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/*
* Aethyra
* Copyright (C) 2006 The Mana World Development Team
*
* This file is part of Aethyra based on original code
* from The Mana World.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <cmath>
/**
* Returns a random numeric value that is larger than or equal min and smaller
* than max
*/
enum ChangeFunc
{
FUNC_NONE,
FUNC_SINE,
FUNC_SAW,
FUNC_TRIANGLE,
FUNC_SQUARE
};
template <typename T> struct ParticleEmitterProp
{
ParticleEmitterProp():
changeFunc(FUNC_NONE)
{
}
void set(T min, T max)
{
minVal=min; maxVal=max;
}
void set(T val)
{
set(val, val);
}
void setFunction(ChangeFunc func, T amplitude, int period, int phase)
{
changeFunc = func;
changeAmplitude = amplitude;
changePeriod = period;
changePhase = phase;
}
T value(int tick)
{
tick += changePhase;
T val = (T) (minVal + (maxVal - minVal) * (rand() / ((double) RAND_MAX + 1)));
switch (changeFunc)
{
case FUNC_SINE:
val += (T) std::sin(M_PI * 2 * ((double)(tick%changePeriod) / (double)changePeriod)) * changeAmplitude;
break;
case FUNC_SAW:
val += (T) (changeAmplitude * ((double)(tick%changePeriod) / (double)changePeriod)) * 2 - changeAmplitude;
break;
case FUNC_TRIANGLE:
if ((tick%changePeriod) * 2 < changePeriod)
{
val += changeAmplitude - (T)((tick%changePeriod) / (double)changePeriod) * changeAmplitude * 4;
} else {
val += changeAmplitude * -3 + (T)((tick%changePeriod) / (double)changePeriod) * changeAmplitude * 4;
// I have no idea why this works but it does
}
break;
case FUNC_SQUARE:
if ((tick%changePeriod) * 2 < changePeriod)
{
val += changeAmplitude;
} else {
val -= changeAmplitude;
}
break;
case FUNC_NONE:
default:
//nothing
break;
}
return val;
}
T minVal;
T maxVal;
ChangeFunc changeFunc;
T changeAmplitude;
int changePeriod;
int changePhase;
};
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