Tint color could be applied to colDiffuse... but what's the best way?
Replace it? Multiply by? A point to think about...

texture2D() is deprecated on GLSL 330

NOTE: It requires a depth texture as input, it should be configured on
rlgl, by default RenderTexture (fbo) uses Depth Renderbuffer instead of
Depth Texture. Check rlglLoadRenderTexture()