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blender/intern/cycles/kernel/kernel_bvh_traversal.h
Brecht Van Lommel f811e6e3ae Cycles: optimized SSE BVH traversal now also works with SSE2 CPUs, so all the 
way back to Pentium 4, using a slightly less efficient instruction.

Also ensure /Ox is used for Visual Studio for RelWithDebInfo builds.
2013-06-19 17:54:26 +00:00

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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.
*/
/* 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, float difl, float extmax
#endif
)
{
/* todo:
* - 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 */
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;
#if defined(__KERNEL_SSE2__) && !FEATURE(BVH_HAIR_MINIMUM_WIDTH)
const shuffle_swap_t shuf_identity = shuffle_swap_identity();
const shuffle_swap_t shuf_swap = shuffle_swap_swap();
const __m128i pn = _mm_set_epi32(0x80000000, 0x80000000, 0x00000000, 0x00000000);
__m128 Psplat[3], idirsplat[3];
Psplat[0] = _mm_set_ps1(P.x);
Psplat[1] = _mm_set_ps1(P.y);
Psplat[2] = _mm_set_ps1(P.z);
idirsplat[0] = _mm_xor_ps(_mm_set_ps1(idir.x), _mm_castsi128_ps(pn));
idirsplat[1] = _mm_xor_ps(_mm_set_ps1(idir.y), _mm_castsi128_ps(pn));
idirsplat[2] = _mm_xor_ps(_mm_set_ps1(idir.z), _mm_castsi128_ps(pn));
__m128 tsplat = _mm_set_ps(-isect->t, -isect->t, 0.0f, 0.0f);
shuffle_swap_t shufflex = (idir.x >= 0)? shuf_identity: shuf_swap;
shuffle_swap_t shuffley = (idir.y >= 0)? shuf_identity: shuf_swap;
shuffle_swap_t shufflez = (idir.z >= 0)? shuf_identity: shuf_swap;
#endif
/* traversal loop */
do {
do
{
/* traverse internal nodes */
while(nodeAddr >= 0 && nodeAddr != ENTRYPOINT_SENTINEL)
{
bool traverseChild0, traverseChild1;
int nodeAddrChild1;
#if !defined(__KERNEL_SSE2__) || FEATURE(BVH_HAIR_MINIMUM_WIDTH)
/* Intersect two child bounding boxes, non-SSE version */
float t = isect->t;
/* fetch node data */
float4 node0 = kernel_tex_fetch(__bvh_nodes, nodeAddr*BVH_NODE_SIZE+0);
float4 node1 = kernel_tex_fetch(__bvh_nodes, nodeAddr*BVH_NODE_SIZE+1);
float4 node2 = kernel_tex_fetch(__bvh_nodes, nodeAddr*BVH_NODE_SIZE+2);
float4 cnodes = kernel_tex_fetch(__bvh_nodes, nodeAddr*BVH_NODE_SIZE+3);
/* intersect ray against child nodes */
NO_EXTENDED_PRECISION float c0lox = (node0.x - P.x) * idir.x;
NO_EXTENDED_PRECISION float c0hix = (node0.z - P.x) * idir.x;
NO_EXTENDED_PRECISION float c0loy = (node1.x - P.y) * idir.y;
NO_EXTENDED_PRECISION float c0hiy = (node1.z - P.y) * idir.y;
NO_EXTENDED_PRECISION float c0loz = (node2.x - P.z) * idir.z;
NO_EXTENDED_PRECISION float c0hiz = (node2.z - P.z) * idir.z;
NO_EXTENDED_PRECISION float c0min = max4(min(c0lox, c0hix), min(c0loy, c0hiy), min(c0loz, c0hiz), 0.0f);
NO_EXTENDED_PRECISION float c0max = min4(max(c0lox, c0hix), max(c0loy, c0hiy), max(c0loz, c0hiz), t);
NO_EXTENDED_PRECISION float c1lox = (node0.y - P.x) * idir.x;
NO_EXTENDED_PRECISION float c1hix = (node0.w - P.x) * idir.x;
NO_EXTENDED_PRECISION float c1loy = (node1.y - P.y) * idir.y;
NO_EXTENDED_PRECISION float c1hiy = (node1.w - P.y) * idir.y;
NO_EXTENDED_PRECISION float c1loz = (node2.y - P.z) * idir.z;
NO_EXTENDED_PRECISION float c1hiz = (node2.w - P.z) * idir.z;
NO_EXTENDED_PRECISION float c1min = max4(min(c1lox, c1hix), min(c1loy, c1hiy), min(c1loz, c1hiz), 0.0f);
NO_EXTENDED_PRECISION float c1max = min4(max(c1lox, c1hix), max(c1loy, c1hiy), max(c1loz, c1hiz), t);
#if FEATURE(BVH_HAIR_MINIMUM_WIDTH) && !FEATURE(BVH_SUBSURFACE)
if(difl != 0.0f) {
float hdiff = 1.0f + difl;
float ldiff = 1.0f - difl;
if(__float_as_int(cnodes.z) & PATH_RAY_CURVE) {
c0min = max(ldiff * c0min, c0min - extmax);
c0max = min(hdiff * c0max, c0max + extmax);
}
if(__float_as_int(cnodes.w) & PATH_RAY_CURVE) {
c1min = max(ldiff * c1min, c1min - extmax);
c1max = min(hdiff * c1max, c1max + extmax);
}
}
#endif
/* decide which nodes to traverse next */
#ifdef __VISIBILITY_FLAG__
/* this visibility test gives a 5% performance hit, how to solve? */
traverseChild0 = (c0max >= c0min) && (__float_as_uint(cnodes.z) & visibility);
traverseChild1 = (c1max >= c1min) && (__float_as_uint(cnodes.w) & visibility);
#else
traverseChild0 = (c0max >= c0min);
traverseChild1 = (c1max >= c1min);
#endif
#else // __KERNEL_SSE2__
/* Intersect two child bounding boxes, SSE3 version adapted from Embree */
/* fetch node data */
__m128 *bvh_nodes = (__m128*)kg->__bvh_nodes.data + nodeAddr*BVH_NODE_SIZE;
float4 cnodes = ((float4*)bvh_nodes)[3];
/* intersect ray against child nodes */
const __m128 tminmaxx = _mm_mul_ps(_mm_sub_ps(shuffle_swap(bvh_nodes[0], shufflex), Psplat[0]), idirsplat[0]);
const __m128 tminmaxy = _mm_mul_ps(_mm_sub_ps(shuffle_swap(bvh_nodes[1], shuffley), Psplat[1]), idirsplat[1]);
const __m128 tminmaxz = _mm_mul_ps(_mm_sub_ps(shuffle_swap(bvh_nodes[2], shufflez), Psplat[2]), idirsplat[2]);
const __m128 tminmax = _mm_xor_ps(_mm_max_ps(_mm_max_ps(tminmaxx, tminmaxy), _mm_max_ps(tminmaxz, tsplat)), _mm_castsi128_ps(pn));
const __m128 lrhit = _mm_cmple_ps(tminmax, shuffle_swap(tminmax, shuf_swap));
/* decide which nodes to traverse next */
#ifdef __VISIBILITY_FLAG__
/* this visibility test gives a 5% performance hit, how to solve? */
traverseChild0 = (_mm_movemask_ps(lrhit) & 1) && (__float_as_uint(cnodes.z) & visibility);
traverseChild1 = (_mm_movemask_ps(lrhit) & 2) && (__float_as_uint(cnodes.w) & visibility);
#else
traverseChild0 = (_mm_movemask_ps(lrhit) & 1);
traverseChild1 = (_mm_movemask_ps(lrhit) & 2);
#endif
#endif // __KERNEL_SSE2__
nodeAddr = __float_as_int(cnodes.x);
nodeAddrChild1 = __float_as_int(cnodes.y);
if(traverseChild0 && traverseChild1) {
/* both children were intersected, push the farther one */
#if !defined(__KERNEL_SSE2__) || FEATURE(BVH_HAIR_MINIMUM_WIDTH)
bool closestChild1 = (c1min < c0min);
#else
union { __m128 m128; float v[4]; } uminmax;
uminmax.m128 = tminmax;
bool closestChild1 = uminmax.v[1] < uminmax.v[0];
#endif
if(closestChild1) {
int tmp = nodeAddr;
nodeAddr = nodeAddrChild1;
nodeAddrChild1 = tmp;
}
++stackPtr;
traversalStack[stackPtr] = nodeAddrChild1;
}
else {
/* one child was intersected */
if(traverseChild1) {
nodeAddr = nodeAddrChild1;
}
else if(!traverseChild0) {
/* neither child was intersected */
nodeAddr = traversalStack[stackPtr];
--stackPtr;
}
}
}
/* 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) {
bool hit;
#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)
hit = bvh_cardinal_curve_intersect(kg, isect, P, idir, visibility, object, primAddr, segment, lcg_state, difl, extmax);
else
hit = bvh_curve_intersect(kg, isect, P, idir, visibility, object, primAddr, segment, lcg_state, difl, extmax);
#else
hit = bvh_cardinal_curve_intersect(kg, isect, P, idir, visibility, object, primAddr, segment);
else
hit = 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
{
hit = bvh_triangle_intersect_subsurface(kg, isect, P, idir, object, primAddr, tmax, &num_hits, subsurface_random);
(void)hit;
}
}
#else
hit = bvh_triangle_intersect(kg, isect, P, idir, visibility, object, primAddr);
/* shadow ray early termination */
#if defined(__KERNEL_SSE2__) && !FEATURE(BVH_HAIR_MINIMUM_WIDTH)
if(hit) {
if(visibility == PATH_RAY_SHADOW_OPAQUE)
return true;
tsplat = _mm_set_ps(-isect->t, -isect->t, 0.0f, 0.0f);
}
#else
if(hit && visibility == PATH_RAY_SHADOW_OPAQUE)
return true;
#endif
#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
#if defined(__KERNEL_SSE2__) && !FEATURE(BVH_HAIR_MINIMUM_WIDTH)
Psplat[0] = _mm_set_ps1(P.x);
Psplat[1] = _mm_set_ps1(P.y);
Psplat[2] = _mm_set_ps1(P.z);
idirsplat[0] = _mm_xor_ps(_mm_set_ps1(idir.x), _mm_castsi128_ps(pn));
idirsplat[1] = _mm_xor_ps(_mm_set_ps1(idir.y), _mm_castsi128_ps(pn));
idirsplat[2] = _mm_xor_ps(_mm_set_ps1(idir.z), _mm_castsi128_ps(pn));
tsplat = _mm_set_ps(-isect->t, -isect->t, 0.0f, 0.0f);
shufflex = (idir.x >= 0)? shuf_identity: shuf_swap;
shuffley = (idir.y >= 0)? shuf_identity: shuf_swap;
shufflez = (idir.z >= 0)? shuf_identity: shuf_swap;
#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
#if defined(__KERNEL_SSE2__) && !FEATURE(BVH_HAIR_MINIMUM_WIDTH)
Psplat[0] = _mm_set_ps1(P.x);
Psplat[1] = _mm_set_ps1(P.y);
Psplat[2] = _mm_set_ps1(P.z);
idirsplat[0] = _mm_xor_ps(_mm_set_ps1(idir.x), _mm_castsi128_ps(pn));
idirsplat[1] = _mm_xor_ps(_mm_set_ps1(idir.y), _mm_castsi128_ps(pn));
idirsplat[2] = _mm_xor_ps(_mm_set_ps1(idir.z), _mm_castsi128_ps(pn));
tsplat = _mm_set_ps(-isect->t, -isect->t, 0.0f, 0.0f);
shufflex = (idir.x >= 0)? shuf_identity: shuf_swap;
shuffley = (idir.y >= 0)? shuf_identity: shuf_swap;
shufflez = (idir.z >= 0)? shuf_identity: shuf_swap;
#endif
object = ~0;
nodeAddr = traversalStack[stackPtr];
--stackPtr;
}
#endif
} while(nodeAddr != ENTRYPOINT_SENTINEL);
#if FEATURE(BVH_SUBSURFACE)
return (num_hits != 0);
#else
return (isect->prim != ~0);
#endif
}
#undef FEATURE
#undef BVH_FUNCTION_NAME
#undef BVH_FUNCTION_FEATURES
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