hit;
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if(*num_hits <= max_hits) {
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hit = *num_hits - 1;
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}
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else {
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/* reservoir sampling: if we are at the maximum number of
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* hits, randomly replace element or skip it */
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hit = lcg_step_uint(lcg_state) % *num_hits;
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if(hit >= max_hits)
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return;
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}
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/* record intersection */
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Intersection *isect = &isect_array[hit];
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isect->t = t;
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isect->u = u;
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isect->v = v;
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isect->prim = triAddr;
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isect->object = object;
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isect->type = PRIMITIVE_TRIANGLE;
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}
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}
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}
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}
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#endif
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CCL_NAMESPACE_END
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