/*
   Hyllian's 2xBR v3.5b 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 float coef           = 2.0;
const static float3 dtt           = float3(65536,255,1);
const static half y_weight        = 48.0;
const static half u_weight        = 7.0;
const static half v_weight        = 6.0;
const static half3x3 yuv          = half3x3(0.299, 0.587, 0.114, -0.169, -0.331, 0.499, 0.499, -0.418, -0.0813);
const static half3x3 yuv_weighted = half3x3(y_weight*yuv[0], u_weight*yuv[1], v_weight*yuv[2]);

//const static half3x3 yuv_weighted = half3x3(14.352, 28.176, 5.472, -1.183, -2.317, 3.5, 3.0, -2.514, -0.486);


float3 RGBtoYUV(half3x3 mat_color)
{
	float a= abs(mul(yuv_weighted, mat_color[0]));
	float b= abs(mul(yuv_weighted, mat_color[1]));
	float c= abs(mul(yuv_weighted, mat_color[2]));

	return float3(a, b, c);
}

float3 df(float3 A, float3 B)
{
	return float3(abs(A-B));
}

bool3 eq(float3 A, float3 B)
{
	return (df(A, B) < float3(1.0));
}

float3 weighted_distance(float3 a, float3 b, float3 c, float3 d, float3 e, float3 f, float3 g, float3 h)
{
	return (df(a,b) + df(a,c) + df(d,e) + df(d,f) + 4.0*df(g,h));
}



struct input
{
	half2 video_size;
	float2 texture_size;
	half2 output_size;
};


struct out_vertex {
	half4 position : POSITION;
	half4 color    : COLOR;
	float2 texCoord : TEXCOORD0;
	half4 t1 : TEXCOORD1;
};

/*    VERTEX_SHADER    */
out_vertex main_vertex
(
	half4 position	: POSITION,
	half4 color	: COLOR,
	float2 texCoord : TEXCOORD0,

   	uniform half4x4 modelViewProj,
	uniform input IN
)
{
	out_vertex OUT;

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

	half2 ps = half2(1.0/IN.texture_size.x, 1.0/IN.texture_size.y);
	half dx = ps.x;
	half dy = ps.y;

	OUT.texCoord = texCoord;
	OUT.t1.xy = half2(  0,-dy); // B
	OUT.t1.zw = half2(-dx,  0); // D

	return OUT;
}


/*    FRAGMENT SHADER    */
half4 main_fragment(in out_vertex VAR, uniform sampler2D decal : TEXUNIT0, uniform input IN) : COLOR
{
	bool3 edr, edr_left, edr_up, px; // px = pixel, edr = edge detection rule
	bool3 interp_restriction_lv1, interp_restriction_lv2_left, interp_restriction_lv2_up;
	half3 E3;
	half3 P[3];

	float2 fp = frac(VAR.texCoord*IN.texture_size);

	half2 st = step(0.5,fp);

	half2 g1 = VAR.t1.xy*(st.x + st.y - 1.0) + VAR.t1.zw*(st.x - st.y    );
	half2 g2 = VAR.t1.xy*(st.y - st.x    ) + VAR.t1.zw*(st.x + st.y - 1.0);

	half3 A = tex2D(decal, VAR.texCoord +g1+g2).xyz;
	half3 B = tex2D(decal, VAR.texCoord +g1   ).xyz;
	half3 C = tex2D(decal, VAR.texCoord +g1-g2).xyz;
	half3 D = tex2D(decal, VAR.texCoord    +g2).xyz;
	half3 E = tex2D(decal, VAR.texCoord       ).xyz;
	half3 F = tex2D(decal, VAR.texCoord    -g2).xyz;
	half3 G = tex2D(decal, VAR.texCoord -g1+g2).xyz;
	half3 H = tex2D(decal, VAR.texCoord -g1   ).xyz;
	half3 I = tex2D(decal, VAR.texCoord -g1-g2).xyz;

	half3  C1 = tex2D(decal,VAR.texCoord +2.0*g1-g2   ).xyz;
	half3  G0 = tex2D(decal,VAR.texCoord -g1+2.0*g2   ).xyz;
	half3  C4 = tex2D(decal,VAR.texCoord +g1-2.0*g2   ).xyz;
	half3  F4 = tex2D(decal,VAR.texCoord    -2.0*g2   ).xyz;
	half3  I4 = tex2D(decal,VAR.texCoord -g1-2.0*g2   ).xyz;
	half3  G5 = tex2D(decal,VAR.texCoord -2.0*g1+g2   ).xyz;
	half3  H5 = tex2D(decal,VAR.texCoord -2.0*g1      ).xyz;
	half3  I5 = tex2D(decal,VAR.texCoord -2.0*g1-g2   ).xyz;
	half3  B1 = tex2D(decal,VAR.texCoord +2.0*g1      ).xyz;
	half3  D0 = tex2D(decal,VAR.texCoord +2.0*g2      ).xyz;
	half3  A1 = tex2D(decal,VAR.texCoord +2.0*g1+g2   ).xyz;
	half3  A0 = tex2D(decal,VAR.texCoord +2.0*g2+g1   ).xyz;

	float3 a = RGBtoYUV( half3x3(A, G, C) );
	float3 b = RGBtoYUV( half3x3(B, D, F) );
	float3 c = RGBtoYUV( half3x3(C, A, I) );
	float3 d = RGBtoYUV( half3x3(D, H, B) );
	float3 e = RGBtoYUV( half3x3(E, E, E) );
	float3 f = RGBtoYUV( half3x3(F, B, H) );
	float3 g = RGBtoYUV( half3x3(G, I, A) );
	float3 h = RGBtoYUV( half3x3(H, F, D) );
	float3 i = RGBtoYUV( half3x3(I, C, G) );

	float3 a1 = RGBtoYUV( half3x3(A1, G0, C4) );
	float3 c1 = RGBtoYUV( half3x3(C1, A0, I4) );
	float3 a0 = RGBtoYUV( half3x3(A0, G5, C1) );
	float3 g0 = RGBtoYUV( half3x3(G0, I5, A1) );
	float3 c4 = RGBtoYUV( half3x3(C4, A1, I5) );
	float3 i4 = RGBtoYUV( half3x3(I4, C1, G5) );
	float3 g5 = RGBtoYUV( half3x3(G5, I4, A0) );
	float3 i5 = RGBtoYUV( half3x3(I5, C4, G0) );
	float3 b1 = RGBtoYUV( half3x3(B1, D0, F4) );
	float3 d0 = RGBtoYUV( half3x3(D0, H5, B1) );
	float3 h5 = RGBtoYUV( half3x3(H5, F4, D0) );
	float3 f4 = RGBtoYUV( half3x3(F4, B1, H5) );

	interp_restriction_lv1      = ((e!=f) && (e!=h));
	interp_restriction_lv2_left = ((e!=g) && (d!=g));
	interp_restriction_lv2_up   = ((e!=c) && (b!=c));

	edr      = (weighted_distance( e, c, g, i, h5, f4, h, f) < weighted_distance( h, d, i5, f, i4, b, e, i)) && interp_restriction_lv1 && ( !eq(f,b) && !eq(f,c) || !eq(h,d) && !eq(h,g) || eq(e,i) && (!eq(f,f4) && !eq(f,i4) || !eq(h,h5) && !eq(h,i5)) || eq(e,g) || eq(e,c));
	edr_left = ((coef*df(f,g)) <= df(h,c)) && interp_restriction_lv2_left;
	edr_up   = (df(f,g) >= (coef*df(h,c))) && interp_restriction_lv2_up;

	px = (df(e,f) <= df(e,h));

	E3 = E;

	P[0] = px.x ? F : H;
	P[1] = px.y ? B : F;
	P[2] = px.z ? H : D;


	if (edr.x && edr_left.x && edr_up.x)
	{
		E3  = lerp(E3 , P[0],  0.833333);
	}
	else if (edr.x && (edr_left.x || edr_up.x))
	{
		E3  = lerp(E3 , P[0],  0.75);
	}
	else if (edr.y && edr_left.y && edr.z && edr_up.z)
	{
		E3  = lerp(E3 , P[1],  0.25);
		E3  = lerp(E3 , P[2],  0.25);
	}
	else if (edr.y && edr_left.y)
	{
		E3  = lerp(E3 , P[1],  0.25);
	}
	else if (edr.z && edr_up.z)
	{
		E3  = lerp(E3 , P[2],  0.25);
	}
	else if (edr.x)
	{
		E3  = lerp(E3 , P[0],  0.5);
	}


//	E3 = (edr.x && edr_left.x && edr_up.x) ? lerp(E3 , P[0],  0.833333) : (edr.x && (edr_left.x || edr_up.x)) ? lerp(E3 , P[0],  0.75) : (edr.y && edr_left.y) ? lerp(E3 , P[1],  0.25) : (edr.z && edr_up.z) ? lerp(E3 , P[2],  0.25) : (edr.x) ? lerp(E3 , P[0],  0.5) : E;

	return half4(E3, 1.0);
}

