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//
// Copyright 2014 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// random_utils:
// Helper functions for random number generation.
//
#ifndef UTIL_RANDOM_UTILS_H
#define UTIL_RANDOM_UTILS_H
#include <random>
#include <vector>
#include "common/vector_utils.h"
#include "util/util_export.h"
namespace angle
{
class ANGLE_UTIL_EXPORT RNG
{
public:
// Seed from clock
RNG();
// Seed from fixed number.
RNG(unsigned int seed);
~RNG();
void reseed(unsigned int newSeed);
bool randomBool(float probTrue = 0.5f);
int randomInt();
int randomIntBetween(int min, int max);
unsigned int randomUInt();
float randomFloat();
float randomFloatBetween(float min, float max);
float randomFloatNonnegative();
float randomNegativeOneToOne();
template <class T>
T &randomSelect(std::vector<T> &elements)
{
return elements[randomIntBetween(0, static_cast<int>(elements.size()) - 1)];
}
template <class T>
const T &randomSelect(const std::vector<T> &elements)
{
return elements.at(randomIntBetween(0, static_cast<int>(elements.size()) - 1));
}
private:
std::default_random_engine mGenerator;
};
// Implemented inline to avoid cross-module allocation issues.
inline void FillVectorWithRandomUBytes(RNG *rng, std::vector<uint8_t> *data)
{
for (size_t i = 0; i < data->size(); ++i)
{
(*data)[i] = static_cast<uint8_t>(rng->randomIntBetween(0, 255));
}
}
inline void FillVectorWithRandomUBytes(std::vector<uint8_t> *data)
{
RNG rng;
FillVectorWithRandomUBytes(&rng, data);
}
inline Vector3 RandomVec3(int seed, float minValue, float maxValue)
{
RNG rng(seed);
srand(seed);
return Vector3(rng.randomFloatBetween(minValue, maxValue),
rng.randomFloatBetween(minValue, maxValue),
rng.randomFloatBetween(minValue, maxValue));
}
inline Vector4 RandomVec4(int seed, float minValue, float maxValue)
{
RNG rng(seed);
srand(seed);
return Vector4(
rng.randomFloatBetween(minValue, maxValue), rng.randomFloatBetween(minValue, maxValue),
rng.randomFloatBetween(minValue, maxValue), rng.randomFloatBetween(minValue, maxValue));
}
} // namespace angle
#endif // UTIL_RANDOM_UTILS_H
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