SOLVED: Weird behavior of Analyze TOP

Bugs
1

I’m trying to do some calculations on input luminance with Touch Designer and I’m getting weird results with the Analyze TOP. Using a solid white rectangle, analyzing minimum pixel shows 0.502 for all 4 channels (R,G,B,A). Why isn’t it 1?
If I instead analyze the maximum pixel it tracks R,G,B correctly but when the rectangle is solid black the alpha shows 0.502. I’m not changing alpha at all, so I expected it to remain at 1.
If I instead analyze the average, the maximum is 0.9804 instead of 1.

I think it’s easier to understand by watching this short screen capture as I adjust the rectangle color from black to white.

This is macOS build 2022.21460.

2

I think the issue is with the blending around the borders of the rectangle top. Even with the size set to 1, if you look closely, the outer pixel is probably a little dimmer than 1 because it’s being antialiased with the surrounding black.

If you turn off the ‘anti-alias’ parameter, you should get a uniform color across the entire top and your analyze will likely work as expected.

Hope that helps. Let me know if you’re still having problems.

3

Oh! Thanks, yes that was it!