71 lines
2.0 KiB
Scala
71 lines
2.0 KiB
Scala
$input a_position
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$output v_skyColor, v_screenPos, v_viewDir
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/*
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* Copyright 2017 Stanislav Pidhorskyi. All rights reserved.
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* License: https://github.com/bkaradzic/bgfx/blob/master/LICENSE
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*/
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uniform vec4 u_sunDirection;
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uniform vec4 u_skyLuminanceXYZ;
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uniform vec4 u_parameters; // x - sun size, y - sun bloom, z - exposition
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uniform vec4 u_perezCoeff[5];
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#include "../common/common.sh"
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vec3 Perez(vec3 A,vec3 B,vec3 C,vec3 D, vec3 E,float costeta, float cosgamma)
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{
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float _1_costeta = 1.0 / costeta;
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float cos2gamma = cosgamma * cosgamma;
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float gamma = acos(cosgamma);
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vec3 f = (vec3_splat(1.0) + A * exp(B * _1_costeta))
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* (vec3_splat(1.0) + C * exp(D * gamma) + E * cos2gamma);
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return f;
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}
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void main()
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{
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v_screenPos = a_position.xy;
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vec4 rayStart = mul(u_invViewProj, vec4(vec3(a_position.xy, -1.0), 1.0));
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vec4 rayEnd = mul(u_invViewProj, vec4(vec3(a_position.xy, 1.0), 1.0));
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rayStart = rayStart / rayStart.w;
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rayEnd = rayEnd / rayEnd.w;
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v_viewDir = normalize(rayEnd.xyz - rayStart.xyz);
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v_viewDir.y = abs(v_viewDir.y);
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gl_Position = vec4(a_position.xy, 1.0, 1.0);
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vec3 lightDir = normalize(u_sunDirection.xyz);
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vec3 skyDir = vec3(0.0, 1.0, 0.0);
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// Perez coefficients.
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vec3 A = u_perezCoeff[0].xyz;
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vec3 B = u_perezCoeff[1].xyz;
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vec3 C = u_perezCoeff[2].xyz;
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vec3 D = u_perezCoeff[3].xyz;
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vec3 E = u_perezCoeff[4].xyz;
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float costeta = max(dot(v_viewDir, skyDir), 0.001);
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float cosgamma = clamp(dot(v_viewDir, lightDir), -0.9999, 0.9999);
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float cosgammas = dot(skyDir, lightDir);
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vec3 P = Perez(A,B,C,D,E, costeta, cosgamma);
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vec3 P0 = Perez(A,B,C,D,E, 1.0, cosgammas);
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vec3 skyColorxyY = vec3(
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u_skyLuminanceXYZ.x / (u_skyLuminanceXYZ.x+u_skyLuminanceXYZ.y + u_skyLuminanceXYZ.z)
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, u_skyLuminanceXYZ.y / (u_skyLuminanceXYZ.x+u_skyLuminanceXYZ.y + u_skyLuminanceXYZ.z)
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, u_skyLuminanceXYZ.y
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);
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vec3 Yp = skyColorxyY * P / P0;
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vec3 skyColorXYZ = vec3(Yp.x * Yp.z / Yp.y,Yp.z, (1.0 - Yp.x- Yp.y)*Yp.z/Yp.y);
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v_skyColor = convertXYZ2RGB(skyColorXYZ * u_parameters.z);
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}
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