// $Id: //sw/devtools/FXComposer2/Alpha4+/SDK/MEDIA/CgFX1.4/noise_3d.cgh#1 $
// noise_3d VM function
// $Revision: #1 $ 

#ifndef _H_NOISE3D
#define _H_NOISE3D

#ifndef NOISE_SCALE
#define NOISE_SCALE 2.0
#endif /* NOISE_SCALE */

// predefine as 1 for "pure" noise
#ifndef NOISE3D_LIMIT
#define NOISE3D_LIMIT 256
#endif /* NOISE3D_LIMIT */

// function used to fill the volume noise texture
float4 noise_3d(float3 Pos : POSITION) : COLOR
{
    float4 Noise = (float4)0;
    for (int i = 1; i < NOISE3D_LIMIT; i += i) {
        Noise.r += (noise(Pos * NOISE_SCALE * i)) / i;
        Noise.g += (noise((Pos + 1)* NOISE_SCALE * i)) / i;
        Noise.b += (noise((Pos + 2) * NOISE_SCALE * i)) / i;
        Noise.a += (noise((Pos + 3) * NOISE_SCALE * i)) / i;
    }
    return (Noise+0.5);
}

#ifndef NOISE_VOLUME_SIZE
#define NOISE_VOLUME_SIZE 32
#endif /* NOISE_VOLUME_SIZE */

texture NoiseTex  <
    string TextureType = "VOLUME";
    string function = "noise_3d";
    string UIWidget = "None";
    int width = NOISE_VOLUME_SIZE, height = NOISE_VOLUME_SIZE, depth = NOISE_VOLUME_SIZE;
>;

// samplers
sampler NoiseSamp = sampler_state 
{
    texture = <NoiseTex>;
	MinFilter = LinearMipMapLinear;
	MagFilter = Linear;
    WrapS = Repeat;
    WrapT = Repeat;
    WrapR = Repeat;
};

#define NOISE3D(p) tex3D(NoiseSamp,(p))
#define SNOISE3D(p) (NOISE3D(p)-0.5)

#endif /* _H_NOISE3D */