Hello,
As the subject suggests, I am trying to use a texture shader to generate a world space normal map from a heightmap at initialisation.
My question is, can I use the textureshader to sample another texture (ie the heightmap)
This is the sort of thing I want in the shader:
// normalGen.fx - uses a texture Shader to procedurally generate a normal map from the supplied heightmap
// Texture
texture heightMap;
sampler heightSampler = sampler_state
{
Texture = (heightMap);
AddressU = CLAMP;
AddressV = CLAMP;
AddressW = CLAMP;
MipFilter = LINEAR;
MinFilter = LINEAR;
MagFilter = LINEAR;
};
float4 TX( float2 Tex : POSITION ) : COLOR
{
float stepsize = 0.001;
// Get height from heightmap
float4 Height1 = tex2D( heightSampler, Tex );
float4 Height2 = tex2D( heightSampler, float2(Tex.x - stepsize, Tex.y );
float4 Height2 = tex2D( heightSampler, float2(Tex.x, Tex.y + stepsize );
// etc ....to work out average normal at point
// pack vector info into 0-1 range
Normal *= 0.5;
Normal += 0.5;
return float4( Normal, 1.0 ); // return as a colour
}
This is how I am setting up:
HRESULT cTerrainManager::CreateNormalMap( void )
{
HRESULT hr;
LPD3DXBUFFER pShader = NULL;
// Create the procedural texture
hr = D3DXCompileShaderFromFile(
L"data\\shaders\\normalGen.fx",
NULL, // A NULL terminated array of D3DXMACROs
NULL, // A #include handler
"TX",
"tx_1_0",
D3DXSHADER_DEBUG,
&pShader,
NULL, // error messages
NULL ); // constant table pointer
if( FAILED( hr ) )
{
SAFE_RELEASE( pShader );
return hr;
}
// Procedurally fill texture
hr = D3DXFillTextureTX( m_normalMap, (LPD3DXTEXTURESHADER)pShader->GetBufferPointer() );
if( FAILED( hr ) )
{
SAFE_RELEASE( m_normalMap );
SAFE_RELEASE( pShader );
return hr;
}
return S_OK;
}
Is this possible? how do I set the heightmap texture? Through a constant table perhaps?
If this isnt possible, can I just do it with D3DXFillTexture and a software function? Its not a runtime thing so speed isnt so important.
Thanks for your advice
Simon
