SpritesMind.Net

Not sure if this is the right forum, but I have kind of an odd question. Given the simplicity of using SGDK (to which I am forever grateful), outside of rotation and scaling, is there any benefit to creating a game for Sega CD (in ASM) versus creating a bank-switched Genesis game that utilizes Mode 1 music?

Depends on the game. If you have a game that needs direct access to a lot of stored data, cart + mode 1 is probably the way to go. If the game can be split into levels of < 768KB, Sega CD may be the way to go. Remember that you "only" have 512KB program ram, and 256KB of word ram in the Sega CD. The Genesis only has 64KB of ram, but can have up to 32MB of rom if using the standard mapper, or 4MB if not using a mapper.

Thanks Chilly! I was quite surprised to get a response from you of all people. I have been lurking on these boards for awhile now and have learned quite a bit from your posts alone.

My initial goal is to recreate an infamously hard platformer using SGDK, of which I feel I am making decent progress. Once that is complete, I am going to iterate on it and attempt to create a metroidvania-esque version. The path of least resistance would be to continue using SGDK. However, I was trying to figure out if I wanted to transition it to Sega CD, but that is a big mountain to climb as I have NO experience with Assembly.

If I were to go the ASM route, I figured I might as well go whole hog and take on the 32x as well. But after reading your posts here: https://www.sega-16.com/forum/archive/i ... -6697.html, and here: https://www.sega-16.com/forum/archive/i ... 13927.html, I see that there is not a whole lot to gain by creating a 32x CD game versus just a Sega CD game for the amount of hassle it would be to make.

If you're going to make a cart game with SGDK to start with, then going to Mode 1 for CD support from the cart is probably the better way to go. Make the cart so that it plays the "standard" game if the CD isn't detected, but if the CD is detected and has an expansion CD in it, the cart then uses the expansion paks on the CD for extended game play. Something like that would be really cool.

So, if I understand you correctly, I can create an initial program on a cart which can detect whether there is a CD present or not. If it detects that a CD is present, I could send a call to the sub-cpu in the Sega CD to fetch whatever data I want on the disc (given the constraints of the hardware).

If this is true, I could place all of the data that needs to persist (e.g. main game logic, player sprites, menus, loading screens, etc.) on a cart then load modules from the disc as needed, which should decrease load times. I would assume then, that theoretically, one can make a multi-disc game and save progress to the cart if it had an EEPROM.

Is this really possible?

Sure, but creating multiple CDs worth of content will be your blocker.

Thank goodness I have no intention of doing that! I lack the time, resources, and will to take on a project that large. Even if I were to make a game that big, relatively speaking, releasing it on a retro console would not be my first choice.

However, this does reinforce the idea that the Sega CD was vastly underutilized, and it is a shame that it never really got its own killer app.

Check out Wolf32X or Doom 32X Resurrection source for how to start up the CD from a cart game. While both just use the CD for CDDA music, it can easily be modified for data CDs as well. I've released a number of demos for SCD showing how to read ISO 9660 CDs.