Projectile speed = bad aim?

This problem came up while I was testing stuff on Doom Connecter earlier tonight. I was exchanging dehs with somebody, which changed weapons. This guy, he had a deh that made plasma and rockets shoot faster (but plasma explodes, which I didn't like, but oh well). My deh was a BFG modification. Faster shot, less ammo used, half as powerful. We both had the same problem: our projectiles would fly off-target 90% of the time. WAY off target.

I'll bet this problem has been mentioned before... but it must have a solution, since otherwise how could anyone make projectile weapon mods? What am I missing?

Also, I heard that you can edit the damage the BFG gives someone in your shot area (the smart-bomb-type damage) using Whacked 2. Is this true (I have yet to try, but I can't do it in Dehacked)?

any speed going past 32 will not go in a straight line...its just the way the Doom engine handles things. Consider that as the limit for projectile speeds.


This was why the P_BlasterMobjThinker was implented in the Heretic and Hexen games to control the super fast projectiles from some of the weapons.


Of course Doom doesn't have this.

It all works like it should in ZDoom (later versions).

Ultraviolet said:

It all works like it should in ZDoom (later versions).

Ooooh, so it does. I didn't realise Randy had changed that.

edit source code :)

The precise reason for this is numeric overflow in the fixed-point math used to calculate the x and y momenta of the missile object from its speed and angle:

momx = speed * finecosine[angle]
momy = speed * finesine[angle]

The two axes will necessarily overflow in different manners at any one time, so the direction of the missile will go haywire when the numbers are too big.

zdoom won't suffer this not because it "fixes" anything, but because it uses floating-point arithmetic instead of fixed-point, which has vastly greater precision. You'd have to change a missile's speed to some truly astronomic value before zdoom would have any trouble with it.

Quasar said:

You'd have to change a missile's speed to some truly astronomic value...

I am SO on it!

If you want to make projectile go that fast, you might as well use hitscan attacks instead.

Ichor said:

If you want to make projectile go that fast, you might as well use hitscan attacks instead.

You can't change the damage of a bullet.

Maybe that will hopefully change in the next update, heheh.

One can only hope.

I changed the speed to 32 and it works fine; however I would still like to edit the special BFG damage that occurs when the shot hits the wall and someone's in the area (dunno what the technical name for this is, if any). I was told Whacked 2 can edit this, is that true?

I got someone to send me that program (since it seems not to be available here... weird), but it complains that I am missing a MSSTDMFT.dll, or something like that. Everyone I talked to doesn't have a copy of this file anywhere on their system, and it works fine. What could be the problem, or where can I find that file?

If it matters any, this particular machine uses Win98... the people I talked to use XP though.

Ichor said:

If you want to make projectile go that fast, you might as well use hitscan attacks instead.

There are uses for fast projectiles, like making trails.

The mage wand and the cleric's firestorm are projectiles with a speed of 200, and are set to drop little sprites in their path.

Also, I've always thought that making a projectile with a speed of ~200 would make for a more realistic pistol. Bullets shouldn't be entirely instant, especially since even in freeze mode they hit things, while if they were projectiles, you could set them in the air like other projectiles. =)

Nanami said:

Also, I've always thought that making a projectile with a speed of ~200 would make for a more realistic pistol. Bullets shouldn't be entirely instant, especially since even in freeze mode they hit things, while if they were projectiles, you could set them in the air like other projectiles. =)

...and also do some 1337 Matrix/Max Payne effects and stuff.

netnomad32 said:
I got someone to send me that program (since it seems not to be available here... weird), but it complains that I am missing a MSSTDMFT.dll, or something like that. Everyone I talked to doesn't have a copy of this file anywhere on their system, and it works fine. What could be the problem, or where can I find that file?

Are you sure you have the latest version? The newest is 0.50.something. MSSTDMFT.DLL was missing in older versions of the setup package but it is included since that version.

Heh, I have no idea what version was sent to me. But I noticed that convinient link in your sig...

Anyway, now I've got it running. Two things: one, I can't load ANY of my patches, as they seem do be a "different version" than the "engine." Two, I can't see any option to edit the special BFG damage, anyway. Is it even possible?

netnomad312 said:

Two, I can't see any option to edit the special BFG damage, anyway. Is it even possible?

I've never checked but I don't think you can edit how much damage the BFG tracers do.

netnomad312 said:

Heh, I have no idea what version was sent to me. But I noticed that convinient link in your sig...

Anyway, now I've got it running. Two things: one, I can't load ANY of my patches, as they seem do be a "different version" than the "engine." Two, I can't see any option to edit the special BFG damage, anyway. Is it even possible?

Not with standard dehacked. It may be possible in the .bex format though.... look it up.

It's not possible in DeHackEd nor in WhackEd(2). Not even in Boom's BEX either. Perhaps in ZDoom's BEX extensions?

Your patches obviously use the Doom2 v1.9 engine. WhackEd2 currently only has the Ultimate Doom v1.9 engine (yes, they're different, there's even a TNT\Plutonia engine, but the only differences are extra strings). But if it's for Doom 2 then you can just substitute the "engine version = 19" line in the patch file for "engine version = 21" so it should work just fine. Yes that also means in source ports.

Source ports do not use any of the version information in DeHackEd files. That information is only used by 1. the original DeHackEd program and 2. by people interested in making sure that the patches they use are of the proper version. Source ports can only support a few DeHackEd patch versions, since they have the thing and state tables of Ultimate DOOM/DOOM II/Final DOOM. Thing and frame numbers from earlier versions will be incorrect and MAY result in problems (though possibly not depending on the nature of the stuff being edited).

netnomad312 said:This problem came up while I was testing stuff on Doom Connecter earlier tonight. I was exchanging dehs with somebody, which changed weapons. This guy, he had a deh that made plasma and rockets shoot faster (but plasma explodes, which I didn't like, but oh well). My deh was a BFG modification. Faster shot, less ammo used, half as powerful. We both had the same problem: our projectiles would fly off-target 90% of the time. WAY off target.

I'll bet this problem has been mentioned before... but it must have a solution, since otherwise how could anyone make projectile weapon mods? What am I missing?

Also, I heard that you can edit the damage the BFG gives someone in your shot area (the smart-bomb-type damage) using Whacked 2. Is this true (I have yet to try, but I can't do it in Dehacked)?

I ran into the same problem trying to make the plasma rifle fire faster. Your BFG idea sounds great! I hope you are able to find a way to get it to work. I'd be very interested in such a mod.

It all works like it should in ZDoom (later versions).

So you mean the bug won't show up in newer versions of Zdoom and only in older versions and in vanilla doom?

If this is the case, frabjous day! calooh! calay!!

Hellbent said:

I ran into the same problem trying to make the plasma rifle fire faster. Your BFG idea sounds great! I hope you are able to find a way to get it to work. I'd be very interested in such a mod.

It works all right, I just can't edit the BFG Tracer damage. If that's fine with you, download here. I already uploaded this to our clan server so I could test it on Doom Connector. I think that's the right address, but if Tripod bitches at you, it's Tripods fault and not mine..... :-/

Heh, i dont think you can even edit the BFG tracer damage in EDGE

Speaking of EDGE, the projectile speed limit is, for some reason, slightly faster in that port, 40 seems to be the maximum instead, which isnt that great, but still, lasers do go faster than rockets in real life XD (though the difference is a bit bigger)

ZDoom's maximum is much higher, I believe. I've just tried the plasma ball at 120, and it's still fully accurate and doesn't go through walls or have any other side effects.

Doing this, though, I have discovered that in ZDoom, the sound for the plasma shot comes from the projectile itself. As it speeds off, the volume diminishes. You don't hear that with the normal speed because by the time it is far enough out to make a difference, the sound is already done playing anyway.

Ultraviolet said:

ZDoom's maximum is much higher, I believe. I've just tried the plasma ball at 120, and it's still fully accurate and doesn't go through walls or have any other side effects.

ZDoom doesn't have any limits anymore because they have been removed. Theoretically even infinite speed should work.

Doing this, though, I have discovered that in ZDoom, the sound for the plasma shot comes from the projectile itself.

Yes, that has always been so for most Doom projectiles.

Ultraviolet said:

ZDoom's maximum is much higher, I believe. I've just tried the plasma ball at 120, and it's still fully accurate and doesn't go through walls or have any other side effects.

Yeah, as Graf said you can pretty much use any speed. If you read my post you'd know at least 200 is possible. =P