c35db25269
git-svn-id: http://mc-server.googlecode.com/svn/trunk@115 0a769ca7-a7f5-676a-18bf-c427514a06d6
54 lines
1.4 KiB
C++
54 lines
1.4 KiB
C++
#ifndef __C_NOISE_INC__
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#define __C_NOISE_INC__
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#include <math.h>
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/****************
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* Random value generator
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**/
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float cNoise::IntNoise( int a_X ) const
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{
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int x = ((a_X*m_Seed)<<13) ^ a_X;
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return ( 1.0f - ( (x * (x * x * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0f);
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}
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float cNoise::IntNoise2D( int a_X, int a_Y ) const
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{
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int n = a_X + a_Y * 57 + m_Seed*57*57;
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n = (n<<13) ^ n;
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return ( 1.0f - ( (n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0f);
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}
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float cNoise::IntNoise3D( int a_X, int a_Y, int a_Z ) const
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{
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int n = a_X + a_Y * 57 + a_Z * 57*57 + m_Seed*57*57*57;
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n = (n<<13) ^ n;
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return ( 1.0f - ( (n * (n * n * 15731 + 789221) + 1376312589) & 0x7fffffff) / 1073741824.0f);
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}
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/****************
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* Interpolation functions
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**/
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float cNoise::CubicInterpolate( float a_A, float a_B, float a_C, float a_D, float a_Pct ) const
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{
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float P = (a_D - a_C) - (a_A - a_B);
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float Q = (a_A - a_B) - P;
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float R = a_C - a_A;
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float S = a_B;
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return P*(a_Pct*a_Pct*a_Pct) + Q*(a_Pct*a_Pct) + R*a_Pct + S;
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}
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float cNoise::CosineInterpolate( float a_A, float a_B, float a_Pct ) const
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{
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const float ft = a_Pct * 3.1415927f;
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const float f = (1.f - cosf(ft)) * 0.5f;
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return a_A*(1-f) + a_B*f;
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}
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float cNoise::LinearInterpolate( float a_A, float a_B, float a_Pct ) const
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{
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return a_A*(1.f-a_Pct) + a_B*a_Pct;
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}
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#endif |