Sprite splitting issues

[Major Cooke]

On MAP01


You can try it out for yourself by downloading:

D4D - http://forum.zdoom.org/viewtopic.php?t=52164
DUMP2 - http://forum.zdoom.org/viewtopic.php?t=51072

Start the game on Nightmare difficulty, bind a key to +reload, face the rough direction as seen in the image and plopping down a syphon grenade (reload key). You'll immediately see how sliced up these discs are.

[Graf Zahl]

It's your feature, isn't it? Haven't you actually tried this in some more complex situations ?

[Major Cooke]

Partly. It was originally Nash's, Marrubs and fgsfds's before Nash upped and quit because Randi told him to rename the flags... But I do take responsibility for maintaining it after all that, so in a way, yes, it pretty much now is.

Yes, I did test it in a few more complex environments, but for some reason it never really went THIS apeshit on me.

Camera facing sprites by biospud also has this problem at times as well. So I figured it was more of a joint problem. See the tree in the upper left corner of the pic? Standard tree, with Sprites Face Camera enabled.

[Major Cooke]

Since the changing of flat sprites, this has started to become more noticeable than before. I know nothing about the splitting stuff though. And, again, this also affects facing sprites, roll sprites and flat sprites all the same.

[Graf Zahl]

I need some test map where this can be checked with non-moving sprites. Debugging a moving sprite is not very easy.

[Major Cooke]

https://drive.google.com/file/d/0B6VLnV ... sp=sharing

Just go right up to the front of those three trees in front of you. They're splitting into thirds.

[Rachael]

Has your code been merged with GZDoom's master, yet? I tried doing a pull in my child port and I am not getting the issue. I pulled and compiled not 20 minutes ago.

Also, has your build environment been cleaned lately? Sometimes you have to reset it from scratch - pull from a fresh Git, redo cmake, all that fun stuff.

[Major Cooke]

Do you have Sprites Face Camera enabled? Because I just cleaned it out like you suggested but no change.



I even tried it on my older laptop. Same deal. So, at least I know it's not NVidia card type specific...

[Rachael]

That explains a lot. I never play like that. XD

I got the issue, too, now.

[Graf Zahl]

No luck with this so far, so you'll have to wait a bit longer. Before doing a release I at least want to know if this is something critical or just a rare occurence.

[Major Cooke]

It causes no crash -- merely an annoying visual glitch.
It's done this for the longest time -- it just tends to misbehave when more complex geometry is involved.

However I did find a way to make it trigger based on what angle you're facing.



Press yourself up against this tree and the wall. When you look more to the left, it becomes visible. Turning right will return it to normal.

Hopefully that helps.

[Graf Zahl]

Ok, well, I now know what's happening. These sprites all alter their vertices in the render pass, but the splitter for translucent stuff is run before that on the original vertex data.
Unfortunately this is not an easy fix because a lot of code would have to be rewritten and a few assumptions tossed out. On top of that my math is a bit rusty and I just can't quickly roll out a generic 'split a generic shape in 3D by an arbitrary plane' code - which is what's needed here.

So for now I just patched it over so that these sprites just get sorted by their center.

[Major Cooke]

Fair enough! I'll try it when you push and see if anything else comes up.

[Major Cooke]

Works well enough. Thanks!