/*
--------------------------------------------------------------------------------
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 lightning ----------------------------------
// ------------------------------ GLSL Vertex -----------------------------------
#define USE_OGRE_FROM_FUTURE
#include <OgreUnifiedShader.h>

OGRE_UNIFORMS(
uniform vec3 uColor;
)

MAIN_PARAMETERS
IN(vec3 vUV, TEXCOORD0)
IN(vec4 vData, TEXCOORD1)
MAIN_DECLARATION
{
  float intensity = 0.0;
	float mult = 1.0;
	float smoothAvance = 16.0;
	
	vec3 UV = vUV;

	if (vData.x + UV.y * (vData.y - vData.x) > vData.z)
	{
		UV.z *= 1.0 - saturate(length(vData.x + UV.y * (vData.y - vData.x) - vData.z) * smoothAvance);
	}
	
	if (UV.y > 2.0)
	{
		UV.y -= 2.0; // Get back y coord
		intensity = saturate((1.0 - 2.0 * length(vec2(0.5, 0.0) - UV.xy))) * mult;
	}
	else
	{
		intensity = (1.0 - 2.0 * length(0.5 - UV.x)) * mult;
	}
	
	intensity = pow(intensity, 1.0 / (0.1 + UV.z));
	
	// Falling effect
	smoothAvance = 6.0;
	UV.z *= 1.0 - vData.w * saturate(length(vData.x + UV.y * (vData.y - vData.x) - vData.z) * smoothAvance);
	
	// Final color
	gl_FragColor = vec4(uColor * vec3_splat(UV.z) * vec3_splat(intensity), 1.0);
}