blender/intern/cycles/kernel/geom/geom_bvh_subsurface.h
Sergey Sharybin 828abaf11c Cycles: Split BVH nodes storage into inner and leaf nodes
This way we can get rid of inefficient memory usage caused by BVH boundbox
part being unused by leaf nodes but still being allocated for them. Doing
such split allows to save 6 of float4 values for QBVH per leaf node and 3
of float4 values for regular BVH per leaf node.

This translates into following memory save using 01.01.01.G rendered
without hair:

                   Device memory size   Device memory peak   Global memory peak
Before the patch:  4957                 5051                 7668
With the patch:    4467                 4562                 7332

The measurements are done against current master. Still need to run speed tests
and it's hard to predict if it's faster or not: on the one hand leaf nodes are
now much more coherent in cache, on the other hand they're not so much coherent
with regular nodes anymore.

Reviewers: brecht, juicyfruit

Subscribers: venomgfx, eyecandy

Differential Revision: https://developer.blender.org/D1236
2015-04-20 17:29:51 +05:00

339 lines
11 KiB
C

/*
* 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.
*/
#ifdef __QBVH__
#include "geom_qbvh_subsurface.h"
#endif
/* 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_INSTANCING: object instancing
* BVH_MOTION: motion blur rendering
*
*/
ccl_device uint BVH_FUNCTION_FULL_NAME(BVH)(KernelGlobals *kg,
const Ray *ray,
Intersection *isect_array,
int subsurface_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
* - 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 */
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;
uint num_hits = 0;
#if BVH_FEATURE(BVH_MOTION)
Transform ob_tfm;
#endif
#if defined(__KERNEL_SSE2__)
const shuffle_swap_t shuf_identity = shuffle_swap_identity();
const shuffle_swap_t shuf_swap = shuffle_swap_swap();
const ssef pn = cast(ssei(0, 0, 0x80000000, 0x80000000));
ssef Psplat[3], idirsplat[3];
shuffle_swap_t shufflexyz[3];
Psplat[0] = ssef(P.x);
Psplat[1] = ssef(P.y);
Psplat[2] = ssef(P.z);
ssef tsplat(0.0f, 0.0f, -isect_t, -isect_t);
gen_idirsplat_swap(pn, shuf_identity, shuf_swap, idir, idirsplat, shufflexyz);
#endif
IsectPrecalc isect_precalc;
triangle_intersect_precalc(dir, &isect_precalc);
/* traversal loop */
do {
do
{
/* traverse internal nodes */
while(nodeAddr >= 0 && nodeAddr != ENTRYPOINT_SENTINEL)
{
bool traverseChild0, traverseChild1;
int nodeAddrChild1;
#if !defined(__KERNEL_SSE2__)
/* 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);
/* decide which nodes to traverse next */
traverseChild0 = (c0max >= c0min);
traverseChild1 = (c1max >= c1min);
#else // __KERNEL_SSE2__
/* Intersect two child bounding boxes, SSE3 version adapted from Embree */
/* fetch node data */
const ssef *bvh_nodes = (ssef*)kg->__bvh_nodes.data + nodeAddr*BVH_NODE_SIZE;
const float4 cnodes = ((float4*)bvh_nodes)[3];
/* intersect ray against child nodes */
const ssef tminmaxx = (shuffle_swap(bvh_nodes[0], shufflexyz[0]) - Psplat[0]) * idirsplat[0];
const ssef tminmaxy = (shuffle_swap(bvh_nodes[1], shufflexyz[1]) - Psplat[1]) * idirsplat[1];
const ssef tminmaxz = (shuffle_swap(bvh_nodes[2], shufflexyz[2]) - Psplat[2]) * idirsplat[2];
/* calculate { c0min, c1min, -c0max, -c1max} */
const ssef minmax = max(max(tminmaxx, tminmaxy), max(tminmaxz, tsplat));
const ssef tminmax = minmax ^ pn;
const sseb lrhit = tminmax <= shuffle<2, 3, 0, 1>(tminmax);
/* decide which nodes to traverse next */
traverseChild0 = (movemask(lrhit) & 1);
traverseChild1 = (movemask(lrhit) & 2);
#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__)
bool closestChild1 = (c1min < c0min);
#else
bool closestChild1 = tminmax[1] < tminmax[0];
#endif
if(closestChild1) {
int tmp = nodeAddr;
nodeAddr = nodeAddrChild1;
nodeAddrChild1 = tmp;
}
++stackPtr;
kernel_assert(stackPtr < BVH_STACK_SIZE);
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_leaf_nodes, (-nodeAddr-1)*BVH_NODE_LEAF_SIZE);
int primAddr = __float_as_int(leaf.x);
#if BVH_FEATURE(BVH_INSTANCING)
if(primAddr >= 0) {
#endif
const int primAddr2 = __float_as_int(leaf.y);
const uint type = __float_as_int(leaf.w);
/* pop */
nodeAddr = traversalStack[stackPtr];
--stackPtr;
/* primitive intersection */
switch(type & PRIMITIVE_ALL) {
case PRIMITIVE_TRIANGLE: {
/* intersect ray against primitive */
for(; primAddr < primAddr2; primAddr++) {
kernel_assert(kernel_tex_fetch(__prim_type, primAddr) == type);
/* only primitives from the same object */
uint tri_object = (object == OBJECT_NONE)? kernel_tex_fetch(__prim_object, primAddr): object;
if(tri_object != subsurface_object)
continue;
triangle_intersect_subsurface(kg, &isect_precalc, isect_array, P, object, primAddr, isect_t, &num_hits, lcg_state, max_hits);
}
break;
}
#if BVH_FEATURE(BVH_MOTION)
case PRIMITIVE_MOTION_TRIANGLE: {
/* intersect ray against primitive */
for(; primAddr < primAddr2; primAddr++) {
kernel_assert(kernel_tex_fetch(__prim_type, primAddr) == type);
/* only primitives from the same object */
uint tri_object = (object == OBJECT_NONE)? kernel_tex_fetch(__prim_object, primAddr): object;
if(tri_object != subsurface_object)
continue;
motion_triangle_intersect_subsurface(kg, isect_array, P, dir, ray->time, object, primAddr, isect_t, &num_hits, lcg_state, max_hits);
}
break;
}
#endif
default: {
break;
}
}
}
#if BVH_FEATURE(BVH_INSTANCING)
else {
/* instance push */
if(subsurface_object == kernel_tex_fetch(__prim_object, -primAddr-1)) {
object = subsurface_object;
#if BVH_FEATURE(BVH_MOTION)
bvh_instance_motion_push(kg, object, ray, &P, &dir, &idir, &isect_t, &ob_tfm);
#else
bvh_instance_push(kg, object, ray, &P, &dir, &idir, &isect_t);
#endif
triangle_intersect_precalc(dir, &isect_precalc);
#if defined(__KERNEL_SSE2__)
Psplat[0] = ssef(P.x);
Psplat[1] = ssef(P.y);
Psplat[2] = ssef(P.z);
tsplat = ssef(0.0f, 0.0f, -isect_t, -isect_t);
gen_idirsplat_swap(pn, shuf_identity, shuf_swap, idir, idirsplat, shufflexyz);
#endif
++stackPtr;
kernel_assert(stackPtr < BVH_STACK_SIZE);
traversalStack[stackPtr] = ENTRYPOINT_SENTINEL;
nodeAddr = kernel_tex_fetch(__object_node, object);
}
else {
/* pop */
nodeAddr = traversalStack[stackPtr];
--stackPtr;
}
}
}
#endif /* FEATURE(BVH_INSTANCING) */
} while(nodeAddr != ENTRYPOINT_SENTINEL);
#if BVH_FEATURE(BVH_INSTANCING)
if(stackPtr >= 0) {
kernel_assert(object != OBJECT_NONE);
/* instance pop */
#if BVH_FEATURE(BVH_MOTION)
bvh_instance_motion_pop(kg, object, ray, &P, &dir, &idir, &isect_t, &ob_tfm);
#else
bvh_instance_pop(kg, object, ray, &P, &dir, &idir, &isect_t);
#endif
triangle_intersect_precalc(dir, &isect_precalc);
#if defined(__KERNEL_SSE2__)
Psplat[0] = ssef(P.x);
Psplat[1] = ssef(P.y);
Psplat[2] = ssef(P.z);
tsplat = ssef(0.0f, 0.0f, -isect_t, -isect_t);
gen_idirsplat_swap(pn, shuf_identity, shuf_swap, idir, idirsplat, shufflexyz);
#endif
object = OBJECT_NONE;
nodeAddr = traversalStack[stackPtr];
--stackPtr;
}
#endif /* FEATURE(BVH_INSTANCING) */
} while(nodeAddr != ENTRYPOINT_SENTINEL);
return num_hits;
}
ccl_device_inline uint BVH_FUNCTION_NAME(KernelGlobals *kg,
const Ray *ray,
Intersection *isect_array,
int subsurface_object,
uint *lcg_state,
int max_hits)
{
#ifdef __QBVH__
if(kernel_data.bvh.use_qbvh) {
return BVH_FUNCTION_FULL_NAME(QBVH)(kg,
ray,
isect_array,
subsurface_object,
lcg_state,
max_hits);
}
else
#endif
{
kernel_assert(kernel_data.bvh.use_qbvh == false);
return BVH_FUNCTION_FULL_NAME(BVH)(kg,
ray,
isect_array,
subsurface_object,
lcg_state,
max_hits);
}
}
#undef BVH_FUNCTION_NAME
#undef BVH_FUNCTION_FEATURES