/*
   Hyllian's xBR LV2 B (semi rounded) - pass0 Shader
   
   Copyright (C) 2011-2015 Hyllian - sergiogdb@gmail.com

   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files (the "Software"), to deal
   in the Software without restriction, including without limitation the rights
   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   copies of the Software, and to permit persons to whom the Software is
   furnished to do so, subject to the following conditions:

   The above copyright notice and this permission notice shall be included in
   all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   THE SOFTWARE.


   Incorporates some of the ideas from SABR shader. Thanks to Joshua Street.
*/

const static float coef            = 2.0;
const static float4 eq_threshold   = float4(15.0, 15.0, 15.0, 15.0);
const static float y_weight        = 48.0;
const static float u_weight        = 7.0;
const static float v_weight        = 6.0;
const static float3x3 yuv          = float3x3(0.299, 0.587, 0.114, -0.169, -0.331, 0.499, 0.499, -0.418, -0.0813);
const static float3x3 yuv_weighted = float3x3(y_weight*yuv[0], u_weight*yuv[1], v_weight*yuv[2]);
const static float4 delta          = float4(0.4, 0.4, 0.4, 0.4);


float3 remapTo01(float3 v, float3 low, float3 high)
{
	return saturate((v - low)/(high-low));
}


float4 df(float4 A, float4 B)
{
	return float4(abs(A-B));
}

float c_df(float3 c1, float3 c2)
{
	float3 df = abs(c1 - c2);
	return df.r + df.g + df.b;
}


bool4 eq(float4 A, float4 B)
{
	return (df(A, B) < eq_threshold);
}

float4 weighted_distance(float4 a, float4 b, float4 c, float4 d, float4 e, float4 f, float4 g, float4 h)
{
	return (df(a,b) + df(a,c) + df(d,e) + df(d,f) + 4.0*df(g,h));
}



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;
	float4 t2       : TEXCOORD2;
	float4 t3       : TEXCOORD3;
	float4 t4       : TEXCOORD4;
	float4 t5       : TEXCOORD5;
	float4 t6       : TEXCOORD6;
	float4 t7       : TEXCOORD7;
};

/*    VERTEX_SHADER    */
out_vertex main_vertex
(
	float4 position	: POSITION,
	float4 color	: COLOR,
	float2 texCoord : 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;

	//    A1 B1 C1
	// A0  A  B  C C4
	// D0  D  E  F F4
	// G0  G  H  I I4
	//    G5 H5 I5

	OUT.texCoord = texCoord;
	OUT.t1 = texCoord.xxxy + float4( -dx, 0, dx,-2.0*dy); // A1 B1 C1
	OUT.t2 = texCoord.xxxy + float4( -dx, 0, dx,    -dy); //  A  B  C
	OUT.t3 = texCoord.xxxy + float4( -dx, 0, dx,      0); //  D  E  F
	OUT.t4 = texCoord.xxxy + float4( -dx, 0, dx,     dy); //  G  H  I
	OUT.t5 = texCoord.xxxy + float4( -dx, 0, dx, 2.0*dy); // G5 H5 I5
	OUT.t6 = texCoord.xyyy + float4(-2.0*dx,-dy, 0,  dy); // A0 D0 G0
	OUT.t7 = texCoord.xyyy + float4( 2.0*dx,-dy, 0,  dy); // C4 F4 I4

	return OUT;
}


/*    FRAGMENT SHADER    */
float4 main_fragment(in out_vertex VAR, uniform sampler2D decal : TEXUNIT0, uniform input IN) : COLOR
{
	bool4 edr, edr_left, edr_up; 
	bool4 interp_restriction_lv1, interp_restriction_lv2_left, interp_restriction_lv2_up;

	float3 A1 = tex2D(decal, VAR.t1.xw).rgb;
	float3 B1 = tex2D(decal, VAR.t1.yw).rgb;
	float3 C1 = tex2D(decal, VAR.t1.zw).rgb;

	float3 A  = tex2D(decal, VAR.t2.xw).rgb;
	float3 B  = tex2D(decal, VAR.t2.yw).rgb;
	float3 C  = tex2D(decal, VAR.t2.zw).rgb;

	float3 D  = tex2D(decal, VAR.t3.xw).rgb;
	float3 E  = tex2D(decal, VAR.t3.yw).rgb;
	float3 F  = tex2D(decal, VAR.t3.zw).rgb;

	float3 G  = tex2D(decal, VAR.t4.xw).rgb;
	float3 H  = tex2D(decal, VAR.t4.yw).rgb;
	float3 I  = tex2D(decal, VAR.t4.zw).rgb;

	float3 G5 = tex2D(decal, VAR.t5.xw).rgb;
	float3 H5 = tex2D(decal, VAR.t5.yw).rgb;
	float3 I5 = tex2D(decal, VAR.t5.zw).rgb;

	float3 A0 = tex2D(decal, VAR.t6.xy).rgb;
	float3 D0 = tex2D(decal, VAR.t6.xz).rgb;
	float3 G0 = tex2D(decal, VAR.t6.xw).rgb;

	float3 C4 = tex2D(decal, VAR.t7.xy).rgb;
	float3 F4 = tex2D(decal, VAR.t7.xz).rgb;
	float3 I4 = tex2D(decal, VAR.t7.xw).rgb;

	float4 b = mul( float4x3(B, D, H, F), yuv_weighted[0] );
	float4 c = mul( float4x3(C, A, G, I), yuv_weighted[0] );
	float4 e = mul( float4x3(E, E, E, E), yuv_weighted[0] );
	float4 d = b.yzwx;
	float4 f = b.wxyz;
	float4 g = c.zwxy;
	float4 h = b.zwxy;
	float4 i = c.wxyz;

	float4 i4 = mul( float4x3(I4, C1, A0, G5), yuv_weighted[0] );
	float4 i5 = mul( float4x3(I5, C4, A1, G0), yuv_weighted[0] );
	float4 h5 = mul( float4x3(H5, F4, B1, D0), yuv_weighted[0] );
	float4 f4 = h5.yzwx;

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

	float3 info;

	info.x = dot(float4(edr     ), float4(8.0f, 4.0f, 2.0f, 1.0f));
	info.y = dot(float4(edr_left), float4(8.0f, 4.0f, 2.0f, 1.0f));
	info.z = dot(float4(edr_up  ), float4(8.0f, 4.0f, 2.0f, 1.0f));

	return float4(remapTo01(info, float3(0.0f, 0.0f, 0.0f), float3(255.0f, 255.0f, 255.0f)), 1.0);
}
