Ramp Lighting

Based on http://wiki.unity3d.com/index.php/TeamFortress2Shader

Also includes specular highlighting and rim lighting.

Ramp textures must have “Repeat” import parameter set to “Disabled”, otherwise they will generate artifacts. Screenshots include example ramps.

For GLES3, change DIFFUSE_LIGHT to the following(Might need further adjustments but this seems to work well enough): DIFFUSE_LIGHT += ALBEDO * lit+((spec*(1.0f-ROUGHNESS))*lit)+((rim*ALBEDO)*lit);

Shader code

uniform sampler2D LightRamp;

void fragment() {
	ALBEDO = texture(Albedo, UV).rgb;
	ROUGHNESS = Roughness;
	NORMALMAP = texture(BumpMap, UV).rgb;
}

void light() {
	vec4 rampTex = texture(LightRamp, vec2(dot(LIGHT, NORMAL))-(1.0f-ATTENUATION.xy));
	float spec = max(pow(dot(NORMAL, normalize(LIGHT + VIEW)), (1.0f-ROUGHNESS)*128.0f),0.0f)*((rampTex.r+rampTex.g+rampTex.b)/3.0f);
	float rim = max(RimDist - dot(VIEW, NORMAL), 0.0f)*RimPower;
	vec3 lit =  min(rampTex.rgb * LIGHT_COLOR, 1.0f);
	
	DIFFUSE_LIGHT = ALBEDO * lit+((spec*(1.0f-ROUGHNESS))*lit)+((rim*ALBEDO)*lit);
}