/** 
 * @file transportF.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
 * $/LicenseInfo$
 */
 
//////////////////////////////////////////////////////////
// The fragment shader for the terrain atmospherics
//////////////////////////////////////////////////////////

vec3 getAdditiveColor();
vec3 getAtmosAttenuation();

uniform int no_atmo;

vec3 atmosTransportFrag(vec3 light, vec3 additive, vec3 atten)
{
    if (no_atmo == 1)
	{
        return light;
    }
	return (light + additive) * atten * 2.0;
}

vec3 fullbrightAtmosTransportFrag(vec3 light, vec3 additive, vec3 atten)
{
    if (no_atmo == 1)
    {
		return light;
	}
	float brightness = dot(light.rgb, vec3(0.33333));
	return mix(atmosTransportFrag(light.rgb, additive,atten), light.rgb + additive.rgb, brightness * brightness);
}

vec3 fullbrightShinyAtmosTransportFrag(vec3 light, vec3 additive, vec3 atten)
{
    if (no_atmo == 1)
    {
		return light;
	}
	float brightness = dot(light.rgb, vec3(0.33333));
	return mix(atmosTransportFrag(light.rgb, additive, atten), (light.rgb + additive.rgb) * (2.0 - brightness), brightness * brightness);
}

vec3 atmosTransport(vec3 light) {
     return (no_atmo == 1) ? light : atmosTransportFrag(light, getAdditiveColor(), getAtmosAttenuation());
}

vec3 fullbrightAtmosTransport(vec3 light) {
     return (no_atmo == 1) ? light : fullbrightAtmosTransportFrag(light, GetAdditiveColor(), getAtmosAttenuation());
}

vec3 fullbrightShinyAtmosTransport(vec3 light) {
    return (no_atmo == 1) ? light : fullbrightShinyAtmosTransportFrag(light, getAdditiveColor(), getAtmosAttenuation());
}