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Welcome to IWETHEY!

New don't need an emulator
I have a 128 in the other room with a uIEC/SD adapter - it makes the SD card look like a 1541. It can mount disk images as well as load/save files to directories on the FAT formatted card.
http://store.go4retr...EC%7B47%7DSD.html

Works great, just wish it supported the 128's Fast Serial mode that's supported by the 1571 and 1581 drives. There's been some progress made on that though:
http://www.commodore....php?topic=3739.0

The uIEC/SD adapter supports the JiffyDOS protocol, so I've been using this:
http://sites.google....C128/JiffySoft128
New Just wondering ...
Do any of you guys working on that stuff think you're sane?
--

Drew
New You haven't spoken to any synthesizor fanatics, then.
I have a 15 year old sampler (an Ensoniq ASR-10). It represents state-of-the-art of about 15 years ago, which means floppy disks, SCSI 1 and 8Mb of RAM.

But that's tame. There are people who still use Ensoniq Mirages: that's SSSD floppies and a few hundred K. Or early E-mus. Or DX-7s. And so on and so on.

Wade.

Q:Is it proper to eat cheeseburgers with your fingers?
A:No, the fingers should be eaten separately.
New Ensoniq EPS here.
Where I got ESQ from I'll never know.

The ESQ is a digital waveform generator. The EPS is a sampler.

23 years old. :-)

I still have the Atari TT030 I used as a sequencer as well.
Regards,
-scott
Welcome to Rivendell, Mr. Anderson.
Expand Edited by malraux May 11, 2011, 11:44:24 PM EDT
New Cool.

Q:Is it proper to eat cheeseburgers with your fingers?
A:No, the fingers should be eaten separately.
New Non sequitur..
(Only those of us running WordStar in 58K on CP/M are demonstrably sane.. the rest have become terminally infected with Bloatison's Disease)

:-0
New sure - it's just a hobby
My current project is another Atari 2600 game, but it's using a cartridge with an ARM processor in it. The ARM runs the game logic, but must hand back control to the 6507* so it can update the video chip.
http://www.atariage....48/cat-59-frantic


I did a 3D wireframe demo using the cartridge last year. It updates the 3D data at 60 fps.
http://www.youtube.c...tch?v=wIrbCsqQEi8

* a reduced package 6502 - it's missing the IRQ line as well as a few address lines which limits it to an 8K address space.
New The cartridge is more powerful than the console? :-D
How odd.

Wade.

Q:Is it proper to eat cheeseburgers with your fingers?
A:No, the fingers should be eaten separately.
New Yep
Still constrained by how video works on the Atari. There's not enough RAM for a frame buffer, so you must update the video chip's registers on every scanline.

There's 76 cycles of CPU time per scanline. One of the more common routines to update a single sprite & it's color (for the common line-by-line color change in later games) takes 26 cycles
   lda #SPRITEHEIGHT

dcp SpriteTemp
bcs DoDraw
lda #0
.byte $2C
DoDraw
lda (GfxPtr),Y
sta GRP0 ;+18 cycles <--- sprite image register
lda (ColorPtr),y
sta COLUP0 <--- sprite color register


For my game Stay Frosty, I used a mask overlay, which greatly increased ROM usage but only took 21 cycles
   LDA (SpritePtr),y  ; 5

AND (SpriteMask),y ; 5
STA GRP0 ; 3
LDA (ColorPtr),y ; 5
STA COLUP0 ; 3


PitFall 2 uses coprocessor, known as DPC (display processor chip), that knocked that down to 14 cycles
   LDA DF0DATAW ; 4 <--- DPC register

STA GRP0 ; 3
LDA DF1DATA ; 4 <--- DPC register
STA COLUP0 ; 3


The ARM cartridge has support to emulate the DPC so you can use it to play Pitfall 2. We modified it to take advantage of the capabilities of the ARM cartridge, such as monitoring what's read from the cartridge so we could override the LDA Immediate mode and reduce that down to 10 cycles.
   LDA #<DF0DATAW ; 2

STA GRP0 ; 3
LDA #<DF1DATA ; 2
STA COLUP0 ; 3


The saved cycles can be used to do other video chip updates, giving you the ability to do better graphics than normal for the Atari. I posted sample code for DPC+, of which the last demo does 29 updates of the video chip over 2 scanlines.
http://www.atariage....-dpc-programming/
New I can see why you enjoy the challenge! :-)

Q:Is it proper to eat cheeseburgers with your fingers?
A:No, the fingers should be eaten separately.
New digitized audio on the 2600
Yes - that primitive hardware can be made to play back digitized samples! It's limited to 4-bit samples. It can easily handle 8000 Hz, but this demo is at 4000 Hz due to RAM and ROM limitations for use in a game.

http://www.youtube.c...tch?v=NEDP0Ch0j8M
New Looks like Tempest ... I loved that game
Oh awesome. The Wikipedia Tempest linked to Space Duel. Loved that one, too.
--

Drew
New Frantic's now playable
Something to remember when viewing this - the Atari only has 2 sprites and 2 missiles.

http://www.youtube.c...tch?v=wRxdl2T8nlQ

The color's didn't come out well with the camera, here's a screen capture video of the new stealth mode
http://www.spiceware...ranticStealth.mov

I'm able to draw all those robots by repositioning the sprites on the fly as the screen is drawn. One of them takes 2 scan lines to reposition, the other 3. The ARM code implements a flicker routine for the instances when there are more than 2 sprites in the same horizontal band. This is noticeable in the screen capture video, especially the first room where there are 5 robots at the bottom of the screen. On a real CRT the flicker isn't as bad as in the screen capture as the phosphors glow long enough to make it more subtle. However, it's not as good as the YouTube video where no flicker is apparent.

If you'd like to try it out yourself you can use Stella.
http://stella.sourceforge.net/

Instructions in the first post, along with a link to the rely with the latest build.
http://www.atariage....560-frantic-2600/
New Reminds me of Shamus
http://en.wikipedia....hamus_(video_game)

Very nice.
Regards,
-scott
Welcome to Rivendell, Mr. Anderson.
New Thanks!
I'd forgotten about Shamus - have it for my Vic 20.
New took a diversion
http://www.youtube.c...tch?v=uErk65UgCpo

in contrast, here's the original version of Asteroids for it.
http://www.youtube.c...tch?v=JEsJJe5y8Kk

To deal with al the objects on the original version they flicker everything. One frame of video displays the ship, enemy saucer, and the player's shots. The other frame draws all the asteroids and the saucer's shots. To prevent further flicker, the asteroids move up/down at a constant rate of speed. This allows one of the two sprites to draw all the upward moving asteroids (as they never cross each other's path) while the other sprite draws all the downward moving asteroids. The only speed variation is in the left/right movement. Some game variations add additional left/right speeds, but they're still quite limited.

In my version I reuse both sprites to draw everything and only flicker if more than 3 objects occupy the same horizontal zone. I always flicker the two missiles and ball in order to draw up to 6 shots (4 for the player, 2 for the saucer)
     Its baaack! - (beepster) - (18)
         saw that a while back - (SpiceWare) - (17)
             The other interesting piece - (beepster) - (16)
                 don't need an emulator - (SpiceWare) - (15)
                     Just wondering ... - (drook) - (14)
                         You haven't spoken to any synthesizor fanatics, then. - (static) - (2)
                             Ensoniq EPS here. - (malraux) - (1)
                                 Cool. -NT - (static)
                         Non sequitur.. - (Ashton)
                         sure - it's just a hobby - (SpiceWare) - (9)
                             The cartridge is more powerful than the console? :-D - (static) - (3)
                                 Yep - (SpiceWare) - (2)
                                     I can see why you enjoy the challenge! :-) -NT - (static) - (1)
                                         digitized audio on the 2600 - (SpiceWare)
                             Looks like Tempest ... I loved that game - (drook)
                             Frantic's now playable - (SpiceWare) - (3)
                                 Reminds me of Shamus - (malraux) - (1)
                                     Thanks! - (SpiceWare)
                                 took a diversion - (SpiceWare)

I wanted to request installing a suggestion box at work, but I had no way of doing it.
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