Ponder's Blog

It’s alive!

The last part of the PSU arrived today, so I cobbled the parts together and plugged it in.

There is no sound, but I strongly suspect the cable is at fault. I await an RCA cable and will test again when it arrives. Maybe earlier if I can find an old RF cable, but I remember dumping the last one I found because I didn’t think I’d ever need it!

UPDATE: the audio issue is down the the 9V supply. I can’t fix this until next payday.

As for the game, I’m hoping to continue with that later today. There have been too many distractions and I need a bit of uninterrupted time for that.

I bought an old C64C from a friend last Sunday.

Sorry about the blurry pic, the rear camera in my phone needs replacing. I have one here and intend to do so this weekend.

Progress so far: keyboard filled up!

This is what I have ready to build a PSU. The 9V AC adaptor (in the post) will plug in to the Belkin. The USB cable will be cut, and both soldered into the DIN plug. I also have shrink tubing in the post to make a good job of that connection.

Once the composite cable arrives I’ll be able to power it on and test it. Once I know it powers on, I’ll replace the capacitors. Solder sucker and braid also purchased for the operation.

Once I know it’s all working well, I’ll add an SD2IEC device so I’ll be able to treat SD cards as disks, and a joystick, and I’ll be ready for action!

The last part of this project will have to wait until next summer though. The most tedious part, but the one that will complete its look. Retro brighting!

This won’t be taking over from my game development. That’s going to continue as normal (whatever that is) 😉

I now have an enemy to play against!

This was quite a headache to write and earlier edits came back to haunt me, but I solved all the problems and gained a whole new level of respect for those who had to debug more complex programs in the past!

Unlike the original, the game will eventually include lives. Please note, the flickering is just to show me how much CPU time is being used and won’t be present when I finish the major parts of the game.

I’m planning to draw the title screen next, but that won’t be until next weekend. Work is going to take a toll until then, but that leads to a long weekend off, hopefully with few distractions 🙂

Just a minor update today. Added chaser init and player movement detects collision with chaser. It does currently mean the first level never completes due to a static chaser, but tomorrow I’ll get them moving 🙂

Quite a bit of fine tuning today and a few routines added and updated.

Side panel text added. Player can now create a time limited gap to block chasers (NB this also blocks the player). Scoring and an end of level sequence also added.

I’m not planning on updating until Saturday, but my target then is to add the chasers, and maybe the intro screen text.

Today I got to work on the gradual draw routine. At first I tried the lazy way, but using loops as delays isn’t exactly neat and I had problems, so I dug straight into the interrupt driven timing.

After the usual schoolboy errors, which are becoming less frequent and easier to debug (and I’m looking at reference material less often now) the result was pretty decent, so to complete the map level data I decided to write the player routine, because that was the easiest way to count the blocks needed to complete a level.

Well another oops, the number of blocks needed more than 8 bits on the last 2 levels!

That sorted, here is the result so far. I’m quite pleased with the progress I made today 🙂

Test audio has now been added along with the screen driven interrupt routine that will form the main game loop, so it’ll run smoothly.

Tomorrow I’ll work on drawing the levels in a more interesting manner that fits the final game.

All 4 default levels have been designed and are easy to push to the draw routine.

I’ve been too busy to do much today and my head is currently in a mess so that’s all I’m doing until Sunday (out tomorrow).

The image shows loading the code, listing what’s visible to BASIC and running. Level displayed is changed by pressing the joystick button. Exits when all 4 have been displayed.

These images show the start locations of the player (blue) and the chasers for each level.

Today’s goal achieved after some hair pulling. My draw routine was giving nonsense results until I realised I’d used the same variable locations! Once I figured that out it went a lot faster.

The level draw routine is now working, and tested with map data! The map data holds number of blocks to cover to complete the level, player and chaser start locations, level draw start positions and draw data. The latter is shown here:

$27,$59,$26,$20,$6f,$21,$26,$58,$27,$21,$6e,$20,$00

This draws the following:

This is already the most complex 6502 code I’ve ever written and I’m learning all the time. Tomorrow’s target is to design the same levels as the original, and set up the interrupt driven routine that will be the core of the whole game.