blender/intern/cycles/bvh/bvh_sort.cpp
Brecht Van Lommel 48a6fe86ca Fix #34172: cycles BVH build crashing in some rare circumstances on 32 bit linux.
The problem was (again) the x86 extended precision float register being used for
one float value while the other was rounded to lower precision. This caused the
strictly weak order requirement for std::sort to be broken.
2013-04-26 02:18:29 +00:00

70 lines
2.0 KiB
C++

/*
* 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_build.h"
#include "bvh_sort.h"
#include "util_algorithm.h"
#include "util_debug.h"
CCL_NAMESPACE_BEGIN
/* silly workaround for float extended precision that happens when compiling
* on x86, due to one float staying in 80 bit precision register and the other
* not, which causes the strictly weak ordering to break */
#if !defined(__i386__)
#define NO_EXTENDED_PRECISION
#else
#define NO_EXTENDED_PRECISION volatile
#endif
struct BVHReferenceCompare {
public:
int dim;
BVHReferenceCompare(int dim_)
{
dim = dim_;
}
bool operator()(const BVHReference& ra, const BVHReference& rb)
{
NO_EXTENDED_PRECISION float ca = ra.bounds().min[dim] + ra.bounds().max[dim];
NO_EXTENDED_PRECISION float cb = rb.bounds().min[dim] + rb.bounds().max[dim];
if(ca < cb) return true;
else if(ca > cb) return false;
else if(ra.prim_object() < rb.prim_object()) return true;
else if(ra.prim_object() > rb.prim_object()) return false;
else if(ra.prim_index() < rb.prim_index()) return true;
else if(ra.prim_index() > rb.prim_index()) return false;
else if(ra.prim_segment() < rb.prim_segment()) return true;
else if(ra.prim_segment() > rb.prim_segment()) return false;
return false;
}
};
void bvh_reference_sort(int start, int end, BVHReference *data, int dim)
{
BVHReferenceCompare compare(dim);
sort(data+start, data+end, compare);
}
CCL_NAMESPACE_END