d7d40745fa
* Split render/ into scene/ and session/. The scene/ folder now contains the scene and its nodes. The session/ folder contains the render session and associated data structures like drivers and render buffers. * Move top level kernel headers into new folders kernel/camera/, kernel/film/, kernel/light/, kernel/sample/, kernel/util/ * Move integrator related kernel headers into kernel/integrator/ * Move OSL shaders from kernel/shaders/ to kernel/osl/shaders/ For patches and branches, git merge and rebase should be able to detect the renames and move over code to the right file.
95 lines
3.2 KiB
C++
95 lines
3.2 KiB
C++
/*
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* Sobol sequence direction vectors.
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*
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* This file contains code to create direction vectors for generating sobol
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* sequences in high dimensions. It is adapted from code on this webpage:
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*
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* http://web.maths.unsw.edu.au/~fkuo/sobol/
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*
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* From these papers:
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*
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* S. Joe and F. Y. Kuo, Remark on Algorithm 659: Implementing Sobol's quasirandom
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* sequence generator, ACM Trans. Math. Softw. 29, 49-57 (2003)
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*
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* S. Joe and F. Y. Kuo, Constructing Sobol sequences with better two-dimensional
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* projections, SIAM J. Sci. Comput. 30, 2635-2654 (2008)
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*/
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/* Copyright (c) 2008, Frances Y. Kuo and Stephen Joe
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* * Neither the names of the copyright holders nor the names of the
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* University of New South Wales and the University of Waikato
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* and its contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "util/util_types.h"
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#include "scene/sobol.h"
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CCL_NAMESPACE_BEGIN
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#include "sobol.tables"
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void sobol_generate_direction_vectors(uint vectors[][SOBOL_BITS], int dimensions)
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{
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assert(dimensions <= SOBOL_MAX_DIMENSIONS);
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const uint L = SOBOL_BITS;
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/* first dimension is exception */
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uint *v = vectors[0];
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for (uint i = 0; i < L; i++)
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v[i] = 1 << (31 - i); // all m's = 1
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for (int dim = 1; dim < dimensions; dim++) {
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const SobolDirectionNumbers *numbers = &SOBOL_NUMBERS[dim - 1];
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const uint s = numbers->s;
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const uint a = numbers->a;
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const uint *m = numbers->m;
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v = vectors[dim];
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if (L <= s) {
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for (uint i = 0; i < L; i++)
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v[i] = m[i] << (31 - i);
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}
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else {
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for (uint i = 0; i < s; i++)
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v[i] = m[i] << (31 - i);
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for (uint i = s; i < L; i++) {
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v[i] = v[i - s] ^ (v[i - s] >> s);
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for (uint k = 1; k < s; k++)
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v[i] ^= (((a >> (s - 1 - k)) & 1) * v[i - k]);
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}
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}
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}
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}
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CCL_NAMESPACE_END
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