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/**
* @file waterFogF.glsl
*
* $LicenseInfo:firstyear=2007&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2007, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
uniform vec4 lightnorm;
uniform vec4 waterPlane;
uniform vec4 waterFogColor;
uniform float waterFogDensity;
uniform float waterFogKS;
vec3 getPositionEye();
vec4 applyWaterFog(vec4 color)
{
//normalize view vector
vec3 view = normalize(getPositionEye());
float es = -(dot(view, waterPlane.xyz));
//find intersection point with water plane and eye vector
//get eye depth
float e0 = max(-waterPlane.w, 0.0);
vec3 int_v = waterPlane.w > 0.0 ? view * waterPlane.w/es : vec3(0.0, 0.0, 0.0);
//get object depth
float depth = length(getPositionEye() - int_v);
//get "thickness" of water
float l = max(depth, 0.1);
float kd = waterFogDensity;
float ks = waterFogKS;
vec4 kc = waterFogColor;
float F = 0.98;
float t1 = -kd * pow(F, ks * e0);
float t2 = kd + ks * es;
float t3 = pow(F, t2*l) - 1.0;
float L = min(t1/t2*t3, 1.0);
float D = pow(0.98, l*kd);
color.rgb = color.rgb * D + kc.rgb * L;
color.a = kc.a + color.a;
return color;
}
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