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/*
* Adapted from code Copyright 2009-2010 NVIDIA Corporation
* Modifications Copyright 2011, 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, where various features can be
* enabled/disabled. This way we can compile optimized versions for each case
* without new features slowing things down.
*
* BVH_INSTANCING: object instancing
* BVH_HAIR: hair curve rendering
* BVH_HAIR_MINIMUM_WIDTH: hair curve rendering with minimum width
* BVH_SUBSURFACE: subsurface same object, random triangle intersection
* BVH_MOTION: motion blur rendering
*
*/
#define FEATURE(f) (((BVH_FUNCTION_FEATURES) & (f)) != 0)
__device bool BVH_FUNCTION_NAME
(KernelGlobals *kg, const Ray *ray, Intersection *isect
#if FEATURE(BVH_SUBSURFACE)
, int subsurface_object, float subsurface_random
#else
, const uint visibility
#endif
#if FEATURE(BVH_HAIR_MINIMUM_WIDTH) && !FEATURE(BVH_SUBSURFACE)
, uint *lcg_state = NULL, float difl = 0.0f, float extmax = 0.0f
#endif
)
{
/* traversal stack in CUDA thread-local memory */
int traversalStack[BVH_STACK_SIZE];
traversalStack[0] = ENTRYPOINT_SENTINEL;
/* traversal variables in registers */
int stackPtr = 0;
int nodeAddr = kernel_data.bvh.root;
/* ray parameters in registers */
const float tmax = ray->t;
float3 P = ray->P;
float3 idir = bvh_inverse_direction(ray->D);
int object = ~0;
#if FEATURE(BVH_SUBSURFACE)
const uint visibility = ~0;
int num_hits = 0;
#endif
#if FEATURE(BVH_MOTION)
Transform ob_tfm;
#endif
isect->t = tmax;
isect->object = ~0;
isect->prim = ~0;
isect->u = 0.0f;
isect->v = 0.0f;
/* traversal loop */
do {
do
{
/* traverse internal nodes */
while(nodeAddr >= 0 && nodeAddr != ENTRYPOINT_SENTINEL)
{
bool traverseChild0, traverseChild1, closestChild1;
int nodeAddrChild1;
#if FEATURE(BVH_HAIR_MINIMUM_WIDTH) && !FEATURE(BVH_SUBSURFACE)
bvh_node_intersect(kg, &traverseChild0, &traverseChild1,
&closestChild1, &nodeAddr, &nodeAddrChild1,
P, idir, isect->t, visibility, nodeAddr, difl, extmax);
#else
bvh_node_intersect(kg, &traverseChild0, &traverseChild1,
&closestChild1, &nodeAddr, &nodeAddrChild1,
P, idir, isect->t, visibility, nodeAddr);
#endif
if(traverseChild0 != traverseChild1) {
/* one child was intersected */
if(traverseChild1) {
nodeAddr = nodeAddrChild1;
}
}
else {
if(!traverseChild0) {
/* neither child was intersected */
nodeAddr = traversalStack[stackPtr];
--stackPtr;
}
else {
/* both children were intersected, push the farther one */
if(closestChild1) {
int tmp = nodeAddr;
nodeAddr = nodeAddrChild1;
nodeAddrChild1 = tmp;
}
++stackPtr;
traversalStack[stackPtr] = nodeAddrChild1;
}
}
}
/* if node is leaf, fetch triangle list */
if(nodeAddr < 0) {
float4 leaf = kernel_tex_fetch(__bvh_nodes, (-nodeAddr-1)*BVH_NODE_SIZE+(BVH_NODE_SIZE-1));
int primAddr = __float_as_int(leaf.x);
#if FEATURE(BVH_INSTANCING)
if(primAddr >= 0) {
#endif
int primAddr2 = __float_as_int(leaf.y);
/* pop */
nodeAddr = traversalStack[stackPtr];
--stackPtr;
/* primitive intersection */
while(primAddr < primAddr2) {
#if FEATURE(BVH_SUBSURFACE)
/* only primitives from the same object */
uint tri_object = (object == ~0)? kernel_tex_fetch(__prim_object, primAddr): object;
if(tri_object == subsurface_object) {
#endif
/* intersect ray against primitive */
#if FEATURE(BVH_HAIR)
uint segment = kernel_tex_fetch(__prim_segment, primAddr);
#if !FEATURE(BVH_SUBSURFACE)
if(segment != ~0) {
if(kernel_data.curve_kernel_data.curveflags & CURVE_KN_INTERPOLATE)
#if FEATURE(BVH_HAIR_MINIMUM_WIDTH)
bvh_cardinal_curve_intersect(kg, isect, P, idir, visibility, object, primAddr, segment, lcg_state, difl, extmax);
else
bvh_curve_intersect(kg, isect, P, idir, visibility, object, primAddr, segment, lcg_state, difl, extmax);
#else
bvh_cardinal_curve_intersect(kg, isect, P, idir, visibility, object, primAddr, segment);
else
bvh_curve_intersect(kg, isect, P, idir, visibility, object, primAddr, segment);
#endif
}
else
#endif
#endif
#if FEATURE(BVH_SUBSURFACE)
#if FEATURE(BVH_HAIR)
if(segment == ~0)
#endif
bvh_triangle_intersect_subsurface(kg, isect, P, idir, object, primAddr, tmax, &num_hits, subsurface_random);
}
#else
bvh_triangle_intersect(kg, isect, P, idir, visibility, object, primAddr);
/* shadow ray early termination */
if(visibility == PATH_RAY_SHADOW_OPAQUE && isect->prim != ~0)
return true;
#endif
primAddr++;
}
}
#if FEATURE(BVH_INSTANCING)
else {
/* instance push */
#if FEATURE(BVH_SUBSURFACE)
if(subsurface_object == kernel_tex_fetch(__prim_object, -primAddr-1)) {
object = subsurface_object;
#else
object = kernel_tex_fetch(__prim_object, -primAddr-1);
#endif
#if FEATURE(BVH_MOTION)
bvh_instance_motion_push(kg, object, ray, &P, &idir, &isect->t, &ob_tfm, tmax);
#else
bvh_instance_push(kg, object, ray, &P, &idir, &isect->t, tmax);
#endif
++stackPtr;
traversalStack[stackPtr] = ENTRYPOINT_SENTINEL;
nodeAddr = kernel_tex_fetch(__object_node, object);
#if FEATURE(BVH_SUBSURFACE)
}
else {
/* pop */
nodeAddr = traversalStack[stackPtr];
--stackPtr;
}
#endif
}
}
#endif
} while(nodeAddr != ENTRYPOINT_SENTINEL);
#if FEATURE(BVH_INSTANCING)
if(stackPtr >= 0) {
kernel_assert(object != ~0);
/* instance pop */
#if FEATURE(BVH_MOTION)
bvh_instance_motion_pop(kg, object, ray, &P, &idir, &isect->t, &ob_tfm, tmax);
#else
bvh_instance_pop(kg, object, ray, &P, &idir, &isect->t, tmax);
#endif
object = ~0;
nodeAddr = traversalStack[stackPtr];
--stackPtr;
}
#endif
} while(nodeAddr != ENTRYPOINT_SENTINEL);
#if FEATURE(BVH_SUBSURAFACE)
return (num_hits != 0);
#else
return (isect->prim != ~0);
#endif
}
#undef FEATURE
#undef BVH_FUNCTION_NAME
#undef BVH_FUNCTION_FEATURES
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