cbuffer Screen : register(b0, space3) {
	float x;
	float y;
	float c;
	float d;
};

float srgb( float color )
{
	return (color<0.0031308) ? color*12.92:1.055*pow(color,(1.0/2.4))-0.055;
}

float3 oklab_srgb(float3 c) 
{
    float l_ = c.x + 0.3963377774f * c.y + 0.2158037573f * c.z;
    float m_ = c.x - 0.1055613458f * c.y - 0.0638541728f * c.z;
    float s_ = c.x - 0.0894841775f * c.y - 1.2914855480f * c.z;

    float l = l_*l_*l_;
    float m = m_*m_*m_;
    float s = s_*s_*s_;

    float3 lin = float3(
		+4.0767416621f * l - 3.3077115913f * m + 0.2309699292f * s,
		-1.2684380046f * l + 2.6097574011f * m - 0.3413193965f * s,
		-0.0041960863f * l - 0.7034186147f * m + 1.7076147010f * s
    );
	return float3(srgb(lin.x), srgb(lin.y), srgb(lin.z)); 
}

float3 oklch_oklab(float3 lch) {
	float a = lch.y * cos(lch.z);
	float b = lch.y * sin(lch.z);
	return float3(lch.x, a, b);
}

float3 please(float3 col) {
	return oklab_srgb(oklch_oklab(col));
}

float sdCircle(float2 p, float r) {
	return length(p)-r;
}

float2 smin( float a, float b, float k )
{
    float h = 1.0 - min( abs(a-b)/(4.0*k), 1.0 );
    float w = h*h;
    float m = w*0.5;
    float s = w*k;
    return (a<b) ? float2(a-s,m) : float2(b-s, 1-m);
}

float3 dcol(float3 col, float d) {
	float blend = min(pow(2, d/100), 1.0);
	col.x = lerp(1.0, col.x, blend);
	return col;
}

float3 lcol(float3 col, float3 col2, float b) {
	float d = abs(col.z - col2.z);
	if (d>radians(180)) {
		col.z = ( col.z + radians(180)) % radians(360);
		col2.z = ( col2.z + radians(180)) % radians(360);
		float3 l = lerp(col, col2, b);
		l.z = (l.z + radians(180)) % radians(360);
		return l;
	}
	return lerp(col, col2, b);
}

float4 main(float4 pos : SV_Position) : SV_Target {
	float2 p = float2(pos.x - ( x/2 ), pos.y - ( y / 2));


	float d = sdCircle(p, 100.0);
	float3 scol = dcol(float3(0.75, 0.14, radians(360.0)), d);

	float d2 = sdCircle(p-float2(100.0, 120.0), 80.0);
	float3 scol2 = dcol(float3(0.75, 0.14, radians(173.0)), d2);

	float d3 = sdCircle(p-float2(-100.0, 120.0), 70.0);
	float3 scol3 = dcol(float3(0.75, 0.14, radians(250.0)), d3);

	float2 d_d2 = smin(d, d2, 20);
	float3 c_c2 = lcol(scol, scol2, d_d2.y);
	float cl = max(-d_d2.x, 0.0);

	float2 d_d3 = smin(d, d3, 20);
	float3 c_c3 = lcol(scol, scol3, d_d3.y);
	float cl2 = max(-d_d3.x, 0.0);

	float2 d2_d3 = smin(d2, d3, 20);
	float3 c2_c3 = lcol(scol2, scol3, d2_d3.y);
	float cl3 = max(-d2_d3.x, 0.0);

	float dist = min(min(d_d2.x, d_d3.x), d2_d3.x);

	float sum = cl + cl2 + cl3;
	float3 col = lcol(lcol(c_c2, c_c3, cl2/(cl+cl2)), c2_c3, cl3/sum);

	if (any(isnan(col))){
		col = float3(0, 0, 0);
	}

	float aaf = fwidth(dist);
	float alpha = smoothstep(0, -aaf, dist);
	col = please(col) * alpha;

	float3 bg = float3(pos.x / x, pos.y / y, 1.0) * (1-alpha);

	return float4(col + bg, 1.0);
}