e955c94ed3
Listing the "Blender Foundation" as copyright holder implied the Blender Foundation holds copyright to files which may include work from many developers. While keeping copyright on headers makes sense for isolated libraries, Blender's own code may be refactored or moved between files in a way that makes the per file copyright holders less meaningful. Copyright references to the "Blender Foundation" have been replaced with "Blender Authors", with the exception of `./extern/` since these this contains libraries which are more isolated, any changed to license headers there can be handled on a case-by-case basis. Some directories in `./intern/` have also been excluded: - `./intern/cycles/` it's own `AUTHORS` file is planned. - `./intern/opensubdiv/`. An "AUTHORS" file has been added, using the chromium projects authors file as a template. Design task: #110784 Ref !110783.
123 lines
2.4 KiB
C++
123 lines
2.4 KiB
C++
/* SPDX-FileCopyrightText: 2012-2022 Blender Authors
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*
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* SPDX-License-Identifier: GPL-2.0-or-later */
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/** \file
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* \ingroup freestyle
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* \brief Pseudo-random number generator
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*/
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#include "RandGen.h"
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#include "BLI_sys_types.h"
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namespace Freestyle {
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//
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// Macro definitions
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//
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///////////////////////////////////////////////////////////////////////////////
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#define N 16
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#define MASK (uint(1 << (N - 1)) + (1 << (N - 1)) - 1)
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#define X0 0x330E
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#define X1 0xABCD
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#define X2 0x1234
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#define A0 0xE66D
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#define A1 0xDEEC
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#define A2 0x5
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#define C 0xB
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#if 0 // XXX Unused
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# define HI_BIT (1L << (2 * N - 1))
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#endif
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#define LOW(x) (uint(x) & MASK)
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#define HIGH(x) LOW((x) >> N)
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#define MUL(x, y, z) \
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{ \
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long l = long(x) * long(y); \
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(z)[0] = LOW(l); \
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(z)[1] = HIGH(l); \
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} \
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((void)0)
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#define CARRY(x, y) (ulong(long(x) + long(y)) > MASK)
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#define ADDEQU(x, y, z) (z = CARRY(x, (y)), x = LOW(x + (y)))
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#define SET3(x, x0, x1, x2) ((x)[0] = (x0), (x)[1] = (x1), (x)[2] = (x2))
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#if 0 // XXX, unused
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# define SETLOW(x, y, n) SET3(x, LOW((y)[n]), LOW((y)[(n) + 1]), LOW((y)[(n) + 2]))
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#endif
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#define SEED(x0, x1, x2) (SET3(x, x0, x1, x2), SET3(a, A0, A1, A2), c = C)
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#if 0 // XXX, unused
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# define REST(v) \
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for (i = 0; i < 3; i++) { \
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xsubi[i] = x[i]; \
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x[i] = temp[i]; \
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} \
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return (v); \
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(void)0
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# define NEST(TYPE, f, F) \
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TYPE f(ushort *xsubi) \
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{ \
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int i; \
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TYPE v; \
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uint temp[3]; \
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for (i = 0; i < 3; i++) { \
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temp[i] = x[i]; \
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x[i] = LOW(xsubi[i]); \
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} \
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v = F(); \
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REST(v); \
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}
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#endif
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static uint x[3] = {
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X0,
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X1,
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X2,
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};
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static uint a[3] = {
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A0,
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A1,
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A2,
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};
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static uint c = C;
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//
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// Methods implementation
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//
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///////////////////////////////////////////////////////////////////////////////
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real RandGen::drand48()
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{
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static real two16m = 1.0 / (1L << N);
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next();
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return (two16m * (two16m * (two16m * x[0] + x[1]) + x[2]));
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}
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void RandGen::srand48(long seedval)
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{
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SEED(X0, LOW(seedval), HIGH(seedval));
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}
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void RandGen::next()
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{
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uint p[2], q[2], r[2], carry0, carry1;
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MUL(a[0], x[0], p);
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ADDEQU(p[0], c, carry0);
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ADDEQU(p[1], carry0, carry1);
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MUL(a[0], x[1], q);
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ADDEQU(p[1], q[0], carry0);
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MUL(a[1], x[0], r);
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x[2] = LOW(carry0 + carry1 + CARRY(p[1], r[0]) + q[1] + r[1] + a[0] * x[2] + a[1] * x[1] +
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a[2] * x[0]);
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x[1] = LOW(p[1] + r[0]);
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x[0] = LOW(p[0]);
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}
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} /* namespace Freestyle */
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