Hi all,
I tried to copy some shader code from the awesome deferred engine here:
To add displacement to my own custom effects, but for some reason it doesn't work and I just can't figure out why..
Here's my vertex shader:
VertexShaderOutput VertexShaderMain(VertexShaderInput input)
{
// Initialize Output
VertexShaderOutput output;
// Transform Position
float4 worldPosition = mul(input.Position, World);
float4 viewPosition = mul(worldPosition, View);
float4 fragPosition = mul(viewPosition, Projection);
output.Position = fragPosition;
output.FragPosition = fragPosition;
// Pass Depth
output.Depth.x = output.Position.z;
output.Depth.y = output.Position.w;
output.Depth.z = viewPosition.z;
// Build TBN Matrix (Tangent, Bitangent, Normals)
float3x3 TBN;
TBN[0] = normalize(mul(input.Tangent, (float3x3)WorldViewIT));
TBN[1] = normalize(mul(input.BiTangent, (float3x3)WorldViewIT));
TBN[2] = normalize(mul(input.Normal, (float3x3)WorldViewIT));
output.TBN = TBN;
// Pass UV
output.UV = TextureOffset + input.UV * TexturesTiling;
// Return Output
return output;
}
and here's the part that do displacement in the pixel shader:
// get pixel height from depth map
float pixelHeight = tex2D(NormalSampler, UV).a;
// get tangent pos and tangent camera
float3 tangentPos = mul(input.FragPosition.xyz, input.TBN);
float3 tangentCamera = mul(CameraPosition, input.TBN);
// calculate view direction
float3 viewDir = normalize(tangentPos - tangentCamera);
// calculate new UV
float2 p = viewDir.xy / viewDir.z * pixelHeight * 0.01f;
UV = UV - p;
Which should do the same as the code from the deferred engine. However, the result I'm getting looks like this:
Where the distort line "moves" along the surface as I change the camera angle / position.
BTW before I tried this code I had the much more primitive displacement code:
float2 offset = EyeTangent.xy * (pixelHeight * 0.04f * DisplacementScale - 0.01f) + DisplacementBias;
return uv + offset;
Which was sort-of working but looks pretty ugly and basic.
@kosmonautgames hope you see this 
