SpritesMind.Net

My next article is on ADSR, it's been in draft form for a long time though due to work commitments :( Just in case it's of any use to you: Welcome to the second article in the Megadrive Sound series! I've been hard at work on my PSG sequencer, making a few improvements, adding new features, and mess...

If you can manipulate individual pixels, you can draw anything

A basic line rasteriser shouldn't be too tricky to knock up with some basic maths. You'll need enough spare VDP memory for one tile per cell (for the area you want to draw on).

I'm guessing whatever hardware you tried had clean VRAM? My kit contains garbage on startup (and I assume retail machines will behave in the same way), I've had to start clearing pretty much everything on startup. Emulators are too kind :) http://i.imgur.com/bygj08F.jpg Try this, after initialising ...

My Cross products kit is hooked up via SCART to quite a high quality Samsung, send over the ROM and I'll get you some photos of it running.

Watch out for address errors. Those are the bugs I run into the most! Tell me about it. This one was really tricky to find, I actually ran into the problem code by mistake (luckily). I ran into another issue today, I was tempted to ask for help but I stuck to it this time. I'm not going to learn mu...

I'm glad you're finding it useful! Just make sure to proof read everything and don't take anything I wrote as gospel, it's more of a diary than a tutorial and there are a lot of mistakes.

Excellent! Look into calling conventions (passing params via regs or stacks, how to back up regs before jumping, where return values are stored, etc) and design one to suit your coding style, then stick to it. Some macros help - BACKUP_REGS, RESTORE_REGS, that kind of thing. At the moment I use regs...

Branches are not subroutines, they don't push the return address and cannot be jumped back to with rts - you need to jsr ( J ump to S ub R outine) if you want to return to that location with rts ( R e T urn from S ubroutine) Unfortunately this means changing your code a little, since you'll need to ...

The VDP register calculator from here is my new best friend: http://www.pascalorama.com/article.php?news=28&cat=21

Cheers, I'll research into Listing files and see what I make of it. How do you mean 'seems to be offset' - in what sense? Only going by visuals, my characters' tiles start a few lines down (I should find the actual offset in bytes, that might help my case :lol:) - the only difference is where in my ...

I might not use a script for th elong run but it would certainly help me learn where I'm going wrong at the moment. My code is now behaving itself but when trying to load my "Hello world" character set it seems to be offset. I've added an EVEN before including the file and verified in the memory vie...

Hi all! I'm trying to replicate the VDP setup and clear screen process in the Sonic 1 disassembly from SonicRetro.org, and this issue is bugging me. There's two sets of VDP registers, one for initial setup (clearing CRAM, displaying checksum error) and one for the game itself: VDPSetupArray: dc.w $8...

That's the kind of explanation I needed, cheers! So far so good, a full reorganisation of my project seems to have eliminated all of the "subtle change = catastrophic results" cases I was getting frustrated with, and no need for ALIGN or CNOP so far. I didn't know about word alignment of data, I've ...

Awesome, I understand that bit then. What can I do in code to ensure I stick to the alignment? Where and when would I expect to use a CNOP or ALIGN directive? Maybe some general rules about where data needs to be put? So far I've reorganised everything so that no code at all is below any data, and i...

Hi! I've spent the last hell-knows-how-long trying to port my framework to real hardware. I have a Cross Products MegaCD kit with SNASM2 interface, assembler and debugger, and I'm very slowly making progress. My latest hurdle is that when making subtle changes (adding a new palette, changing my memo...