forked from bartvdbraak/blender
03f28553ff
This commit implements traversal for QBVH tree, which is based on the old loop code for traversal itself and Embree for node intersection. This commit also does some changes to the loop inspired by Embree: - Visibility flags are only checked for primitives. Doing visibility check for every node cost quite reasonable amount of time and in most cases those checks are true-positive. Other idea here would be to do visibility checks for leaf nodes only, but this would need to be investigated further. - For minimum hair width we extend all the nodes' bounding boxes. Again doing curve visibility check is quite costly for each of the nodes and those checks returns truth for most of the hierarchy anyway. There are number of possible optimization still, but current state is good enough in terms it makes rendering faster a little bit after recent watertight commit. Currently QBVH is only implemented for CPU with SSE2 support at least. All other devices would need to be supported later (if that'd make sense from performance point of view). The code is enabled for compilation in kernel. but blender wouldn't use it still.
321 lines
9.8 KiB
C
321 lines
9.8 KiB
C
/*
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* Adapted from code Copyright 2009-2010 NVIDIA Corporation,
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* and code copyright 2009-2012 Intel Corporation
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*
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* Modifications Copyright 2011-2014, Blender Foundation.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/* This is a template BVH traversal function for volumes, where
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* various features can be enabled/disabled. This way we can compile optimized
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* versions for each case without new features slowing things down.
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*
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* BVH_INSTANCING: object instancing
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* BVH_HAIR: hair curve rendering
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* BVH_MOTION: motion blur rendering
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*
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*/
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ccl_device bool BVH_FUNCTION_FULL_NAME(QBVH)(KernelGlobals *kg,
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const Ray *ray,
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Intersection *isect)
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{
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/* TODO(sergey):
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* - Test if pushing distance on the stack helps.
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* - Likely and unlikely for if() statements.
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* - Test restrict attribute for pointers.
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*/
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/* Traversal stack in CUDA thread-local memory. */
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int traversalStack[BVH_STACK_SIZE];
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traversalStack[0] = ENTRYPOINT_SENTINEL;
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/* Traversal variables in registers. */
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int stackPtr = 0;
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int nodeAddr = kernel_data.bvh.root;
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/* Ray parameters in registers. */
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float3 P = ray->P;
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float3 dir = bvh_clamp_direction(ray->D);
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float3 idir = bvh_inverse_direction(dir);
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int object = OBJECT_NONE;
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const uint visibility = PATH_RAY_ALL_VISIBILITY;
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#if BVH_FEATURE(BVH_MOTION)
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Transform ob_tfm;
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#endif
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isect->t = ray->t;
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isect->u = 0.0f;
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isect->v = 0.0f;
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isect->prim = PRIM_NONE;
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isect->object = OBJECT_NONE;
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ssef tnear(0.0f), tfar(ray->t);
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sse3f idir4(ssef(idir.x), ssef(idir.y), ssef(idir.z));
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#ifdef __KERNEL_AVX2__
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float3 P_idir = P*idir;
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sse3f P_idir4 = sse3f(P_idir.x, P_idir.y, P_idir.z);
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#else
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sse3f org = sse3f(ssef(P.x), ssef(P.y), ssef(P.z));
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#endif
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/* Offsets to select the side that becomes the lower or upper bound. */
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int near_x, near_y, near_z;
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int far_x, far_y, far_z;
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if(idir.x >= 0.0f) { near_x = 0; far_x = 1; } else { near_x = 1; far_x = 0; }
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if(idir.y >= 0.0f) { near_y = 2; far_y = 3; } else { near_y = 3; far_y = 2; }
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if(idir.z >= 0.0f) { near_z = 4; far_z = 5; } else { near_z = 5; far_z = 4; }
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IsectPrecalc isect_precalc;
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triangle_intersect_precalc(dir, &isect_precalc);
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/* Traversal loop. */
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do {
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do {
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/* Traverse internal nodes. */
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while(nodeAddr >= 0 && nodeAddr != ENTRYPOINT_SENTINEL) {
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#if defined(__KERNEL_DEBUG__)
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isect->num_traversal_steps++;
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#endif
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ssef dist;
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int traverseChild = qbvh_node_intersect(kg,
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tnear,
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tfar,
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#ifdef __KERNEL_AVX2__
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P_idir4,
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#else
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org,
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#endif
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idir4,
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near_x, near_y, near_z,
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far_x, far_y, far_z,
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nodeAddr,
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&dist);
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if(traverseChild != 0) {
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float4 cnodes = kernel_tex_fetch(__bvh_nodes, nodeAddr*BVH_QNODE_SIZE+6);
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/* One child is hit, continue with that child. */
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int r = __bscf(traverseChild);
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if(traverseChild == 0) {
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nodeAddr = __float_as_int(cnodes[r]);
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continue;
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}
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/* Two children are hit, push far child, and continue with
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* closer child.
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*/
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int c0 = __float_as_int(cnodes[r]);
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float d0 = ((float*)&dist)[r];
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r = __bscf(traverseChild);
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int c1 = __float_as_int(cnodes[r]);
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float d1 = ((float*)&dist)[r];
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if(traverseChild == 0) {
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if(d1 < d0) {
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nodeAddr = c1;
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++stackPtr;
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traversalStack[stackPtr] = c0;
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continue;
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}
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else {
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nodeAddr = c0;
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++stackPtr;
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traversalStack[stackPtr] = c1;
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continue;
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}
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}
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/* Here starts the slow path for 3 or 4 hit children. We push
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* all nodes onto the stack to sort them there.
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*/
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++stackPtr;
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traversalStack[stackPtr] = c1;
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++stackPtr;
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traversalStack[stackPtr] = c0;
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/* Three children are hit, push all onto stack and sort 3
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* stack items, continue with closest child.
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*/
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r = __bscf(traverseChild);
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int c2 = __float_as_int(cnodes[r]);
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float d2 = ((float*)&dist)[r];
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if(traverseChild == 0) {
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++stackPtr;
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traversalStack[stackPtr] = c2;
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qbvh_stack_sort(&traversalStack[stackPtr],
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&traversalStack[stackPtr - 1],
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&traversalStack[stackPtr - 2],
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&d2, &d1, &d0);
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nodeAddr = traversalStack[stackPtr];
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--stackPtr;
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continue;
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}
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/* Four children are hit, push all onto stack and sort 4
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* stack items, continue with closest child.
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*/
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r = __bscf(traverseChild);
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int c3 = __float_as_int(cnodes[r]);
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float d3 = ((float*)&dist)[r];
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++stackPtr;
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traversalStack[stackPtr] = c3;
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++stackPtr;
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traversalStack[stackPtr] = c2;
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qbvh_stack_sort(&traversalStack[stackPtr],
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&traversalStack[stackPtr - 1],
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&traversalStack[stackPtr - 2],
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&traversalStack[stackPtr - 3],
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&d3, &d2, &d1, &d0);
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}
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nodeAddr = traversalStack[stackPtr];
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--stackPtr;
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}
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/* If node is leaf, fetch triangle list. */
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if(nodeAddr < 0) {
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float4 leaf = kernel_tex_fetch(__bvh_nodes, (-nodeAddr-1)*BVH_QNODE_SIZE+6);
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int primAddr = __float_as_int(leaf.x);
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#if BVH_FEATURE(BVH_INSTANCING)
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if(primAddr >= 0) {
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#endif
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int primAddr2 = __float_as_int(leaf.y);
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/* Pop. */
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nodeAddr = traversalStack[stackPtr];
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--stackPtr;
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/* Primitive intersection. */
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for(; primAddr < primAddr2; primAddr++) {
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/* Only primitives from volume object. */
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uint tri_object = (object == OBJECT_NONE)? kernel_tex_fetch(__prim_object, primAddr): object;
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int object_flag = kernel_tex_fetch(__object_flag, tri_object);
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if((object_flag & SD_OBJECT_HAS_VOLUME) == 0) {
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continue;
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}
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/* Intersect ray against primitive. */
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uint type = kernel_tex_fetch(__prim_type, primAddr);
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switch(type & PRIMITIVE_ALL) {
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case PRIMITIVE_TRIANGLE: {
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triangle_intersect(kg, &isect_precalc, isect, P, dir, visibility, object, primAddr);
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break;
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}
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#if BVH_FEATURE(BVH_MOTION)
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case PRIMITIVE_MOTION_TRIANGLE: {
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motion_triangle_intersect(kg, isect, P, dir, ray->time, visibility, object, primAddr);
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break;
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}
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#endif
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#if BVH_FEATURE(BVH_HAIR)
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case PRIMITIVE_CURVE:
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case PRIMITIVE_MOTION_CURVE: {
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if(kernel_data.curve.curveflags & CURVE_KN_INTERPOLATE)
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bvh_cardinal_curve_intersect(kg, isect, P, dir, visibility, object, primAddr, ray->time, type, NULL, 0, 0);
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else
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bvh_curve_intersect(kg, isect, P, dir, visibility, object, primAddr, ray->time, type, NULL, 0, 0);
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break;
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}
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#endif
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default: {
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break;
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}
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}
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}
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}
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#if BVH_FEATURE(BVH_INSTANCING)
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else {
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/* Instance push. */
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object = kernel_tex_fetch(__prim_object, -primAddr-1);
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int object_flag = kernel_tex_fetch(__object_flag, object);
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if(object_flag & SD_OBJECT_HAS_VOLUME) {
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#if BVH_FEATURE(BVH_MOTION)
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bvh_instance_motion_push(kg, object, ray, &P, &dir, &idir, &isect->t, &ob_tfm);
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#else
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bvh_instance_push(kg, object, ray, &P, &dir, &idir, &isect->t);
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#endif
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if(idir.x >= 0.0f) { near_x = 0; far_x = 1; } else { near_x = 1; far_x = 0; }
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if(idir.y >= 0.0f) { near_y = 2; far_y = 3; } else { near_y = 3; far_y = 2; }
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if(idir.z >= 0.0f) { near_z = 4; far_z = 5; } else { near_z = 5; far_z = 4; }
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tfar = ssef(isect->t);
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idir4 = sse3f(ssef(idir.x), ssef(idir.y), ssef(idir.z));
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#ifdef __KERNEL_AVX2__
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P_idir = P*idir;
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P_idir4 = sse3f(P_idir.x, P_idir.y, P_idir.z);
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#else
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org = sse3f(ssef(P.x), ssef(P.y), ssef(P.z));
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#endif
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triangle_intersect_precalc(dir, &isect_precalc);
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++stackPtr;
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traversalStack[stackPtr] = ENTRYPOINT_SENTINEL;
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nodeAddr = kernel_tex_fetch(__object_node, object);
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}
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else {
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/* Pop. */
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object = OBJECT_NONE;
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nodeAddr = traversalStack[stackPtr];
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--stackPtr;
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}
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}
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}
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#endif /* FEATURE(BVH_INSTANCING) */
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} while(nodeAddr != ENTRYPOINT_SENTINEL);
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#if BVH_FEATURE(BVH_INSTANCING)
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if(stackPtr >= 0) {
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kernel_assert(object != OBJECT_NONE);
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/* Instance pop. */
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#if BVH_FEATURE(BVH_MOTION)
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bvh_instance_motion_pop(kg, object, ray, &P, &dir, &idir, &isect->t, &ob_tfm);
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#else
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bvh_instance_pop(kg, object, ray, &P, &dir, &idir, &isect->t);
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#endif
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if(idir.x >= 0.0f) { near_x = 0; far_x = 1; } else { near_x = 1; far_x = 0; }
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if(idir.y >= 0.0f) { near_y = 2; far_y = 3; } else { near_y = 3; far_y = 2; }
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if(idir.z >= 0.0f) { near_z = 4; far_z = 5; } else { near_z = 5; far_z = 4; }
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tfar = ssef(isect->t);
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idir4 = sse3f(ssef(idir.x), ssef(idir.y), ssef(idir.z));
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#ifdef __KERNEL_AVX2__
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P_idir = P*idir;
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P_idir4 = sse3f(P_idir.x, P_idir.y, P_idir.z);
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#else
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org = sse3f(ssef(P.x), ssef(P.y), ssef(P.z));
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#endif
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triangle_intersect_precalc(dir, &isect_precalc);
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object = OBJECT_NONE;
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nodeAddr = traversalStack[stackPtr];
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--stackPtr;
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}
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#endif /* FEATURE(BVH_INSTANCING) */
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} while(nodeAddr != ENTRYPOINT_SENTINEL);
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return (isect->prim != PRIM_NONE);
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}
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