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Sega had a series of Arcade games in the mid to late 1980s which used what they called a "Super Scaler" technique. By scaling and rotating large numbers of sprites, they were able to do some relatively robust pseudo-3D effects:

https://en.wikipedia.org/wiki/After_Burner#/media/File:ARC_After_Burner_II.png

Here, the jets, segments of missile exhaust, trees, houses, etc. are all sprites. In motion it's actually quite good.

This started to peter out towards the mid-90s and 1995's "Slip Stream" is often credited as the last major use of it:

https://www.giantbomb.com/slipstream/3030-41902/images/

It seems that with the launch of the PlayStation and other fifth-generation consoles, this was almost entirely phased out in favor of polygonal 3D. The odd billboard was used from time to time which is sort-of a similar technique (items and characters were sprites in Klonoa, but most of the environment was polygonal):

https://upload.wikimedia.org/wikipedia/en/6/6a/Klonoa_screenshot.png

I don't however remember seeing any games from that generation built almost entirely from them. I guess fillrate may have been an issue with the numerous and large overlapping sprites?

Recently there has been something of a revival of this style with games like Victory Heat Rally, but it looks to me like there was a big gap of about 25 years in which this technique wasn't really used.

Is this right or are there overlooked games after Slip Stream which used techniques similar to Sega's "Super Scaler"?

2 Answers 2

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Well arguably every game on the Sega Saturn is exactly that, they just worked a lot harder to hide it.

The Nintendo 64 had clean, mathmatically correct 3D polygons with a complete Z-buffer. Granted this was expensive and the cost was a bottle necked texture cache unit.

The Playstation had hacky but importantly cheap 3D polygons using some integer math shortcuts and a "it's close enough" approach to averaging one Z value over an entire polygon (instead of per pixel) leading to its famous texture warping.

The Sega Saturn had no polygons to speak of. It was a console designed to offer arcade level 2D sprite graphics. When it became apparent that 5th generation consoles were going to be all about 3D they had to utilize the Saturn's powerful VDP1 sprite stretching hardware to fake it (with help from the VDP2's equally powerful mode-7 background capabilities).

As a result every "polygon" on the Saturn is really a square sprite that's been arbitrary stretched at all 4 corners (meaning you could warp sprites like Yoshi's Island, not just make them bigger or smaller).

This had some interesting implications, like what to do when part of a "polygon" went behind the camera (negative Z value). Saturn developers ended up with a lot of tricks to make the hardware appear to correctly emulate 3D. Since the consoles they were being compared to had their own limitations to deal with they were ultimately able to pass the Saturn off as a 3D console.

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    Scare quotes, "fake", "emulated" etc are not warranted. Other machines "polygons" are triangles. Trigons and tetragons are polygons. If you can do homogeneous transformations whether a system uses something they call sprites or textures or something else is just an implementation detail. If they can only do affine transformations like I think the PS1 could that's a bigger difference and I dunno the details. Sprites and textures are both "really" just rectangles in memory. Once you can do affine transforms you're doing u, v lookups. 3D is a number of dimensions. Screens are 2D. It's all tricks. Jun 10, 2023 at 1:58
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    @hippietrail I think one of the key differences is that the PS1 lets you specify texture coordinates per vertex and supports wrapping textures. The Saturn can only take a fixed-dimensions source rectangle and distort it. Which in the world of ~1mb VRAM is a difference with substantial effect. Whether that crosses your threshold for calling the Saturn’s distorted sprites rather than affine-mapped geometry, I guess is up to you.
    – Tommy
    Jun 10, 2023 at 2:33
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    Umm no. Affine and homogeneous transformations have technical mathematical meanings which are not up to me at all. It's about whether perspective is taken into account when interpolating the texture u,v for the pixels in between the vertices. PS1 doesn't. For Saturn I don't know so asked a new question after my Googling attempts failed. Jun 10, 2023 at 2:47
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    Yeah, I misunderstood the question. As far as I’m aware, the Saturn is purely affine. One supplies the four destination screen coordinates only — no depths — and the hardware makes no further assumptions about whether you got to them by stretching, projecting or by other means.
    – Tommy
    Jun 10, 2023 at 11:00
  • There's a funny thing about homogeneous mapping that means you don't have to express a depth. But that's where my math fails. I'm not good at matrices. Homogeneous matrices have an extra row or column or both and the perspective is represented in there somehow. So either in software or hardware the depth must be converted to what goes in the matrices. But then to actually render the texture fast you need hardware that can interpolate the coordinates using those matrices to get u,v texture coordinates that make near parts look bigger than distant parts. Jun 10, 2023 at 12:31
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The Nintendo GBA handheld had no hardware 3D support, so several 3D games on the Nintendo GBA continued to use a mixture of scaled sprites and "Mode 7"-style perspective-transformed backgrounds. I won't give many examples, but there are plenty of racing games that look like this, such as OutRun from 2003.

OutRun GBA

The Nintendo DS series did have limited 3D support, but many games continued to use sprite scaling techniques in the early days of the handheld, possibly in order to transfer code frome the GBA.

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    From what I remember, the GBA's niche was essentially "Super Nintendo in your pocket, but with an ARM chip fast enough that things like Mode 7 which were fixed-function silicon in the SNES to be handled in software instead."
    – ssokolow
    Jun 10, 2023 at 18:04
  • Most of those racing games with curving roads going into the distance don't actually use anything like Mode 7 or sprite/texture scaling. Such games predate such techniques and hardware by years are were common on 8-bit home computers with basically no graphics hardware like the ZX Spectrum. Mode 7 draws an actual bitmap onto a flat horizontal surface. Jun 15, 2023 at 9:37

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