105 lines
3.2 KiB
GLSL
105 lines
3.2 KiB
GLSL
/**
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* @file WLCloudsF.glsl
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*
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* $LicenseInfo:firstyear=2005&license=viewerlgpl$
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* Second Life Viewer Source Code
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* Copyright (C) 2005, Linden Research, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation;
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* version 2.1 of the License only.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
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* $/LicenseInfo$
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*/
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#ifdef DEFINE_GL_FRAGCOLOR
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out vec4 frag_color;
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#else
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#define frag_color gl_FragColor
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#endif
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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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VARYING vec2 vary_texcoord0;
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VARYING vec2 vary_texcoord1;
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VARYING vec2 vary_texcoord2;
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VARYING vec2 vary_texcoord3;
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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 = vary_texcoord0.xy;
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vec2 uv2 = vary_texcoord1.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 = vary_texcoord2.xy;
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vec2 uv4 = vary_texcoord3.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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frag_color.rgb = scaleSoftClip(color.rgb);
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frag_color.a = alpha1;
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}
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