Can someone explain how to use the glow filter?

I’m trying to make a game in which there are some plants that have parts that glow. The entire plant does not glow, just a part of it.
I tried looking up explanations for the glow filter tutorial, but I haven’t found anything helpful.
Can someone explain to me how it works? Mainly, I’m trying to figure out how the filter chooses what glows. I’m really confused how the tron model only has little strips that glow, and I want to know how that is done. Can someone explain please?

It’s all controlled by the “blend” parameter to setBloom:

setBloom(blend=(0.3,0.4,0.3,0.0), mintrigger=0.6, maxtrigger=1.0, desat=0.6, intensity=1.0, size="medium")

The blend parameter has four components, R, G, B and A. They indicate how to blend the scene colour to determine how much which colours should light up. For instance, if you set it to (1, 0, 0, 0), every colour in the scene that contains red will glow by as much red as they contain. If you set it to (0.1, 0.1, 0.1), the entire scene will glow, but only by a little bit.

The alpha parameter is special, though: when setting that, you’re actually blending in any glow maps that are applied to a model. So, setting it to (0, 0, 0, 1) makes only the glow maps play a role in determining which areas of the scene should glow and how much.

Also of note is mintrigger, which indicates the minimum brightness that the scene colour must be for something to glow. If you set it to 0.5, only colours with a combined glow blending value of at least 0.5 will glow. If you have a glow map, you will likely want to set this to 0.

desat indicates how much to desaturate the colours when determining the colour of the glow they emit. A value of 0.0 will make a red object emit a pure red glow, whereas a value of 1.0 will make the glow always greyscale.

You need to call setShaderAuto() on the models that have a glow map (or on the entire scene) to make glow maps work.

Ahh, thank you so much for the quick reply, this explains a lot and I’m very grateful!!
However, just one question, what is a glow map? … w_Map_Mode

Thank you sooo much. However, this one line scares me a little bit:

“Currently, Panda3D only allows one glow map per polygon, additional glow maps will be ignored.”

What does this mean exactly? Can I only use one glow map for my whole game?

Sorry if I’m asking dumb questions, I’m super new to programming and panda. But thank you so much for your help

No, per mesh. Per piece of geometry. You can have different glow maps on different objects, but you can’t overlay two glow maps on top of each other on the same object.

Ah, okay, perfect. That’s what I thought.
Thank you sooo much, this was very helpful!