forked from bartvdbraak/blender
Brecht Van Lommel
7a92b8820b
This never really worked as it was supposed to. The main goal of this is to turn noise from sampling tiny hairs into multiple layers of transparency that do not need to be sampled stochastically. However the implementation of this worked by randomly discarding hair intersections in BVH traversal, which defeats the purpose. If it ever comes back, it's best implemented outside the kernel as a preprocess that changes hair radius before BVH building. This would also make it work with Embree, where it's not supported now. But it's not so clear anymore that with many AA samples and GPU rendering this feature is as helpful as it once was for CPU raytracers with few AA samples. The benefit of removing this feature is improved hair ray tracing performance, tested on NVIDIA Titan Xp: bmw27: +0.37% classroom: +0.26% fishy_cat: -7.36% koro: -12.98% pabellon: -0.12% Differential Revision: https://developer.blender.org/D4532
403 lines
13 KiB
C
403 lines
13 KiB
C
/*
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* Adapted from code Copyright 2009-2010 NVIDIA Corporation,
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* and code copyright 2009-2012 Intel Corporation
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*
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* Modifications 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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#ifdef __QBVH__
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# include "kernel/bvh/qbvh_shadow_all.h"
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# ifdef __KERNEL_AVX2__
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# include "kernel/bvh/obvh_shadow_all.h"
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# endif
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#endif
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#if BVH_FEATURE(BVH_HAIR)
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# define NODE_INTERSECT bvh_node_intersect
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#else
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# define NODE_INTERSECT bvh_aligned_node_intersect
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#endif
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/* This is a template BVH traversal function, where various features can be
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* enabled/disabled. This way we can compile optimized versions for each case
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* without new features slowing things down.
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*
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* BVH_INSTANCING: object instancing
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* BVH_HAIR: hair curve rendering
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* BVH_MOTION: motion blur rendering
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*/
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#ifndef __KERNEL_GPU__
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ccl_device
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#else
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ccl_device_inline
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#endif
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bool BVH_FUNCTION_FULL_NAME(BVH)(KernelGlobals *kg,
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const Ray *ray,
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Intersection *isect_array,
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const uint visibility,
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const uint max_hits,
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uint *num_hits)
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{
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/* todo:
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* - likely and unlikely for if() statements
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* - test restrict attribute for pointers
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*/
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/* traversal stack in CUDA thread-local memory */
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int traversal_stack[BVH_STACK_SIZE];
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traversal_stack[0] = ENTRYPOINT_SENTINEL;
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/* traversal variables in registers */
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int stack_ptr = 0;
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int node_addr = kernel_data.bvh.root;
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/* ray parameters in registers */
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const float tmax = ray->t;
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float3 P = ray->P;
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float3 dir = bvh_clamp_direction(ray->D);
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float3 idir = bvh_inverse_direction(dir);
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int object = OBJECT_NONE;
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float isect_t = tmax;
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#if BVH_FEATURE(BVH_MOTION)
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Transform ob_itfm;
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#endif
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#if BVH_FEATURE(BVH_INSTANCING)
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int num_hits_in_instance = 0;
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#endif
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*num_hits = 0;
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isect_array->t = tmax;
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#if defined(__KERNEL_SSE2__)
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const shuffle_swap_t shuf_identity = shuffle_swap_identity();
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const shuffle_swap_t shuf_swap = shuffle_swap_swap();
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const ssef pn = cast(ssei(0, 0, 0x80000000, 0x80000000));
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ssef Psplat[3], idirsplat[3];
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# if BVH_FEATURE(BVH_HAIR)
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ssef tnear(0.0f), tfar(isect_t);
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# endif
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shuffle_swap_t shufflexyz[3];
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Psplat[0] = ssef(P.x);
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Psplat[1] = ssef(P.y);
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Psplat[2] = ssef(P.z);
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ssef tsplat(0.0f, 0.0f, -isect_t, -isect_t);
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gen_idirsplat_swap(pn, shuf_identity, shuf_swap, idir, idirsplat, shufflexyz);
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#endif /* __KERNEL_SSE2__ */
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/* traversal loop */
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do {
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do {
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/* traverse internal nodes */
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while (node_addr >= 0 && node_addr != ENTRYPOINT_SENTINEL) {
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int node_addr_child1, traverse_mask;
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float dist[2];
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float4 cnodes = kernel_tex_fetch(__bvh_nodes, node_addr + 0);
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#if !defined(__KERNEL_SSE2__)
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traverse_mask = NODE_INTERSECT(kg,
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P,
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# if BVH_FEATURE(BVH_HAIR)
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dir,
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# endif
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idir,
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isect_t,
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node_addr,
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visibility,
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dist);
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#else // __KERNEL_SSE2__
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traverse_mask = NODE_INTERSECT(kg,
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P,
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dir,
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# if BVH_FEATURE(BVH_HAIR)
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tnear,
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tfar,
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# endif
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tsplat,
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Psplat,
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idirsplat,
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shufflexyz,
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node_addr,
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visibility,
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dist);
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#endif // __KERNEL_SSE2__
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node_addr = __float_as_int(cnodes.z);
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node_addr_child1 = __float_as_int(cnodes.w);
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if (traverse_mask == 3) {
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/* Both children were intersected, push the farther one. */
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bool is_closest_child1 = (dist[1] < dist[0]);
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if (is_closest_child1) {
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int tmp = node_addr;
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node_addr = node_addr_child1;
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node_addr_child1 = tmp;
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}
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++stack_ptr;
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kernel_assert(stack_ptr < BVH_STACK_SIZE);
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traversal_stack[stack_ptr] = node_addr_child1;
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}
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else {
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/* One child was intersected. */
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if (traverse_mask == 2) {
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node_addr = node_addr_child1;
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}
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else if (traverse_mask == 0) {
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/* Neither child was intersected. */
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node_addr = traversal_stack[stack_ptr];
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--stack_ptr;
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}
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}
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}
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/* if node is leaf, fetch triangle list */
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if (node_addr < 0) {
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float4 leaf = kernel_tex_fetch(__bvh_leaf_nodes, (-node_addr - 1));
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int prim_addr = __float_as_int(leaf.x);
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#if BVH_FEATURE(BVH_INSTANCING)
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if (prim_addr >= 0) {
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#endif
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const int prim_addr2 = __float_as_int(leaf.y);
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const uint type = __float_as_int(leaf.w);
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const uint p_type = type & PRIMITIVE_ALL;
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/* pop */
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node_addr = traversal_stack[stack_ptr];
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--stack_ptr;
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/* primitive intersection */
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while (prim_addr < prim_addr2) {
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kernel_assert((kernel_tex_fetch(__prim_type, prim_addr) & PRIMITIVE_ALL) == p_type);
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bool hit;
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/* todo: specialized intersect functions which don't fill in
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* isect unless needed and check SD_HAS_TRANSPARENT_SHADOW?
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* might give a few % performance improvement */
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switch (p_type) {
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case PRIMITIVE_TRIANGLE: {
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hit = triangle_intersect(kg, isect_array, P, dir, visibility, object, prim_addr);
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break;
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}
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#if BVH_FEATURE(BVH_MOTION)
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case PRIMITIVE_MOTION_TRIANGLE: {
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hit = motion_triangle_intersect(
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kg, isect_array, P, dir, ray->time, visibility, object, prim_addr);
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break;
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}
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#endif
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#if BVH_FEATURE(BVH_HAIR)
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case PRIMITIVE_CURVE:
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case PRIMITIVE_MOTION_CURVE: {
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const uint curve_type = kernel_tex_fetch(__prim_type, prim_addr);
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if (kernel_data.curve.curveflags & CURVE_KN_INTERPOLATE) {
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hit = cardinal_curve_intersect(kg,
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isect_array,
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P,
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dir,
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visibility,
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object,
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prim_addr,
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ray->time,
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curve_type);
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}
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else {
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hit = curve_intersect(kg,
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isect_array,
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P,
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dir,
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visibility,
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object,
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prim_addr,
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ray->time,
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curve_type);
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}
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break;
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}
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#endif
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default: {
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hit = false;
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break;
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}
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}
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/* shadow ray early termination */
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if (hit) {
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/* detect if this surface has a shader with transparent shadows */
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/* todo: optimize so primitive visibility flag indicates if
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* the primitive has a transparent shadow shader? */
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int prim = kernel_tex_fetch(__prim_index, isect_array->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_array->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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int flag = kernel_tex_fetch(__shaders, (shader & SHADER_MASK)).flags;
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/* if no transparent shadows, all light is blocked */
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if (!(flag & SD_HAS_TRANSPARENT_SHADOW)) {
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return true;
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}
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/* if maximum number of hits reached, block all light */
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else if (*num_hits == max_hits) {
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return true;
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}
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/* move on to next entry in intersections array */
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isect_array++;
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(*num_hits)++;
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#if BVH_FEATURE(BVH_INSTANCING)
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num_hits_in_instance++;
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#endif
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isect_array->t = isect_t;
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}
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prim_addr++;
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}
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}
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#if BVH_FEATURE(BVH_INSTANCING)
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else {
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/* instance push */
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object = kernel_tex_fetch(__prim_object, -prim_addr - 1);
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# if BVH_FEATURE(BVH_MOTION)
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isect_t = bvh_instance_motion_push(kg, object, ray, &P, &dir, &idir, isect_t, &ob_itfm);
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# else
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isect_t = bvh_instance_push(kg, object, ray, &P, &dir, &idir, isect_t);
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# endif
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num_hits_in_instance = 0;
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isect_array->t = isect_t;
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# if defined(__KERNEL_SSE2__)
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Psplat[0] = ssef(P.x);
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Psplat[1] = ssef(P.y);
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Psplat[2] = ssef(P.z);
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tsplat = ssef(0.0f, 0.0f, -isect_t, -isect_t);
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# if BVH_FEATURE(BVH_HAIR)
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tfar = ssef(isect_t);
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# endif
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gen_idirsplat_swap(pn, shuf_identity, shuf_swap, idir, idirsplat, shufflexyz);
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# endif
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++stack_ptr;
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kernel_assert(stack_ptr < BVH_STACK_SIZE);
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traversal_stack[stack_ptr] = ENTRYPOINT_SENTINEL;
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node_addr = kernel_tex_fetch(__object_node, object);
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}
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}
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#endif /* FEATURE(BVH_INSTANCING) */
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} while (node_addr != ENTRYPOINT_SENTINEL);
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#if BVH_FEATURE(BVH_INSTANCING)
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if (stack_ptr >= 0) {
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kernel_assert(object != OBJECT_NONE);
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/* Instance pop. */
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if (num_hits_in_instance) {
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float t_fac;
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# if BVH_FEATURE(BVH_MOTION)
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bvh_instance_motion_pop_factor(kg, object, ray, &P, &dir, &idir, &t_fac, &ob_itfm);
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# else
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bvh_instance_pop_factor(kg, object, ray, &P, &dir, &idir, &t_fac);
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# endif
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/* scale isect->t to adjust for instancing */
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for (int i = 0; i < num_hits_in_instance; i++) {
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(isect_array - i - 1)->t *= t_fac;
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}
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}
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else {
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# if BVH_FEATURE(BVH_MOTION)
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bvh_instance_motion_pop(kg, object, ray, &P, &dir, &idir, FLT_MAX, &ob_itfm);
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# else
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bvh_instance_pop(kg, object, ray, &P, &dir, &idir, FLT_MAX);
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# endif
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}
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isect_t = tmax;
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isect_array->t = isect_t;
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# if defined(__KERNEL_SSE2__)
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Psplat[0] = ssef(P.x);
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Psplat[1] = ssef(P.y);
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Psplat[2] = ssef(P.z);
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tsplat = ssef(0.0f, 0.0f, -isect_t, -isect_t);
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# if BVH_FEATURE(BVH_HAIR)
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tfar = ssef(isect_t);
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# endif
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gen_idirsplat_swap(pn, shuf_identity, shuf_swap, idir, idirsplat, shufflexyz);
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# endif
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object = OBJECT_NONE;
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node_addr = traversal_stack[stack_ptr];
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--stack_ptr;
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}
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#endif /* FEATURE(BVH_INSTANCING) */
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} while (node_addr != ENTRYPOINT_SENTINEL);
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return false;
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}
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ccl_device_inline bool BVH_FUNCTION_NAME(KernelGlobals *kg,
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const Ray *ray,
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Intersection *isect_array,
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const uint visibility,
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const uint max_hits,
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uint *num_hits)
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{
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switch (kernel_data.bvh.bvh_layout) {
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#ifdef __KERNEL_AVX2__
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case BVH_LAYOUT_BVH8:
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return BVH_FUNCTION_FULL_NAME(OBVH)(kg, ray, isect_array, visibility, max_hits, num_hits);
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#endif
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#ifdef __QBVH__
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case BVH_LAYOUT_BVH4:
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return BVH_FUNCTION_FULL_NAME(QBVH)(kg, ray, isect_array, visibility, max_hits, num_hits);
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#endif
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case BVH_LAYOUT_BVH2:
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return BVH_FUNCTION_FULL_NAME(BVH)(kg, ray, isect_array, visibility, max_hits, num_hits);
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}
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kernel_assert(!"Should not happen");
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return false;
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}
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#undef BVH_FUNCTION_NAME
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#undef BVH_FUNCTION_FEATURES
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#undef NODE_INTERSECT
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