bullet puffs too low on walls and ceiling

When using freelook and no autoaim, I found that puffs are spawned too low when your shots get up to a certain point near the ceiling. The puffs stay at a certain height, even if you aim higher and higher. Eventually, they start gaining in height again and appear above the wall, but way below your aim. There are no such issues with floors, as far as I can tell.



This happens in every source port with freelook that I tried so far (ZDoom, GZDoom, Legacy Doom, Eternity Engine). The displacement is easily visible, if you use a crosshair and splats. The problem disappears, if you change the graphic options to use particles instead of sprites for puffs.

I guess this isn't really a bug, because I assume that Vanilla Doom just doesn't need to display puffs high up on walls, close to the ceiling. I do wonder why none of the source ports changed this, instead of comming up with an entirely different solution (particles). Would it be too hard to spawn the puffs at the exact same locations as the particles? (And btw, why aren't splats drawn on ceilings and floors at all?)

If I recall correctly, the last time this was pointed out it was eventually figured out that the source of the problem is the height defined for the bullet puff objects in Doom. It's taller than the sprites used for them.

Essel's hit it on the head. The bullet puff has a height of 16, and since actor boundaries can't normally go into the ceiling or floor, they're spawned at the highest height possible, which is lower than the height of the sprite.

There's actually a certain flag (NOINTERACTION) in ZDoom you can give to the bullet puff object to "fix" this, but you'll have to apply it yourself if you're so inclined.

Big thx for your explanations. I'll take a look at the ZDoom fix.


Now, what about these splats not appearing on floors and ceilings, is there a fix for that as well?

doombringa said:

Now, what about these splats not appearing on floors and ceilings, is there a fix for that as well?

The "fix" apparently involves a complete rewrite of the renderer code, from what I recall Graf Zahl saying anyway...

Here it's more the physics code that gets in the way.

Regardless, it's a hopeless situation.

I've never understood why flat decals is always considered such a problem in ZDoom. What makes them so hard to implement?

Ever tried to cut a rectangle to a shapeless form?

Don't forget that ZDoom does not use GL nodes for its sectors.

Could you give the bulletpuffs +NOINTERACTION to solve this? I recall that flag allowing some actors I made to clip into ceilings.

Edit: Oh Xaser beat me to it

Graf Zahl said:

Ever tried to cut a rectangle to a shapeless form?

Don't forget that ZDoom does not use GL nodes for its sectors.

Don't see why it couldn't.

If using GL nodes would allow floor/ceiling decals, could they be implemented in GZDoom? There were some hacky mod implementations through spawning objects with flat models, but they don't look that good on sloped surfaces...

Exactly. Given that good GL nodes define a full convex subsector set, you can trivially "ear-clip" decal primitives (for example).

The fact that I currently don't work on the GL renderer nonwithstanding that was always a thing where the work-to-benefit ratio was not good enough for me to think about it.

I see. Though I can't say I agree with your work-to-benefit analysis (as there are many more benefits to doing this beyond decal clipping) I can certainly appreciate the lack-of-time argument.

I'd probably use decals if they appeared on the floor. In fact, I'd much prefer decals if they appeared ONLY on the floor and not the walls. It doesn't make any visual sense to me that the blood splat sprites fall to the floor, the demons fall to the floor splashed in their own blood, but all the blood decals appear on the walls only leaving the floors perfectly clean. Blood on the floor would look way cooler ala Doom 3

40oz said:

I'd probably use decals if they appeared on the floor. In fact, I'd much prefer decals if they appeared ONLY on the floor and not the walls. It doesn't make any visual sense to me that the blood splat sprites fall to the floor, the demons fall to the floor splashed in their own blood, but all the blood decals appear on the walls only leaving the floors perfectly clean. Blood on the floor would look way cooler ala Doom 3

What are you talking about? How do you not know that the demons go out of their way to not get blood all over the floor and all over the walls?

It's true. Doom's demons have always been very clean creatures. Hell, it wasn't until the age of source ports that they even left behind any nasty permanent blood stains at all. Besides the decorative ones, of course. ;)