Hi,
I've got a problem that normal mapping is dependent on view. It looks like this (sorry for the watermarks):
The normal mapping is calculated in the pixel shader as follows (it is actually taken from http://stackoverflow.com/questions/5255806/how-to-calculate-tangent-and-binormal):
- vertexPosition is a position in SV_POSITION semantic
- shared vertices on in the triangles
float3 computeNormalWithTBN(float3 vertexPosition, float2 texCoord, float3 normal ) {
float3 p_dx = ddx(vertexPosition);
float3 p_dy = ddy(vertexPosition);
float2 tc_dx = ddx(texCoord);
float2 tc_dy = ddy(texCoord);
float3 t = normalize( tc_dy.y * p_dx - tc_dx.y * p_dy );
float3 b = normalize( tc_dy.x * p_dx - tc_dx.x * p_dy );
float3 n = normalize(normal);
float3 x = cross(n, t);
t = cross(x, n);
t = normalize(t);
x = cross(b, n);
b = cross(n, x);
b = normalize(b);
float4 detail = normalMap.Sample( SampleType, texCoord );
detail = (detail * 2.0f) - 1.0f;
detail *= 6.0f;
return normalize( normal + detail.x * t + detail.y * b );
}
// in main function
// ...
input.normal = computeNormalWithTBN( input.position.xyz, input.tex.xy, input.normal;
float light = saturate( dot( input.normal, float3( 0, 0.73, -0.69 ) ) );
float4 color = 0.3f;
color += light;
return color;
}
Why this happens?
Thanks for help.