Implement ambient lighting in the Cook-Torrance shader

[libs/gl.git] / shaderlib / cooktorrance.glsl

diff --git a/shaderlib/cooktorrance.glsl b/shaderlib/cooktorrance.glsl
index 8e95752f7d6dc71b6e8e8fcc942ff2b3da518743..f8aed8267273fcb4f1ac97c929e3823ba29dbcb0 100644 (file)
--- a/shaderlib/cooktorrance.glsl
+++ b/shaderlib/cooktorrance.glsl
@@ -20,6 +20,7 @@ uniform sampler2D metalness_map;
 uniform sampler2D roughness_map;
 uniform sampler2D occlusion_map;
 uniform sampler2D emission_map;
+uniform sampler2D fresnel_lookup;
 
 layout(constant_id=auto) const bool use_base_color_map = false;
 layout(constant_id=auto) const bool use_metalness_map = false;
@@ -131,6 +132,16 @@ vec3 cooktorrance_one_light_direct(vec3 normal, vec3 look, vec3 light, vec3 ligh
        return max(dot(normal, light), 0.0)*light_color*(k_diff*lambert_diffuse(base_color)+k_spec*ndist*geom/spec_denom);
 }
 
+vec3 cooktorrance_environment(vec3 normal, vec3 look, vec3 base_color, float metalness, float roughness)
+{
+       vec3 f0 = mix(vec3(0.04), base_color, metalness);
+       vec2 scale_bias = texture(fresnel_lookup, vec2(roughness, max(dot(normal, -look), 0.0))).rg;
+       vec3 k_spec = f0*scale_bias.x+scale_bias.y;
+       vec3 k_diff = (1.0-k_spec)*(1.0-metalness);
+
+       return (k_diff*base_color+k_spec)*ambient_color.rgb;
+}
+
 vec3 cooktorrance_lighting(vec3 normal, vec3 look, vec3 base_color, float metalness, float roughness)
 {
        vec3 light = normalize(world_light_dir);
@@ -138,6 +149,8 @@ vec3 cooktorrance_lighting(vec3 normal, vec3 look, vec3 base_color, float metaln
        float shadow = get_shadow_factor(0);
        vec3 color = cooktorrance_one_light_direct(normal, look, light, light_sources[0].color, base_color, metalness, roughness)*shadow;
 
+       color += cooktorrance_environment(normal, look, base_color, metalness, roughness);
+
        color *= get_occlusion_value();
 
        if(use_emission)