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#include "math.cginc"
#ifndef __NOISE_INC
#define __NOISE_INC
float cubic_interp(float x)
{
return x * x * (3.0 - 2.0 * x);
}
float2 cubic_interp(float2 x)
{
return x * x * (3.0 - 2.0 * x);
}
float3 cubic_interp(float3 x)
{
return x * x * (3.0 - 2.0 * x);
}
float quintic_interp(float x)
{
return x * x * x * (x * (x * 6 - 15) + 10);
}
float2 quintic_interp(float2 x)
{
return x * x * x * (x * (x * 6 - 15) + 10);
}
float perlin_noise(float2 p)
{
float2 sq = floor(p);
float2 sqi = frac(p);
float r0 = rand2(sq + float2(0,0));
float r1 = rand2(sq + float2(1,0));
float r2 = rand2(sq + float2(0,1));
float r3 = rand2(sq + float2(1,1));
float2 u = cubic_interp(sqi);
return lerp(r0, r1, u.x) +
(r2 - r0) * u.y * (1.0 - u.x) +
(r3 - r1) * u.x * u.y;
}
float perlin_noise_3d(float3 p)
{
float3 sq = floor(p);
float3 sqi = frac(p);
float r0 = rand3(sq + float3(0,0,0));
float r1 = rand3(sq + float3(1,0,0));
float r2 = rand3(sq + float3(0,1,0));
float r3 = rand3(sq + float3(1,1,0));
float r4 = rand3(sq + float3(0,0,1));
float r5 = rand3(sq + float3(1,0,1));
float r6 = rand3(sq + float3(0,1,1));
float r7 = rand3(sq + float3(1,1,1));
float3 u = cubic_interp(sqi);
return lerp(
lerp(r0, r1, u.x) +
(r2 - r0) * u.y * (1.0 - u.x) +
(r3 - r1) * u.x * u.y,
lerp(r4, r5, u.x) +
(r6 - r4) * u.y * (1.0 - u.x) +
(r7 - r5) * u.x * u.y,
u.z);
}
float simplex_noise(float2 p)
{
float2 sq = floor(p);
float2 sqi = frac(p);
float r0 = rand2(sq + float2(0,0));
float r1 = rand2(sq + float2(1,0));
float r2 = rand2(sq + float2(0,1));
float r3 = rand2(sq + float2(1,1));
float2 u = quintic_interp(sqi);
return lerp(r0, r1, u.x) +
(r2 - r0) * u.y * (1.0 - u.x) +
(r3 - r1) * u.x * u.y;
}
#endif // __NOISE_INC
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