Black light shader (fake shadow)

An article by mgear    1 Comment

My first shader test. I know there is already blob shadow, using “projector”, but wanted to try editing some shader examples. You set this shader to the object you want to receive black light from the spotlight.

Instructions:

Get the original code for the shader: Simple Specular
http://unity3d.com/support/documentation/Components/SL-SurfaceShaderLightingExamples.html

Then modify just 1 line,
find:

c.rgb = (s.Albedo * _LightColor0.rgb * diff + _LightColor0.rgb * spec) * (atten * 2);

Replace (or edit the line) with this:

c.rgb = (s.Albedo * _LightColor0.rgb) * ((1-atten*(_LightColor0.a*2)*1.5));

What it does: Attenuation is reversed “1-atten” and the black color strength is taken from “_LightColor0.a”, ie. spotlight Alpha setting.