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.
144 lines
2.7 KiB
C++
144 lines
2.7 KiB
C++
/* SPDX-FileCopyrightText: 2023 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 bli
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*/
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#pragma once
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#include "BLI_math_vector_types.hh"
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#include "BLI_span.hh"
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#include "BLI_utildefines.h"
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namespace blender {
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class RandomNumberGenerator {
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private:
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uint64_t x_;
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public:
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RandomNumberGenerator(uint32_t seed = 0)
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{
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this->seed(seed);
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}
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/**
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* Set the seed for future random numbers.
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*/
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void seed(uint32_t seed)
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{
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constexpr uint64_t lowseed = 0x330E;
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x_ = (uint64_t(seed) << 16) | lowseed;
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}
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/**
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* Set a randomized hash of the value as seed.
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*/
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void seed_random(uint32_t seed);
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uint32_t get_uint32()
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{
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this->step();
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return uint32_t(x_ >> 17);
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}
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int32_t get_int32()
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{
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this->step();
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return int32_t(x_ >> 17);
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}
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/**
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* \return Random value (0..N), but never N.
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*/
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int32_t get_int32(int32_t max_exclusive)
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{
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BLI_assert(max_exclusive > 0);
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return this->get_int32() % max_exclusive;
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}
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/**
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* \return Random value (0..1), but never 1.0.
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*/
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double get_double()
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{
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return double(this->get_int32()) / 0x80000000;
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}
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/**
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* \return Random value (0..1), but never 1.0.
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*/
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float get_float()
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{
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return (float)this->get_int32() / 0x80000000;
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}
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template<typename T> void shuffle(MutableSpan<T> values)
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{
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/* Cannot shuffle arrays of this size yet. */
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BLI_assert(values.size() <= INT32_MAX);
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for (int i = values.size() - 1; i >= 2; i--) {
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int j = this->get_int32(i);
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if (i != j) {
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std::swap(values[i], values[j]);
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}
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}
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}
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/**
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* Compute uniformly distributed barycentric coordinates.
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*/
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float3 get_barycentric_coordinates()
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{
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float rand1 = this->get_float();
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float rand2 = this->get_float();
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if (rand1 + rand2 > 1.0f) {
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rand1 = 1.0f - rand1;
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rand2 = 1.0f - rand2;
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}
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return float3(rand1, rand2, 1.0f - rand1 - rand2);
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}
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/**
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* Round value to the next integer randomly.
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* 4.9f is more likely to round to 5 than 4.6f.
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*/
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int round_probabilistic(float x);
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float2 get_unit_float2();
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float3 get_unit_float3();
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/**
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* Generate a random point inside the given triangle.
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*/
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float2 get_triangle_sample(float2 v1, float2 v2, float2 v3);
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float3 get_triangle_sample_3d(float3 v1, float3 v2, float3 v3);
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void get_bytes(MutableSpan<char> r_bytes);
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/**
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* Simulate getting \a n random values.
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*/
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void skip(int64_t n)
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{
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while (n--) {
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this->step();
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}
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}
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private:
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void step()
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{
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constexpr uint64_t multiplier = 0x5DEECE66Dll;
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constexpr uint64_t addend = 0xB;
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constexpr uint64_t mask = 0x0000FFFFFFFFFFFFll;
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x_ = (multiplier * x_ + addend) & mask;
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}
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};
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} // namespace blender
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