#include "text_shared.hlsli"
#include "fragmentHelpers.hlsli"

Texture2D<float4> Texture0 : register(t0, space2);
SamplerState Sampler0 : register(s0, space2);

StructuredBuffer<FontInfo> fontBuffer: register(t1, space2);

float4 main(
    uint Color : TEXCOORD0,
    float2 UV : TEXCOORD1,
    float2 pixelPosition: TEXCOORD2,
    uint Instance: TEXCOORD3
) :SV_Target0
{
    float4 o;

    // vec4 tex = texture(tex, texCoord);

    float4 tex = Texture0.Sample(Sampler0, UV);
    uint isSdf = fontBuffer[Instance].isSdf;
    float2 position = fontBuffer[Instance].position;
    float2 size = fontBuffer[Instance].size;

    if(!scissor(pixelPosition, position, size))
    //if(pixelPosition.x > (position.x + size.x))
    {
        // return float4(pixelPosition.x / 1920, 0.0, 0.0, 1.0);
        discard;
    }

    float4 textColor = float4(
        getRedFromUint(Color),
        getGreenFromUint(Color),
        getBlueFromUint(Color),
        getAlphaFromUint(Color));

    if(isSdf == 1)
    {
        float dist  = tex.r;
        float width = fwidth(dist);
        float outerEdge = 1.0f - (120.0f / 255.0f);

        float alpha = contour(dist, outerEdge, width);

        float dscale = 0.354; // half of 1/sqrt2; you can play with this
        float2 uv = UV.xy;
        float2 duv = dscale * (ddx(uv) + ddy(uv));
        float4 box = float4(uv - duv, uv + duv);

        float asum = getSample(Texture0, Sampler0, box.xy, outerEdge, width)
                 + getSample(Texture0, Sampler0, box.zw, outerEdge, width)
                 + getSample(Texture0, Sampler0, box.xw, outerEdge, width)
                 + getSample(Texture0, Sampler0, box.zy, outerEdge, width);

        // weighted average, with 4 extra points having 0.5 weight each,
        // so 1 + 0.5*4 = 3 is the divisor
        alpha = (alpha + 0.5 * asum) / 3.0;

        textColor = float4(textColor.xyz, alpha);//textColor.* alpha);
        textColor.xyz = pow(textColor.xyz, 2.2); // gamma correction

        // Premultiplied alpha output.
        o = textColor;
    }
    else 
    {
        float alpha = 1.0;
        float gray = dot(textColor.xyz, float3(0.2126, 0.7152, 0.0722));
        o = float4(textColor.xyz , pow(tex.x / gray, 1/(2.2)) );//textColor.* alpha);
        //outFragColor = vec4(1.0, 0.0, 0.0, 1.0);
    }

#if 0
    float4 outFragColor = 0;

    if(!rect(pixelPosition, position, size))
    {
    }
    outFragColor = float4(1.0, 0.0, 0.0, 1.0);

    return outFragColor + o * 0.00001;
#else
    //float alpha = 1.0;
    // float gray = dot(textColor.xyz, float3(0.2126, 0.7152, 0.0722));
    // o = float4(textColor.xyz,  tex.x);//pow(tex.x / gray, 1/(2.2)) );//textColor.* alpha);
    return o; // float4(1.0, 1.0, 1.0, tex.x) + o * 0.00001;
#endif

}