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## Perlin Noise tiling

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### #1montify  Members

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Posted 25 December 2012 - 10:36 PM

Hello

I implement Libnoise for the Terrain, it works perfect, i have a Quadtree with 33x33 Chunks and i tile this with
perlin.GetValue() <-- Libnoise.

Now for the performance i implement PerlinNoise on the GPU, but anyone can tell me how i can tile the "Heightmap"?

I need for every Chunk that get splitted a new Heightmap with the right coordinates.

Here's the code:

float4x4 World;
float3 coord;

{
float4 Position : POSITION0;
float2 texCoord : TEXCOORD0;
};

{
float4 Position : POSITION0;
float2 texCoord : TEXCOORD0;
float4 wPosition: TEXCOORD1;
};

{

output.Position = input.Position;
output.wPosition = input.Position;
output.texCoord = input.Position;

return output;
}

texture permTexture2d;

sampler permSampler2d = sampler_state
{
texture = <permTexture2d>;
MAGFILTER = POINT;
MINFILTER = POINT;
MIPFILTER = NONE;
};

{
MAGFILTER = POINT;
MINFILTER = POINT;
MIPFILTER = NONE;
};

{
return t * t * t * (t * (t * 6 - 15) + 10); // new curve
}
float4 perm2d(float2 p)
{
return tex2D(permSampler2d, p);
}
{
return dot(sample, p);
}

{
}
float inoise(float3 p)
{

float3 P = fmod(floor(p), 256);
p -= floor(p);

P = P /256;
const float one = -11.0 /256;

float4 AA = perm2d(P.xy) + P.z;

return lerp(lerp( lerp( gradPerm(AA.x, p ),
gradPerm(AA.z, p + float3(-1, 0, 0) ), f.x),
lerp( gradPerm(AA.y, p + float3(0, -1, 0) ),
gradPerm(AA.w, p + float3(-1, -1, 0) ), f.x), f.y),

lerp( lerp( gradPerm(AA.x+one, p + float3(0, 0, -1) ),
gradPerm(AA.z+one, p + float3(-1, 0, -1) ), f.x),
lerp( gradPerm(AA.y+one, p + float3(0, -1, -1) ),
gradPerm(AA.w+one, p + float3(-1, -1, -1) ), f.x), f.y), f.z);
}

float turbulence(float3 p, int octaves, float lacunarity = 2.0, float gain = 1.5)
{
float sum = 0;
float freq = 1.0, amp = 1.0;
for(int i=0; i < octaves; i++) {
sum += abs(inoise(p*freq))*amp;
freq *= lacunarity;
amp *= gain;
}
return sum;
}

float ridge(float h, float offset)
{
h = abs(h);
h = offset - h;
h = h * h;
return h;
}

float ridgedmf(float3 p, int octaves, float lacunarity, float gain, float offset = 1.0)
{
float sum = 0;
float freq = 1.3f;
float amp = 0.5;
float prev = 1.0;
for(int i=0; i < octaves; i++)
{
float n = ridge(inoise(p*freq), offset);
sum += n*amp*prev;
prev = n;
freq *= lacunarity;
amp *= gain;
}
return sum;
}

float fBm(float3 p, int octaves, float lacunarity, float gain = 0.7)
float freq = 1.3f,
amp  = 0.5f;
float sum  = 0.6f;
for(int i=0; i < octaves; i++) {
sum += inoise(p*freq)*amp;
freq *= lacunarity;
amp *= gain;
}
return sum;

float Interpolate(float x, float y, float a)
{
float val = (1 - cos(a * 3.1415926535f)) * .5;
return  x * (1 - val) + y * val;
}

{
float3 p = input.wPosition;
float inz = inoise(p)*0.7+0.7;

/*inz += ridgedmf(p,8,2.0,0.5);
inz *= turbulence(p,8,2.0,0.5);*/
inz *= fBm(p,8,2.0,0.8);
inz *= Interpolate(0.7,0.7,0.5);

return float4(inz,inz,inz,1);
}

technique PerlinNoise
{
pass Pass1
{
}
}

Edited by montify, 25 December 2012 - 11:04 PM.

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