/*
--------------------------------------------------------------------------------
This source file is part of SkyX.
Visit http://www.paradise-studios.net/products/skyx/

Copyright (C) 2009-2012 Xavier Verguín González <xavyiy@gmail.com>

This program 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; either version 2 of the License, or (at your option) any later
version.

This program 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 program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA, or go to
http://www.gnu.org/copyleft/lesser.txt.
--------------------------------------------------------------------------------
*/

#ifdef GL_ES
precision highp int;
precision highp float;
#endif

// --------------------- SkyX ground material ------------------------
// ------------------------ GLSL Fragment ----------------------------
#define USE_OGRE_FROM_FUTURE
#include <OgreUnifiedShader.h>

OGRE_UNIFORMS(
uniform vec3 uLightDir;
uniform float uExposure;
)

MAIN_PARAMETERS
IN(vec3 vRayleighColor, TEXCOORD0)
IN(vec3 vDirection, TEXCOORD1)
MAIN_DECLARATION
{
	float cos = dot(uLightDir, vDirection) / length(vDirection);
	float cos2 = cos * cos;
	
	float rayleighPhase = 0.75 * (1.0 + 0.5 * cos2);
					 
	gl_FragColor = vec4(vec3_splat(rayleighPhase) * vRayleighColor, 1.0);
	
#ifdef LDR
	gl_FragColor.xyz = vec3_splat(1.0) - exp(vec3_splat(-uExposure) * gl_FragColor.xyz);
#endif // LDR
}