94 lines
2.7 KiB
Plaintext
94 lines
2.7 KiB
Plaintext
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/* -*-c++-*- */
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/* osgEarth - Geospatial SDK for OpenSceneGraph
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* Copyright 2020 Pelican Mapping
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* http://osgearth.org
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*
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* osgEarth is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>
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*/
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#ifndef OSGEARTH_RANDOM_H
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#define OSGEARTH_RANDOM_H 1
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#include <osgEarth/Common>
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namespace osgEarth { namespace Util
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{
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/**
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* Psuedo random number generator. Results are guaranteed to be consistent across
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* machines given the same seed value.
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*/
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class OSGEARTH_EXPORT Random
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{
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public:
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enum Method
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{
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METHOD_FAST // not great, but super-fast and cheap.
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};
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public:
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/**
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* Constructs a new random number generator. It is seeded with
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* the system clock.
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* @param method RNG method to use
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*/
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Random( Method method =METHOD_FAST );
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/**
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* Constucts a new random number generator with a user-specified seed.
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* The results are guaranteed to be globally consistent.
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* @param seed RNG seed value
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* @param method RNG method to use
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*/
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Random( unsigned seed, Method method =METHOD_FAST );
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/**
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* Copy constructor.
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*/
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Random( const Random& rhs );
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/** dtor */
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virtual ~Random() { }
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/**
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* Seeds the PRNG with a new seed.
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*/
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void seed(unsigned s);
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/**
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* Resets the PRNG to its initial state (initial seed).
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*/
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void reset();
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/**
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* Gets the next random number as an unsigned int.
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* @param mod Modulus value. The result will fall within the range [0..mod)
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*/
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unsigned next( unsigned mod );
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/**
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* Gets the next random number as a double in the range [0..1].
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*/
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double next();
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private:
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Method _method;
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unsigned _seed;
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unsigned _next;
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};
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} }
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#endif // OSGEARTH_RANDOM_H
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