I recently wrote a GLSL shader that tried to convert light posistion, spot direction, and eye posisition to tangent space. I tried to do this for all eight lights. It didnt’ work. It turns out you can’t pass that much data from a vertex shader to a fragment shader.
Instead, I was wondering if there was some way of translating the normal-map value from tangent space to world space?
This would let me pass only one varying vec4 instead of 13.