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2017-08-02 07:56

pmprog
Account closed

Registered: Nov 2005
Posts: 54

[Req for help] TigerMoth performance

Hi all,

I'm getting to a point in TigerMoth that I'm thinking of dropping it. If you watch the video below, you can see when I start hitting a large number of bullets I get really bad performance.

https://www.youtube.com/watch?v=Lskbol7quDk

It's kind of expected, but this version doesn't even have the raster splits for dealing with the score or player, no collision detection for the TigerMoth or the player, nor any music, so performance is only going to get a lot, lot worse. I really like what I've managed to put together so far, but if it's not going to be playable, then I might as well drop it now.

So I thought I'd pop on here and see if anyone was willing to have a quick look and see if there were any points that look really bad. My code is broken down in to lots of subroutines (this might be a problem regarding performance?) with headers that hopefully explain what it's job is, and I've tried to keep all the related pieces together in aptly named files so it's easy to mooch about.

I've been working in a private git on my local server, but I've uploaded a snapshot of the current code to GitHub. The source code is MIT license, and if the project is finished, the full source will be released with the game.

https://github.com/pmprog/TigerMothC64

Also, for reference, the .spriteproject file can be opened in C64 Studio. Export to data, but change the "!byte" to ".byte"
C64 Studio 4.1

I currently use TASM as my compiler, though I was thinking of trying to move across to the ca65 assembler in the cc65 package. But that doesn't really have any baring on the life of this project.

Oh, and finally, before anyone says, yes, I've got my Sine/Cosine tables all messed up (Sine starts at the positive value, Cosine starts at zero and goes negative before positive), but I'm "okay" with that, I just count my angles anti-clockwise from the "3 o'clock" when dealing with bullets

Thanks in advance

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2017-08-22 16:07

TWW

Registered: Jul 2009
Posts: 541

Description about the plotting routine:

http://codebase64.org/doku.php?id=base:dots_and_plots&s[]=plott

EDIT: And yes, what Oswald say as clearing the entire bitmap screen (32 x 8 x 25 = 6400 bytes) vs. clearing only the plotts you have on the screen.

2017-08-23 19:17

pmprog
Account closed

Registered: Nov 2005
Posts: 54

Thanks for the info on zero page. I've also had an email from BiGFooT with some more stuff.

I apologise for turning this into a kind of developer log. Feel free to tell me to shut up until it's ready. Though I'm finding it quite helpful getting feedback as I'm working through it.

Here's a new video of the current version (The music is not playing from the game BTW, just on my audio player), plus a download of the PRG file, if you want to try it yourself. If you do, please could you provide feedback on whether you think it's responsive enough to make a playable game. Obviously there's still work to be done on optimising, and actual game play, but it's nice to get an idea of it's feel.

https://youtu.be/HHrJiZr4l1A
http://www.pmprog.co.uk/download/tigermoth.zip

2017-08-25 14:41

TWW

Registered: Jul 2009
Posts: 541

As you say, still needs some more spunk.

I'd get rid of that "clearbitmapmemory" routine first of all if I were you and replace it with something like:


plott:
    lda Lobyte
    sta $fb
    sta wiperoutine1+1
    lda Hibyte
    sta $fc
    sta wiperoutine1+2
    //plottit
    rts

wiperoutine:
    lda #$00
wiperoutine1:
    sta $2000
wiperoutine2:
    sta $2000
    //....

    rts

And no worries, wish more people would share their projects on something else than that damn facebook so here is good with me.

2017-08-26 20:48

pmprog
Account closed

Registered: Nov 2005
Posts: 54

Bah, it didn't save my reply. So I've got to rewrite it.

bitmap_clear is only called once at the start of a new game, so I'm not worried about that proc for now. Only things directly related to gameplay.

I really need to get the player firing bullets again, and actually implement bullet collisions, which I think is going to be the hardest part.

I was originally going to raster split two sprites multiple times down the right hand side for the score (that you can see in one of my older videos), but I'm considering just writing some 8x1 and 8x8 blit routines and use a mini "character set" to drop that dara in, as well as a health bar. That way I can save cycles reconfiguring sprites, and just update the bitmap memory when the score or health changes.

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