mirror of https://github.com/axmolengine/axmol.git
63 lines
1.5 KiB
C++
63 lines
1.5 KiB
C++
/*
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Copyright 2010 Google Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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#ifndef GrRandom_DEFINED
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#define GrRandom_DEFINED
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class GrRandom {
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public:
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GrRandom() : fSeed(0) {}
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GrRandom(uint32_t seed) : fSeed(seed) {}
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uint32_t seed() const { return fSeed; }
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uint32_t nextU() {
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fSeed = fSeed * kMUL + kADD;
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return fSeed;
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}
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int32_t nextS() { return (int32_t)this->nextU(); }
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/**
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* Returns value [0...1) as a float
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*/
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float nextF() {
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// const is 1 / (2^32 - 1)
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return (float)(this->nextU() * 2.32830644e-10);
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}
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/**
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* Returns value [min...max) as a float
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*/
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float nextF(float min, float max) {
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return min + this->nextF() * (max - min);
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}
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private:
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/*
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* These constants taken from "Numerical Recipes in C", reprinted 1999
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*/
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enum {
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kMUL = 1664525,
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kADD = 1013904223
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};
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uint32_t fSeed;
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};
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#endif
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