Search found 825 matches

by tokra
Fri Aug 25, 2017 3:57 pm
Forum: Programming
Topic: Raster split and $9002
Replies: 51
Views: 1637

Re: Raster split and $9002

I couldn't resist and wrote a test-program for the $9000 phenomenon: Download Download Source PAL-VIC20 with at least +8K required. First the program fills the screen with the characters from 0 to 255 twice (just 506 visible, screen ratio still 22 x 23 chars) Then it synchronizes with the raster bre...
by tokra
Fri Aug 25, 2017 2:28 pm
Forum: Programming
Topic: 320x200 - a CGA emulator for VIC-20! (+35K RAM req'd)
Replies: 7
Views: 986

Re: 320x200 - a CGA emulator for VIC-20! (+35K RAM req'd)

Neat! This would have been a good starting point for my "VIC Hunt"-picture which uses exactly the same "pixel"-size (2 wide, 3 high) :D
by tokra
Fri Aug 25, 2017 2:55 am
Forum: Programming
Topic: Raster split and $9002
Replies: 51
Views: 1637

Re: Raster split and $9002

I've played around with ex4.prg a little and found that when using the VICE-monitor to change the value you write to $9000 a little I get a result which looks a lot closer to the real machine. Specifically you write $3f to $9000 at $2257. If I change this value to $44 in the VICE-monitor (>2256 44) ...
by tokra
Thu Aug 24, 2017 3:17 am
Forum: Programming
Topic: Raster split and $9002
Replies: 51
Views: 1637

Re: Raster split and $9002

Coming back to the original problem, I get different effects on the real machine, VICE and yet another different output on z64k.com - the newest VIC-20 emulator. Something real odd is going on here obviously, as the VIC-emulation of VICE has been spot-on until now and all of PWP's demos work fine. b...
by tokra
Mon Aug 21, 2017 4:47 pm
Forum: Programming
Topic: Raster split and $9002
Replies: 51
Views: 1637

Re: Raster split and $9002

(there's still a subtle difference in VICE, it allows for 2-pixel accuracy in the horizontal register whereas real h/w only delivers 4-pixel accuracy), which was anyhow good enough to design MINISKETCH in VICE. Is there already a bug-report for this? I'm sure this would be an easy fix in VICE. Rega...
by tokra
Mon Aug 21, 2017 10:06 am
Forum: Programming
Topic: Custom Char Set and Memory
Replies: 3
Views: 193

Re: Custom Char Set and Memory

There is no RAM under ROM on the VIC-20. That is a special feature of the 6510. On the VIC-20 you can only put custom chars (and the video-RAM) in the RAM-area of the unexpanded VIC ($0000-$03ff and $1000-$1fff). The first 1K-area at $0000-$03ff does not make a lot of sense for custom chars in most ...
by tokra
Sun Aug 20, 2017 3:39 pm
Forum: Programming
Topic: Raster split and $9002
Replies: 51
Views: 1637

Re: Raster split and $9002

I don't know why Marko's 'paper' still is used as reference. His code takes *ages* to do the initial sync of the timer, with a linear search process; he uses two timers, where one is entirely sufficient; and finally the interrupt delay compensation is overly complicated yet it still doesn't work in...
by tokra
Sun Aug 20, 2017 3:57 am
Forum: Announcement Board
Topic: VIC-20 Software Releases of 2017
Replies: 15
Views: 3842

Re: VIC-20 Software Releases of 2017

Name : VIC Hunt Author : tokra Released : Aug, 19th 2017 at the Freestyle Graphics Competition at Evoke 2017 (got 8th place out of 26) Requirements : PAL VIC-20 with at least 8K RAM-expansion to view the image (+32K for using fcbpaint) Description : A hand-pixelled conversion of a scene from the NE...
by tokra
Sun Aug 20, 2017 3:56 am
Forum: General Topics
Topic: VIC Hunt - fcbpaint-image released at Evoke 2017
Replies: 7
Views: 417

VIC Hunt - fcbpaint-image released at Evoke 2017

Name : VIC Hunt Author : tokra Released : Aug, 19th 2017 at the Freestyle Graphics Competition at Evoke 2017 Requirements : PAL VIC-20 with at least 8K RAM-expansion to view the image (+32K for using fcbpaint) Description : A hand-pixelled conversion of a scene from the NES classic "Duck Hunt&...
by tokra
Sat Aug 19, 2017 12:00 pm
Forum: Programming
Topic: Raster split and $9002
Replies: 51
Views: 1637

Re: Raster split and $9002

It would probably be best to try to create a test-case that does not rely on the joystick, but runs automatically. Also make sure everything is initialized correctly. Arukanoido had similar problems with some memory cells not initialized on startup.
by tokra
Sat Aug 19, 2017 11:32 am
Forum: Programming
Topic: Raster split and $9002
Replies: 51
Views: 1637

Re: Raster split and $9002

On a real VIC20 the text block skips position on up/down-movement 3 chars to the left and 1 char down and back again.

Are you sure you do not rely on pre-set values for VIA-registers (timers e.g.)? This might cause such issues easily.
by tokra
Sat Aug 19, 2017 11:21 am
Forum: Programming
Topic: Raster split and $9002
Replies: 51
Views: 1637

Re: Raster split and $9002

beamrider wrote:try moving left and right.... :D

How?
by tokra
Sat Aug 19, 2017 11:02 am
Forum: Programming
Topic: Raster split and $9002
Replies: 51
Views: 1637

Re: Raster split and $9002

IMG_1351.jpg
Real VIC20 PAL


IMG_1352.jpg
VICE 33524


No flicker on real VIC-20 here, although I use a TFT which just MIGHT delete the flicker... the other artifacts are harder to explain. What is displayed here? Could it be memory that is initialized differently on real machines and VICE?
by tokra
Wed Aug 16, 2017 3:29 pm
Forum: Games
Topic: Sprites and Color Clash
Replies: 6
Views: 348

Re: Sprites and Color Clash

Dragonfire by Imagic is in my opinion the most technically impressive one for it's sprite-techniques which predate VIC-20-Pitfall by about 30 years. Just look at the player "sprite" which is in hires-mode, yet has multiple colors, which are kept even when the player jumps. I think it uses ...
by tokra
Wed Aug 16, 2017 6:34 am
Forum: Games
Topic: Sprites and Color Clash
Replies: 6
Views: 348

Re: Sprites and Color Clash

Also see my post here regarding color-clash and how to avoid it.

Pitfall can be found here.

Go to advanced search