152 lines
3.8 KiB
GLSL
152 lines
3.8 KiB
GLSL
#version 460 core
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// gbuffer textures
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uniform sampler2D s_albedo;
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uniform sampler2D s_depth;
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uniform sampler2D s_normal;
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uniform sampler2D s_material;
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uniform sampler2D s_position;
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// lights
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#define MAX_LIGHT_COUNT 100
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#define POINT 0
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#define SPOT 1
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#define DIRECTIONAL 2
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#define AMBIENT 3
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struct light_t {
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vec3 color;
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vec3 position;
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vec3 direction;
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float intensity;
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int type;
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};
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uniform light_t lights[MAX_LIGHT_COUNT];
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uniform int light_count;
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uniform vec3 view_pos;
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// from vertex shader
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in vec3 pos;
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in vec2 tex;
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out vec4 FragColor;
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vec3 albedo;
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float depth;
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vec3 normal;
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vec3 material; // specular, roughness, metalic
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vec3 position;
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// float specular;
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float roughness;
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float metalic;
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const float PI = 3.14159265359;
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float DistributionGGX(vec3 N, vec3 H, float roughness)
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{
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float a = roughness*roughness;
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float a2 = a*a;
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float NdotH = max(dot(N, H), 0.0);
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float NdotH2 = NdotH*NdotH;
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float nom = a2;
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float denom = (NdotH2 * (a2 - 1.0) + 1.0);
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denom = PI * denom * denom;
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return nom / denom;
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}
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float GeometrySchlickGGX(float NdotV, float roughness)
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{
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float r = (roughness + 1.0);
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float k = (r*r) / 8.0;
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float nom = NdotV;
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float denom = NdotV * (1.0 - k) + k;
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return nom / denom;
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}
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float GeometrySmith(vec3 N, vec3 V, vec3 L, float roughness)
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{
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float NdotV = max(dot(N, V), 0.0);
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float NdotL = max(dot(N, L), 0.0);
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float ggx2 = GeometrySchlickGGX(NdotV, roughness);
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float ggx1 = GeometrySchlickGGX(NdotL, roughness);
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return ggx1 * ggx2;
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}
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vec3 fresnelSchlick(float cosTheta, vec3 F0)
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{
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return F0 + (1.0 - F0) * pow(clamp(1.0 - cosTheta, 0.0, 1.0), 5.0);
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}
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void main() {
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albedo = pow(texture(s_albedo, tex).rgb, vec3(2.2));
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depth = texture(s_depth, tex).x;
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normal = normalize(texture(s_normal, tex).rgb);
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material = texture(s_material, tex).xyz;
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{
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// specular = material.x;
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roughness = 1 - material.y;
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metalic = material.z;
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// metalic = 0;
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}
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position = texture(s_position, tex).xyz;
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vec3 N = normal;
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vec3 V = normalize(view_pos - position);
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vec3 F0 = vec3(0.04);
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F0 = mix(F0, albedo, metalic);
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vec3 Lo = vec3(0.0);
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for(int i = 0; i < light_count; i++)
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{
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// calculate per-light radiance
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vec3 L = normalize(lights[i].position - position);
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vec3 H = normalize(V + L);
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float distance = length(lights[i].position - position);
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float attenuation = 1.0 / (distance * distance);
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vec3 radiance = lights[i].color * lights[i].intensity * attenuation;
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// Cook-Torrance BRDF
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float NDF = DistributionGGX(N, H, roughness);
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float G = GeometrySmith(N, V, L, roughness);
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vec3 F = fresnelSchlick(max(dot(H, V), 0.0), F0);
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vec3 numerator = NDF * G * F;
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float denominator = 4.0 * max(dot(N, V), 0.0) * max(dot(N, L), 0.0) + 0.0001; // + 0.0001 to prevent divide by zero
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vec3 specular = numerator / denominator;
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// kS is equal to Fresnel
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vec3 kS = F;
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// for energy conservation, the diffuse and specular light can't
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// be above 1.0 (unless the surface emits light); to preserve this
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// relationship the diffuse component (kD) should equal 1.0 - kS.
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vec3 kD = vec3(1.0) - kS;
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// multiply kD by the inverse metalness such that only non-metals
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// have diffuse lighting, or a linear blend if partly metal (pure metals
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// have no diffuse light).
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kD *= 1.0 - metalic;
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// scale light by NdotL
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float NdotL = max(dot(N, L), 0.0);
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// add to outgoing radiance Lo
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Lo += (kD * albedo / PI + specular) * radiance * NdotL; // note that we already multiplied the BRDF by the Fresnel (kS) so we won't multiply by kS again
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}
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vec3 ambient = vec3(0.03) * albedo * 1.0;
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vec3 color = ambient + Lo;
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color = color / (color + vec3(1.0));
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color = pow(color, vec3(1.0/2.2));
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FragColor = vec4(color, 1.0);
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}
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