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/*
* Adapted from code Copyright 2009-2010 NVIDIA Corporation,
* and code copyright 2009-2012 Intel Corporation
*
* Modifications Copyright 2011-2013, Blender Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#if BVH_FEATURE(BVH_HAIR)
# define NODE_INTERSECT bvh_node_intersect
#else
# define NODE_INTERSECT bvh_aligned_node_intersect
#endif
/* This is a template BVH traversal function for finding local intersections
* around the shading point, for subsurface scattering and bevel. We disable
* various features for performance, and for instanced objects avoid traversing
* other parts of the scene.
*
* BVH_MOTION: motion blur rendering
*/
#ifndef __KERNEL_GPU__
ccl_device
#else
ccl_device_inline
#endif
bool BVH_FUNCTION_FULL_NAME(BVH)(const KernelGlobals *kg,
const Ray *ray,
LocalIntersection *local_isect,
int local_object,
uint *lcg_state,
int max_hits)
{
/* todo:
* - test if pushing distance on the stack helps (for non shadow rays)
* - separate version for shadow rays
* - likely and unlikely for if() statements
* - test restrict attribute for pointers
*/
/* traversal stack in CUDA thread-local memory */
int traversal_stack[BVH_STACK_SIZE];
traversal_stack[0] = ENTRYPOINT_SENTINEL;
/* traversal variables in registers */
int stack_ptr = 0;
int node_addr = kernel_tex_fetch(__object_node, local_object);
/* ray parameters in registers */
float3 P = ray->P;
float3 dir = bvh_clamp_direction(ray->D);
float3 idir = bvh_inverse_direction(dir);
int object = OBJECT_NONE;
float isect_t = ray->t;
if (local_isect != NULL) {
local_isect->num_hits = 0;
}
kernel_assert((local_isect == NULL) == (max_hits == 0));
const int object_flag = kernel_tex_fetch(__object_flag, local_object);
if (!(object_flag & SD_OBJECT_TRANSFORM_APPLIED)) {
#if BVH_FEATURE(BVH_MOTION)
Transform ob_itfm;
isect_t *= bvh_instance_motion_push(kg, local_object, ray, &P, &dir, &idir, &ob_itfm);
#else
isect_t *= bvh_instance_push(kg, local_object, ray, &P, &dir, &idir);
#endif
object = local_object;
}
/* traversal loop */
do {
do {
/* traverse internal nodes */
while (node_addr >= 0 && node_addr != ENTRYPOINT_SENTINEL) {
int node_addr_child1, traverse_mask;
float dist[2];
float4 cnodes = kernel_tex_fetch(__bvh_nodes, node_addr + 0);
traverse_mask = NODE_INTERSECT(kg,
P,
#if BVH_FEATURE(BVH_HAIR)
dir,
#endif
idir,
isect_t,
node_addr,
PATH_RAY_ALL_VISIBILITY,
dist);
node_addr = __float_as_int(cnodes.z);
node_addr_child1 = __float_as_int(cnodes.w);
if (traverse_mask == 3) {
/* Both children were intersected, push the farther one. */
bool is_closest_child1 = (dist[1] < dist[0]);
if (is_closest_child1) {
int tmp = node_addr;
node_addr = node_addr_child1;
node_addr_child1 = tmp;
}
++stack_ptr;
kernel_assert(stack_ptr < BVH_STACK_SIZE);
traversal_stack[stack_ptr] = node_addr_child1;
}
else {
/* One child was intersected. */
if (traverse_mask == 2) {
node_addr = node_addr_child1;
}
else if (traverse_mask == 0) {
/* Neither child was intersected. */
node_addr = traversal_stack[stack_ptr];
--stack_ptr;
}
}
}
/* if node is leaf, fetch triangle list */
if (node_addr < 0) {
float4 leaf = kernel_tex_fetch(__bvh_leaf_nodes, (-node_addr - 1));
int prim_addr = __float_as_int(leaf.x);
const int prim_addr2 = __float_as_int(leaf.y);
const uint type = __float_as_int(leaf.w);
/* pop */
node_addr = traversal_stack[stack_ptr];
--stack_ptr;
/* primitive intersection */
switch (type & PRIMITIVE_ALL) {
case PRIMITIVE_TRIANGLE: {
/* intersect ray against primitive */
for (; prim_addr < prim_addr2; prim_addr++) {
kernel_assert(kernel_tex_fetch(__prim_type, prim_addr) == type);
if (triangle_intersect_local(kg,
local_isect,
P,
dir,
object,
local_object,
prim_addr,
isect_t,
lcg_state,
max_hits)) {
return true;
}
}
break;
}
#if BVH_FEATURE(BVH_MOTION)
case PRIMITIVE_MOTION_TRIANGLE: {
/* intersect ray against primitive */
for (; prim_addr < prim_addr2; prim_addr++) {
kernel_assert(kernel_tex_fetch(__prim_type, prim_addr) == type);
if (motion_triangle_intersect_local(kg,
local_isect,
P,
dir,
ray->time,
object,
local_object,
prim_addr,
isect_t,
lcg_state,
max_hits)) {
return true;
}
}
break;
}
#endif
default: {
break;
}
}
}
} while (node_addr != ENTRYPOINT_SENTINEL);
} while (node_addr != ENTRYPOINT_SENTINEL);
return false;
}
ccl_device_inline bool BVH_FUNCTION_NAME(const KernelGlobals *kg,
const Ray *ray,
LocalIntersection *local_isect,
int local_object,
uint *lcg_state,
int max_hits)
{
return BVH_FUNCTION_FULL_NAME(BVH)(kg, ray, local_isect, local_object, lcg_state, max_hits);
}
#undef BVH_FUNCTION_NAME
#undef BVH_FUNCTION_FEATURES
#undef NODE_INTERSECT
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