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refraction_C_fp.glsl
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refraction_C_fp.glsl
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/*
===========================================================================
Copyright (C) 2006 Robert Beckebans <trebor_7@users.sourceforge.net>
This file is part of XreaL source code.
XreaL source code is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.
XreaL source code 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with XreaL source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
===========================================================================
*/
/* refraction_C_fp.glsl */
uniform samplerCube u_ColorMap;
uniform vec3 u_ViewOrigin;
uniform float u_RefractionIndex;
uniform float u_FresnelPower;
uniform float u_FresnelScale;
uniform float u_FresnelBias;
varying vec3 var_Position;
varying vec3 var_Normal;
#if __VERSION__ > 120
out vec4 outputColor;
#else
#define outputColor gl_FragColor
#endif
void main()
{
// compute incident ray
vec3 I = normalize(var_Position - u_ViewOrigin);
// compute normal
vec3 N = normalize(var_Normal);
// compute reflection ray
vec3 R = reflect(I, N);
// compute refraction ray
vec3 T = refract(I, N, u_RefractionIndex);
// compute fresnel term
float fresnel = u_FresnelBias + pow(1.0 - dot(I, N), u_FresnelPower) * u_FresnelScale;
vec3 reflectColor = textureCube(u_ColorMap, R).rgb;
vec3 refractColor = textureCube(u_ColorMap, T).rgb;
// compute final color
vec4 color;
color.r = (1.0 - fresnel) * refractColor.r + reflectColor.r * fresnel;
color.g = (1.0 - fresnel) * refractColor.g + reflectColor.g * fresnel;
color.b = (1.0 - fresnel) * refractColor.b + reflectColor.b * fresnel;
color.a = 1.0;
outputColor = color;
}