Question: What is the internal basis of the "generatePixelAreaLookup" function about react-three-lightmap

[unframework]

Hi Oliver, this function computes the multiplier for each pixel of the light probe half-cube (well, of each side of the half-cube). The pixels near corners/edges of the cube are weighted less than center pixels in the resulting average. In other words, this is mapping cube pixels onto a sphere before combining them into a final sum. Actual mathematics here are very much approximated, I actually did not test this for physical precision or anything - the aim of the whole project is to be a quick convincing hack instead of a full mathematically correct solution. Hope this helps!

[OliverXH]

@unframework
Thank you for your answer
I drew the following figure based on the source code and your answer, which is very useful for me to understand how it works:

This also makes me understand the following program:

const area = probePixelAreaLookup[py * probeTargetSize + px];

r += area * probeData[i];
g += area * probeData[i + 1];
b += area * probeData[i + 2];

[unframework]

Yep that describes it nicely, thanks for the diagram!