UE4 Color Grade Nodes

//Color balls with spherical falloff
//Lerp between start to end colors
float distToSphere = distance(inPixelWpos, inSphereCenterWpos);

float alpha = saturate(distToSphere / sphereRadius);
float3 outColor = lerp(StartColor, EndColor, alpha);

//Determine falloff power to sphere radius
float falloff = saturate(falloffScale * (alpha -  0.5) + 0.5 - falloffBias);
float falloffPower = -(falloff * falloff * (3 - 2 * falloff)) + 1;

return float4(outColor, distToSphere > sphereRadius ? 0 : falloffPower);





//Gradient Remap based on luminosity
//Lerp between start to end colors
float distToSphere = distance(inPixelWpos, inSphereCenterWpos);

//float alpha = smoothstep(0, sphereRadius, distToSphere);
float alpha = saturate(distToSphere / sphereRadius);

//Calculate luminosity
float luminosity = saturate(dot(float3(0.299, 0.587, 0.114), inColor));
float3 outColor = lerp(StartColor, EndColor, smoothstep(0,1,luminosity));

//Determine falloff power to sphere radius
float falloff = saturate(falloffScale * (alpha -  0.5) + 0.5 - falloffBias);
float falloffPower = -(falloff * falloff * (3 - 2 * falloff)) + 1;

return float4(outColor, distToSphere > sphereRadius ? 0 : falloffPower);