[LVL ED] Particle Fading

[BonesTheRabbit]

So, this may be an odd question, but how does particle fading work? There's four values, and after playing around, I'm really not too sure how it all works. Could someone help me understand? What does min and max start and end do exactly?

[TheGreatCthulhu]

If you're referring to the script function, the 4 values fade the particle system as a whole, not by particle age. (It is possible that the level editor provides similar option, didn't check.) This is mainly used to limit the visibility range of the particle system (if you get too close, or if the PS is to far, so that GPU resources can be conserved (for example, the dust particles that float near the windows, in the initial level of amnesia, where the game starts)).
The meaning of the params is:

Code: (Select All)

FadeMinEnd       - FadeMinStart - FadeMaxStart -   FadeMaxEnd
too_close_to_see - full_opacity - full_opacity - too_far_to_see

In the particle editor you can create your own particle system (don't overwrite the ones that Amnesia uses - save somewhere else), and you can control how a particle fades during it's life time by going to the color tab, and playing around with the options in the Fading group (you can tint them, or make them more or less transparent by modifying the alpha value). You can set:
start color/alpha
mid color/alpha
end color/alpha

This effectively defines 2 time spans in the particle lifetime, so there are also two numeric parameters which you can use to control where exactly the mid point is ("mid relative start" - values near 0 mean close to start, values near 1 mean close to the end), and how long the particle should retain the "mid" state ("mid relative length" - 0 makes it transition at once, values near 1 should take up the entire time span).

[BonesTheRabbit]

Okay, regarding the space between FadeMinEnd and FadeMinStart, is the near point measured as a radius from the particle's origin? Like, the actual PS point in the Amnesia Editor? Or does it have a larger field based on the effect itself?

[TheGreatCthulhu]

(EDITED: In the original post, I've mistakenly reached a completely opposite conclusion! XD)
It appears to me that it's measured from the origin of the PS source (that is, from where you placed it in the editor), to the position of the player's "head" (camera); the best way to check is to create a test custom story, simple map with a PS, and then start the game and walk back and forth. You can also add some distance-reference objects to the map, like several pillars spaced at unit distance, so that you have some sense of the lengths involved, and how the values of the parameters relate to each other.

For example, I created a relatively large smoke PS (a higher-than-player column of smoke, like from a somewhat larger fire), and when I set the first two values close (I used, 2.9 and 3.0), and then get at about 3m away, I can find the point where I can see the PS when I'm standing, but not when I'm crouching (which means that the measuring origin is on the ground, where I placed the PS object in the editor (and not somewhere up in the air, where the center of the effect is), so the distance calculated is smaller when I crouch). And if I jump, the PS goes full opacity while I'm in the air.

[BonesTheRabbit]

Yeah, looks like it. Thank you very much, oh great old one!