Things about Doom you still don't understand

[Edward850]

28 minutes ago, Lucius Wooding said:

You could also simply make a series of 1px wide linedefs with progressive offsets on each one and they'd have the same effect as scrolling right. Couldn't be simpler.

Only if you are using a port that doesn't have interpolation, otherwise you'll still see the subpixel offsets. Even the official port has that now.

[HERRGOTT]

7 hours ago, Lucius Wooding said:

You could also simply make a series of 1px wide linedefs with progressive offsets on each one and they'd have the same effect as scrolling right. Couldn't be simpler.

Simpler, xD

[Wagi]

On 9/12/2022 at 6:46 PM, Alex S. said:

Why does the word 'fuck' appear in HERETIC.EXE at 0x8A15C?

It also appears in Doom, a printf format string "fuck %d". It appears to be leftover debugging code for the automap. They have code that tests for a condition where an automap line's coordinates escape the boundaries of the screen, and it prints "fuck 0", "fuck 1", "fuck 2", etc. for each time that condition occurs. It obviously doesn't ever seem to happen in practice, of course.

[Scypek2]

21 hours ago, HERRGOTT said:

In Heretic there are left and right scroll.

 

On the walls, perhaps... but at the same time, the scrolling floors can only scroll the texture east in vanilla. I can see how one direction of scrolling may be easier to code than another - I don't know much about how rendering works, but I know wall textures are drawn line by line in a certain order, which could make a texture scrolling "upstream" a lot less elegant to implement than the opposite. John Carmack was known for liking to keep things simple, even if it created all sorts of limitations that the others had to pester him to get rid of. Without Hall's and Romero's insistence, we wouldn't have had pushable walls in wolf 3d, teleporters in Doom, or maybe even sectors inside sectors. I may be wrong about the specifics of the last one, so feel free to correct me, but I know that the view from the beginning of E1M2 used to create some sort of infinite loop until the renderer was reworked.

 

It's true that most linedef actions (and other rendering-unrelated stuff, like monster AI) was created by Romero, but since a scrolling texture is a visual effect, I imagine it might have been more fundamental.

[Maximum Matt]

I'd like to know why, when you're noclipping around a level, minding your own business, if you walk on a damaging floor, then go through a wall into the void on that same floor, you continue to take damage.  

[Kyka]

59 minutes ago, Maximum Matt said:

I'd like to know why, when you're noclipping around a level, minding your own business, if you walk on a damaging floor, then go through a wall into the void on that same floor, you continue to take damage.  

 

Because life is not fair.

 

Also because I believe that sectors continue indefinitely until cut off by something else, such as another sector. (Hardly a technical explanation, but I'm not a technical guy.)

[Edward850]

3 hours ago, Maximum Matt said:

I'd like to know why, when you're noclipping around a level, minding your own business, if you walk on a damaging floor, then go through a wall into the void on that same floor, you continue to take damage.  

 

2 hours ago, Kyka said:

so because I believe that sectors continue indefinitely until cut off by something else, such as another sector. (Hardly a technical explanation, but I'm not a technical guy.)

That's pretty close to the answer.

The misconception is in @Maximum Matt's own question, "void space". There is no void space in Doom, the BSP used to identify sector locations has no void condition as after all it's binary. The BSP lookup checks A and B which must contain either a sector or a branch to another A and B, and you keep going down each branch until you find your sector location.

 

So evidently when exploring "outside" the map, you are still doing these AB lookups to plant you in a sector nearest to you, and thus will still have sector effects and heights apply.

 

Incidentally Doom's software renderer is accidentally effective at showing you this visually, as the flats keep drawing until they reach the bottom of the screen with no seg to cut them, which usually lines up how the BSP places you as well from the node tree.

 

This is also the same problem as to why a lot of things like enemy targeting and explosions stop working if you only have one sector in the map, as BSP lookups no longer work. You need a minimum of two sectors to have a complete BSP.

[Quasar]

3 hours ago, Edward850 said:

This is also the same problem as to why a lot of things like enemy targeting and explosions stop working if you only have one sector in the map, as BSP lookups no longer work. You need a minimum of two sectors to have a complete BSP.

Incorrect from a technical POV. Various versions of the game have had problems with this case but it was because they were doing it wrong, not because there isn't a way it can be handled properly.

[Ordon]

i still have no idea how the armor works

[philcul]

40 minutes ago, Ordon said:

i still have no idea how the armor works

 

Take a look at this! :)