Tiny Galaga

[skyzoo73]

Fantastic! Will there ever be a non-tiny Galaga?

[DamienD]

Originally Posted by skyzoo73

Fantastic! Will there ever be a non-tiny Galaga?

There are already two of these; which are also very good:

• Galaxy 89
• Galaga 94 [hack]

[Liqourice]

Originally Posted by skyzoo73

Fantastic! Will there ever be a non-tiny Galaga?

Have you missed DeLuxe Galaga?


It's even better than the original Galaga in my opinion.

[skyzoo73]

Ok these are nice games, but they are different from the arcade anyway. A faithful conversion to the original would be nice. IMHO

[coldacid]

If they were intended to be "faithful conversion[s]", they wouldn't be Tiny.

[Tigerskunk]

Originally Posted by pink^abyss

Collision detection is done with Morton codes for broadphase culling..
.

That sounds interesting.
Care to elaborate?

[DamienD]

Originally Posted by skyzoo73

Ok these are nice games, but they are different from the arcade anyway. A faithful conversion to the original would be nice. IMHO

I think Galaxy 89 is pretty faithful to the arcade; and has the extra ability to tilt left / right

[hexaae]

Originally Posted by DamienD

There are already two of these; which are also very good:

• Galaxy 89
• Galaga 94 [hack]

... and don't forget excellent variant Deluxe Galaga AGA (free from Aminet)! Still one of the best clones...

[pink^abyss]

Originally Posted by Steril707

That sounds interesting.
Care to elaborate?

The basic idea is to have a 1-dimensional array of linked pointers to hold your collision objects. To get a 1-dimensional array index from your X/Y pos you can use morton codes (see wikipedia).

My implementation looks like this:
- Divide X/Y pos by 16
- Have a table that converts each X/Y value into a value interleaved with a 0 for each bit. So for instance 0b1111 becomes 0b10101010.
- Shift converted X left by 1 and or with converted Y pos
- Now you have a 1 dimensional hash of your position (the morton code)
- In my case i insert then the enemies each frame with this hash into predefined bins of an array (just like a hash table).
- To test for collision you calc the morton code for your bullet and look into the corresponding bin. Usually the bin is empty. If not you need to make a aabb test against all entries of that bin.

This algorithm allows to get the number of comparisons from num_bullets*numEnemies to roughly num_bullets+numEnemies, of course with a much more complicated setup.

If you have many comparisons each frame it can be a real time saver.

In comparison to array sorting it also doesn't suffer from axis clustering.
If your objects can be easily sorted among a single axis then lazy array sorting is usually faster. If you have only a few comparisons then just brute force.

[Tigerskunk]

Originally Posted by pink^abyss

The basic idea is to have a 1-dimensional array of linked pointers to hold your collision objects. To get a 1-dimensional array index from your X/Y pos you can use morton codes (see wikipedia).

My implementation looks like this:
- Divide X/Y pos by 16
- Have a table that converts each X/Y value into a value interleaved with a 0 for each bit. So for instance 0b1111 becomes 0b10101010.
- Shift converted X left by 1 and or with converted Y pos
- Now you have a 1 dimensional hash of your position (the morton code)
- In my case i insert then the enemies each frame with this hash into predefined bins of an array (just like a hash table).
- To test for collision you calc the morton code for your bullet and look into the corresponding bin. Usually the bin is empty. If not you need to make a aabb test against all entries of that bin.

This algorithm allows to get the number of comparisons from num_bullets*numEnemies to roughly num_bullets+numEnemies, of course with a much more complicated setup.

If you have many comparisons each frame it can be a real time saver.

In comparison to array sorting it also doesn't suffer from axis clustering.
If your objects can be easily sorted among a single axis then lazy array sorting is usually faster. If you have only a few comparisons then just brute force.

First off, greets from München Schwabing...

Interesting explanation, thank you..
Not a long time ago, I was starting a thread with this kind of question (how to speed up bounding box checks with bullets etc), leading to various results.

But this sounds quite brilliant.
Not understanding it yet, but will look into it..

[blakespot]

I grabbed the ADF and wrote it out to disk and tried it on my A1000 with 1.3 KS and 512K CHIP and 2MB FAST and it crashes during boot. Is it supposed to run in this machine? Thanks.



bp

[ross]

Originally Posted by blakespot

I grabbed the ADF and wrote it out to disk and tried it on my A1000 with 1.3 KS and 512K CHIP and 2MB FAST and it crashes during boot. Is it supposed to run in this machine? Thanks.



bp

I suppose you've a NTSC A1000.

If the case, no.

[blakespot]

Originally Posted by ross

I suppose you've a NTSC A1000.

If the case, no.

Sadly, it is indeed an NTSC A1000. The game works great on the A2000 via WHDLoad (with ECS Agnus), where it goes PAL. Would've loved to see this on my A1000. Glad to have it for the A2000 tho -- thanks for the effort.


bp

[skyzoo73]

Originally Posted by DamienD

There are already two of these; which are also very good:

• Galaxy 89
• Galaga 94 [hack]

They are all beautiful games, clones of Galaga, but they are not faithful to the original. Different spaceship sprites, different enemy sprites, different music and sounds not really my idea of ??arcade conversion. From this point of view, it is much more reminiscent of the original game Tiny Galaga.

[honx]

on tiny galaga i encountered a bug: if i score highest highscore (1st), my score is mirrored in 2nd. see screenshot.

another question: how can i exit to workbench without reboot?

[hexaae]

Originally Posted by honx

another question: how can i exit to workbench without reboot?

LMB to quit.

[honx]

this score duplication bug can be reproduced, see screenshot.

[honx]

another bug: if i'm about to enter challenge mode and i get bonus then challenge mode is quit.

[Photon]

Seems more faithful than Deluxe Galaga, I miss colors though and the screen could be full width. Doesn't mean you can't have a bit of fun with it!

[honx]

this score duplication bug is recurring. really annoying!
and there won't be a bug fix i assume...