Let me first say that if you ever get the idea to drive an hour both ways in a major snow storm, quickly forget that idea. Trust me.

Apart from my 2 hour turned 6 disaster, some good additions tonight. After banging my head against the wall the last few nights with getting raster interrupts working with my code and the way the compiler writes the executable, I finally got it working tonight. The speed of the program is just sick now, I think I’ll be able to add some better graphics into the program while still maintaining necessary speed for SID processing and reading the guitar. Which is good, because it will look better, and a few people have written in with some nice examples of how it could look. And since I am definitely not an artist I’ll be writing you guys back. 🙂

The program has come a long way since I posted that video a few days ago (I’m almost tempted to take it down since it goes so much faster now, but I’ll keep it up until I get a new video online). Checklist of things left to do:

1. Finish and debug button/scoring code that detects whether a correct button combination was pressed or not.
2. Implement an in-game editor that allows creating note-button data for any given song (pretty necessary for both now and end-user expansion)
3. Create intro screen, game menu, song selection, etc
4. Allow saving of score to disk
5. Add some nice backgrounds, better sprites and graphics if possible (most likely will be at this point)

Also, PSX64 related, after the game is completed I’m going to be getting some professionally made PCBs to sell if anyone is interested, more on that later though. Remember, the PSX64 can be used with any playstation controlled on any DB9 digital joystick system (C64, Amiga, Atari, SMS, etc)

Oh man, lots of coding tonight. I rewrote pretty much the whole graphic/sprite engine and optimized a ton of crap, I didn’t realize how much unneccessary code I had in there until the SID file exposed just how much processor time it was taking up. The majority of the fixes were things like only redrawing a specific area instead of a general region, precalculating sprite movement ahead of time instead of running division and multiplication operations every refresh to figure out where to put a sprite, stuff like that.

Long story short, songs now play at full speed, even while the maximum number of notes are on screen and hammering away at the strum bar. There are still a few more things to add into the gameplay that will slow it down a bit, but I’m confident now it won’t be an issue. Actually, after all the work tonight, there really aren’t a lot of major obstacles left, the only thing that will be a pain at this point is getting real button-note data in there so notes on the fret board actually line up with the music. I was thinking of writing an editor that could be used in game to add your own note data, allowing you to add any sid file you want and turn it into a Shredz64 song. This is probably what I’ll do, as I need to make a tool to get it in there anyway, no way am I typing out the millisecond of every note to appear on the board.

I’m thinking that it will function by playing a SID very very slowly, letting you play the notes on the guitar where you want them, and then records this to the note file. The only thing that might be weird is some sound envelope processing won’t work correctly playing the PSID file so slowly, and might not play at all. We’ll see, it doesn’t have to be perfect by any means.

I’m confident that in a months time I will have a full video of at least 1 demo song in action. Check back often! 🙂

After finishing up some other projects going on, I’ve finally been able to work on Shredz64 again, which I’m pretty happy about. Lots of good updates, and even a movie (please read disclaimer before watching!)

First off, I had to abandon my work with the SID converter. It was a neat idea and was kind of working, but the files it made were waaaay too huge for a C64, the timing didn’t work properly (and was never going to), and would require an extra step whenever I (or anyone else) wanted to add a new SID to the game. So instead I decided to focus more on having Shredz64 support (most) SID files with no conversion necessary.

As mentioned before, sid files, unlike other music files, are actually executable code (with a header) and not just music data. They have hard coded addresses in them and must be loaded at an exact address or nothing will work properly. I modified Shredz64 to reserve a 10K block in memory (leaving a little room for the loader, but up to $2FFF is for the SID) which allows most SIDs that execute within that space to work. I then wrote a few quick assembly routines to initialize and play the sid, and inserted them in the appropriate places in code. The result was that a sid file can now be placed on disk and read by Shredz64, and played, with correct timing (well, correct timing when nothing else is happening).

Below is a link to a video that shows Shredz64 in action. It’s fairly painful at the moment, but I was so excited to finally get the SID code working properly that I wanted to upload it. If you take a gander at it, please keep the following in mind:

1. I haven’t optimized any of the code yet, and it lags the song. There are a number of places where I can save a lot of processing time, so I’m not too worried.

2. Except for some note-buttons at the beginning, I just plugged in the same two notes over and over again for test purposes. Plus, the note-button timing is working off the old system and zips by. It will obviously go slower when the game is done.

3. I wasn’t playing the guitar while this demo was recording, so no score will increase and the crowd meter falls. Also, thanks to Marc Fischer for creating the SID

I’m very excited, I see this new sid code working out a lot better than the old. Also, I’ve got a few SIDs in mind for the final product that are going to be freaking sweet. 😉

Just a quick note to everyone taking an interest in this project – I am still indeed working on it, I’ve just been sidetracked (until mid July) on a big side project (IE paying the bills). Expect more updates in a few weeks! Thanks!

Lots of very promising progress tonight (and a few nights ago). First off, I implemented code that will read both note data for fret buttons and music data from SID files off of floppy disk. I also wrote some quick utilities on my Linux box to generate note files for testing. So all the static values are out of the program and its reading off files now. More importantly though, I implemented a good portion of the SID -> Shredz64 converter tonight – this sounds much fancier than it actually is. The issue is normal SID files are big blocks of 6502 machine code that have been ripped (or created), but they contain code for manipulating the processor, memory, etc as opposed to just being music data. Not only does this waste CPU time, but its also difficult to switch back and forth between executing Shredz64 code and executing SID code. My solution for now was to hack the libsidplay library on my Linux box, and intercept any memory writes to the virtual SID chip (0xD4XX) and dump the address and the value to a binary file, along with the relative time the memory write was made. E.g. I play a SID file on my computer, and in addition to playing it it dumps all the SID chip data to a file. Shredz64 then uses that file as its music data. Actually, I didn’t implement the timing tonight, but I did manually set the timing inside the game just to test it out, and it played the music pretty accurately! Very promising for first try. I do need to compress the files somehow, at least look for repeating sequences, since they get pretty big. Hopefully filesize won’t end up being an impossible issue. But hearing music out of the game for the first time tonight sure was awesome!

I added the applause meter tonight that shows how well you’re doing overall and how close you are to failing. As can be seen, its a vertical bar separated into three sections, filling from bottom to top. When doing well, the bar fill is green, when okay its yellow, and when bad its red. When empty its game over! (Though I don’t have a game over yet). Your applause increases when you correctly strum a note, and decreases if you miss a note or incorrectly strum. I also fixed up some bugs recognizing correct strumming, and separated the code out into multiple files now that things are getting bigger. Next up is reading note and song data from files, and then the SID converter plugin!

I snuck some hours in yesterday before I went to the dentist and worked on things. Shredz64 can now take a (static) list of button data (e.g. buttons to be pressed at what time and in what order) and correctly show it on the screen. For instance, I can encode data that says “A green button should be pressed at 00:00:10, 00:00:20, and 00:00:45, a red button should be pressed at 00:00:10, 00:00:30, etc, and it will correctly show and scroll the sprites on screen. It will also detect if you strum the correct chords at the correct times and increase your score upon success. I’ve also added a “Shredocity” meter that mirrors the functionality of Star Power in Guitar Hero for the Playstation. I will soon be adding a crowd meter that will determine how well you’re playing. Here is a screenshot that shows some button data on the screen. The Shredocity meter is a bit chunky looking right now, I’ll be thinning out the graphics.

Overall, things are going really well. The framework of all the controls and graphics are pretty much done, there is only the big project left of incorporating SIDs in as the source of the music, and the smaller task of reading the song data from files on disk. SID music is ironically incredibly hard to work with on a C64 since its just machine code that was ripped from some other program, but I have plans incorporating SID plugins for XMMS to convert it over to a different usable format. More on that later after some code has been written.

Well, I got a few more things done. As I mention on the Shredz64 page, graphics are simple and confined to PETSCII and sprites right now, no high res stuff. I want to save all the processing power I can for good response and music. I’ll tweak up the sprites later on, but for now this is fine. Anyway – I have the fret board showing, and button indicators at the bottom. They do respond to the guitar controller now, so if you press a button on the guitar it will light up on the screen. I have the strum bar just playing a beep out of the C64 right now to let me know its working. As can be seen, I also did a simple sprite to represent the note/button as it slides down the fret board.

I had a day off from work today, though I ended up sleeping pretty late and not getting everything done I wanted to. I did, however, build a PC64 cable and get cbmlink installed and running on my Debian box. Now I can successfully read/write files/disk images to my C64 from my PC, read/write memory, remotely execute programs, run disk commands, etc. The reason this is related to Shredz64 is now I can actually test it on a real C64 with the controller as opposed to only the emulator with no controller. The cable isn’t too exciting looking to no pictures, but it does operate on a 4-bit parallel connection between the user port and the parallel port, as opposed to a serial connection.

Well, I updated the webpage a bit. Nothing too fancy, but I wanted to clean it up a bit so some sections were separated out. This page will still serve as a log of things I’m doing.

In technical news, I’ve got some graphical routines done and have a fretboard on the screen with scrolling buttons. Screenshots later when I have something a little more to show.