5 layout(constant_id=auto) const bool use_base_color_map = false;
6 layout(constant_id=auto) const bool use_metalness_map = false;
7 layout(constant_id=auto) const bool use_roughness_map = false;
8 layout(constant_id=auto) const bool use_occlusion_map = false;
9 layout(constant_id=auto) const bool use_emission = false;
10 layout(constant_id=auto) const bool use_emission_map = false;
12 const float PI = 3.1415926535;
14 #pragma MSP stage(fragment)
17 if(use_base_color_map)
18 return texture(base_color_map, texcoord.xy);
20 return pbr_material.base_color;
23 float get_metalness_value()
26 return texture(metalness_map, texcoord.xy).r;
28 return pbr_material.metalness;
31 float get_roughness_value()
34 return texture(roughness_map, texcoord.xy).r;
36 return pbr_material.roughness;
39 float get_occlusion_value()
42 return texture(occlusion_map, texcoord.xy).r;
47 vec3 get_emission_color()
50 return texture(emission_map, texcoord.xy).rgb;
52 return pbr_material.emission.rgb;
55 /* Computes the diffuse reflection of the macrosurface */
56 vec3 lambert_diffuse(vec3 base_color)
58 // Scale by pi to get a result per steradian, suitable for integration
62 /* Computes the fraction of microfacets aligned at the halfway vector
63 (Trowbridge-Reitz GGX) */
64 float normal_distribution_ggxtr(vec3 normal, vec3 halfway, float roughness)
66 float n_dot_h = max(dot(normal, halfway), 0.0);
67 float rough_q = roughness * roughness;
69 float denom = n_dot_h*n_dot_h*(rough_q-1)+1;
70 // Scale by pi to get a result per steradian, suitable for integration
71 return rough_q/(PI*denom*denom);
74 /* Computes shadowing and masking of a microfacet surface from a given
76 float geometry_schlick_ggx(vec3 normal, vec3 view, float k)
78 float n_dot_v = max(dot(normal, view), 0.0);
79 return n_dot_v/(n_dot_v*(1.0-k)+k);
82 /* Computes shadowing and masking of a microfacet surface for a combination of
83 look and light directions */
84 float geometry_smith(vec3 normal, vec3 look, vec3 light, float roughness)
86 float k = (roughness+1.0)*(roughness+1.0)/8.0;
87 float ggx_look = geometry_schlick_ggx(normal, look, k);
88 float ggx_light = geometry_schlick_ggx(normal, light, k);
89 return ggx_look*ggx_light;
92 /* Computes the reflectance of the material at a given reflection angle */
93 vec3 fresnel_schlick(vec3 halfway, vec3 look, vec3 base_color, float metalness)
95 // 0.04 is a decent approximation for dielectric base reflectivity
96 vec3 f0 = mix(vec3(0.04), base_color, metalness);
97 return mix(f0, vec3(1.0), pow(1.0-dot(halfway, look), 5.0));
100 /* Computes the full contribution of a single light */
101 vec3 cooktorrance_one_light_direct(vec3 normal, vec3 look, vec3 light, vec3 light_color, vec3 base_color, float metalness, float roughness)
103 vec3 halfway = normalize(light-look);
104 float ndist = normal_distribution_ggxtr(normal, halfway, roughness);
105 float geom = geometry_smith(normal, -look, light, roughness);
107 vec3 k_spec = fresnel_schlick(halfway, light, base_color, metalness);
108 vec3 k_diff = (1.0-k_spec)*(1.0-metalness);
110 float denom = max(4.0*max(dot(normal, -look), 0.0)*max(dot(normal, light), 0.0), 0.001);
111 return max(dot(normal, light), 0.0)*light_color*(k_diff*lambert_diffuse(base_color)+k_spec*ndist*geom/denom);
114 vec3 cooktorrance_lighting(vec3 normal, vec3 look, vec3 base_color, float metalness, float roughness)
118 light = normalize(tbn_light_dir);
120 light = normalize(eye_light_dir);
122 float shadow = get_shadow_factor(0);
123 vec3 color = cooktorrance_one_light_direct(normal, look, light, light_sources[0].diffuse.rgb, base_color, metalness, roughness)*shadow;
125 color *= get_occlusion_value();
128 color += get_emission_color();
139 normal = get_fragment_normal();
140 look = normalize(tbn_look_dir);
144 normal = normalize(eye_normal);
145 look = normalize(eye_look_dir);
148 vec4 base_color = get_base_color();
149 float metalness = get_metalness_value();
150 float roughness = get_roughness_value();
152 vec3 lit_color = cooktorrance_lighting(normal, look, base_color.rgb, metalness, roughness);
154 frag_color = vec4(lit_color, base_color.a);