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/*
* 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.
*/
/* This is a template BVH traversal function for subsurface scattering, where
* various features can be enabled/disabled. This way we can compile optimized
* versions for each case without new features slowing things down.
*
* BVH_MOTION: motion blur rendering
*
*/
#if BVH_FEATURE(BVH_HAIR)
# define NODE_INTERSECT qbvh_node_intersect
#else
# define NODE_INTERSECT qbvh_aligned_node_intersect
#endif
ccl_device void BVH_FUNCTION_FULL_NAME(QBVH)(KernelGlobals *kg,
const Ray *ray,
SubsurfaceIntersection *ss_isect,
int subsurface_object,
uint *lcg_state,
int max_hits)
{
/* TODO(sergey):
* - Test if pushing distance on the stack helps (for non shadow rays).
* - Separate version for shadow rays.
* - Likely and unlikely for if() statements.
* - SSE for hair.
* - Test restrict attribute for pointers.
*/
/* Traversal stack in CUDA thread-local memory. */
QBVHStackItem traversal_stack[BVH_QSTACK_SIZE];
traversal_stack[0].addr = ENTRYPOINT_SENTINEL;
/* Traversal variables in registers. */
int stack_ptr = 0;
int node_addr = kernel_tex_fetch(__object_node, subsurface_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;
ss_isect->num_hits = 0;
const int object_flag = kernel_tex_fetch(__object_flag, subsurface_object);
if(!(object_flag & SD_TRANSFORM_APPLIED)) {
#if BVH_FEATURE(BVH_MOTION)
Transform ob_itfm;
bvh_instance_motion_push(kg,
subsurface_object,
ray,
&P,
&dir,
&idir,
&isect_t,
&ob_itfm);
#else
bvh_instance_push(kg, subsurface_object, ray, &P, &dir, &idir, &isect_t);
#endif
object = subsurface_object;
}
#ifndef __KERNEL_SSE41__
if(!isfinite(P.x)) {
return;
}
#endif
ssef tnear(0.0f), tfar(isect_t);
#if BVH_FEATURE(BVH_HAIR)
sse3f dir4(ssef(dir.x), ssef(dir.y), ssef(dir.z));
#endif
sse3f idir4(ssef(idir.x), ssef(idir.y), ssef(idir.z));
#ifdef __KERNEL_AVX2__
float3 P_idir = P*idir;
sse3f P_idir4(P_idir.x, P_idir.y, P_idir.z);
#endif
#if BVH_FEATURE(BVH_HAIR) || !defined(__KERNEL_AVX2__)
sse3f org4(ssef(P.x), ssef(P.y), ssef(P.z));
#endif
/* Offsets to select the side that becomes the lower or upper bound. */
int near_x, near_y, near_z;
int far_x, far_y, far_z;
qbvh_near_far_idx_calc(idir,
&near_x, &near_y, &near_z,
&far_x, &far_y, &far_z);
IsectPrecalc isect_precalc;
triangle_intersect_precalc(dir, &isect_precalc);
/* Traversal loop. */
do {
do {
/* Traverse internal nodes. */
while(node_addr >= 0 && node_addr != ENTRYPOINT_SENTINEL) {
ssef dist;
int child_mask = NODE_INTERSECT(kg,
tnear,
tfar,
#ifdef __KERNEL_AVX2__
P_idir4,
#endif
#if BVH_FEATURE(BVH_HAIR) || !defined(__KERNEL_AVX2__)
org4,
#endif
#if BVH_FEATURE(BVH_HAIR)
dir4,
#endif
idir4,
near_x, near_y, near_z,
far_x, far_y, far_z,
node_addr,
&dist);
if(child_mask != 0) {
float4 inodes = kernel_tex_fetch(__bvh_nodes, node_addr+0);
float4 cnodes;
#if BVH_FEATURE(BVH_HAIR)
if(__float_as_uint(inodes.x) & PATH_RAY_NODE_UNALIGNED) {
cnodes = kernel_tex_fetch(__bvh_nodes, node_addr+13);
}
else
#endif
{
cnodes = kernel_tex_fetch(__bvh_nodes, node_addr+7);
}
/* One child is hit, continue with that child. */
int r = __bscf(child_mask);
if(child_mask == 0) {
node_addr = __float_as_int(cnodes[r]);
continue;
}
/* Two children are hit, push far child, and continue with
* closer child.
*/
int c0 = __float_as_int(cnodes[r]);
float d0 = ((float*)&dist)[r];
r = __bscf(child_mask);
int c1 = __float_as_int(cnodes[r]);
float d1 = ((float*)&dist)[r];
if(child_mask == 0) {
if(d1 < d0) {
node_addr = c1;
++stack_ptr;
kernel_assert(stack_ptr < BVH_QSTACK_SIZE);
traversal_stack[stack_ptr].addr = c0;
traversal_stack[stack_ptr].dist = d0;
continue;
}
else {
node_addr = c0;
++stack_ptr;
kernel_assert(stack_ptr < BVH_QSTACK_SIZE);
traversal_stack[stack_ptr].addr = c1;
traversal_stack[stack_ptr].dist = d1;
continue;
}
}
/* Here starts the slow path for 3 or 4 hit children. We push
* all nodes onto the stack to sort them there.
*/
++stack_ptr;
kernel_assert(stack_ptr < BVH_QSTACK_SIZE);
traversal_stack[stack_ptr].addr = c1;
traversal_stack[stack_ptr].dist = d1;
++stack_ptr;
kernel_assert(stack_ptr < BVH_QSTACK_SIZE);
traversal_stack[stack_ptr].addr = c0;
traversal_stack[stack_ptr].dist = d0;
/* Three children are hit, push all onto stack and sort 3
* stack items, continue with closest child.
*/
r = __bscf(child_mask);
int c2 = __float_as_int(cnodes[r]);
float d2 = ((float*)&dist)[r];
if(child_mask == 0) {
++stack_ptr;
kernel_assert(stack_ptr < BVH_QSTACK_SIZE);
traversal_stack[stack_ptr].addr = c2;
traversal_stack[stack_ptr].dist = d2;
qbvh_stack_sort(&traversal_stack[stack_ptr],
&traversal_stack[stack_ptr - 1],
&traversal_stack[stack_ptr - 2]);
node_addr = traversal_stack[stack_ptr].addr;
--stack_ptr;
continue;
}
/* Four children are hit, push all onto stack and sort 4
* stack items, continue with closest child.
*/
r = __bscf(child_mask);
int c3 = __float_as_int(cnodes[r]);
float d3 = ((float*)&dist)[r];
++stack_ptr;
kernel_assert(stack_ptr < BVH_QSTACK_SIZE);
traversal_stack[stack_ptr].addr = c3;
traversal_stack[stack_ptr].dist = d3;
++stack_ptr;
kernel_assert(stack_ptr < BVH_QSTACK_SIZE);
traversal_stack[stack_ptr].addr = c2;
traversal_stack[stack_ptr].dist = d2;
qbvh_stack_sort(&traversal_stack[stack_ptr],
&traversal_stack[stack_ptr - 1],
&traversal_stack[stack_ptr - 2],
&traversal_stack[stack_ptr - 3]);
}
node_addr = traversal_stack[stack_ptr].addr;
--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);
int prim_addr2 = __float_as_int(leaf.y);
const uint type = __float_as_int(leaf.w);
/* Pop. */
node_addr = traversal_stack[stack_ptr].addr;
--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);
triangle_intersect_subsurface(kg,
&isect_precalc,
ss_isect,
P,
object,
prim_addr,
isect_t,
lcg_state,
max_hits);
}
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);
motion_triangle_intersect_subsurface(kg,
ss_isect,
P,
dir,
ray->time,
object,
prim_addr,
isect_t,
lcg_state,
max_hits);
}
break;
}
#endif
default:
break;
}
}
} while(node_addr != ENTRYPOINT_SENTINEL);
} while(node_addr != ENTRYPOINT_SENTINEL);
}
#undef NODE_INTERSECT
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