/*
   Hyllian's 5xBR v1.1 Shader
   
   Copyright (C) 2011 Hyllian/Jararaca - sergiogdb@gmail.com

   This program 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.

   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 General Public License for more details.

   You should have received a copy of the GNU 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.

*/

const static float3 dtt = float3(65536,255,1);

float reduce(float3 color)
{
	return dot(color, dtt);
}

struct input
{
	float2 video_size;
	float2 texture_size;
	float2 output_size;
        float frame_count;
        float frame_direction;
        float frame_rotation;
};


struct out_vertex {
	float4 position : POSITION;
	float4 color    : COLOR;
	float2 texCoord : TEXCOORD0;
	float4 t1 : TEXCOORD1;
};

/*    VERTEX_SHADER    */
out_vertex main_vertex
(
	float4 position	: POSITION,
	float4 color	: COLOR,
	float2 texCoord1 : TEXCOORD0,

   	uniform float4x4 modelViewProj,
	uniform input IN
)
{
	out_vertex OUT;

	OUT.position = mul(modelViewProj, position);
	OUT.color = color;

	float2 ps = float2(1.0/IN.texture_size.x, 1.0/IN.texture_size.y);
	float dx = ps.x;
	float dy = ps.y;

	// This line fix a bug in ATI cards.
	float2 texCoord = texCoord1 + float2(0.0000001, 0.0000001);

	OUT.texCoord = texCoord;
	OUT.t1.xy = float2(  0,-dy); // B
	OUT.t1.zw = float2(-dx,  0); // D

	return OUT;
}


/*    FRAGMENT SHADER    */
float4 main_fragment(in out_vertex VAR, uniform sampler2D decal : TEXUNIT0, uniform input IN) : COLOR
{
	float2 fp = frac(VAR.texCoord*IN.texture_size);

	float2 st = step(0.5,fp);

	float2 g1 = VAR.t1.xy*(st.x + st.y - 1.0) + VAR.t1.zw*(st.x - st.y      );
	float2 g2 = VAR.t1.xy*(st.y - st.x      ) + VAR.t1.zw*(st.x + st.y - 1.0);

	float AO  = 2.0*st.y - 1.0;
	float BO  = 2.0*st.x - 1.0;
	float CO  = st.x + st.y - 0.5;

	float3 B = tex2D(decal, VAR.texCoord +g1   ).xyz;
	float3 C = tex2D(decal, VAR.texCoord +g1-g2).xyz;
	float3 D = tex2D(decal, VAR.texCoord    +g2).xyz;
	float3 E = tex2D(decal, VAR.texCoord       ).xyz;
	float3 F = tex2D(decal, VAR.texCoord    -g2).xyz;
	float3 G = tex2D(decal, VAR.texCoord -g1+g2).xyz;
	float3 H = tex2D(decal, VAR.texCoord -g1   ).xyz;
	float3 I = tex2D(decal, VAR.texCoord -g1-g2).xyz;

	float3  C4 = tex2D(decal,VAR.texCoord +g1-2.0*g2   ).xyz;
	float3  G5 = tex2D(decal,VAR.texCoord -2.0*g1+g2   ).xyz;
	
	float b = reduce(B);
	float c = reduce(C);
	float d = reduce(D);
	float e = reduce(E);
	float f = reduce(F);
	float g = reduce(G);
	float h = reduce(H);
	float i = reduce(I);

	float  c4 = reduce( C4);
	float  g5 = reduce( G5);
	
	float3 res = E;

	bool fx_1 = (AO*fp.y+BO*fp.x > CO);

	if (fx_1)
	{
		bool condition_1, condition_2, condition_3;
		condition_1 = (  e!=h  && (
				   ( h==f  && ( ( e!=i  && ( e!=b  ||  e!=d ||  f!=b  &&  f!=c  ||  h!=d  &&  h!=g ))
	   			                || ( e==g  && ( i==h  ||  e==d  ||  h!=d )) || ( e==c  && ( i==h  ||  e==b  ||  f!=b ))))
				   || ( e!=f  && ( h!=i  &&  e==g  && ( f==i  &&  h!=d  ||  e!=i  &&  h==g5))))
		      );

		condition_2 = ( e!=h  &&  e!=f  && ( f!=i  &&  e==c  && ( h==i  &&  f!=b  ||  e!=i  &&  f==c4)));
		condition_3 = ( e!=h  &&  g==e  &&  e==c  &&  e!=i  &&  e!=f  );

		res = ( condition_1 ) ? H : (condition_2) ? F : (condition_3) ? (F+H)*0.5 : E;

	}

	return float4(res, 1.0);
}
