83 lines
2.3 KiB
GLSL
83 lines
2.3 KiB
GLSL
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#version 330 core
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layout(location = 0) out vec3 fragColor;
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in vec2 texcoord;
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uniform sampler2D gbuffer0_tex;
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uniform sampler2D gbuffer1_tex;
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uniform samplerCube prefiltered_envmap_tex;
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uniform mat4 fg_ViewMatrixInverse;
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uniform vec3 fg_SunDirection;
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// math.glsl
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float M_PI();
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float M_1_PI();
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float pow5(float x);
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// normal_encoding.glsl
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vec3 decode_normal(vec2 f);
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// pos_from_depth.glsl
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vec3 get_view_space_from_depth(vec2 uv);
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// aerial_perspective.glsl
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vec3 add_aerial_perspective(vec3 color, vec2 coord, float depth);
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vec3 get_sun_radiance_sea_level();
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// exposure.glsl
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vec3 apply_exposure(vec3 color);
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float F_Schlick(float VdotH, float f0)
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{
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return f0 + (1.0 - f0) * pow5(clamp(1.0 - VdotH, 0.0, 1.0));
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}
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float D_GGX(float NdotH, float a2)
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{
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float f = (NdotH * a2 - NdotH) * NdotH + 1.0;
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return a2 / (M_PI() * f * f);
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}
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void main()
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{
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// Unpack G-Buffer
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vec4 gbuffer0 = texture(gbuffer0_tex, texcoord);
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vec4 gbuffer1 = texture(gbuffer1_tex, texcoord);
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vec3 N = decode_normal(gbuffer0.rg);
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vec3 sea_color = gbuffer1.rgb;
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vec3 P = get_view_space_from_depth(texcoord);
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vec3 V = normalize(-P);
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vec3 L = fg_SunDirection;
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vec3 refl = reflect(-V, N);
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vec3 ws_N = (fg_ViewMatrixInverse * vec4(N, 0.0)).xyz;
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vec3 ws_refl = (fg_ViewMatrixInverse * vec4(refl, 0.0)).xyz;
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vec3 H = normalize(L + V);
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float VdotH = max(dot(V, H), 1e-4);
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float NdotL = max(dot(N, L), 1e-4);
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float NdotV = max(dot(N, V), 1e-4);
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float NdotH = max(dot(N, H), 1e-4);
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const float f0 = 0.02; // For IOR = 1.33
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float fresnel = F_Schlick(NdotV, f0);
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// Refracted light, diffuse light coming from the sea floor
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vec3 sky_color = textureLod(prefiltered_envmap_tex, ws_N, 4.0).rgb;
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vec3 refracted = (1.0 - f0) * sea_color * sky_color * M_1_PI();
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// Reflected light, specular light coming from the sky
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vec3 reflected = textureLod(prefiltered_envmap_tex, ws_refl, 0.0).rgb * M_1_PI();
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vec3 color = mix(refracted, reflected, fresnel);
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// Add reflected Sun light
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vec3 sun_intensity = get_sun_radiance_sea_level();
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color += M_1_PI() * fresnel * D_GGX(NdotH, 0.001) * sun_intensity * NdotL;
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color = add_aerial_perspective(color, texcoord, length(P));
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// Pre-expose
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color = apply_exposure(color);
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fragColor = color;
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}
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