13c827367444ee418f129b2c238299f49d3264554Jarkko Poyry/*------------------------------------------------------------------------- 23c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * drawElements Base Portability Library 33c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * ------------------------------------- 43c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * 53c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * Copyright 2014 The Android Open Source Project 63c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * 73c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * Licensed under the Apache License, Version 2.0 (the "License"); 83c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * you may not use this file except in compliance with the License. 93c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * You may obtain a copy of the License at 103c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * 113c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * http://www.apache.org/licenses/LICENSE-2.0 123c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * 133c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * Unless required by applicable law or agreed to in writing, software 143c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * distributed under the License is distributed on an "AS IS" BASIS, 153c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 163c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * See the License for the specific language governing permissions and 173c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * limitations under the License. 183c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * 193c827367444ee418f129b2c238299f49d3264554Jarkko Poyry *//*! 203c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \file 213c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \brief Random number generation. 223c827367444ee418f129b2c238299f49d3264554Jarkko Poyry *//*--------------------------------------------------------------------*/ 233c827367444ee418f129b2c238299f49d3264554Jarkko Poyry 243c827367444ee418f129b2c238299f49d3264554Jarkko Poyry#include "deRandom.h" 253c827367444ee418f129b2c238299f49d3264554Jarkko Poyry 263c827367444ee418f129b2c238299f49d3264554Jarkko Poyry#include <float.h> 273c827367444ee418f129b2c238299f49d3264554Jarkko Poyry#include <math.h> 283c827367444ee418f129b2c238299f49d3264554Jarkko Poyry 293c827367444ee418f129b2c238299f49d3264554Jarkko PoyryDE_BEGIN_EXTERN_C 303c827367444ee418f129b2c238299f49d3264554Jarkko Poyry 313c827367444ee418f129b2c238299f49d3264554Jarkko Poyry/*--------------------------------------------------------------------*//*! 323c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \brief Initialize a random number generator with a given seed. 333c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \param rnd RNG to initialize. 343c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \param seed Seed value used for random values. 353c827367444ee418f129b2c238299f49d3264554Jarkko Poyry *//*--------------------------------------------------------------------*/ 363c827367444ee418f129b2c238299f49d3264554Jarkko Poyryvoid deRandom_init (deRandom* rnd, deUint32 seed) 373c827367444ee418f129b2c238299f49d3264554Jarkko Poyry{ 383c827367444ee418f129b2c238299f49d3264554Jarkko Poyry rnd->x = (deUint32)(-(int)seed ^ 123456789); 393c827367444ee418f129b2c238299f49d3264554Jarkko Poyry rnd->y = (deUint32)(362436069 * seed); 403c827367444ee418f129b2c238299f49d3264554Jarkko Poyry rnd->z = (deUint32)(521288629 ^ (seed >> 7)); 413c827367444ee418f129b2c238299f49d3264554Jarkko Poyry rnd->w = (deUint32)(88675123 ^ (seed << 3)); 423c827367444ee418f129b2c238299f49d3264554Jarkko Poyry} 433c827367444ee418f129b2c238299f49d3264554Jarkko Poyry 443c827367444ee418f129b2c238299f49d3264554Jarkko Poyry/*--------------------------------------------------------------------*//*! 453c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \brief Get a pseudo random uint32. 463c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \param rnd Pointer to RNG. 473c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \return Random uint32 number. 483c827367444ee418f129b2c238299f49d3264554Jarkko Poyry *//*--------------------------------------------------------------------*/ 493c827367444ee418f129b2c238299f49d3264554Jarkko PoyrydeUint32 deRandom_getUint32 (deRandom* rnd) 503c827367444ee418f129b2c238299f49d3264554Jarkko Poyry{ 513c827367444ee418f129b2c238299f49d3264554Jarkko Poyry deUint32 w = rnd->w; 523c827367444ee418f129b2c238299f49d3264554Jarkko Poyry deUint32 t; 533c827367444ee418f129b2c238299f49d3264554Jarkko Poyry 543c827367444ee418f129b2c238299f49d3264554Jarkko Poyry t = rnd->x ^ (rnd->x << 11); 553c827367444ee418f129b2c238299f49d3264554Jarkko Poyry rnd->x = rnd->y; 563c827367444ee418f129b2c238299f49d3264554Jarkko Poyry rnd->y = rnd->z; 573c827367444ee418f129b2c238299f49d3264554Jarkko Poyry rnd->z = w; 583c827367444ee418f129b2c238299f49d3264554Jarkko Poyry rnd->w = w = (w ^ (w >> 19)) ^ (t ^ (t >> 8)); 593c827367444ee418f129b2c238299f49d3264554Jarkko Poyry return w; 603c827367444ee418f129b2c238299f49d3264554Jarkko Poyry} 613c827367444ee418f129b2c238299f49d3264554Jarkko Poyry 623c827367444ee418f129b2c238299f49d3264554Jarkko Poyry/*--------------------------------------------------------------------*//*! 633c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \brief Get a pseudo random uint64. 643c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \param rnd Pointer to RNG. 653c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \return Random uint64 number. 663c827367444ee418f129b2c238299f49d3264554Jarkko Poyry *//*--------------------------------------------------------------------*/ 673c827367444ee418f129b2c238299f49d3264554Jarkko PoyrydeUint64 deRandom_getUint64 (deRandom* rnd) 683c827367444ee418f129b2c238299f49d3264554Jarkko Poyry{ 693c827367444ee418f129b2c238299f49d3264554Jarkko Poyry deUint64 x = deRandom_getUint32(rnd); 703c827367444ee418f129b2c238299f49d3264554Jarkko Poyry return x << 32 | deRandom_getUint32(rnd); 713c827367444ee418f129b2c238299f49d3264554Jarkko Poyry} 723c827367444ee418f129b2c238299f49d3264554Jarkko Poyry 733c827367444ee418f129b2c238299f49d3264554Jarkko Poyry/*--------------------------------------------------------------------*//*! 743c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \brief Get a pseudo random float in range [0, 1[. 753c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \param rnd Pointer to RNG. 763c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \return Random float number. 773c827367444ee418f129b2c238299f49d3264554Jarkko Poyry *//*--------------------------------------------------------------------*/ 783c827367444ee418f129b2c238299f49d3264554Jarkko Poyryfloat deRandom_getFloat (deRandom* rnd) 793c827367444ee418f129b2c238299f49d3264554Jarkko Poyry{ 803c827367444ee418f129b2c238299f49d3264554Jarkko Poyry return (float)(deRandom_getUint32(rnd) & 0xFFFFFFFu) / (float)(0xFFFFFFFu+1); 813c827367444ee418f129b2c238299f49d3264554Jarkko Poyry} 823c827367444ee418f129b2c238299f49d3264554Jarkko Poyry 833c827367444ee418f129b2c238299f49d3264554Jarkko Poyry/*--------------------------------------------------------------------*//*! 843c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \brief Get a pseudo random float in range [0, 1[. 853c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \param rnd Pointer to RNG. 863c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \return Random float number. 873c827367444ee418f129b2c238299f49d3264554Jarkko Poyry *//*--------------------------------------------------------------------*/ 883c827367444ee418f129b2c238299f49d3264554Jarkko Poyrydouble deRandom_getDouble (deRandom* rnd) 893c827367444ee418f129b2c238299f49d3264554Jarkko Poyry{ 903c827367444ee418f129b2c238299f49d3264554Jarkko Poyry DE_STATIC_ASSERT(FLT_RADIX == 2); 913c827367444ee418f129b2c238299f49d3264554Jarkko Poyry return ldexp((double)(deRandom_getUint64(rnd) & ((1ull << DBL_MANT_DIG) - 1)), 923c827367444ee418f129b2c238299f49d3264554Jarkko Poyry -DBL_MANT_DIG); 933c827367444ee418f129b2c238299f49d3264554Jarkko Poyry} 943c827367444ee418f129b2c238299f49d3264554Jarkko Poyry 953c827367444ee418f129b2c238299f49d3264554Jarkko Poyry/*--------------------------------------------------------------------*//*! 963c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \brief Get a pseudo random boolean value (DE_FALSE or DE_TRUE). 973c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \param rnd Pointer to RNG. 983c827367444ee418f129b2c238299f49d3264554Jarkko Poyry * \return Random float number. 993c827367444ee418f129b2c238299f49d3264554Jarkko Poyry *//*--------------------------------------------------------------------*/ 1003c827367444ee418f129b2c238299f49d3264554Jarkko PoyrydeBool deRandom_getBool (deRandom* rnd) 1013c827367444ee418f129b2c238299f49d3264554Jarkko Poyry{ 1023c827367444ee418f129b2c238299f49d3264554Jarkko Poyry deUint32 val = deRandom_getUint32(rnd); 1033c827367444ee418f129b2c238299f49d3264554Jarkko Poyry return ((val & 0xFFFFFF) < 0x800000); 1043c827367444ee418f129b2c238299f49d3264554Jarkko Poyry} 1053c827367444ee418f129b2c238299f49d3264554Jarkko Poyry 1063c827367444ee418f129b2c238299f49d3264554Jarkko PoyryDE_END_EXTERN_C 107