Writing a game sprite driver

[mcgeezer]

Originally Posted by Shatterhand

Nowadays I understand it very well and even explains it to other people.

Champion, when I get stuck with my title screen I'll give you a shout!

I'm thinking a more complex version of the SR intro below:

[ Show youtube player ]

Instead of those orbs, it will be the Red bombs circling over the Bomb Jack logo....

Just a thought... along with maybe a wavy scroller etc....

The title screen will be fun to code... will be like doing a cracktro.

[phx]

Originally Posted by mcgeezer

Here's my current memory map.

I think I would pack all the initialised data (graphics assets, music, etc.) tightly at the beginning of the memory space. Then manage the remaining, uninitialised space, with internal alloc/dealloc routines.

The deallocation could be really simple, like remembering the memory pointer at the beginning of the game's main loop and then restoring it when leaving the main loop again.

Moving the uninitialised space to the end of your program also makes the file much smaller. You don't have to store that part.

I keep all of the assets compressed which then unpack to chip ram. I think a good compromise for the game would be full load if the target has a 1/2 meg expansion but if it's a stock Amiga A500 then it'll be track loading the levels.

Yes. That's always a good last option.

[Asman]

+1 for phx solution with memory pointer. It's really simple and will give you opportunity to check available memory in every moment of you game and there is a possibility to check if you cross the bound. If you interested I can post here my proposal which I use.

I think that is possible to fit everything into naked A500 (0.5 MB CHIP) but is just my opinion and this needs much more work to do. There are exists very nice packers like shrinkler and I was so surprised when I packed assets. For example file assets_G16x16.iff (40kb) was packed to 6000 bytes. Of course depacking take some time and will need additional 4k but I think that is worth to test it.

In your memory map I can't find tiles for levels, where are they stored ?
No offence but I also think that fixed addresses are so wrong. If I were you then I would sacrificed one register (i.e. a4) for DT. You can save a lot cycles.
I saw your sources on git and there is a plenty things which could be faster but for sure You already know that. Good luck with your project.

[mcgeezer]

Originally Posted by Asman

+1 for phx solution with memory pointer. It's really simple and will give you opportunity to check available memory in every moment of you game and there is a possibility to check if you cross the bound. If you interested I can post here my proposal which I use.

I think that is possible to fit everything into naked A500 (0.5 MB CHIP) but is just my opinion and this needs much more work to do. There are exists very nice packers like shrinkler and I was so surprised when I packed assets. For example file assets_G16x16.iff (40kb) was packed to 6000 bytes. Of course depacking take some time and will need additional 4k but I think that is worth to test it.

In your memory map I can't find tiles for levels, where are they stored ?
No offence but I also think that fixed addresses are so wrong. If I were you then I would sacrificed one register (i.e. a4) for DT. You can save a lot cycles.
I saw your sources on git and there is a plenty things which could be faster but for sure You already know that. Good luck with your project.

When I get the game fully up and running I'll be happy to come back to this. There is no offense taken at all. The tiles are stored at $20000 with the sprite assets. The packer I use is the RNC Pro Packer.

I'm happy to upload my latest source, but it will be without the sfx/mods as they are not mine. Let me know and I will upload them and you can help me solve the problem.

[saimon69]

From my side you can upload my mod files and sound effects, as long as credit is given ^^

[mcgeezer]

So I finally got round to doing some more work and what I was keen on doing is testing the game on real Amiga hardware. I managed to optimise the blitter routines by running just one blit instead of one for each bitplane - it made a massive difference. The other change I've made is moving Jack, the Bonus token and Powerball as hardware sprites.

Aside from the bugs which I know about, such as
-Graphics/Colour bugs
-Collision bugs here and there
-Some sound bugs
-Scoring bugs...

...I now have a playable game.

Here's the home amateur video
[ Show youtube player ]


If you want to try it for yourself you can go right ahead and download this ADF

Note, the game will need to run on an A500(+) with 0.5mb chip and 0.5mb fast ram. It will not run on an A1200 (yet) or other config, compatibility will be improved later.

Release date will probably now be pushed to March or February as there's still quite a lot to sort out and I'm getting less time to work on it for various reasons (mainly family time).

I hope you enjoy it.

[saimon69]

I just realized i will need to debug mods too ^^

[mcgeezer]

Originally Posted by saimon69

I just realized i have to move the songs in the second pair of audio channels, will send you updated mods ^^

No mate, u dont need to i just havent spent enough time working on the sfx yet.

[LeCaravage]

Considering the number of persons (two ?) involved in the game dev. I'm pretty impressed by the fast progress you've been making and, all during spare time.

[mcgeezer]

Originally Posted by LeCaravage

Considering the number of persons (two ?) involved in the game dev. I'm pretty impressed by the fast progress you've been making and, all during spare time.

Development started around 8th November 2017 so has been going about 3 months.

One of the great things that came out of my last update was that a few Youtuber's seem to have downloaded the ADF to show off the progress of the game in their channels. It's very handy because it has unearthed lots of bugs for me!

Here's a list of them that I know about in no particular order

1. Enemies don't appear on the next round until the Powerball resets them
2. Bombs colour issue during start sequence
3. Scene colour issue during start sequence, affects rounds 2 & 3
4. ESB collision is broken when Powerball is active at the same time
5. ESB has double collision when collected (or so it seems - strange)
6. Sound effects are not fixed to last 2 channels
7. The Extra token needs to appear after a number of enemies have been killed
8. Powerball colour cycle issues, should cycle when touches a platform
9. ESB won't fall from a left platform
10. The jump/fall routine needs rewriting
11. The colour cycle needs to made into proper HSL

There'll be other bugs I haven't noticed yet but I'll keep striking them off.
Tonight I nailed the ESB double collision issue (or provided a workaround).

It's an interesting one because each frame I read CLXDAT into a word. The ESB is assigned to sprites 2&3 while Jack is assigned in sprites 0&1. For some reason, even if I move sprites 2&3 after a collision is detected, CLXDAT still returns a collision even after the sprites 2&3 has been moved off screen.

Thinking about it now it may be an issue with the vertical beam and I probably have to wait until the beam is in the blanking period before I read the sprite registers.

Sorry, no video as not much to show. When I iron out most of the bugs I'll do another one and maybe add another enemy.

[Tigerskunk]

Nice to read your progress here, McGeezer...

Have a good time coding...!

[phx]

Originally Posted by mcgeezer

It's an interesting one because each frame I read CLXDAT into a word. The ESB is assigned to sprites 2&3 while Jack is assigned in sprites 0&1. For some reason, even if I move sprites 2&3 after a collision is detected, CLXDAT still returns a collision even after the sprites 2&3 has been moved off screen.

IIRC CLXDAT is only updated once per frame. I'm not sure at which point exactly.

[Toni Wilen]

CLXDAT is updated in real-time, pixel by pixel.

[mcgeezer]

I thought I would do a quick video update as I haven't done one in a fair number of days.

I've been mainly concentrating on the things that I knew would be the most challenging - stuff with math. Not sure about you, but when I went school way back in the late 80's early 90's they didn't teach mathematics. They probably did but most of the kids back then were more worried about not getting bashed than doing their home work.

Anyway, I digress - this video shows some more enemies added, nearly there with the UFO which I'm really pleased about. If I can crack the UFO then I can crack the rest of the enemies.

I've also fixed a shit load of bugs, one in particular was the music/sfx which was a simple mistake of not looking at input data sizes (l/w/b) - gets me every time!

A few of the other coders have really helped me out and I can't thank you enough.

Here's the video. Collisions are disabled on purpose as the video is a performance test.

[ Show youtube player ]

[mcgeezer]

Technical update on Bomb Jack progress.

I decided to take a little break from coding the enemy AI as it nearly broke my brain so Friday night I knocked up a little intro routine which reminded me of my cracking days.... (them were the days).

In this update I've focused on getting rid of most of the bugs, but I've also added some nice little additions most of which revolve around colour.

When Jack collects the Powerball he changes colour to the colour you collected.
The colour cycle routine is now on HSL rather than RGB, so you get a nice rainbow effect.
Added an intro routine as I mentioned with a little scroller.

From my last video I've re-enabled all of the collisions etc... the video shows me playing the game which at the moment is insanely hard (and I'm good at Bomb Jack).

Over the last couple of weeks I've learned a couple of tricks on the enemies, along with my lessons in trigonometry I'm going to re-code them all - Better, Faster, Stronger, Harder.

[ Show youtube player ]

You can download another ADF beta here - http://109.228.4.199/bombjack2.adf

Geezer

[phx]

Hey, I'm in the credits! Thanks.

Keep on the good work! The game has progressed so far now that I am convinced you will finish it.

[mcgeezer]

Originally Posted by phx

Hey, I'm in the credits! Thanks.

Keep on the good work! The game has progressed so far now that I am convinced you will finish it.

Thanks man. Come too far now not to finish it.
For me it will be an awesome personal acheivement.

[Tigerskunk]

Amazing progress again, McGeezer.
Looking forward to the final game.

The last 5 percent of completing something are always the hardest.

[mcgeezer]

Originally Posted by Steril707

Amazing progress again, McGeezer.
Looking forward to the final game.

The last 5 percent of completing something are always the hardest.

Yeah. Hardest part will be doing the bird enemy code, but it wont be any harder than what i already did in the sprite driver.

There’s a couple of tricks i’ve learned now which will make recoding the enemies much easier. That and my new found trigonometry skills

[mcgeezer]

Here's another update to the game, I've included a link to this Beta 2 release but it has a rather nasty bug that I have only *just* discovered! Doh. The video I've taken here is for me to try and iron out what the hell is going on with the bug.

Anyway, I've done a fair update on the difficulty, enemies now increase in angst gradually the longer you are on a round, also the difficulty is increased depending on how many rounds you get up to.

Also what I've done is put in all 63 rounds into the game. After level 63 it will loop back to round 32 inline with the arcade game.

Lots of bugs also fixed including quite a few GFX glitches.

ADF here - http://109.228.4.199/bombjack3.adf

Video here - [ Show youtube player ]

Enjoy