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PerlinGPU and QuadTree


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#1 montify   Members   -  Reputation: 365

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Posted 20 December 2012 - 02:23 PM

Hello

I use Libnoise.XNA for creating the height of my Terrain.

I have implemented a Quadtree with LOD.

So with Libnoise i Choose the right Position of the Heightmap with:

  float[] v = new float[Planet.size * Planet.size];
			for (int z = 0; z < Planet.size; z++)
				for (int x = 0; x < Planet.size; x++)
				{
					test = new Vector3(MathHelper.Lerp(-1, 1, (float)x / (Planet.size - 1)), 0, MathHelper.Lerp(-1, 1, (float)z / (Planet.size - 1)));
					test = Vector3.Transform(test, world);
					test = Vector3.Normalize(test);
					v[x + z * Planet.size] = (float)perlin.GetValue(test.X, 0, test.Z); ;

perlin.GetValue.


So i Implemented the GPU Perlin

float4x4 World;
float3 coord;
struct VertexShaderInput
{
	float4 Position : POSITION0;
	float2 texCoord : TEXCOORD0;
};
struct VertexShaderOutput
{
	float4 Position : POSITION0;
	float2 texCoord : TEXCOORD0;
	float4 wPosition: TEXCOORD1;
};
VertexShaderOutput VertexShaderFunction(VertexShaderInput input)
{
	VertexShaderOutput output;
	output.Position = input.Position;
	output.wPosition = input.Position;
	output.texCoord = input.texCoord;
	return output;
}
texture permTexture2d;
texture permGradTexture;
sampler permSampler2d = sampler_state
{
	texture = <permTexture2d>;
	AddressU  = Wrap;	  
	AddressV  = Wrap;
	MAGFILTER = POINT;
	MINFILTER = POINT;
	MIPFILTER = NONE;  
};
sampler permGradSampler = sampler_state
{
	texture = <permGradTexture>;
	AddressU  = Wrap;	  
	AddressV  = Clamp;
	MAGFILTER = POINT;
	MINFILTER = POINT;
	MIPFILTER = NONE;
};
float3 fade(float3 t)
{
	return t * t * t * (t * (t * 6 - 15) + 10); // new curve
}
float4 perm2d(float2 p)
{
	return tex2D(permSampler2d, p);
}
float gradperm(float x, float3 p)
{
	float3 sample = tex1D(permGradSampler, x);
	return dot(sample, p);
}
float gradPerm(float x, float3 p)
{
return dot(tex1D(permGradSampler, x), p);
}
float inoise(float3 p)
{
//new Vector3(MathHelper.Lerp(-1, 1, (float)x / (Planet.size - 1)), 0, MathHelper.Lerp(-1, 1, (float)z / (Planet.size - 1)));
  float3 xx;
   xx.x = lerp( -1 ,1, coord.x);
   xx.y = 0;
			  xx.z =lerp( -1 ,1, coord.z);
  
	 xx = normalize(xx);
  float3 P = fmod(floor(p), 256);
   p -= floor(p);					
float3 f = fade(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 = 0.5)
{
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;
}
float4 PixelShaderFunction(VertexShaderOutput input) : COLOR0
{
	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
	{
		VertexShader = compile vs_3_0 VertexShaderFunction();
		PixelShader = compile ps_3_0 PixelShaderFunction();
	}
}

But how can i get the Coords similar like perlin.GetValue?

Anyone can help me? :/

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