Tiny Galaga

[lesta_smsc]

Game was mentioned on an Amiga channel which is broadcasting live right now!

[ Show youtube player ]

Tiny Galaga mentioned around 1:07 or so...

[pink^abyss]

Originally Posted by Mathesar

Never , although I did program the Amiga waaaaay back ago.
But please don't be offended, I never meant to criticize.


However, I am just wondering. For example regarding CPU's. This game was written in C and compiled with GCC right? Isn't there a "universal" CPU setting that works with all CPU's? Surely there is a common set of instructions that are supported by all CPU variations. When programming in assembler I am sure it must be more difficult to avoid some instructions that are not supported on some CPU's. However, with C it should be easier as the compiler can handle it.

I compiled the game for 68000, so no instructions from later CPUs are used.

[pink^abyss]

Originally Posted by khayoz

@pink^abyss

Thank you!
Looks and play great!

Thanks khayoz!

[hexaae]

@pink^abyss
Adding P=Pause and native screen initialization (it freezes when starting from a Picasso RTG Workbench. Have to switch to native mode before launch)?

[nobody]

Just an idea, include an option with different color schemes Gameboy (green), CGA etc.

[Nightshft]

Originally Posted by nobody

Just an idea, include an option with different color schemes Gameboy (green), CGA etc.

Excellent Idea.
Maybe also green and amber monitor, ...

[Havie]

Played - excellent and really well done. Plays really smoothly and is very enjoyable. No sprites is impressive too!

I may be being stupid but it looks like at least 3 colours to me - white, black and grey? Surely this is 2 bitplanes?

[nobody]

Maybe around 30 objects including bullets, I guess this is easy for the blitter and given that it's only using 4 colors, and small size of objects.

[Tigerskunk]

Originally Posted by Havie

Played - excellent and really well done. Plays really smoothly and is very enjoyable. No sprites is impressive too!

I may be being stupid but it looks like at least 3 colours to me - white, black and grey? Surely this is 2 bitplanes?

2 bitplanes = 3 colours plus background...

[Havie]

I get that but Pinky says that it is only 1 bitplane in his initial post so I wondered if there was something clever going on?

[britelite]

Originally Posted by Havie

I get that but Pinky says that it is only 1 bitplane in his initial post so I wondered if there was something clever going on?

Everything is rendered on one bitplane, with that same bitplane being reused with a slight offset to create the subtle shadow.

[Mathesar]

Originally Posted by britelite

Everything is rendered on one bitplane, with that same bitplane being reused with a slight offset to create the subtle shadow.

Now thay you mention it I see it !

Very nice effect.

Would he only use a single buffer for that?
And just offset the second bitplane pointer?

[Antiriad_UK]

Yep.

 00030d80: 0100 2200          	;  BPLCON0 := 0x2200
 00030d94: 00e0 0003          	;  BPL1PTH := 0x0003
 00030d98: 00e2 8d72          	;  BPL1PTL := 0x8d72
 00030d9c: 00e4 0003          	;  BPL2PTH := 0x0003
 00030da0: 00e6 8d42          	;  BPL2PTL := 0x8d42

2bpl screen, pointers to same bitplane buffer 30 bytes apart.

[JudasEZT]

Great stuff. I love its smoothness and that shadow. =)

[ross]

You also need to set a horizontal shift (so the odd and even bplanes are not only vertically far):

0102 0020          	;  BPLCON1 := 0x0020

It's the easiest and most effective way (and requires practically no resources) to create shadows on characters with the Amiga

[roondar]

I've finally been able to put a bit more than 5 minutes into this and I am even more impressed now than I was before. Not only is the executable tiny, but the game is really, really good. It's super smooth, the art style works and it plays like a dream.

Excellent stuff

[pink^abyss]

Originally Posted by roondar

I've finally been able to put a bit more than 5 minutes into this and I am even more impressed now than I was before. Not only is the executable tiny, but the game is really, really good. It's super smooth, the art style works and it plays like a dream.

Excellent stuff

Thanks a lot. There are some rough edges here and there but overall i'm satisfied how it plays.

[pink^abyss]

Originally Posted by nobody

Maybe around 30 objects including bullets, I guess this is easy for the blitter and given that it's only using 4 colors, and small size of objects.

Here are some more details:

The maximum you can see in one frame is
64 pixel stars with different speeds

32 enemies
8 enemy shots4 player shots
2 player ships
1 bonus pod

The whole screen is 'cleared' with the blitter by copying the hud

onto the screen without mask. Then all bobs are blitted with mask and then all stars are plotted with the cpu.

Collision detection is done with Morton codes for broadphase culling and then simple aabb overlap checks.

If i remember correctly then the blitter used around 30% of available dma cycles. Most blitter time was spend for copy clearing.

The music/sfx replayer (PreTracker) takes around 35 rasterlines. The fx are programmed and not just samples.

[pink^abyss]

Originally Posted by JudasEZT

Great stuff. I love its smoothness and that shadow. =)

thanks Javier

[hexaae]

Originally Posted by hexaae

@pink^abyss
Adding P=Pause and native screen initialization (it freezes when starting from a Picasso RTG Workbench. Have to switch to native mode before launch)?

Should I still hope to see at least RTG fix when starting from non-native screen?
At present I have to launch the game from degraders like "C:JST EXECUTE ays-galaga" which opens a PAL screen right before the exe is launched...