PrBoom-Plus' texture/patch specifications

[Doom Marine]

I'm wondering about the current PrBoom-Plus-2.5.0.5's texture and patch's dimensional constraints. Some stuff I found through experience with past PrBooms:

1. Mid-textures with "transparent" in them (e.g. rails, stargate, lasers) cannot be greater than 256 units in the Y-dimension without looking all funky. Why is this?

2. I've attempted to create a texture that is 4096x256 using same sized patch, it didn't work. The next step that worked for me was 2048x256 patch ---> 2048x256 texture. Explanation behind the constraint?

3. As far as I can recall, PrBoom's will display textures properly all the way up to 504 units in the Y-dimension. Why not 512 units? Or am I wrong? Explanation?

[entryway]

PrBoom-Plus and zdoom support any sizes for patches (tall patches)

Eternal uses 2048px in height transparent middles for map06 @ epic.wad

Try to use DeePsea for creation

504 (should be 509 = 0xFE (max offset) + 0xFF (max length)) is a limit of standard doom format

2.5.0.2 @ 2008-May-09
[+] Support for DeePsea's tall patch method: Now it's possible to use patches of any height.

[entryway]

Example of tall patches in wad

http://prboom-plus.sourceforge.net/tall_patches.zip

Works fine with pr(gl)boom-plus, (g)zdoom, vavoom and risen3d

Does not work with pr(gl)boom, edge, eternity and DoomBuilder1/2

[Csonicgo]

entryway said:

Try to use DeePsea for creation

There's gotta be a way to do it other than using that horrible program.

[esselfortium]

Is the tall patch format documented or explained in an easily-digestible way anywhere? I've been trying to get Quasar or SoM to add support for it in Eternity, but Quas doesn't seem to understand exactly how it works and I know nothing about it at all...

[Quasar]

esselfortium said:

Is the tall patch format documented or explained in an easily-digestible way anywhere? I've been trying to get Quasar or SoM to add support for it in Eternity, but Quas doesn't seem to understand exactly how it works and I know nothing about it at all...

Basically until somebody points me to the actual code differences between texture drawing in BOOM and texture drawing in ports that support these mutant "tall patches," they're not gonna happen in EE :)

[entryway]

It's easy to support

    while (oldColumn->topdelta != 0xff) {

      // support for DeePsea's true tall patches
      if (oldColumn->topdelta <= top)
        top += oldColumn->topdelta;
      else
        top = oldColumn->topdelta;

      // set up the post's data
      patch->posts[numPostsUsedSoFar].topdelta = top;

http://pastebin.com/m591b225f

They are not mutant :), they use relative offset instead of absolute

[SoM]

entryway said:

http://pastebin.com/m591b225f

They are not mutant :), they use relative offset instead of absolute

unknown pastebin id :(

[entryway]

SoM said:

unknown pastebin id :(

You do not need it. Code above explains all you need.

Full diff for prboom-plus:
http://pastebin.com/ZX10t8ch