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I have a shader that creates specular highlights on an object. It uses normal maps and works fine. The images below show the shader applied to a red plane:



The images show the plane with four different normal maps applied. All of the normal maps were made from the same bump map but made with different normal scales.

What I want to do is to use only one normal map and use a 0.0 - 1.0 range variable to control the strength of the normals in the shader. A value of 0.0 would look like the top image. A value of 1.0 would look like the bottom image. This is the pixel shader code that generates the specular highlight:



The normal color is derived from a tex2D() texture lookup. The view and light vectors are passed from the vertex shader. SpecularPower is a float variable defined at the beginning of the shader file.

My question is: How do I use a variable to control the normal strength in the shader?

Thanks for reading and for any thoughts.

In standard normal mapping the blue component corresponds to the axis which is perpendicular to the surface. For a rough surface that value needs to be low and high for a smooth surface. The way I do it is to pass a vector4 to the shader as follows:



then use the vector in the shader as follows.

Add the declaration to the "tweaks" at the start:



then change your normal map code to



That should be it - apart from giving roughness# a suitable value in DBPro.

[Health warning: untested. ]

Edit: the variable roughness# should not be restricted, just keep it non-negative. The normalization step takes care of the rest.

GG: Once again, your the man!

It works perfectly. Thank you.