3 ms·

I had a couple of games on Mega Drive that did basic 3D, or seemed to. One was F1, where a few objects seemed to be true 3D. See the overbridge at 59s and then

by Nition 9y ago

I had a couple of games on Mega Drive that did basic 3D, or seemed to. One was F1, where a few objects seemed to be true 3D. See the overbridge at 59s and then the long tunnel at 1:01 here for instance: https://youtu.be/qofonsN3Nwc?t=57 https://youtu.be/qofonsN3Nwc?t=57 The long tunnel is made of several short tunnels. The other was Gunstar Heroes, where the first boss is made of 3D cubes. See here at 4:00: https://youtu.be/9v3B1hzMwnQ?t=240 https://youtu.be/9v3B1hzMwnQ?t=240 I'm just interested if you know or can guess anything about how the "3D" might have been done in those.

MBCook 9y ago
I don't know about the F1 game but I can take a guess on Gunstar Heroes. I noticed the cubes are always aligned perfectly to the axis. And they have an isomorphic projection so the cube is always the same height (although that shouldn't be strictly necessary) as it's rotating. I also noticed the cubes never seem to get smaller if they are closer to the background. Because of this you could just have a series of sprites each showing the cube in a different angle of rotation. Now all you need to do is properly position a bunch of sprite (16 cubes + head) and it looks like a bunch of cubes that are actually drawn in 3-D. It wouldn't surprise me if they have some small table of the X/Y positions of the cubes precomputed so they don't have to do that in real time. In fact since every cube is always rotated at the same angle you could just have one sprite in the system table and update it every frame. That's my guess anyway. Clever sprite trickery. It wouldn't surprise me if F1 uses something closer to what is described in the article (although much less capable).
- niftich 9y ago
  Your analysis appears correct, as several sources write that Gunstar Heroes uses multi-sprite bosses [1][2]. F1 on the Mega Drive owes its existence to an earlier game for the Atari ST, Vroom [5]. The brainchild behind that game, "Dan McRae", talks in a video interview [3] about how he arrived at that particular version of the game from his earlier revisions on older platforms -- where techniques shown in Lou's Pseudo 3d Page [4] apply, to more advanced techniques [6] similar to the ones presented in this submission. F1 on the Mega Drive was done by the same dev studio that collaborated with McRae on Vroom, and at least one of the same programmers, but presumably had to do some advanced tilemap trickery specific to the console. Unfortunately, compared to other games in this series, there is very little information on the technical aspects of the Mega Drive version. [1] http://www.hardcoregaming101.net/gunstarheroes/gunstarheroes.htm http://www.hardcoregaming101.net/gunstarheroes/gunstarheroes... [2] http://www.racketboy.com/retro/sega/genesis/best-sega-genesis-graphics-sound http://www.racketboy.com/retro/sega/genesis/best-sega-genesi... [3] https://youtu.be/ZTd-fFScLGA https://youtu.be/ZTd-fFScLGA [4] http://www.extentofthejam.com/pseudo/ http://www.extentofthejam.com/pseudo/ [5] https://youtu.be/ZTd-fFScLGA?t=7m33s https://youtu.be/ZTd-fFScLGA?t=7m33s [6] https://youtu.be/ZTd-fFScLGA?t=10m28s https://youtu.be/ZTd-fFScLGA?t=10m28s
  - Nition 9y ago
    Thanks for that information, that's still really interesting. And wow, Vroom looks exactly like F1: I even see many of the exact same track assets.
throwaypestban 9y ago
sonic 2 https://youtu.be/9Q0NCY-zhGg?t=1540 https://youtu.be/9Q0NCY-zhGg?t=1540 The rotation of the character is just made of different sprites.
jix 9y ago
I've never had a Mega Drive before working on this, so I wasn't really familiar with a lot of its games. I took a quick look at F1 just now though. The way it makes use of the nametable and patterns is very similar to what I do. There are precomputed fully solid patterns at a fixed location and the non-solid patterns seem to be bump allocated. It makes use of both layers though, drawing the street on one and everything else on the other. I think it uses per scanline scrolling to apply correct perspective to the street. I can't say anything about how it actually renders into the tile map for now. That would require a lot more than looking at the VDP (graphics chip) debugger in an emulator.
- Nition 9y ago
  Thanks so much for taking the time to check it out. I've had that game for >20 years now so it's nice to learn a little bit more about it. Cool that they were doing something similar 24 years ago.
pjtr 9y ago
The Gunstar Heroes boss reminds me of an old demo effect called vectorballs or "bobs" https://youtu.be/Itv3f7o7Zac?t=167 https://youtu.be/Itv3f7o7Zac?t=167 combined with a Doom-style pre-rendered set of rotated sprites.

by Nition 9y ago

MBCook 9y ago

I don't know about the F1 game but I can take a guess on Gunstar Heroes. I noticed the cubes are always aligned perfectly to the axis. And they have an isomorphic projection so the cube is always the same height (although that shouldn't be strictly necessary) as it's rotating. I also noticed the cubes never seem to get smaller if they are closer to the background. Because of this you could just have a series of sprites each showing the cube in a different angle of rotation. Now all you need to do is properly position a bunch of sprite (16 cubes + head) and it looks like a bunch of cubes that are actually drawn in 3-D. It wouldn't surprise me if they have some small table of the X/Y positions of the cubes precomputed so they don't have to do that in real time. In fact since every cube is always rotated at the same angle you could just have one sprite in the system table and update it every frame. That's my guess anyway. Clever sprite trickery. It wouldn't surprise me if F1 uses something closer to what is described in the article (although much less capable).

niftich 9y ago
Your analysis appears correct, as several sources write that Gunstar Heroes uses multi-sprite bosses [1][2]. F1 on the Mega Drive owes its existence to an earlier game for the Atari ST, Vroom [5]. The brainchild behind that game, "Dan McRae", talks in a video interview [3] about how he arrived at that particular version of the game from his earlier revisions on older platforms -- where techniques shown in Lou's Pseudo 3d Page [4] apply, to more advanced techniques [6] similar to the ones presented in this submission. F1 on the Mega Drive was done by the same dev studio that collaborated with McRae on Vroom, and at least one of the same programmers, but presumably had to do some advanced tilemap trickery specific to the console. Unfortunately, compared to other games in this series, there is very little information on the technical aspects of the Mega Drive version. [1] http://www.hardcoregaming101.net/gunstarheroes/gunstarheroes.htm http://www.hardcoregaming101.net/gunstarheroes/gunstarheroes... [2] http://www.racketboy.com/retro/sega/genesis/best-sega-genesis-graphics-sound http://www.racketboy.com/retro/sega/genesis/best-sega-genesi... [3] https://youtu.be/ZTd-fFScLGA https://youtu.be/ZTd-fFScLGA [4] http://www.extentofthejam.com/pseudo/ http://www.extentofthejam.com/pseudo/ [5] https://youtu.be/ZTd-fFScLGA?t=7m33s https://youtu.be/ZTd-fFScLGA?t=7m33s [6] https://youtu.be/ZTd-fFScLGA?t=10m28s https://youtu.be/ZTd-fFScLGA?t=10m28s
- Nition 9y ago
  Thanks for that information, that's still really interesting. And wow, Vroom looks exactly like F1: I even see many of the exact same track assets.

throwaypestban 9y ago

sonic 2 https://youtu.be/9Q0NCY-zhGg?t=1540 https://youtu.be/9Q0NCY-zhGg?t=1540 The rotation of the character is just made of different sprites.

jix 9y ago

I've never had a Mega Drive before working on this, so I wasn't really familiar with a lot of its games. I took a quick look at F1 just now though. The way it makes use of the nametable and patterns is very similar to what I do. There are precomputed fully solid patterns at a fixed location and the non-solid patterns seem to be bump allocated. It makes use of both layers though, drawing the street on one and everything else on the other. I think it uses per scanline scrolling to apply correct perspective to the street. I can't say anything about how it actually renders into the tile map for now. That would require a lot more than looking at the VDP (graphics chip) debugger in an emulator.

Nition 9y ago
Thanks so much for taking the time to check it out. I've had that game for >20 years now so it's nice to learn a little bit more about it. Cool that they were doing something similar 24 years ago.

pjtr 9y ago

The Gunstar Heroes boss reminds me of an old demo effect called vectorballs or "bobs" https://youtu.be/Itv3f7o7Zac?t=167 https://youtu.be/Itv3f7o7Zac?t=167 combined with a Doom-style pre-rendered set of rotated sprites.