first commit

2024-08-22 14:06:11 +02:00
commit 830cc47cf4
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+#version 330 core
+
+// https://github.com/Nadrin/PBR/blob/master/data/shaders/glsl/pbr_fs.glsl
+
+#define PI 3.1415926538
+
+out vec4 FragColor;
+
+in vec3 frag_normal;
+in vec3 fragPos;
+in vec4 frag_pos_light_space;
+
+uniform sampler2D shadow_map;
+uniform vec3 viewPos;
+
+uniform float perceptualRoughness; //  [0, 1]
+uniform float metallic; // [0, 1]
+uniform float reflectance; // [0, 1]
+uniform vec3  baseColor;
+
+uniform vec3 lightDir;
+uniform vec3 lightColor;
+
+// IBL
+uniform samplerCube irradianceMap;
+uniform samplerCube prefilterMap;
+uniform sampler2D   brdfLUT;  
+
+float shadow_factor(vec4 frag_pos_light_space);
+
+float distribGGX(float NoH, float a) {
+    float a2 = a * a;
+    float f = (NoH * a2 - NoH) * NoH + 1.0;
+    return a2 / (PI * f * f);
+}
+
+vec3 fresnelSchlick(float u, vec3 f0) {
+    return f0 + (vec3(1.0) - f0) * pow(1.0 - u, 5.0);
+}
+
+vec3 fresnelSchlickRoughness(float cosTheta, vec3 F0, float roughness)
+{
+    return F0 + (max(vec3(1.0 - roughness), F0) - F0) * pow(clamp(1.0 - cosTheta, 0.0, 1.0), 5.0);
+}   
+
+float geometrySmith(float NoV, float NoL, float a) {
+    float a2 = a * a;
+    float GGXL = NoV * sqrt((-NoL * a2 + NoL) * NoL + a2);
+    float GGXV = NoL * sqrt((-NoV * a2 + NoV) * NoV + a2);
+    return 0.5 / (GGXV + GGXL);
+}
+
+void main()
+{
+    vec3 l = normalize(lightDir);
+    vec3 v = normalize(viewPos - fragPos);
+    vec3 n = frag_normal;
+    vec3 h = normalize(v + l);
+
+    float light_intensity = 1;
+
+    float perceptualRoughness2 = max(perceptualRoughness, 0.089);
+    float roughness = perceptualRoughness2 * perceptualRoughness2;
+
+    vec3 f0 = 0.16 * reflectance * reflectance * (1.0 - metallic) + baseColor * metallic;
+
+    float NoV = abs(dot(n, v)) + 1e-5;
+    float NoL = clamp(dot(n, l), 0.0, 1.0);
+    float NoH = clamp(dot(n, h), 0.0, 1.0);
+    float LoH = clamp(dot(l, h), 0.0, 1.0);
+
+    vec3 color = vec3(0);
+
+    // Direct lighting
+    {
+        float D = distribGGX(NoH, roughness);
+        vec3  F = fresnelSchlick(LoH, f0);
+        float V = geometrySmith(NoV, NoL, roughness);
+
+        vec3 specular = (F * D * V) / (4.0 * NoV * NoL + 0.0001);
+
+        vec3 diffuse = (1 - F) * (1 - metallic) * baseColor / PI;
+
+        color = (diffuse + specular) * lightColor * light_intensity * NoL;
+    }
+
+    // Ambient lighting with IBL
+	vec3 ambient;
+    {
+		vec3 F = fresnelSchlickRoughness(NoV, f0, roughness);
+
+		vec3 irradiance = texture(irradianceMap, n).rgb;
+		vec3 diffuse = irradiance * baseColor;
+
+		float max_lod = 4;
+		float lod = roughness * max_lod;
+
+		vec3 r = reflect(-v, n); // -v?
+		vec3 prefilterColor = textureLod(prefilterMap, r, lod).rgb;
+
+		vec2 brdf = texture(brdfLUT, vec2(NoV, roughness)).rg;
+		vec3 specular = prefilterColor * (F * brdf.x + brdf.y);
+
+		float ao = 1;
+		ambient = ((1 - F) * (1 - metallic) * diffuse + specular) * ao;
+    }
+
+	float shadow = shadow_factor(frag_pos_light_space);
+
+	color = color + ambient;
+
+    color = color / (color + vec3(1.0)); // HDR tonemapping
+    color = pow(color, vec3(1.0/2.2)); // gamma correct
+
+    FragColor = vec4(color, 1.0);
+}
+
+float shadow_factor(vec4 frag_pos_light_space)
+{
+    vec3 proj_coords = frag_pos_light_space.xyz / frag_pos_light_space.w;
+    proj_coords = proj_coords * 0.5 + 0.5;
+
+    float closest_depth = texture(shadow_map, proj_coords.xy).r;
+    float current_depth = proj_coords.z;
+
+    float bias = 0.005;
+    float shadow = 0;
+    vec2 delta = 1.0 / textureSize(shadow_map, 0);
+    for (int i = -1; i < 2; i++)
+        for (int j = -1; j < 2; j++) {
+            float closest_depth = texture(shadow_map, proj_coords.xy + vec2(i, j) * delta).r;
+            shadow += (current_depth - bias > closest_depth) ? 1.0 : 0.0;
+        }
+    shadow /= 9;
+    return shadow;
+}