/** 
 * @file multiPointLightF.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
 * $/LicenseInfo$
 */

#extension GL_ARB_texture_rectangle : enable

/*[EXTRA_CODE_HERE]*/

#ifdef DEFINE_GL_FRAGCOLOR
out vec4 frag_color;
#else
#define frag_color gl_FragColor
#endif

uniform sampler2DRect depthMap;
uniform sampler2DRect diffuseRect;
uniform sampler2DRect specularRect;
uniform samplerCube environmentMap;
uniform sampler2D noiseMap;
uniform sampler2D lightFunc;


uniform vec3 env_mat[3];
uniform float sun_wash;

uniform int light_count;

uniform vec4 light[LIGHT_COUNT];
uniform vec4 light_col[LIGHT_COUNT];

VARYING vec4 vary_fragcoord;
uniform vec2 screen_res;

uniform float far_z;

uniform mat4 inv_proj;

vec4 getPosition(vec2 pos_screen);
vec3 getNorm(vec2 pos_screen);
vec3 srgb_to_linear(vec3 c);

void main() 
{
	vec3 out_col = vec3(0,0,0);

#if defined(LOCAL_LIGHT_KILL)
    discard;
#else
	vec2 frag = (vary_fragcoord.xy*0.5+0.5)*screen_res;
	vec3 pos = getPosition(frag.xy).xyz;
	if (pos.z < far_z)
	{
		discard;
	}
	
	vec3 norm = getNorm(frag.xy);

	vec4 spec = texture2DRect(specularRect, frag.xy);
	vec3 diff = texture2DRect(diffuseRect, frag.xy).rgb;
    diff.rgb = srgb_to_linear(diff.rgb);
	
	float noise = texture2D(noiseMap, frag.xy/128.0).b;
	vec3 npos = normalize(-pos);

	// As of OSX 10.6.7 ATI Apple's crash when using a variable size loop
	for (int i = 0; i < LIGHT_COUNT; ++i)
	{
		vec3 lv = light[i].xyz-pos;
		float dist = length(lv);
		dist /= light[i].w;
		if (dist <= 1.0)
		{
			float da = dot(norm, lv);
			if (da > 0.0)
		{
			lv = normalize(lv);
			da = dot(norm, lv);
			
			float fa = light_col[i].a+1.0;
			float dist_atten = clamp(1.0-(dist-1.0*(1.0-fa))/fa, 0.0, 1.0);
			dist_atten *= dist_atten;
            
            // Tweak falloff slightly to match pre-EEP attenuation
			dist_atten *= 2.2;
			
			dist_atten *= noise;

			float lit = da * dist_atten;
						
			vec3 col = light_col[i].rgb*lit*diff;
			
			//vec3 col = vec3(dist2, light_col[i].a, lit);
			
			if (spec.a > 0.0)
			{
				lv = normalize(lv);
				da = dot(norm, lv);
				
				float fa = light_col[i].a+1.0;
				float dist_atten = clamp(1.0-(dist-1.0*(1.0-fa))/fa, 0.0, 1.0);
				dist_atten *= dist_atten;
				dist_atten *= 2.0;
				
				dist_atten *= noise;
	
				float lit = da * dist_atten;
							
				vec3 col = light_col[i].rgb*lit*diff;
				
				//vec3 col = vec3(dist2, light_col[i].a, lit);
				
				if (spec.a > 0.0)
				{
					lit = min(da*6.0, 1.0) * dist_atten;
					//vec3 ref = dot(pos+lv, norm);
					vec3 h = normalize(lv+npos);
					float nh = dot(norm, h);
					float nv = dot(norm, npos);
					float vh = dot(npos, h);
					float sa = nh;
					float fres = pow(1 - dot(h, npos), 5)*0.4+0.5;
	
					float gtdenom = 2 * nh;
					float gt = max(0, min(gtdenom * nv / vh, gtdenom * da / vh));
									
					if (nh > 0.0)
					{
						float scol = fres*texture2D(lightFunc, vec2(nh, spec.a)).r*gt/(nh*da);
						col += lit*scol*light_col[i].rgb*spec.rgb;
						//col += spec.rgb;
					}
				}
				
				out_col += col;
			}
		}
	}
 out_col *= global_light_strength;
	}
#endif
	
	frag_color.rgb = out_col;
	frag_color.a = 0.0;
	
#ifdef IS_AMD_CARD
	// If it's AMD make sure the GLSL compiler sees the arrays referenced once by static index. Otherwise it seems to optimise the storage awawy which leads to unfun crashes and artifacts.
	vec4 dummy1 = light[0];
	vec4 dummy2 = light_col[0];
	vec4 dummy3 = light[LIGHT_COUNT-1];
	vec4 dummy4 = light_col[LIGHT_COUNT-1];
#endif
}
