[won't change] Grenade Bounces Off Sky "Virtual Ceiling

Deathlike2 · Post by **Deathlike2** » Wed Dec 14, 2005 13:42

When aiming the grenade weapon into the sky, it bounces off of "the sky" like if there was a virtual ceiling there. I don't think that's normal (not sure if its intentional though).

In comparison to the rocket launcher... at least the rocket "disappears" into the sky.

Post by **Graf Zahl** » Wed Dec 14, 2005 13:53

Last time you complained when it did explode. Then I've changed it and now you complain again?

Make up your mind!

Deathlike2 · Post by **Deathlike2** » Wed Dec 14, 2005 14:31

Well, there is a difference between the older report and this report.

The expected output was that the grenades when shot into the sky.. would come back down within whatever physics model you are using assuming there is nothing in the sky that is blocking you. This should ideally happen barring intended limitations...

The first bug was that it exploded in the sky... and it shouldn't... what I should of added is related to the second bug (this bug) I reported.

This bug (the second one) is the fact that there is a "virtual ceiling" that affected the grenades. Ideally this ceiling should not exist. If it were supposed to exist (assume this was intended), it should technically affect the rocket launcher similarly, yes? I'm just saying that there should be some consistancy in terms of that how the weapons are dealt with when shot into the sky.

Post by **Graf Zahl** » Wed Dec 14, 2005 14:45

Judging from your reports today I'd have to assume that you don't understand the physics engine. Above the sky ceiling there is nothing and the grenade can't go there without creating problems. Effectively you are shooting the grenade against the ceiling and it's bouncing off - as expected. If it bothers you you have to redesign the level but in the Doom engine's context the behavior is exactly what it is supposed to be.

Deathlike2 · Post by **Deathlike2** » Wed Dec 14, 2005 14:59

I have no problem with it if is imposed by the Doom engine.. I'm only saying that ideally if you were able to remove this limitation.. that would be great. Obviously if that is not worthwhile, then so be it.

The reason why this was in any discussion was because GZDoom doesn't have the same restriction as ZDoom has when it deals with looking up and down. You are better able to view your surroundings with GZDoom and hence able to expose the grenades-sky ceiling behavior.

Post by **Graf Zahl** » Wed Dec 14, 2005 15:05

I know that freelook is quite revealing for engine limitations - but the limitations are still there and can't be ignored. Guess why so many players stick to the more basic Doom ports.

Deathlike2 · Post by **Deathlike2** » Wed Dec 14, 2005 15:20

I guess the current state of the grenades and the virtual ceiling is fine. It gives the player the ability to avoid misfires into the sky.

Post by **Enjay** » Wed Dec 14, 2005 16:22

Deathlike2 wrote:I'm only saying that ideally if you were able to remove this limitation.. that would be great. Obviously if that is not worthwhile, then so be it.

Graf already explained this, but to try and put it another way - the sky in a level may look like it is as high as a sky should be, but in reality, it is only as high as the ceiling value for the sector. Sectors with a low ceiling - just tall enough for the player to walk in - will look just as tall (barring certain considerations) as a sector where the ceiling is hundreds of units above the player, if both sectors have the F_SKY flat allocated to them. You could only tell by things like jumping (in the low sector you would bang your head off the sky and not jump as high) or firing a rocket upwards - in the low sector it would disappear immediately but in the high one it would fly for some time before disappearing. Replacing F_SKY with a different flat in your editor and then checking the map would make it clear just how close the ceiling was in the maps where you have found the problem. So with the grenade, it's really just bouncing off a ceiling that looks like a sky. Just like any other normal sector in the Doom engine, there is nothing above it, so nowhere for the rocket/ grenade to go - even though it may look like there is miles of space.

However, the behaviour is a touch inconsistent apparently. Most projectiles disappear when they hit the sky - which is a good system if you consider the alternative of a rocket blowing up in a ceiling a few units above your head but which looked like you had loads of room to fire. However, the grenades apparently bounce off it. I *think* these are the only projectiles that do not disappear so perhaps they should do that rather than bouncing off the sky?

Deathlike2 · Post by **Deathlike2** » Wed Dec 14, 2005 16:35

I understand your explaination better Enjay.

Well, if you want to keep some consistancy, it would make sense to do what you are suggesting. Then all you will have to say is, "Don't shoot into the sky and expect the projectile to come down"...

It would obviously be difficult to use a weapon designed like a mortar... but whatever I guess.

Post by **Enjay** » Wed Dec 14, 2005 17:19

I suppose that is the difference - a grenade is expected to come down again. Personally I'm not bothered which way Graf goes with this, just so long as grenades aren't blowing up just above my head.

With the mortar thing, you'd just have to hope that anyone who made a level where a mortar was intended to be used would also give you enough head room to use it. If the ceiling is set high enough by the person making the level, it should never be an issue because the mortars will never reach the invisible ceiling.

TheDarkArchon · Post by **TheDarkArchon** » Wed Dec 14, 2005 17:42

There's also a flag for explosion on the sky.

Post by **Graf Zahl** » Wed Dec 14, 2005 18:07

Enjay wrote: With the mortar thing, you'd just have to hope that anyone who made a level where a mortar was intended to be used would also give you enough head room to use it. If the ceiling is set high enough by the person making the level, it should never be an issue because the mortars will never reach the invisible ceiling.

Exactly. Anything else would just be poor level design. In properly made levels this should never become an issue.

Post by **Enjay** » Thu Dec 15, 2005 19:44

To illustrate the sky height thing even further than it really needs to be, and for no better reason than I felt like throwing this together...

Load up the attached WAD and pick a door.

The door on the left will take you to an "outside" corridor with a low ceiling. Try and jump and you'll see you don't jump as high as normal. Walk to the end and go through the door. The corridor beyond is exactly the same as the corridor you just passed through but it has RROCK10 on the ceiling instead of F_SKY1 so it lets you see exactly where the ceiling is. Jump into the teleport at the end to return to the start point.

The door to the right will take you to an identical looking "outside" corridor. However, try jumping and you'll get your full jump height. Proceed to the door at the end and you'll see how high the ceiling really is in the corridor.