Tech demo of my game

[remz]

Hello everyone!

I have assembled an ADF image on my little game/tech-demo I have been working on for the past few months. This is my first C/ASM Amiga game, so it took a fairly long time and was very challenging and fun to work on.

I would be extremely grateful to have your input, comments, suggestions about it. Should it be useful to others, I could put the whole project and source code on GitHub, but otherwise I would be happy to answer any questions too. As I mentioned, this being my first serious game project on an Amiga, it is certain that a lot of things could be done better, safer, more compatible, more efficient, etc.

Here's a screenshot of what it looks like:


The technical specs:
- Detects PAL and NTSC, so it should work on both systems
- Runs at full frame rate (50Hz or 60Hz), scrolling in 8 directions
- Uses lowres HAM 6-bitplane mode
- Dynamic sprite management system: it groups sprites by pair, and recycles sprites across the screen vertically: the system can display a maximum of 104 sprites.
- On an example screen like the one in the screenshot, there is about 80 visible moving sprites, some are animating
- Sprites are being recolored by the copper: 12 colors per scanline to be precise. This means a theoretical limit of 2880 colors could be displayed just for the sprites. With the current sprite sheet I used, the sprites are using 265 colors.
- The background tiles are in HAM, which means up to the full palette of 4096 colors, and arranged in such a way show fringeless horizontally scrolling
- The tiles are shaded at runtime according to light sources (i.e., torches) with a scanline-dithering technique to allow approximately 30 level of darkening
- There is a single bitmap buffer (i.e.: no double buffering), so everything is rendered with carefully timed 'racing-the-beam' blits.
- The copper list is also a single list, so all real-time modification of the copper list is done with careful timing
- joystick control (port 2) and keyboard are supported
- I tried to make it as system friendly as I could: the game can be directly booted from floppy or installed on RAM: or hard drive or anything else and should work correctly.
- It works on kickstart 1.2 and anything above. However, on Amiga 1000 with a kickstart older than that, my startup-sequence is doing run <NIL: >NIL: RemGame.exe >NIL: which is not supported so it fails to start; but removing that and it works fine (tested in WinUAE)
- So far, I've only tested it on WinUAE: my only attempt to run it on hardware was on my Vampire V4, and it crashed horribly. I cannot fully trust that the V4 implementation is 100% compliant with a real Amiga, so for now I do not know how well my game would fare on real hardware.
- Technically it should boot and work on a real CDTV and Amiga CD32, but I've only tested on WinUAE for now.
- It runs on OCS, and requires only a 512KB chip ram Amiga, so normally any plain Amiga 500/2000, or Amiga 1000 with 512KB should work

In the screenshot shown here, there are 1458 colors displayed on the screen and it scrolls at full framerate on any Amiga model.

EDIT: I fixed a graphic glitch on several fast amiga models but I left the original ADF package here in case of future reference. The new and fixed version is called v2:
https://eab.abime.net/attachment.php...1&d=1675381348

[TCD]

When you posted a screenshot I didn't think it would work even as a tech demo. Congratulations Just tried it and it looks amazing Will be interesting if you can implement basic interactions (pick stuff up, open doors) and enemy movement.

[Jobbo]

This looks really lovely.

It'd be interesting to see how the Ham tiles hold up with a more organic background like a Zelda style forest. I'm sure it'd look great!

Really hope you'll keep going and turn it into a finished game.

[khph_re]

Blimey! lovely looking work. We don't get many games involving HAM, let alone copper recolour.

I'll find a blank disk for my A500 and report back (Kick 1.2)

[paraj]

That's very cool! Awesome job. It crashes very shortly after starting on my A1200 though (with or without accelerator - more quickly with). Seems to work in WinUAE A1200 quickstart (with a glitchy screen during loading).

[Aardvark]

Working on 68060 when cache is disabled with somewhat glitchy graphics.
[ Show youtube player ]
When running under generic WHDLoad slave all these glitches are fixed.

[Thorham]

Only ran it on WinUae, but if it runs well on an A500, then it's very impressive indeed Would love to see more of this

[remz]

Originally Posted by paraj

That's very cool! Awesome job. It crashes very shortly after starting on my A1200 though (with or without accelerator - more quickly with). Seems to work in WinUAE A1200 quickstart (with a glitchy screen during loading).

Thank you, crashing on A1200 is certainly unexpected. I'll have to investigate.

Side note: The glitchy brief loading garbage is "normal" at current stage and will happen on any Amiga models.

[remz]

Originally Posted by Aardvark

Working on 68060 when cache is disabled with somewhat glitchy graphics.
[ Show youtube player ]
When running under generic WHDLoad slave all these glitches are fixed.

Ah, very nice to know: I manage to see that similar color glitch in WinUAE when using a certain combination of AGA workbench + fast system + not waiting for blitter: I'm expecting my code is doing something incorrect. I'll have to dig more into it!

[StingRay]

This looks really nice indeed, you should definitely turn it into a finished game.

Originally Posted by Aardvark

When running under generic WHDLoad slave all these glitches are fixed.

Cache is disabled when WHDLoad starts a slave, the slaves have to enable the cache or it is not used.

[saimon69]

If you decide to make it a game i can help with the audio part

[Thorham]

Checked it on my A1200 with Blizzard 1230 MK4 and getting similar graphics glitches as seen in the video.

[Aardvark]

Originally Posted by StingRay

Cache is disabled when WHDLoad starts a slave, the slaves have to enable the cache or it is not used.

This demo works without glitches under GenericKick31.slave with or without Cache option. Only when running natively it crashes with cache.

[alexh]

Looks very good. Hoping to try it on real hardware (A1200 + Pistorm32-Lite) in the near future.

[zzbylu]

Great tech demo! Time for a beta version of the game!
Gameplay: [ Show youtube player ]

[paraj]

Originally Posted by remz

Thank you, crashing on A1200 is certainly unexpected. I'll have to investigate.

Side note: The glitchy brief loading garbage is "normal" at current stage and will happen on any Amiga models.

Could be that my amiga is going bad. Retried a bunch of times (maybe 50) and couldn't reproduce the crash. Now it seems to work fine most of the time, but sometimes I get persistent glitches after moving (like in the screenshot).


You can probably ignore it if it doesn't show up for anyone else. System is ancient KS3.0 A1200+Blizzard 060(disabled)+gotek.

[remz]

Originally Posted by paraj

Could be that my amiga is going bad. Retried a bunch of times (maybe 50) and couldn't reproduce the crash. Now it seems to work fine most of the time, but sometimes I get persistent glitches after moving (like in the screenshot).


You can probably ignore it if it doesn't show up for anyone else. System is ancient KS3.0 A1200+Blizzard 060(disabled)+gotek.

The glitch your screenshot shows looks like if one the palette was incorrectly set: I would guess palette #1 (since if it was palette 0, the border wouldn't be black).
Because the game is in HAM, every pixel using palette #1 is shown with an incorrect color and it "fringes" up until the next color index pixel because of how HAM works. Very strange indeed.

[Torti-the-Smurf]

This looks very cute and i really dig the Chiptune Music

[pixie]

Played it on WinUAE, but still I have to say that I'm quite impressed!

[remz]

Originally Posted by Torti-the-Smurf

This looks very cute and i really dig the Chiptune Music

For those that likes that music, it is a chiptune version from CError of the lovely KT Tunstall song: [ Show youtube player ]