** Sega Megadrive 3D engine day 2 **
Been playing around with Line & Triangle Drawing on the MD after thinking about doing something in 3d on the system for a while.
Theres no hardware for this sort of thing on the MD so its a real optimisation game.
All in C so far , 68k ASM next !!
I just saw somebody cheese the 3-2 boss in Moonwalker and I feel dumb for not thinking about it before.
(stay on one side of the screen and make sure to keep kicking the two zombies so they split their bodies when they're on the other side to make it easier to jump over them)
Frédérick Raynal, the creator of Alone in the Dark and Little Big Adventure, is crowdfunding a new Sega MegaDrive / Genesis game (complete with a cool spinner controller)!
Here: www.kickstarter.com/projects/107...
Frédérick Raynal, the director of the original Alone in the Dark is kickstarting a new genesis game - a remake and expansion of his old arkanoid Popcorn - and a paddle controller to go with it. www.kickstarter.com/projects/107...
input a6.l = controller port address; output d7.b = $00 modem, $0d = Mega Drive Joy Stick, $0e = Ram Disk, $0f = ETC. or None; use d0, a0
Peripheral ID 0x0E is still one of the biggest mysteries.
Screenshot of the Data Select screen. It has a bunch of vertical-shaped slots for each file (and a smaller square one labeled "No Save"). For the larger slots, it shows a level icon ("New" since they're unused) as well as the selected characters (Sonic and Tails). There's a red frame around the selected slot, as well as arrows indicating you can change the character. The background is a low contrast Sonic. At the bottom there's a text saying "Data Select".
NBG0: only the background.
NBG1: the frame with the slots for the files, as well as the level icon ("New" in this case) and "No Save" label.
Sprites: the characters, the cursor, and the "Data Select" text.
Amusingly they "undid" that in Sonic Jam, it uses NBG0, NBG1 and sprites (NBG2 and NBG3 are unused). Besides pause menu can't show up here anyway. Leaves me wondering how they handled planes.
My question was more why they didn't use NBG3 to avoid "window" and pause menu sharing the same layer.
To clarify, this is how it works in the original version as well.
The entire platform is copied to the VDP's window plane, erased from Plane A, then Plane A scrolls up and offscreen.
Then finally, the platform is copied back to plane A and the window plane is disabled.
TIL that the window plane is actually used.
But also doesn't explain why NBG3 remains unused (the whole thing could have been easily avoided by using that plane and I somehow don't think that this game is using up a lot of VRAM… memory access slots, maybe?)
The funny thing is that NBG3 remains unused, by the way.
NBG0 layer: the part of the Death Egg the platform was attached to.
NBG1 layer: the dark sky in the background.
NBG2 layer: pause menu and the platform.
Sprite layer. Don't mind the garbage (I used debug mode to place some monitors).
They rewrote the effect so the platform is on another layer (instead of splitting the foreground in two through scrolling) but the platform is now on the pause layer so it sits on top of everything (oops)
Sonic is looking up on the final boss platform as the Death Egg detaches. The left side of the platform is covering the I in "rings" as well as the "Sonic" and lives count at the bottom left (but not the icon).
For whatever reason in the Sonic Jam version of Sonic 3 (NOT the original) the HUD gets hidden for a moment when the platform detaches from the Death Egg.
1:09:39 youtu.be/CVZcCK0skLY?...
'Phantasy Star II' was released on the SEGA Mega Drive 37 years ago today in Japan.
New Video, new Sega 32X games. youtu.be/rR-arrDKu3s
I'm afraid it's not going to get much lower without switching to downloading ROM images (cartridges are just pricey and you need to charge a margin on top of that, not to mention shipping).
I'm wondering more about the bridge because it just blends into the background (both of them are black).
So yeah, it may have been like this, or there may be an issue with the palette causing some colors to turn black. I can't tell, honestly.
'Sonic's Bonus Game' was a Flash game available on SEGA's website back in 1997, based on the SEGA Genesis special stages from 'Sonic 3D Blast'. This is some footage of it in action.
Sprite order is what determines who's in front of what, regardless of priority.
All one needs to do is ensure the high priority sprite is bellow the low priority sprite while in front of a high priority tile layer.
Footage from "I made you a Salad" (SHC 2019)
Triggers INT2 on the Sub CPU via the IFL2 bit (for this reason, it should be called during VBLANK). Also syncs the COMCMD cache values to the GA registers and the COMSTAT values from registers to the cache.
Apparently whoever designed the syscalls had the same idea as me (treat IRQ2 as a way to get the Sub CPU's attention rather than only as a way to pass vblank timing)
Does the Sub CPU BIOS use it for anything beyond the user call timing?
To be pedantic, "Main BIOS" is somewhat of a misnomer here. A more accurate term may be "Boot ROM System Library", and indeed for a while in Megadev we prefixed these calls with "bootlib". However, we eventually decided to go with "bios" as it is shorter and there is a symmetry to having a bios on both the Main and Sub side. Moreover, the entire internal ROM is very often colloquially called "the BIOS" especially in terms of emulation.
It has VDP and joypad routines (and even routines for the communication ports), it's more of a BIOS than the Sub CPU one lmao
Calling it Main CPU BIOS probably makes sense (also to set it apart from the rest of the boot ROM).
It's a been a long time coming... MEGADEV, a development kit for the Sega Mega CD, version 1.0 is released!
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🔗https://github.com/drojaazu/megadev
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promising!
doing something, getting some M68K assembly practice in.
Sonic The Hedgehog
In Australia, many SEGA Mega Drive games would come with a fold out promotional piece for other games. This is their promotion for the original 'Sonic The Hedgehog'.
Chords:
- SEGA CD Snatcher-inspired adventure
- Energy-filled OST by @superjetspade.bsky.social
- Gorgeous pixel art by @108stars-pixelart.bsky.social
- A storyline with more twists than SEGA OutRun
- A @hideokojimaen.bsky.kojimaproductions.jp indie love letter
#MegaDrive #SegaGenesis #IndieDev
Screenshot of Pebble Beach Golf Links, about to take the first shot. There are trees and houses in the direction we're looking at, made out of scaled sprites. The ground is grass and a pavement road made out of a handful of untextured polygons, the sky is blue with hand drawn clouds.
Another screenshot, looking at a long white building with large black windows and green roof, made out of polygons this time.
Yet another viewpoint, looking at the lake, made out of blue polygons. Some of the trees from earlier are visible.
Next-gen graphics.
Would you rather flip gravity, swap dimensions… or blow up a cave? 👀
Good news—you don’t have to choose!
Mega Cat Studios’ triple launch hits #SEGAGenesis and #MegaDrive on March 31, 2026 featuring:
🌀 #Gravibots: bit.ly/MCSGSM
👥 #AlterEgoDreamWalker: bit.ly/MCSAEDWSM
💎 #Tourmaline: bit.ly/MCSTSM
We can finally show our secret feature!
We've been working on a tracker that will be shipped with MD Engine!
ヾ(´〇`)ﾉ♪♪♪
It won't be as powerful as Deflemask or Furnace, but it should be capable of doing music composition for most cases!
#megadrive #mdengine #homebrew #indiedev #gamedev #sgdk
Play Sonic Eraser.
I just finished updating the latest version of Chords with Vic's Sega CD Fusion Driver. It's now doing both streaming PCM speech and background music and it seems pretty good if you ask me. More devs should really use this! #gamedev #indiedev #sega #segagenesis #megadrive
