Search found 4648 matches

by Mike
Mon Jan 28, 2013 3:28 pm
Forum: General Topics
Topic: What is happening here?
Replies: 33
Views: 10301

I'm quite aware that opening the case and doing modifications on the mainboard is crossing the line for many people. Especially when it's in working order and there's no 'reserve' VIC-20 at hand. But then, how is applying the S-Video mod or internally wiring a uIEC (both of which have been done by o...
by Mike
Mon Jan 28, 2013 2:42 pm
Forum: Programming
Topic: New Platform Game Programming Tool
Replies: 12
Views: 3262

I want to skip redefining characters for mid positions for everything that is part of the decor, while having scrolling smoother than full character. Your routine just needs to take those characters of the background which are located 'beneath' the intended position of the player, and replace them ...
by Mike
Mon Jan 28, 2013 1:41 pm
Forum: Programming
Topic: DO .. LOOP in BASIC V2
Replies: 12
Views: 2116

Actually, in the example I gave, such a DISPOSE NEXT command was not necessary, as the dangling FOR loop gets removed with a NEXT of the further enclosing FOR loop variable. Sometimes it pays off to know a little more about the inner workings of the BASIC interpreter. ;) Likewise, if there's a FOR l...
by Mike
Sun Jan 27, 2013 3:18 pm
Forum: Programming
Topic: DO .. LOOP in BASIC V2
Replies: 12
Views: 2116

Re: improper programming

wimoos wrote:modifying the loopvariable from within the loop is ...
... much more harmless than leaving a dangling FOR loop on the stack. ;)
by Mike
Sun Jan 27, 2013 11:38 am
Forum: Programming
Topic: DO .. LOOP in BASIC V2
Replies: 12
Views: 2116

DO .. LOOP in BASIC V2

I happened to use the following construct quite often lately - the lines: DO <statement> LOOP WHILE <condition> can easily be translated with a FOR loop in BASIC V2 thus: FOR P=-1 TO 0 <statement> P=<condition> NEXT P ... where <condition> is a Boolean expression which evaluates to either -1 (true) ...
by Mike
Sun Jan 27, 2013 4:03 am
Forum: Programming
Topic: New Platform Game Programming Tool
Replies: 12
Views: 3262

Re: New Platform Game Programming Tool

d) I don't know how to handle the collisions between the heroes and decor You could do with either with a simple distance calcution, or an off-screen bitmap to check if the player collides with background features or enemies. Sorry, my bad, I wasn't clear. I mean how to draw the decor and the heroe...
by Mike
Sat Jan 26, 2013 12:06 pm
Forum: Programming
Topic: New Platform Game Programming Tool
Replies: 12
Views: 3262

Re: New Platform Game Programming Tool

a) Does it already exist? Depends. Horizontal scrolling is not too unusual in VIC-20 games. Examples: Splatform , Level edit (also vertical), Dragonwing , ... b) Any problems to expect (apart from finding the time to do it!!!) The difficulty only ramps up if you proceed to pixel-wise scrolling (as ...
by Mike
Sat Jan 26, 2013 8:02 am
Forum: Games
Topic: Randomness in games
Replies: 23
Views: 4485

Re: Randomness in games

PhilRanger wrote:Better watch out for differences between versions though (PAL vs NTSC, etc.). Is this an issue on the VIC?
The KERNAL ROM is different between PAL and NTSC (VIA Jiffy clock and RS232 register values, and VIC register values), but the BASIC ROM is the same.
by Mike
Sat Jan 26, 2013 7:19 am
Forum: General Topics
Topic: What is happening here?
Replies: 33
Views: 10301

The two 4416 chips are exactly what I need for the VIC-20 extended color ram! NO!!! The 4416s are DRAMs, they have a completely different pinout and method to signal them. What you need is a 16Kx4 SRAM, like the CY7C164 I used. Alternatives are the Hitachi HM6788P-35 and Intel P51C98-45. See this p...
by Mike
Thu Jan 24, 2013 2:54 pm
Forum: Games
Topic: New Release: Doom
Replies: 328
Views: 95773

NTSC + Final Expansion 3 -> broken Could it be the Easy Wedge was active by chance with this combination? In that case, the memory between $0400 and $0FFF is write-protected by FE3, and Doom can't use it anymore. I'd try the combination I/O Register on (R, x), Easy Wedge off (W, .) and All RAM (F7)...
by Mike
Sun Jan 20, 2013 3:16 pm
Forum: Programming
Topic: MINIGRAFIK batch processing suite
Replies: 55
Views: 49861

Today I wrote a small program, which plots the Barnsley fern ( download ): 1 FORI=0TO3:READA(I),B(I),C(I),D(I),E(I),F(I):NEXT 2 POKE36879,8:POKE646,5:@ON:@CLR:X=0:Y=0 3 @1,16*Y,39.5*X+86.5:P=RND(1):I=-(P>.01)-(P>.86)-(P>.93) 4 U=A(I)*X+B(I)*Y+E(I):V=C(I)*X+D(I)*Y+F(I):X=U:Y=V:GOTO3 5 DATA 0 , 0 , 0 ...
by Mike
Thu Jan 17, 2013 3:54 pm
Forum: Programming
Topic: Hires Graphics
Replies: 111
Views: 88511

PM sent.
by Mike
Thu Jan 17, 2013 1:53 pm
Forum: Programming
Topic: Hires Graphics
Replies: 111
Views: 88511

Hi, lordbubsy, it's rather strange to see this thread revived after nearly 4 years. :) I’ve read this thread and I’d love to have commented sources of MINIGRAFIK! Especially the @CLR, @RETURN, @LOAD and @SAVE parts ([...]) @RETURN is rather easy, it just calls $E518 to reset the VIC registers and in...
by Mike
Tue Jan 15, 2013 2:32 pm
Forum: General Topics
Topic: Vic-20 Service manual or vic parts list
Replies: 2
Views: 1649

It's stored on DLH's Commodore Archive:

The Friendly Computer Technical Manual, Model VIC-20

It contains the schematics of both (major) board revisions as well as a parts list, views of the PCBs, component diagrams, and a page describing how the keyboard matrix is wired.

Greetings,

Michael
by Mike
Thu Jan 10, 2013 12:45 pm
Forum: Programming
Topic: ML noob
Replies: 12
Views: 1464

Might be an idea to include a note as to which assembler / language-extension you need to build this, as it's certainly not DASM... :wink: It's the inline assembler of HI BASIC, an implementation of BBC BASIC running on the BBC Micro expansion unit . Oh...kay. So, in a thread started by a self-conf...