// Quick try at doing a "print value" node for Unity ShaderGraph.
// Tested on Unity 2019.2.17 with ShaderGraph 6.9.2.
//
// Use with CustomFunction node, with two inputs:
// - Vector1 Value, the value to display,
// - Vector2 UV, the UVs of area to display at.
// And one output:
// - Vector4 Color, the color.
// Function name is DoDebug.

// "print in shader" based on this excellent ShaderToy by @P_Malin:
// https://www.shadertoy.com/view/4sBSWW

float DigitBin(const int x)
{
    return x == 0 ? 480599.0 : x == 1 ? 139810.0 : x == 2 ? 476951.0 : x == 3 ? 476999.0 : x == 4 ? 350020.0 : x == 5 ? 464711.0 : x == 6 ? 464727.0 : x == 7 ? 476228.0 : x == 8 ? 481111.0 : x == 9 ? 481095.0 : 0.0;
}

float PrintValue(float2 vStringCoords, float fValue, float fMaxDigits, float fDecimalPlaces)
{
    if ((vStringCoords.y < 0.0) || (vStringCoords.y >= 1.0))
        return 0.0;

    bool bNeg = (fValue < 0.0);
    fValue = abs(fValue);

    float fLog10Value = log2(abs(fValue)) / log2(10.0);
    float fBiggestIndex = max(floor(fLog10Value), 0.0);
    float fDigitIndex = fMaxDigits - floor(vStringCoords.x);
    float fCharBin = 0.0;
    if (fDigitIndex > (-fDecimalPlaces - 1.01))
    {
        if (fDigitIndex > fBiggestIndex)
        {
            if ((bNeg) && (fDigitIndex < (fBiggestIndex + 1.5)))
                fCharBin = 1792.0;
        }
        else
        {
            if (fDigitIndex == -1.0)
            {
                if (fDecimalPlaces > 0.0)
                    fCharBin = 2.0;
            }
            else
            {
                float fReducedRangeValue = fValue;
                if (fDigitIndex < 0.0)
                {
                    fReducedRangeValue = frac(fValue);
                    fDigitIndex += 1.0;
                }
                float fDigitValue = (abs(fReducedRangeValue / (pow(10.0, fDigitIndex))));
                fCharBin = DigitBin(int(floor(fmod(fDigitValue, 10.0))));
            }
        }
    }
    return floor(fmod((fCharBin / pow(2.0, floor(frac(vStringCoords.x) * 4.0) + (floor(vStringCoords.y * 5.0) * 4.0))), 2.0));
}

float PrintValue(const in float2 fragCoord, const in float2 vPixelCoords, const in float2 vFontSize, const in float fValue, const in float fMaxDigits, const in float fDecimalPlaces)
{
    float2 vStringCharCoords = (fragCoord.xy - vPixelCoords) / vFontSize;
    return PrintValue(vStringCharCoords, fValue, fMaxDigits, fDecimalPlaces);
}

void DoDebug_float(float val, float2 uv, out float4 res)
{
    res = float4(0.3, 0.2, 0.1, 1);
    res = PrintValue(uv * 200, float2(10, 100), float2(8, 15), val, 10, 3);
}