88 lines
2.7 KiB
GLSL
88 lines
2.7 KiB
GLSL
#version 450 core
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out vec4 frag_color;
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in vec2 tex_coords;
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uniform sampler2D albedoGbuffer;
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uniform sampler2D positionGbuffer;
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uniform sampler2D normalGbuffer;
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layout(std140, binding = 0) uniform SceneUniforms
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{
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mat4 PV; //camera projection * view matrix
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vec4 eye_w; //world-space eye position
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};
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vec3 calculateDisneySpecular(vec3 N, vec3 V, vec3 L, vec3 albedo) {
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vec3 H = normalize(V + L);
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// Fresnel - Schlick's Approximation
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vec3 F0 = vec3(0.04f);
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vec3 F = F0 + (1.0f - F0) * pow(1.0f - dot(H, V), 5.0f);
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// Normal Distribution Function (GGX)
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float roughness = 0.7f;
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float alpha = roughness * roughness;
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float alpha2 = alpha * alpha;
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float NdotH = max(dot(N, H), 0.0f);
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float D = alpha2 / (3.14159265359 * pow(NdotH * NdotH * (alpha2 - 1.0f) + 1.0f, 2.0f));
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// Geometry Function (Smith's G)
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float NdotV = max(dot(N, V), 0.0f);
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float NdotL = max(dot(N, L), 0.0f);
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float k = (roughness + 1.0f) * (roughness + 1.0f) / 8.0f;
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float G1V = NdotV / (NdotV * (1.0f - k) + k);
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float G1L = NdotL / (NdotL * (1.0f - k) + k);
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float G = G1V * G1L;
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vec3 specular = (D * G * F) / (4.0f * NdotL * NdotV + 0.001f); // Adding a small bias to prevent division by zero
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return specular;
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}
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void main()
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{
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vec4 albedo = texture(albedoGbuffer, tex_coords);
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// albedo = vec4(vec3(0.18f), texture(albedoGbuffer, tex_coords).a);
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vec4 position = texture(positionGbuffer, tex_coords);
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vec4 normal = texture(normalGbuffer, tex_coords);
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vec4 lightDirection = vec4(0.707f, 0.707f, 0.0f, 0.0f);
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vec3 N = normalize(normal.xyz);
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vec3 L = normalize(lightDirection.xyz);
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vec3 V = normalize(eye_w.xyz);
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float NdotL = max(dot(N, L), 0.0f);
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vec4 skyColor = vec4(0.6f, 0.7f, 0.8f, 0.0f); // Light blue sky
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vec4 groundColor = vec4(0.2f, 0.2f, 0.2f, 0.0f); // Dark gray ground
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float factor = 0.5f * (N.y + 1.0f); // Blend factor based on normal's Y component
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vec4 ambientLight = mix(groundColor, skyColor, factor);
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// Disney Diffuse Fresnel
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vec3 F0 = vec3(0.04f);
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vec3 fresnel = F0 + (1.0f - F0) * (pow(1.0f - NdotL, 5.0f));
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// Disney Diffuse Term
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vec4 diffuse = vec4(vec3((albedo.rgb / 3.14159265359f) * NdotL * fresnel), albedo.a);
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// Disney Specular Term
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vec4 specular = vec4(calculateDisneySpecular(N, V, L, albedo.rgb), albedo.a);
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// Light Intensity
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vec4 lightColor = vec4(vec3(25.0f), 1.0f);
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vec4 finalDiffuse = (diffuse + specular) * lightColor + (ambientLight * 0.1f);
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vec4 hdr_color = finalDiffuse;
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vec4 tone_mapped_color = hdr_color / (hdr_color + vec4(vec3(1.0f), 0.0f));
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tone_mapped_color = pow(tone_mapped_color, vec4(vec3(1.0f/2.2f), 1.0f));
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frag_color = tone_mapped_color;
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}
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