float2 uv = _surface.diffuseTexcoord;
uv = uv*2.0 - 1.0;

float r_big = .225;
float hl_big = smoothstep(1.0 - r_big,
                          1.0 - r_big + 0.05,
                          1.0 - length(uv - float2(-0.15, -0.15)));

float r_small = .075;
float hl_small = smoothstep(1.0 - r_small,
                            1.0 - r_small + 0.05,
                            1.0 - length(uv - float2(00.1750,00.1750)));

_output.color.rgb += hl_big * 1.0 + hl_small * 0.9;