Search found 262 matches

by cero
Sun May 06, 2018 7:28 am
Forum: SGDK
Topic: Simple index compression surprisingly effective
Replies: 5
Views: 1167

Re: Simple index compression surprisingly effective

Yeah, the sprites are big and have a lot of frames, but still it was surprising how well they packed with this. One sheet got to 58% (includes both the index and the stream), while zlib got it to 30% and lz4w 51% (numbers from memory).
by cero
Sat May 05, 2018 6:00 pm
Forum: SGDK
Topic: Simple index compression surprisingly effective
Replies: 5
Views: 1167

Simple index compression surprisingly effective

For an upcoming game, I tried some different compression approaches for sprite tiles, since lz4w was too slow. The amount of data being great enough that even plain memcpy is close to limits, I wondered what approaches would then be fast, even if not as good in compression. About 160 tiles per frame...
by cero
Sat Apr 28, 2018 4:59 pm
Forum: Megadrive/Genesis
Topic: How to do binary OR for gas/as?
Replies: 10
Views: 2344

Re: How to do binary OR for gas/as?

It's an option to as, not gcc. To pass assembler commands via gcc, use -Wa,--bitwise-or
by cero
Sat Apr 28, 2018 7:27 am
Forum: Megadrive/Genesis
Topic: How to do binary OR for gas/as?
Replies: 10
Views: 2344

Re: How to do binary OR for gas/as?

File: as.info, Node: M68K-Chars, Prev: M68K-Branch, Up: M68K-opcodes 9.23.6.2 Special Characters ........................... Line comments are introduced by the `|' character appearing anywhere on a line, unless the `--bitwise-or' command line option has been specified. An asterisk (`*') as the fir...
by cero
Sat Apr 07, 2018 8:11 am
Forum: Megadrive/Genesis
Topic: Iridon Introduction
Replies: 13
Views: 3451

Re: Iridon Introduction

In my TD demo, actors only reside in one cell, but when searching the searcher's radius determines how many cells to check.
by cero
Thu Apr 05, 2018 5:56 pm
Forum: SGDK
Topic: GCC inline asm tutorial
Replies: 4
Views: 6747

Re: GCC inline asm tutorial

Updated.
by cero
Thu Mar 15, 2018 6:21 pm
Forum: Megadrive/Genesis
Topic: Where do I start? I'm seeking technical documents.
Replies: 40
Views: 7949

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

SGDK. You can call the same functions as in C, but write your own code in GNU as.
by cero
Thu Mar 08, 2018 9:06 am
Forum: Video Display Processor
Topic: Tectoy's weird VDP behavior
Replies: 24
Views: 5767

Re: Tectoy's weird VDP behavior

I already tried to just have the image writing code and fade in a sample program - it didn't show the bug. Something in the larger program triggers this, maybe the clone has several modes, tuned for specific games (yay for game-specific hacks due to bad quality emulation), and mine somehow gets into...
by cero
Wed Mar 07, 2018 10:29 am
Forum: Video Display Processor
Topic: Tectoy's weird VDP behavior
Replies: 24
Views: 5767

Re: Tectoy's weird VDP behavior

How about sending a DMA request... After the manual writes?
I did:
...
- DMA write one tile
- DMA write a few tiles
- DMA queue one tile
...
by cero
Tue Feb 20, 2018 6:33 pm
Forum: Video Display Processor
Topic: Tectoy's weird VDP behavior
Replies: 24
Views: 5767

Re: Tectoy's weird VDP behavior

Everything from me was run from the cart port, not the SD card.
by cero
Tue Feb 20, 2018 9:39 am
Forum: Video Display Processor
Topic: Tectoy's weird VDP behavior
Replies: 24
Views: 5767

Re: Tectoy's weird VDP behavior

The DMA queue operation happens after rendering is on, so that one was tried already.
by cero
Mon Feb 19, 2018 6:56 pm
Forum: Video Display Processor
Topic: Tectoy's weird VDP behavior
Replies: 24
Views: 5767

Re: Tectoy's weird VDP behavior

Tried a few workarounds, nothing worked. Still, that does rule out some things, like sane chip design :?

- read the vram after writing it
- DMA write one tile
- DMA write a few tiles
- DMA queue one tile
- draw an invisible sprite

Whatever they were smoking, it must be good stuff.
by cero
Sun Feb 18, 2018 6:43 pm
Forum: Demos
Topic: Metal Blast 2277 - Sega Genesis / Mega Drive
Replies: 51
Views: 11994

Re: Project C - WIP - Sega Genesis / Mega Drive

Reminds me more than a bit of Duke Nukem 1.
by cero
Thu Feb 15, 2018 7:06 pm
Forum: Tools
Topic: Algorithm for splitting sprites
Replies: 70
Views: 13132

Re: Algorithm for splitting sprites

Instead of trying to come up with an algorithm, I thought I'd rather make it easy and fast for humans to do it. After all, humans tend to outdo most algos at things like this. WIP screenshot:
screenie.png
screenie.png (22.51 KiB) Viewed 2252 times