SpritesMind.Net

68000 RAM access from Z80 would also be nice.

Here are some examples of Mega Drive music composed by me.
Giga Man Adventure - Sneak peaks

My sound engine doesn't support DAC output while playing music though, because I thought DAC sounds would sound too choppy with music processing going on at the same time.

This is what my command line looks like:

@..\snasm\snasm68k -p -o ow+,os+,oz+ gm.asm,gm.bin,,gm.lst

Make sure you have the -o switch in front of your options. Then it should work.

You should use RAM locations above $ffff8000 for your variables. This ensures that the addresses will be 16 bits if the appropriate assembler option has been given. In Snasm68K, the option -ow+ enables this.

Interesting. You can get a similar sound by using a very low frequency, but in the game, 4-frequency mode is used.

A good method would be: At the start of each frame, make a copy of the sprite table. When a VRAM write happens in the middle of a frame, take a note of it, and on the next line, draw the sprites using the sprite table copy, cutting them off at the top and bottom of the current area. Then, record the...

May I also suggest stepping and breakpoints for Z80?

And selection and editing in memory viewer using the mouse and keyboard (instead of the current approach which reminds me of old computers that were programmed with switchboards, setting the address and data and flipping the "set" switch).

According to the document at SnesWiki, Mode 2 has a separate scrolling offset for each tile, so it's not quite the same. However, if you just want to do 8 line horizontal scrolls, HDMA is much easier to use and much faster than mode 2, since each scrolling value only has to be written once instead o...

BUT that reminds me about in SNES you cann't do vertical scroll inside a plane/BG. So, for example, you cann't port Trouble Shooter 2 from MD to SNES at pixel perfect level. I assume you're talking about per-column vertical scrolling. Well, in modes 2, 4 and 6 every tile can be individually scrolle...

Yes, the Genesis can scroll in either full screen mode, line mode, 8-line mode or repeating 8-line pattern mode. And so can the SNES, with the proper HDMA lists.

In most games, the screen scrolls more often than not, and both planes are scrolled. So even if you only have parallax in the background and not in the foreground (which is common), all the foreground entries must still be set on every frame where the screen scrolls, which happens most of the time. ...

With SNES you have up to 16 DMA's chanenles avaliable, so in practice you cann't do what genesis does. You need to spend all the displaying time (in contrast with vertical retrace time) updating scroll values if you want more than 16 scroll. In the other side, it wastes more memory on MD. Wrong. A ...

Line scrolling is just as simple to implement on SNES as it is on Mega Drive. This is easily done using a HDMA channel. An example of line scrolling is seen in the ground of Ryu's stage in Street Fighter 2, which behaves similar to the water in Launch Base 2 in Sonic 3. Mode 7 screens such as the wo...

Well, that's not hard at all. Just don't update the registers for a music channel when the channel is being used for a sound effect. Turn off the sound for every channel that a sound effect uses at the start of the sound effect. Remember the current instrument in use for a channel, whether it's used...

Why won't you share some of your routines with the community? Please show me some of your code. :) Well, here are some short excerpts. I can't share too many secrets :P The VSync function. vsync: move.l d0-d7/a0-a6,-(a7) move.w #$2700,sr move.w a7,stack1 move.w stack2,a7 move.l (a7)+,d5-d7/a4-a6 ts...