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#ifndef __C_NOISE_INC__
#define __C_NOISE_INC__
#include <math.h>
/****************
* Random value generator
**/
float cNoise::IntNoise( int a_X ) const
{
int x = ((a_X*m_Seed)<<13) ^ a_X;
return ( 1.0f - ( (x * (x * x * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0f);
}
float cNoise::IntNoise2D( int a_X, int a_Y ) const
{
int n = a_X + a_Y * 57 + m_Seed*57*57;
n = (n<<13) ^ n;
return ( 1.0f - ( (n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0f);
}
float cNoise::IntNoise3D( int a_X, int a_Y, int a_Z ) const
{
int n = a_X + a_Y * 57 + a_Z * 57*57 + m_Seed*57*57*57;
n = (n<<13) ^ n;
return ( 1.0f - ( (n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0f);
}
/****************
* Interpolation functions
**/
float cNoise::CubicInterpolate( float a_A, float a_B, float a_C, float a_D, float a_Pct ) const
{
float P = (a_D - a_C) - (a_A - a_B);
float Q = (a_A - a_B) - P;
float R = a_C - a_A;
float S = a_B;
return P*(a_Pct*a_Pct*a_Pct) + Q*(a_Pct*a_Pct) + R*a_Pct + S;
}
float cNoise::CosineInterpolate( float a_A, float a_B, float a_Pct ) const
{
const float ft = a_Pct * 3.1415927f;
const float f = (1.f - cosf(ft)) * 0.5f;
return a_A*(1-f) + a_B*f;
}
float cNoise::LinearInterpolate( float a_A, float a_B, float a_Pct ) const
{
return a_A*(1.f-a_Pct) + a_B*a_Pct;
}
#endif
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