Search found 652 matches

by Sik
Fri Apr 13, 2018 9:13 pm
Forum: Megadrive/Genesis
Topic: Relative offsets in jump tables
Replies: 6
Views: 121

Re: Relative offsets in jump tables

Probably worth noting that often the code is just whatever the programmer could think of first at that moment that was decent enough, not necessarily the best solution. No point changing things as long as they work and don't get in the way.
by Sik
Fri Apr 13, 2018 9:11 pm
Forum: Megadrive/Genesis
Topic: Where do I start? I'm seeking technical documents.
Replies: 40
Views: 1510

Re: Where do I start? I'm seeking technical documents.

Neither NES nor Master System have linked lists. In both cases every sprite in the table is processed in order (there isn't even something to indicate how many sprites were there, you have to move off-screen all unused entries). The NES lets you specify which entry to start from (still processed all...
by Sik
Fri Apr 13, 2018 10:55 am
Forum: Megadrive/Genesis
Topic: Relative offsets in jump tables
Replies: 6
Views: 121

Re: Relative offsets in jump tables

To save on space, pretty much :​P (whether it's worth the effort is questionable, it may make more sense when the table is really large)
by Sik
Fri Apr 13, 2018 4:35 am
Forum: Megadrive/Genesis
Topic: Relative offsets in jump tables
Replies: 6
Views: 121

Re: Relative offsets in jump tables

Remove the ( and ).w, that's already implied by the dc.w.
by Sik
Wed Apr 11, 2018 11:42 am
Forum: Megadrive/Genesis
Topic: Iridon Introduction
Replies: 12
Views: 667

Re: Iridon Introduction

Make the cells too small and you may end up using too much memory, depending how you're implementing it. The trick is to come up with the largest cell size that is not likely to end up with too many active objects at once. What this size is will depend heavily on the particular game (i.e. how much s...
by Sik
Wed Apr 11, 2018 11:40 am
Forum: Megadrive/Genesis
Topic: Where do I start? I'm seeking technical documents.
Replies: 40
Views: 1510

Re: Where do I start? I'm seeking technical documents.

It's not :​D Seems like Sega added it thinking it could help e.g. with sorting and such, but in practice you're more likely to do all that manually before inserting the sprites in the list. I did use it once with that purpose , though that was more of an afterthought. If you want to avoid the linked...
by Sik
Mon Apr 09, 2018 12:04 am
Forum: Exodus
Topic: Third Party Libraries and Includes for Exodus
Replies: 2
Views: 185

Re: Third Party Libraries and Includes for Exodus

The sites for 2 of the libraries for Exodus have dropped off the web, libtiff and zlib, but they are still available via the Way Back Machine: libtiff - https://web.archive.org/web/20170422022912/http://download.osgeo.org/libtiff/tiff-4.0.3.zip zlib - https://web.archive.org/web/20160312092315/http...
by Sik
Thu Apr 05, 2018 6:44 pm
Forum: SGDK
Topic: Layer priority
Replies: 4
Views: 136

Re: Layer priority

And don't forget that the priority bit is per-tile in plane A and B. But yeah, that's the purpose of the priority bit. In order (from furthest to nearest): Background color Low priority plane B Low priority plane A Low priority sprites High priority plane B High priority plane A High priority sprite...
by Sik
Wed Apr 04, 2018 3:36 pm
Forum: Megadrive/Genesis
Topic: Game loops and Vertical Blank interupts
Replies: 10
Views: 277

Re: Game loops and Vertical Blank interupts

Then you have Sonic 3D doing part of the game loop in the main thread and part in the vblank interrupt. And the latter was doing the logic for every object on screen. It took a while to figure out how the heck the two were connected. I honestly prefer the vblank interrupt to just set a flag and noth...
by Sik
Mon Apr 02, 2018 4:41 pm
Forum: Megadrive/Genesis
Topic: Iridon Introduction
Replies: 12
Views: 667

Re: Iridon Introduction

Collision is not necessarily n², more often than not you don't need everything checking collisions against everything (sometimes it may be true, but not always). Of course to take advantage of this you'll want to split objects into groups so you can easily scan only through the groups you're interes...
by Sik
Thu Mar 22, 2018 2:54 am
Forum: Demos
Topic: Unnamed "ninja" game (Dev Diary thread)
Replies: 123
Views: 4659

Re: Unnamed "ninja" game (Dev Diary thread)

Though, I wonder how many people would actually think to switch to 'make debug' after getting an address error. It'd still be helpful for people who know to do it. And we could always just say "use make debug" here as a reply :v I'm completely against checking everything philosophy, on the contrary...
by Sik
Tue Mar 20, 2018 5:12 pm
Forum: Demos
Topic: Unnamed "ninja" game (Dev Diary thread)
Replies: 123
Views: 4659

Re: Unnamed "ninja" game (Dev Diary thread)

Note that most compilers will not bother with a call to subroutine when the function would immediately return once the subroutine is done, they'll just jump straight to it since the result will be the same (this is a common optimization when programming in asm, too).
by Sik
Tue Mar 20, 2018 5:15 am
Forum: Megadrive/Genesis
Topic: Z80 jump table
Replies: 4
Views: 225

Re: Z80 jump table

Z80 have jr (hl) . Just a hint. You mean JP :v But anyway, using that would then require 16-bit operations to calculate the address which is like the whole thing I was trying to avoid (as it starts getting cumbersome). Either that or ensuring the table never crosses a 256 byte boundary (which is no...
by Sik
Sun Mar 18, 2018 11:58 pm
Forum: Demos
Topic: Unnamed "ninja" game (Dev Diary thread)
Replies: 123
Views: 4659

Re: Unnamed "ninja" game (Dev Diary thread)

That 4E75 in the address implies it tried to get its address from somewhere in the code (4E75 is the opcode for RTS).