Overlay Flip Flag

[Major Cooke]

ZDoom
GZDoom

Add PSPF_FLIP to overlays to draw them flipped over the X axis.

If this gets in, I'll update my alpha/renderstyle one accordingly.

[D2JK]

Hmm, interesting, just too bad this doesn't mirror the sprite horizontally across the entire screen (think akimbo weapons).

Did you, by any chance, come up with any sort of formula to solve the X-offset required to mirror a sprite perfectly across the screen? I'd be interested in something more sophisticated than constant trial, error and eyeballing...

[Major Cooke]

Now you know how I felt when trying to make the scaling work.

But if it's of any comfort, try to use the TEXTURES lump to get ideas of an offset. That, I think, should help out (just use it as a test case scenario, and yes I'm talking about SLADE's texture editor). It'll help cut down the amount of eyeballing.

I'm not going to change the coordinate system at all. Doing so could create a huge mess of offsets. Unless Leonard would like to.

[Rachael]

Erm - it should flip on the screen axis, shouldn't it?

It makes no sense to flip on the sprite itself - it's like the vanishing point discussion I had with Major Cooke earlier...?

[Major Cooke]

I stopped supporting it for a certain reason, though I can't remember why now. Probably because it backwardized the coordinates. Also I don't even remember how it was done. I'll look into another flag.

[Major Cooke]

Ah yes I remember now. The damn thing kept misbehaving the whole time no matter which way I tried to put it, so I gave up on it.

By all means, feel free to try if you want.

[Graf Zahl]

Erm - it should flip on the screen axis, shouldn't it?

Why should it? That'd negate all bobbing as well which really makes no sense.

[D2JK]

Re: formula for mirroring a sprite across the screen; judging by a few quick tests, this seems to work:

---

X₂ = (320 - W + X₁) * (-1)

X₁ = offset of the left-hand sprite
X₂ = offset of the right-hand sprite
W = width of the sprite (in pixels)

Applying scaling will probably break it, though.

[Graf Zahl]

Correct, but like I said, all you'd do is flip the entire bobbed sprite, which is certainly not what anyone may want here.

[Rachael]

Why should it? That'd negate all bobbing as well which really makes no sense.

Screen axis relative to bobbing, is what I meant.

[Xaser]

I can't imagine what use this would have if the flipping isn't occurring over the screen axis. Akimbo weapons (or maybe a right/left handedness toggle) are the use case for a "flip" feature, and I expect around 100% of people who try and use this will be unpleasantly surprised.


[I suppose you could still use it by artificially padding your sprites with empty space, but that's not much better in practice than using TEXTURES for doing the flipping in the first place].

[Major Cooke]

By all means. Give it a try yourself. I couldn't really get it to work without it going haywire.

As is, it's useful for not having to deal with the headache of making 400+ TEXTURES entries and sparing myself the pain of writing down offsets/sizes for dual wielding weaponry. I work with vast projects mind you.