[WIP] Galaga conversion

[jotd]

If the stars are moving it means that the game wrongly detected a "fast" machine. So you get 50FPS mode. It should fix the stars and select 25FPS mode for it to be playable on A500. Thanks for reporting.

[saimon69]

Sounds like manual tweaking from an in game menu might be an optimal solution

[jotd]

Final version released on itch. I've added 17FPS option (1 frame out of 3) and it runs but is very jerky.

I've tried everything to make it run faster on plain A500 at 25Hz but it's still slow despite a lot of optimizations.

Runs perfectly at 50FPS on fastmem-equipped amigas...

A lesson learned: too many small objects on the screen is too much for vanilla machines. Slightly disappointed, as the game is great and it took me several months to transcode it prorperly, even with the source code.

[Cris1997XX]

Welp, I guess the Amiga would fare better with a lot of large objects on the screen

[Estrayk]

Originally Posted by jotd

Final version released on itch. I've added 17FPS option (1 frame out of 3) and it runs but is very jerky.

I've tried everything to make it run faster on plain A500 at 25Hz but it's still slow despite a lot of optimizations.

Runs perfectly at 50FPS on fastmem-equipped amigas...

A lesson learned: too many small objects on the screen is too much for vanilla machines. Slightly disappointed, as the game is great and it took me several months to transcode it prorperly, even with the source code.

Well, really at 14Mhz can be playlable. I made a video for that you check it.
Real Amiga A500 OCS Kickstart 1.3 68000 14Mhz. (ACA500+)

[ Show youtube player ]

[saimon69]

The 17FPS is what me and my friends in jargon we used to call "three frames" game

[TCD]

Originally Posted by jotd

Final version released on itch.

So... time for the HOL entry?

[DanyPPC]

Originally Posted by jotd

A lesson learned: too many small objects on the screen is too much for vanilla machines. Slightly disappointed, as the game is great and it took me several months to transcode it prorperly, even with the source code.

Nowadays I think the minimum target for an Amiga game is A1200 + Fast Ram.
So, your perfect arcade conversions are a little miracle when they run on a simple A500 1MB.

Many, many thanks jotd for these arcade port to Amiga.
The whole community is grateful to you.

[DanyPPC]

Occasionally some stars gfx bug and slowdowns starting from Level 4.
More evident on Apollo V4SA (Turtle Mode), less on Minimig (MiST) and real A1200/030.

[jotd]

HOL entry please!

Nice video Estrayk, looks very good at 14Mhz! At level 4 we can see that it still slows down a lot when more enemies arrive. But it's still playable most of the time.

[saimon69]

Originally Posted by jotd

HOL entry please!

Nice video Estrayk, looks very good at 14Mhz! At level 4 we can see that it still slows down a lot when more enemies arrive. But it's still playable most of the time.

Would have this been the same slow if you by hypothesis used bobs instead of sprites and recode the display rendering to be amiga friendly rather than recreate the arcade system?

[ransom1122]

GFX is cropping below with winuae



On my real a500 1084S cropping is ok... ... > see last image

RGBtoHDMI it crops on the top?



Also noticed gfx glitching on the main menu with, real a500 & a500 rgbtohdmi but not in winuae (A500 quickstart)




** It also plays way too slow on A500 both (real A500 & Winuae (A500 quickstarT)

[TCD]

HOL entry: https://amiga.abime.net/games/view/galaga-500

[jotd]

Originally Posted by saimon69

Would have this been the same slow if you by hypothesis used bobs instead of sprites and recode the display rendering to be amiga friendly rather than recreate the arcade system?

How many hardware sprites do the amiga have?

Maybe play Deluxe Galaga instead.

I'm the first to be very disappointed by the speed.

[DanyPPC]

Interesting: https://eab.abime.net/showpost.php?p...28&postcount=2

[jotd]

yes, and I'm using the sprites whenever I can. But there multiplexing the sprites (that I already did in Moon Patrol) is pretty complex.

The copperlist is already complex with stars as sprites, and the alien pictures are all different so it's difficult to chain them. I chose to use only 2 bitplanes to blit them, saving 50% blits but it's not enough.

I'm going to try to profile the CPU part as some 8 bit shifts could probably be much faster if done in 16 bit or such. The blitter is OK on a fast cpu (flies with fastmem) so it's limited by CPU too.

[paraj]

Originally Posted by jotd

yes, and I'm using the sprites whenever I can. But there multiplexing the sprites (that I already did in Moon Patrol) is pretty complex.

The copperlist is already complex with stars as sprites, and the alien pictures are all different so it's difficult to chain them. I chose to use only 2 bitplanes to blit them, saving 50% blits but it's not enough.

I'm going to try to profile the CPU part as some 8 bit shifts could probably be much faster if done in 16 bit or such. The blitter is OK on a fast cpu (flies with fastmem) so it's limited by CPU too.

Seems like you already did a very good job! Unless there are some game specific constraints you can use it's probably going to be tough to optimize more than you've already done.

Looked a bit at it (your code included), and the arcade machine can do 64 16x16 sprites (built from 4 8x8 titles) where each tile can use its own 4 color palette (but doesn't in this game?).

Regardless, changing how the screen is rendered, doesn't seem like something you should rework at this point. I say, enjoy the release but of course if there's a few missing optimizations with a lot of potential go for them.

[saimon69]

I did not ask to rework it, i am doing What If scenarios so that if someone else with coding skills (hence not me) want to do that have an idea on how to proceed

[jotd]

I was just thinking in 25fps mode I could erase the sprites in one interrupt and draw the sprites in the other. maybe currently there are some missed interrupts that make timers drift and cause issues to non interrupt code