blender/intern/cycles/kernel/kernel_qbvh.h

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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.
*/
CCL_NAMESPACE_BEGIN
/*
* "Persistent while-while kernel" used in:
*
* "Understanding the Efficiency of Ray Traversal on GPUs",
* Timo Aila and Samuli Laine,
* Proc. High-Performance Graphics 2009
*/
/* bottom-most stack entry, indicating the end of traversal */
#define ENTRYPOINT_SENTINEL 0x76543210
/* 64 object BVH + 64 mesh BVH + 64 object node splitting */
#define QBVH_STACK_SIZE 192
#define QBVH_NODE_SIZE 8
#define TRI_NODE_SIZE 3
__device_inline float3 qbvh_inverse_direction(float3 dir)
{
// Avoid divide by zero (ooeps = exp2f(-80.0f))
float ooeps = 0.00000000000000000000000082718061255302767487140869206996285356581211090087890625f;
float3 idir;
idir.x = 1.0f/((fabsf(dir.x) > ooeps)? dir.x: copysignf(ooeps, dir.x));
idir.y = 1.0f/((fabsf(dir.y) > ooeps)? dir.y: copysignf(ooeps, dir.y));
idir.z = 1.0f/((fabsf(dir.z) > ooeps)? dir.z: copysignf(ooeps, dir.z));
return idir;
}
__device_inline void qbvh_instance_push(KernelGlobals *kg, int object, const Ray *ray, float3 *P, float3 *idir, float *t, const float tmax)
{
Transform tfm = object_fetch_transform(kg, object, OBJECT_INVERSE_TRANSFORM);
*P = transform_point(&tfm, ray->P);
float3 dir = transform_direction(&tfm, ray->D);
float len;
dir = normalize_len(dir, &len);
*idir = qbvh_inverse_direction(dir);
if(*t != FLT_MAX)
*t *= len;
}
__device_inline void qbvh_instance_pop(KernelGlobals *kg, int object, const Ray *ray, float3 *P, float3 *idir, float *t, const float tmax)
{
Transform tfm = object_fetch_transform(kg, object, OBJECT_TRANSFORM);
if(*t != FLT_MAX)
*t *= len(transform_direction(&tfm, 1.0f/(*idir)));
*P = ray->P;
*idir = qbvh_inverse_direction(ray->D);
}
#ifdef __KERNEL_CPU__
__device_inline void qbvh_node_intersect(KernelGlobals *kg, int *traverseChild,
int nodeAddrChild[4], float3 P, float3 idir, float t, int nodeAddr)
{
/* X axis */
const __m128 bminx = kernel_tex_fetch_m128(__bvh_nodes, nodeAddr*QBVH_NODE_SIZE+0);
const __m128 t0x = _mm_mul_ps(_mm_sub_ps(bminx, _mm_set_ps1(P.x)), _mm_set_ps1(idir.x));
const __m128 bmaxx = kernel_tex_fetch_m128(__bvh_nodes, nodeAddr*QBVH_NODE_SIZE+1);
const __m128 t1x = _mm_mul_ps(_mm_sub_ps(bmaxx, _mm_set_ps1(P.x)), _mm_set_ps1(idir.x));
__m128 tmin = _mm_max_ps(_mm_min_ps(t0x, t1x), _mm_setzero_ps());
__m128 tmax = _mm_min_ps(_mm_max_ps(t0x, t1x), _mm_set_ps1(t));
/* Y axis */
const __m128 bminy = kernel_tex_fetch_m128(__bvh_nodes, nodeAddr*QBVH_NODE_SIZE+2);
const __m128 t0y = _mm_mul_ps(_mm_sub_ps(bminy, _mm_set_ps1(P.y)), _mm_set_ps1(idir.y));
const __m128 bmaxy = kernel_tex_fetch_m128(__bvh_nodes, nodeAddr*QBVH_NODE_SIZE+3);
const __m128 t1y = _mm_mul_ps(_mm_sub_ps(bmaxy, _mm_set_ps1(P.y)), _mm_set_ps1(idir.y));
tmin = _mm_max_ps(_mm_min_ps(t0y, t1y), tmin);
tmax = _mm_min_ps(_mm_max_ps(t0y, t1y), tmax);
/* Z axis */
const __m128 bminz = kernel_tex_fetch_m128(__bvh_nodes, nodeAddr*QBVH_NODE_SIZE+4);
const __m128 t0z = _mm_mul_ps(_mm_sub_ps(bminz, _mm_set_ps1(P.z)), _mm_set_ps1(idir.z));
const __m128 bmaxz = kernel_tex_fetch_m128(__bvh_nodes, nodeAddr*QBVH_NODE_SIZE+5);
const __m128 t1z = _mm_mul_ps(_mm_sub_ps(bmaxz, _mm_set_ps1(P.z)), _mm_set_ps1(idir.z));
tmin = _mm_max_ps(_mm_min_ps(t0z, t1z), tmin);
tmax = _mm_min_ps(_mm_max_ps(t0z, t1z), tmax);
/* compare and get mask */
*traverseChild = _mm_movemask_ps(_mm_cmple_ps(tmin, tmax));
/* get node addresses */
float4 cnodes = kernel_tex_fetch(__bvh_nodes, nodeAddr*QBVH_NODE_SIZE+6);
nodeAddrChild[0] = __float_as_int(cnodes.x);
nodeAddrChild[1] = __float_as_int(cnodes.y);
nodeAddrChild[2] = __float_as_int(cnodes.z);
nodeAddrChild[3] = __float_as_int(cnodes.w);
}
#else
__device_inline bool qbvh_bb_intersect(float3 bmin, float3 bmax, float3 P, float3 idir, float t)
{
float t0x = (bmin.x - P.x)*idir.x;
float t1x = (bmax.x - P.x)*idir.x;
float t0y = (bmin.y - P.y)*idir.y;
float t1y = (bmax.y - P.y)*idir.y;
float t0z = (bmin.z - P.z)*idir.z;
float t1z = (bmax.z - P.z)*idir.z;
float minx = min(t0x, t1x);
float maxx = max(t0x, t1x);
float miny = min(t0y, t1y);
float maxy = max(t0y, t1y);
float minz = min(t0z, t1z);
float maxz = max(t0z, t1z);
float tmin = max4(0.0f, minx, miny, minz);
float tmax = min4(t, maxx, maxy, maxz);
return (tmin <= tmax);
}
/* intersect four bounding boxes */
__device_inline void qbvh_node_intersect(KernelGlobals *kg, int *traverseChild,
int nodeAddrChild[4], float3 P, float3 idir, float t, int nodeAddr)
{
/* fetch node data */
float4 minx = kernel_tex_fetch(__bvh_nodes, nodeAddr*QBVH_NODE_SIZE+0);
float4 miny = kernel_tex_fetch(__bvh_nodes, nodeAddr*QBVH_NODE_SIZE+2);
float4 minz = kernel_tex_fetch(__bvh_nodes, nodeAddr*QBVH_NODE_SIZE+4);
float4 maxx = kernel_tex_fetch(__bvh_nodes, nodeAddr*QBVH_NODE_SIZE+1);
float4 maxy = kernel_tex_fetch(__bvh_nodes, nodeAddr*QBVH_NODE_SIZE+3);
float4 maxz = kernel_tex_fetch(__bvh_nodes, nodeAddr*QBVH_NODE_SIZE+5);
/* intersect bounding boxes */
bool traverseChild0 = qbvh_bb_intersect(make_float3(minx.x, miny.x, minz.x), make_float3(maxx.x, maxy.x, maxz.x), P, idir, t);
bool traverseChild1 = qbvh_bb_intersect(make_float3(minx.y, miny.y, minz.y), make_float3(maxx.y, maxy.y, maxz.y), P, idir, t);
bool traverseChild2 = qbvh_bb_intersect(make_float3(minx.z, miny.z, minz.z), make_float3(maxx.z, maxy.z, maxz.z), P, idir, t);
bool traverseChild3 = qbvh_bb_intersect(make_float3(minx.w, miny.w, minz.w), make_float3(maxx.w, maxy.w, maxz.w), P, idir, t);
*traverseChild = 0;
if(traverseChild0) *traverseChild |= 1;
if(traverseChild1) *traverseChild |= 2;
if(traverseChild2) *traverseChild |= 4;
if(traverseChild3) *traverseChild |= 8;
/* get node addresses */
float4 cnodes = kernel_tex_fetch(__bvh_nodes, nodeAddr*QBVH_NODE_SIZE+6);
nodeAddrChild[0] = __float_as_int(cnodes.x);
nodeAddrChild[1] = __float_as_int(cnodes.y);
nodeAddrChild[2] = __float_as_int(cnodes.z);
nodeAddrChild[3] = __float_as_int(cnodes.w);
}
#endif
/* Sven Woop's algorithm */
__device_inline void qbvh_triangle_intersect(KernelGlobals *kg, Intersection *isect, float3 P, float3 idir, int object, int triAddr)
{
/* compute and check intersection t-value */
float4 v00 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+0);
float4 v11 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+1);
float3 dir = 1.0f/idir;
float Oz = v00.w - P.x*v00.x - P.y*v00.y - P.z*v00.z;
float invDz = 1.0f/(dir.x*v00.x + dir.y*v00.y + dir.z*v00.z);
float t = Oz * invDz;
if(t > 0.0f && t < isect->t) {
/* compute and check barycentric u */
float Ox = v11.w + P.x*v11.x + P.y*v11.y + P.z*v11.z;
float Dx = dir.x*v11.x + dir.y*v11.y + dir.z*v11.z;
float u = Ox + t*Dx;
if(u >= 0.0f) {
/* compute and check barycentric v */
float4 v22 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+2);
float Oy = v22.w + P.x*v22.x + P.y*v22.y + P.z*v22.z;
float Dy = dir.x*v22.x + dir.y*v22.y + dir.z*v22.z;
float v = Oy + t*Dy;
if(v >= 0.0f && u + v <= 1.0f) {
/* record intersection */
isect->prim = triAddr;
isect->object = object;
isect->u = u;
isect->v = v;
isect->t = t;
}
}
}
}
__device_inline bool scene_intersect(KernelGlobals *kg, const Ray *ray, const bool isshadowray, Intersection *isect)
{
/* traversal stack in CUDA thread-local memory */
int traversalStack[QBVH_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 = qbvh_inverse_direction(ray->D);
int object = ~0;
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)
{
int traverseChild, nodeAddrChild[4];
qbvh_node_intersect(kg, &traverseChild, nodeAddrChild,
P, idir, isect->t, nodeAddr);
if(traverseChild & 1) {
++stackPtr;
traversalStack[stackPtr] = nodeAddrChild[0];
}
if(traverseChild & 2) {
++stackPtr;
traversalStack[stackPtr] = nodeAddrChild[1];
}
if(traverseChild & 4) {
++stackPtr;
traversalStack[stackPtr] = nodeAddrChild[2];
}
if(traverseChild & 8) {
++stackPtr;
traversalStack[stackPtr] = nodeAddrChild[3];
}
nodeAddr = traversalStack[stackPtr];
--stackPtr;
}
/* if node is leaf, fetch triangle list */
if(nodeAddr < 0) {
float4 leaf = kernel_tex_fetch(__bvh_nodes, (-nodeAddr-1)*QBVH_NODE_SIZE+(QBVH_NODE_SIZE-2));
int primAddr = __float_as_int(leaf.x);
#ifdef __INSTANCING__
if(primAddr >= 0) {
#endif
int primAddr2 = __float_as_int(leaf.y);
/* pop */
nodeAddr = traversalStack[stackPtr];
--stackPtr;
/* triangle intersection */
while(primAddr < primAddr2) {
/* intersect ray against triangle */
qbvh_triangle_intersect(kg, isect, P, idir, object, primAddr);
/* shadow ray early termination */
if(isshadowray && isect->prim != ~0)
return true;
primAddr++;
}
#ifdef __INSTANCING__
}
else {
/* instance push */
object = kernel_tex_fetch(__prim_object, -primAddr-1);
qbvh_instance_push(kg, object, ray, &P, &idir, &isect->t, tmax);
++stackPtr;
traversalStack[stackPtr] = ENTRYPOINT_SENTINEL;
nodeAddr = kernel_tex_fetch(__object_node, object);
}
#endif
}
} while(nodeAddr != ENTRYPOINT_SENTINEL);
#ifdef __INSTANCING__
if(stackPtr >= 0) {
kernel_assert(object != ~0);
/* instance pop */
qbvh_instance_pop(kg, object, ray, &P, &idir, &isect->t, tmax);
object = ~0;
nodeAddr = traversalStack[stackPtr];
--stackPtr;
}
#endif
} while(nodeAddr != ENTRYPOINT_SENTINEL);
return (isect->prim != ~0);
}
__device_inline float3 ray_offset(float3 P, float3 Ng)
{
#ifdef __INTERSECTION_REFINE__
const float epsilon_f = 1e-5f;
const int epsilon_i = 32;
float3 res;
/* x component */
if(fabsf(P.x) < epsilon_f) {
res.x = P.x + Ng.x*epsilon_f;
}
else {
uint ix = __float_as_uint(P.x);
ix += ((ix ^ __float_as_uint(Ng.x)) >> 31)? -epsilon_i: epsilon_i;
res.x = __uint_as_float(ix);
}
/* y component */
if(fabsf(P.y) < epsilon_f) {
res.y = P.y + Ng.y*epsilon_f;
}
else {
uint iy = __float_as_uint(P.y);
iy += ((iy ^ __float_as_uint(Ng.y)) >> 31)? -epsilon_i: epsilon_i;
res.y = __uint_as_float(iy);
}
/* z component */
if(fabsf(P.z) < epsilon_f) {
res.z = P.z + Ng.z*epsilon_f;
}
else {
uint iz = __float_as_uint(P.z);
iz += ((iz ^ __float_as_uint(Ng.z)) >> 31)? -epsilon_i: epsilon_i;
res.z = __uint_as_float(iz);
}
return res;
#else
const float epsilon_f = 1e-4f;
return P + epsilon_f*Ng;
#endif
}
__device_inline float3 bvh_triangle_refine(KernelGlobals *kg, const Intersection *isect, const Ray *ray)
{
float3 P = ray->P;
float3 D = ray->D;
float t = isect->t;
#ifdef __INTERSECTION_REFINE__
if(isect->object != ~0) {
Transform tfm = object_fetch_transform(kg, isect->object, OBJECT_INVERSE_TRANSFORM);
P = transform_point(&tfm, P);
D = transform_direction(&tfm, D*t);
D = normalize_len(D, &t);
}
P = P + D*t;
float4 v00 = kernel_tex_fetch(__tri_woop, isect->prim*TRI_NODE_SIZE+0);
float Oz = v00.w - P.x*v00.x - P.y*v00.y - P.z*v00.z;
float invDz = 1.0f/(D.x*v00.x + D.y*v00.y + D.z*v00.z);
float rt = Oz * invDz;
P = P + D*rt;
if(isect->object != ~0) {
Transform tfm = object_fetch_transform(kg, isect->object, OBJECT_TRANSFORM);
P = transform_point(&tfm, P);
}
return P;
#else
return P + D*t;
#endif
}
CCL_NAMESPACE_END