The metal shader simulates reflective metals. It has a 24-bit specular map, dual specular highlights (one tight and saturated, one broad and duller), and a mask for reflection (shinier areas get non-blurry reflections). Despite the number of maps required, this is a relatively cheap shader.
diffuseLight Texture: This is your color texture, it should be mostly void of lighting detail. It holds an ambient occlusion map in the alpha.
normal Texture: This is a normal map.
specularRefl Texture: This is the 24-bit specular. It should be quite saturated in color. The alpha holds the reflection mask, where lighter tones correspond to higher reflectivity.
ambCube Texture: This is a diffusely convolved cube map, for ambient lighting.
reflCube Texture: This a “regular” cube map, for reflections in the ambient lighting pass.
specColor: This is the color of the specular highlights.
