163 lines
4.2 KiB
C
163 lines
4.2 KiB
C
/*
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* Copyright 2011-2013 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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#pragma once
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CCL_NAMESPACE_BEGIN
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/* Ray offset to avoid self intersection.
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*
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* This function should be used to compute a modified ray start position for
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* rays leaving from a surface. */
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ccl_device_inline float3 ray_offset(float3 P, float3 Ng)
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{
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#ifdef __INTERSECTION_REFINE__
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const float epsilon_f = 1e-5f;
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/* ideally this should match epsilon_f, but instancing and motion blur
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* precision makes it problematic */
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const float epsilon_test = 1.0f;
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const int epsilon_i = 32;
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float3 res;
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/* x component */
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if (fabsf(P.x) < epsilon_test) {
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res.x = P.x + Ng.x * epsilon_f;
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}
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else {
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uint ix = __float_as_uint(P.x);
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ix += ((ix ^ __float_as_uint(Ng.x)) >> 31) ? -epsilon_i : epsilon_i;
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res.x = __uint_as_float(ix);
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}
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/* y component */
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if (fabsf(P.y) < epsilon_test) {
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res.y = P.y + Ng.y * epsilon_f;
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}
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else {
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uint iy = __float_as_uint(P.y);
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iy += ((iy ^ __float_as_uint(Ng.y)) >> 31) ? -epsilon_i : epsilon_i;
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res.y = __uint_as_float(iy);
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}
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/* z component */
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if (fabsf(P.z) < epsilon_test) {
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res.z = P.z + Ng.z * epsilon_f;
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}
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else {
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uint iz = __float_as_uint(P.z);
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iz += ((iz ^ __float_as_uint(Ng.z)) >> 31) ? -epsilon_i : epsilon_i;
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res.z = __uint_as_float(iz);
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}
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return res;
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#else
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const float epsilon_f = 1e-4f;
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return P + epsilon_f * Ng;
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#endif
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}
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#if defined(__VOLUME_RECORD_ALL__) || (defined(__SHADOW_RECORD_ALL__) && defined(__KERNEL_CPU__))
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/* ToDo: Move to another file? */
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ccl_device int intersections_compare(const void *a, const void *b)
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{
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const Intersection *isect_a = (const Intersection *)a;
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const Intersection *isect_b = (const Intersection *)b;
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if (isect_a->t < isect_b->t)
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return -1;
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else if (isect_a->t > isect_b->t)
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return 1;
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else
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return 0;
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}
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#endif
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#if defined(__SHADOW_RECORD_ALL__)
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ccl_device_inline void sort_intersections(Intersection *hits, uint num_hits)
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{
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kernel_assert(num_hits > 0);
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# ifdef __KERNEL_GPU__
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/* Use bubble sort which has more friendly memory pattern on GPU. */
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bool swapped;
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do {
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swapped = false;
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for (int j = 0; j < num_hits - 1; ++j) {
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if (hits[j].t > hits[j + 1].t) {
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struct Intersection tmp = hits[j];
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hits[j] = hits[j + 1];
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hits[j + 1] = tmp;
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swapped = true;
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}
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}
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--num_hits;
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} while (swapped);
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# else
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qsort(hits, num_hits, sizeof(Intersection), intersections_compare);
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# endif
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}
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#endif /* __SHADOW_RECORD_ALL__ | __VOLUME_RECORD_ALL__ */
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/* Utility to quickly get a shader flags from an intersection. */
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ccl_device_forceinline int intersection_get_shader_flags(KernelGlobals *ccl_restrict kg,
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const Intersection *isect)
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{
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const int prim = kernel_tex_fetch(__prim_index, isect->prim);
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int shader = 0;
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#ifdef __HAIR__
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if (kernel_tex_fetch(__prim_type, isect->prim) & PRIMITIVE_ALL_TRIANGLE)
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#endif
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{
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shader = kernel_tex_fetch(__tri_shader, prim);
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}
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#ifdef __HAIR__
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else {
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float4 str = kernel_tex_fetch(__curves, prim);
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shader = __float_as_int(str.z);
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}
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#endif
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return kernel_tex_fetch(__shaders, (shader & SHADER_MASK)).flags;
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}
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ccl_device_forceinline int intersection_get_shader(KernelGlobals *ccl_restrict kg,
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const Intersection *isect)
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{
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const int prim = kernel_tex_fetch(__prim_index, isect->prim);
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int shader = 0;
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#ifdef __HAIR__
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if (kernel_tex_fetch(__prim_type, isect->prim) & PRIMITIVE_ALL_TRIANGLE)
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#endif
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{
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shader = kernel_tex_fetch(__tri_shader, prim);
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}
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#ifdef __HAIR__
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else {
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float4 str = kernel_tex_fetch(__curves, prim);
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shader = __float_as_int(str.z);
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}
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#endif
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return shader & SHADER_MASK;
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}
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CCL_NAMESPACE_END
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