[HLSL] Smoothness Rectangle Masking

float getRectangleMask(float2 uv, float x, float y, float w, float h)
{
	float lineX, lineY;
    lineX = smoothstep(x + w, 1, uv.x) + smoothstep(x - w,0, uv.x);
    lineY = smoothstep(y + h, 1, uv.y) + smoothstep(y - h,0, uv.y);
    float2 norm = float2(lineX, lineY);
    return length(norm);
}