79 lines
2.1 KiB
GLSL
79 lines
2.1 KiB
GLSL
/**
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* @file WLCloudsF.glsl
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*
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* Copyright (c) 2005-$CurrentYear$, Linden Research, Inc.
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* $License$
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*/
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/////////////////////////////////////////////////////////////////////////
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// The fragment shader for the sky
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/////////////////////////////////////////////////////////////////////////
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varying vec4 vary_CloudColorSun;
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varying vec4 vary_CloudColorAmbient;
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varying float vary_CloudDensity;
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uniform sampler2D cloud_noise_texture;
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uniform vec4 cloud_pos_density1;
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uniform vec4 cloud_pos_density2;
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uniform vec4 gamma;
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/// Soft clips the light with a gamma correction
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vec3 scaleSoftClip(vec3 light) {
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//soft clip effect:
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light = 1. - clamp(light, vec3(0.), vec3(1.));
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light = 1. - pow(light, gamma.xxx);
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return light;
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}
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void main()
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{
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// Set variables
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vec2 uv1 = gl_TexCoord[0].xy;
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vec2 uv2 = gl_TexCoord[1].xy;
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vec4 cloudColorSun = vary_CloudColorSun;
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vec4 cloudColorAmbient = vary_CloudColorAmbient;
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float cloudDensity = vary_CloudDensity;
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vec2 uv3 = gl_TexCoord[2].xy;
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vec2 uv4 = gl_TexCoord[3].xy;
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// Offset texture coords
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uv1 += cloud_pos_density1.xy; //large texture, visible density
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uv2 += cloud_pos_density1.xy; //large texture, self shadow
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uv3 += cloud_pos_density2.xy; //small texture, visible density
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uv4 += cloud_pos_density2.xy; //small texture, self shadow
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// Compute alpha1, the main cloud opacity
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float alpha1 = (texture2D(cloud_noise_texture, uv1).x - 0.5) + (texture2D(cloud_noise_texture, uv3).x - 0.5) * cloud_pos_density2.z;
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alpha1 = min(max(alpha1 + cloudDensity, 0.) * 10. * cloud_pos_density1.z, 1.);
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// And smooth
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alpha1 = 1. - alpha1 * alpha1;
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alpha1 = 1. - alpha1 * alpha1;
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// Compute alpha2, for self shadowing effect
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// (1 - alpha2) will later be used as percentage of incoming sunlight
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float alpha2 = (texture2D(cloud_noise_texture, uv2).x - 0.5);
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alpha2 = min(max(alpha2 + cloudDensity, 0.) * 2.5 * cloud_pos_density1.z, 1.);
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// And smooth
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alpha2 = 1. - alpha2;
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alpha2 = 1. - alpha2 * alpha2;
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// Combine
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vec4 color;
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color = (cloudColorSun*(1.-alpha2) + cloudColorAmbient);
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color *= 2.;
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/// Gamma correct for WL (soft clip effect).
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gl_FragColor.rgb = scaleSoftClip(color.rgb);
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gl_FragColor.a = alpha1;
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}
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