Search found 148 matches

by thomas3
Mon Aug 03, 2020 9:50 pm
Forum: Coding
Topic: Best C2P routine?
Replies: 4
Views: 208

Re: Best C2P routine?

Couple of things. 1) on ste you can change the video address pointer on interrupt to copy lines at almost no cost 2) for 2x2, some algorithms allow you to hold four copies of your texture (each consisting of masks for chunky pixels 0, 1, 2 and 3 for each 8 real pixel block) which means you can skip ...
by thomas3
Sat Aug 01, 2020 10:59 am
Forum: STOS
Topic: New STOS modules, including syncscroll
Replies: 1
Views: 217

New STOS modules, including syncscroll

Hi all, Been a while since I've done anything with STOS, but I've made a couple of things to share. 1) I've converted the Evl/DHS syncscroll to work in STOS. Joystick input still works, and Missing Link timer B commands such as palsplit and raster SHOULD also work. There are still some relatively sm...
by thomas3
Fri Jul 31, 2020 7:30 pm
Forum: Coding
Topic: How to perform vertical scrolling of the screen?
Replies: 9
Views: 468

Re: How to perform vertical scrolling of the screen?

On ST, you cannot do a vertical scroll as simply as you can do on STe by changing the screen address. You have to use the syncscroll technique that is not so obvious. If I remember well there should be several posts in the forum that describe how it works. I haven't found any useful info on syncscr...
by thomas3
Wed Jul 29, 2020 7:57 pm
Forum: Coding
Topic: How to perform vertical scrolling of the screen?
Replies: 9
Views: 468

Re: How to perform vertical scrolling of the screen?

Depending on how much memory you're willing to burn and the size of playfield you are working with, you can also hold several preshifted copies of your screen (e.g. 4, each shifted by 2 lines) and then add multiples of 1280 to your screen addresses to shift in 8 line units. Zero processor time!
by thomas3
Tue Jul 07, 2020 10:14 am
Forum: Demos - General
Topic: SOMMARHACK 2020 - just started!
Replies: 8
Views: 879

Re: SOMMARHACK 2020 - just started!

The chat was lolz, but probably for the best that it wasn't recorded ;)
by thomas3
Mon Apr 13, 2020 6:38 pm
Forum: Ym rockin'
Topic: Looking for tune in SNDH archive
Replies: 2
Views: 410

Re: Looking for tune in SNDH archive

mOdmate wrote:David Whittaker - Weird Dreams #1: https://demozoo.org/music/116144/

Demozoo lists 12 productions using this tune.
Ah I suspected it was Whittaker! Credits on the demo are wrong. Thanks!
by thomas3
Mon Apr 13, 2020 3:03 pm
Forum: Ym rockin'
Topic: Looking for tune in SNDH archive
Replies: 2
Views: 410

Looking for tune in SNDH archive

Hello. I'm looking for an SNDH rip of the Mad Max tune from the second Vector screen (Vector the crew) in the European Demos. (its at the four hour mark on this video - https://m.youtube.com/watch?v=6Z8F5WL7VWg) Does anyone know its title in the SNDH archive? Also, a question for archivists - anyone...
by thomas3
Sun Apr 05, 2020 9:05 am
Forum: 680x0
Topic: synclock twice in a vbl
Replies: 8
Views: 1329

Re: synclock twice in a vbl

Hi Michael,

Glad it helped. Although I've never looked into it, I'm sure that gvodan would use syncscroll. The question is, how, in relation to the overall effect... ;)

Tom
by thomas3
Thu Apr 02, 2020 6:49 am
Forum: 680x0
Topic: synclock twice in a vbl
Replies: 8
Views: 1329

Re: synclock twice in a vbl

Hi Michael, So, all timers all have various ways that they can be configured, and also run at different priority levels. You can absolutely have multiple timers set at the same time. Timer B ticks once per scan line, but only in the visible area of screen. Timer A, conversely, can be configured more...
by thomas3
Wed Apr 01, 2020 6:13 am
Forum: 680x0
Topic: synclock twice in a vbl
Replies: 8
Views: 1329

Re: synclock twice in a vbl

Thanks both!

That solution is beautifully elegant and exactly the kind of thing I was looking for. Thank you so much!
by thomas3
Tue Mar 31, 2020 12:50 am
Forum: 680x0
Topic: synclock twice in a vbl
Replies: 8
Views: 1329

Re: synclock twice in a vbl

UPDATE: well i fixed it, but lost some cycles in the process. depending on whether the syncscroll offset was a multiple of 320, the timer B hardsync was delayed by exactly 16 nops. i hacked out a solution but if anyone knows something neater, that would be great. (also need to test it on different T...
by thomas3
Mon Mar 30, 2020 9:55 pm
Forum: 680x0
Topic: synclock twice in a vbl
Replies: 8
Views: 1329

synclock twice in a vbl

here's one for you clever guys out there. so i'm using a standard syncscroll sitting in a timer A. i then want to have a second synclocked effect in a timer B... let's say half-way down the screen. for the sake of argument, let's say this is a rasterspam plasma or something. i don't need or want the...
by thomas3
Sat Feb 29, 2020 5:03 pm
Forum: CosmosEx
Topic: CosmosEX 3.0
Replies: 209
Views: 91540

Re: CosmosEX 3.0

When/if these things hit the street...
If anyone who is receiving one has an older version of CosmosEX that they wanna sell...
Message me :)
by thomas3
Thu Feb 27, 2020 8:39 pm
Forum: Games - General
Topic: Favourite 3D games that look visually pleasing?
Replies: 34
Views: 5256

Re: Favourite 3D games that look visually pleasing?

Used to love Resolution 101 as a 10 year old
by thomas3
Thu Feb 13, 2020 12:51 pm
Forum: Coding
Topic: Decreasing colours (algorithm)
Replies: 17
Views: 2121

Re: Decreasing colours (algorithm)

(...) for mixing together via interlaced frames to get you an effective palette (~100 colours?) simply with interlacing. Interesting tech but... 50Hz on a CRT is awful but interlacing frames? Wouldn't that flicker even more? Seems I am aiming for the impossible. So maybe I choose Spectrum 512 witho...
by thomas3
Wed Feb 12, 2020 3:31 pm
Forum: Coding
Topic: Decreasing colours (algorithm)
Replies: 17
Views: 2121

Re: Decreasing colours (algorithm)

Hey. One thing I'd be thinking is that the cycles taken to use movem.l to load 32 bytes to registers and then write these 32 bytes back to the palette, along with the time taken to handle the interrupt, will mean that your palette changes somewhere to the right of the left border. So you will have s...
by thomas3
Thu Dec 26, 2019 2:58 pm
Forum: Games - General
Topic: Lotus Esprit Turbo Challenge - STE enhanced (WIP)
Replies: 52
Views: 14805

Re: Lotus Esprit Turbo Challenge - STE enhanced (WIP)

The original car/scenery rendering code is heavily optimised and makes use of unrolled loops and self-modifying code. I'm not entirely sure that I can surpass the performance of the that code with the Blitter. Ah, so, that explains why the game ran so fast anyway. Nice to see that clever/dirty code...
by thomas3
Wed Dec 25, 2019 11:07 am
Forum: Games - General
Topic: Lotus Esprit Turbo Challenge - STE enhanced (WIP)
Replies: 52
Views: 14805

Re: Lotus Esprit Turbo Challenge - STE enhanced (WIP)

One of my favourites from back in the day. Thanks for doing this!!
by thomas3
Sun Nov 03, 2019 6:34 pm
Forum: 680x0
Topic: fastest way to copy a memory block in 68060 assembly
Replies: 18
Views: 6823

Re: fastest way to copy a memory block in 68060 assembly

evil wrote: Second try, movem.l with the source data scrambled backwards, so we can use (an)+ for source and -(an) for destination.
The most obvious gfx optimisation I never thought of, part #4822 of an eternally ongoing series.......
by thomas3
Sun Nov 03, 2019 1:01 am
Forum: 680x0
Topic: fastest way to copy a memory block in 68060 assembly
Replies: 18
Views: 6823

Re: fastest way to copy a memory block in 68060 assembly

swapd0 wrote:something like this.

rept 64*1024/13*4
movem.l (a0),d0-d7/a2-a6
movem.l d0-d7/a2-a6,(a1)
lea 13*4(a0),a0
lea 13*4(a1),a1
endr
You can lose all the a0 leas and almost all the a1 leas by using (a0)+ and then addressing to d(a1).
by thomas3
Fri Oct 18, 2019 8:31 pm
Forum: 680x0
Topic: Bus error caused by YM buzzer?
Replies: 5
Views: 3542

Re: Bus error caused by YM buzzer?

Are you using Steem debug? If so, you can catch the point at which you are getting the crash and check reg values.
by thomas3
Thu Oct 17, 2019 11:02 pm
Forum: 680x0
Topic: unsynchronous fullscreen-routine
Replies: 29
Views: 10049

Re: unsynchronous fullscreen-routine

Programming fullscreens on hatari usually ends with not working on real hardware. You get flicker issues, plane shifting, and if you use keyboard and dma, you get delays. So expect a little fixing-phase on the real hardware. Thanks for the advice ! Do you know if some emulators are more accurate th...
by thomas3
Thu Oct 17, 2019 7:26 am
Forum: News & Announcements
Topic: Do you think the limitation to RE-edit the messages in Atari-forum is appropriate?
Replies: 27
Views: 7540

Re: Do you think the limitation to RE-edit the messages in Atari-forum is appropriate?

Rest assured that a lot of people can't wait for another post in such essential and classic threads as "Atari clothing and accessories", or locked polls that get shot down in a blink of the eye, or dust cover threads, or selling random midi hardware. In fact, they're so flabbergasted by the quality...
by thomas3
Wed Oct 16, 2019 10:48 pm
Forum: 680x0
Topic: unsynchronous fullscreen-routine
Replies: 29
Views: 10049

Re: unsynchronous fullscreen-routine

@uko

Nice. What kind of effect are you planning to use this for?
by thomas3
Sun Sep 29, 2019 3:00 pm
Forum: 680x0
Topic: Help a n00b make a music disk! YAY! :D
Replies: 20
Views: 7540

Re: Help a n00b make a music disk! YAY! :D

Hey YQN! The rept/endr/set thing.... These are what are called macros. They are just directives for the assembler, rather than actual code that gets assembled. Rept and endr simply repeats the text in between them before assembly, and the a variable similarly is replaced by its value before the code...

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