Ship rotations in pre-3D

delMar

Rear Admiral
Creating this thread as a spin-off to @UnnamedCharacter's Adventures in Explorations: WC1 Edition here: https://www.wcnews.com/chatzone/threads/adventures-in-explorations-wc1-edition.29214/

Also, attaching the images in question.



2 and 3 even, yes - check out the third of UnnamedCharacter's images, showing the missile sprites. Basically, it depends on the number of axes of symmetry in an object. If you only have one axis of symmetry (as most ships do), then you only flip horizontally (or only vertically, if you had a ship that has asymmetric sides, but vertical symmetry). The only objects that typically have two axes of symmetry are missiles, and the only ones that might conceivably have three axes of symmetry would be those round WC2-style mines.

Incidentally, it's funny that the Kilrathi starbase *didn't* get flipped on two axes, because it's symmetrical both in X and Z axes. You'd think that would be something someone would have noticed, given the desperate need to save disk space for WC1.


No, because not all images need to be repeated if you abandon symmetry - I mean, you already have half of the images you need included in the 37. If you open up one of the ship sprite compilations, you can see that the number of repeated sprites (conveniently marked grey) adds up to 25. So, take 37, add 25, and you wind up with 62.
right. I see that we can do anything with 37 images.
But I think that 62 slots are not enough.
When thinking through a rotation scenario, there needs to be additional flipping to the 62 slots we have.
For the Tiger's Claw, there's certain positions that aren't covered by any of the slots.

So, I think that when rotating beyond certain angles (eg 180° on the y-axis?), all of the slots can be re-used, but they'll be flipped until rotating beyond that angle again...

I didn't intend to hijack this beautiful thread, though. Sorry
 

Attachments

Quarto

Unknown Enemy
Hmm, I really have a hard time seeing what you mean. Can you specify which Tiger's Claw positions are not covered by any of the slots? I really don't see anything that's missing.
 

delMar

Rear Admiral
In SHIP.V08.png, let's start at Slot #30 (left of #31, there's no label to it)
The Claw is seen from behind, and rotated 30° left, right?
Imagine the ship is flying ahead of you and that's exactly the angle you're looking at it.
Now, the pilot pulls the ship up. You should see the Claw as depicted in #42 (again, no label to it, but left of #43)
If the pilot continues doing that, your perspective will change again and you'll see the Claw as depicted in #54, right?
So, the Claw's nose is now pointing up about 60° and still rotated 30 ° to the left.
The pilot still doesn't stop his maneuver. What image is next? Imo it should be #61, but rotated in an angle that's not readily available in a slot (ie 90°)
The Claw's nose should now be straight up

And what, if he still doesn't stop his maneuver?
Then the Claw would suddenly turn towards us (as opposed to heading away from us before), but upside down.
For this, there's also no slot readily available. But slot #50 flipped accordingly would be a fit.

Hard to explain, I hope that makes sense.

Thanks for your time!
 

UnnamedCharacter

2nd Lieutenant
Imagine a circle around a sphere, from North pole to South pole and back, a full 360 degree. Rotate the circle 30 degrees at a time around the sphere, using the North and South poles as the axis.

Circle 1 = 0 deg
Circle 2 = 30 deg
Circle 3 = 60 deg
Circle 4 = 90 deg
Circle 5 = 120 deg
Circle 6 = 150 deg

There is no need for additional circles, since Circle 7, at 180 deg, is the same as Circle 1. Each circle has 12 images (360 / 30 = 12); the sphere has 6 circles for a total of 72 images (6 * 12 = 72). But the poles are the same images, simply rotated, instead of having six images, you only need one (72 - 5 - 5 = 62 images).

SHIP.V08; 62 Images, Aligned, Expanded.png

This is the same aligned image with the top image (61) and bottom image (00) expanded across the columns and only rotated.
 

Quarto

Unknown Enemy
Ok, I see now what you meant - and UnnamedCharacter has explained better than I could. Keep in mind that in the game, you would actually see ships at many, many more angles than are stored in the files. I mean, think about it - any of the ships in the game are free to rotate one degree at a time. You're constantly going to be seeing ships from strange angles, and going at strange angles. For this reason, you're pretty much constantly seeing ship sprites rotated and transformed in various ways.

The whole system is optimised not for visual quality, but for storage and memory: between the cockpit, all the special effects, missiles, and at least two sprite sets to be displayed at any one time, the memory of a typical PC of the time was being taxed very heavily. And the mathematical transformations of sprites, even though they produced some degree of distortion, ultimately proved quite satisfactory, as evidenced by the fact that the subsequent development of this system in WC2 and Privateer was towards bigger sprites ("higher resolution" in a sense, although obviously the screen resolution remained unchanged), rather than towards more sprites per ship (though maybe Priv did have more? I don't recall).
 

ptiluc

Spaceman
rather than towards more sprites per ship
more sprites per ship would be likely a multiple of and therefore a hugely massive increase in memory. So making the sprites bigger by a fraction made totally sense. And we all were already used to the jumpy rotation. Beside that Origin saw we bought WC1 like crazy ;)
 

ShadowArm

Ensign
more sprites per ship would be likely a multiple of and therefore a hugely massive increase in memory. So making the sprites bigger by a fraction made totally sense. And we all were already used to the jumpy rotation. Beside that Origin saw we bought WC1 like crazy ;)
UC already did a test, the game supports high res sprites, but the limit is 400% from the original size, it works only with the KS version of wing commander
 
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