diff options
Diffstat (limited to 'intern/cycles/bvh/sort.cpp')
| -rw-r--r-- | intern/cycles/bvh/sort.cpp | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/intern/cycles/bvh/sort.cpp b/intern/cycles/bvh/sort.cpp new file mode 100644 index 00000000000..a9975ce6bb2 --- /dev/null +++ b/intern/cycles/bvh/sort.cpp @@ -0,0 +1,187 @@ +/* + * 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. + */ + +#include "bvh/sort.h" + +#include "bvh/build.h" + +#include "util/algorithm.h" +#include "util/task.h" + +CCL_NAMESPACE_BEGIN + +static const int BVH_SORT_THRESHOLD = 4096; + +struct BVHReferenceCompare { + public: + int dim; + const BVHUnaligned *unaligned_heuristic; + const Transform *aligned_space; + + BVHReferenceCompare(int dim, + const BVHUnaligned *unaligned_heuristic, + const Transform *aligned_space) + : dim(dim), unaligned_heuristic(unaligned_heuristic), aligned_space(aligned_space) + { + } + + __forceinline BoundBox get_prim_bounds(const BVHReference &prim) const + { + return (aligned_space != NULL) ? + unaligned_heuristic->compute_aligned_prim_boundbox(prim, *aligned_space) : + prim.bounds(); + } + + /* Compare two references. + * + * Returns value is similar to return value of strcmp(). + */ + __forceinline int compare(const BVHReference &ra, const BVHReference &rb) const + { + BoundBox ra_bounds = get_prim_bounds(ra), rb_bounds = get_prim_bounds(rb); + float ca = ra_bounds.min[dim] + ra_bounds.max[dim]; + float cb = rb_bounds.min[dim] + rb_bounds.max[dim]; + + if (ca < cb) + return -1; + else if (ca > cb) + return 1; + else if (ra.prim_object() < rb.prim_object()) + return -1; + else if (ra.prim_object() > rb.prim_object()) + return 1; + else if (ra.prim_index() < rb.prim_index()) + return -1; + else if (ra.prim_index() > rb.prim_index()) + return 1; + else if (ra.prim_type() < rb.prim_type()) + return -1; + else if (ra.prim_type() > rb.prim_type()) + return 1; + + return 0; + } + + bool operator()(const BVHReference &ra, const BVHReference &rb) + { + return (compare(ra, rb) < 0); + } +}; + +static void bvh_reference_sort_threaded(TaskPool *task_pool, + BVHReference *data, + const int job_start, + const int job_end, + const BVHReferenceCompare &compare); + +/* Multi-threaded reference sort. */ +static void bvh_reference_sort_threaded(TaskPool *task_pool, + BVHReference *data, + const int job_start, + const int job_end, + const BVHReferenceCompare &compare) +{ + int start = job_start, end = job_end; + bool have_work = (start < end); + while (have_work) { + const int count = job_end - job_start; + if (count < BVH_SORT_THRESHOLD) { + /* Number of reference low enough, faster to finish the job + * in one thread rather than to spawn more threads. + */ + sort(data + job_start, data + job_end + 1, compare); + break; + } + /* Single QSort step. + * Use median-of-three method for the pivot point. + */ + int left = start, right = end; + int center = (left + right) >> 1; + if (compare.compare(data[left], data[center]) > 0) { + swap(data[left], data[center]); + } + if (compare.compare(data[left], data[right]) > 0) { + swap(data[left], data[right]); + } + if (compare.compare(data[center], data[right]) > 0) { + swap(data[center], data[right]); + } + swap(data[center], data[right - 1]); + BVHReference median = data[right - 1]; + do { + while (compare.compare(data[left], median) < 0) { + ++left; + } + while (compare.compare(data[right], median) > 0) { + --right; + } + if (left <= right) { + swap(data[left], data[right]); + ++left; + --right; + } + } while (left <= right); + /* We only create one new task here to reduce downside effects of + * latency in TaskScheduler. + * So generally current thread keeps working on the left part of the + * array, and we create new task for the right side. + * However, if there's nothing to be done in the left side of the array + * we don't create any tasks and make it so current thread works on the + * right side. + */ + have_work = false; + if (left < end) { + if (start < right) { + task_pool->push( + function_bind(bvh_reference_sort_threaded, task_pool, data, left, end, compare)); + } + else { + start = left; + have_work = true; + } + } + if (start < right) { + end = right; + have_work = true; + } + } +} + +void bvh_reference_sort(int start, + int end, + BVHReference *data, + int dim, + const BVHUnaligned *unaligned_heuristic, + const Transform *aligned_space) +{ + const int count = end - start; + BVHReferenceCompare compare(dim, unaligned_heuristic, aligned_space); + if (count < BVH_SORT_THRESHOLD) { + /* It is important to not use any mutex if array is small enough, + * otherwise we end up in situation when we're going to sleep far + * too often. + */ + sort(data + start, data + end, compare); + } + else { + TaskPool task_pool; + bvh_reference_sort_threaded(&task_pool, data, start, end - 1, compare); + task_pool.wait_work(); + } +} + +CCL_NAMESPACE_END |