Denial

For this purpose, what's wrong with assuming a 40 column display? That way, someone can easily read the documentation on any CBM 8bit. Your reader could either invoke a VIC20 specific 40 column displayer, ... When I use a full 160x192 bitmap, I get 40x24 characters,[...] However, it wouldn't give a...

I still wonder, why the display is off center in the normal case (in VICE, at least): subtracting 1 off the register 36864 would yield a centered screen then. VICE does a good job of showing more or less what's in the output signal. I think it's actually off by one pixel--showing one less pixel in ...

The current version of the code is: tya lsr lsr lsr tay ; y>>3 --> y lda ROWTAB,y asl sta WORK lda #SCREEN/512 rol sta WORK+1 ; SCREEN+(y>>3)*22 --> WORK, WORK+1 And yes, it must be 22 columns so ROM print routines can be used without...interesting issues. 16+23 bytes, 26 cycles. I use lda #SCREEN/5...

On a Commodore 1702 monitor, it overflows both on the left and right sides. I can adjust the horizontal position knob on the monitor to see the left edge or the right edge, but not both at the same time. The right edge does not show the entire 25'th column. It only shows the left half of the 25th co...

What sort of "bad stuff" might happen if you use locations 217-240 -- the screen line link table? Am I correct in assuming they will neither be accessed or overwritten if you avoid all of the following? 1) Print RETURN, <shift>-RETURN, INSERT, CLR HOME 2) Print something into the right col...

I wrote in more optimizations, and more bloat...it's now 911 bytes big, but it's nice and fast (for small patterns). :D http://members.cox.net/mechdan/vic/dynalife3.prg http://members.cox.net/mechdan/vic/dynalife3.asm ...Even with all of this bloat, I'm surprised at how long it takes for it to fail ...

I wrote in some speed optimizations, although this has increased the size to 799 bytes

http://members.cox.net/mechdan/vic/dynalife2.prg

Here's the source code:

http://members.cox.net/mechdan/vic/dynalife2.asm

Obviously you're not restricted to 160x192. 208x256 pixels are easily possible on a PAL VIC-20; 200x208 pixels should be in order on a NTSC machine. I wrote the dynavic routines around a 160x192 resolution because that way the screen matrix would fit within 256 bytes. That greatly decreased the siz...

I was going to ask if there was any inherent reason why you couldn't do 160x192 version for an unexpanded VIC...but then I figured it would be faster for me to answer it myself (by implementing it). I'm not familiar with algorithms to do Game of Life computations quickly, though. My program works, b...

I've written "Dynavic" graphics routines in DASM which allow 160x192 graphics on an unexpanded VIC. 8) Dynavic utilizes whatever RAM is left over after the end of your program for dynamically allocated custom characters. If you try to draw a pixel in a blank block when there are no more av...

...it's not yet fully debugged... I should have said "tested", rather than "debugged". I've been testing my code, and I actually haven't unearthed a single bug yet. Given the sheer amount of stuff going on with bit twiddling, linked list manipulation, table lookups, and such...p...

update: I bit off more than I knew with my plan to use dynamically allocated character graphics. I had to write it in order to realize how complex the task would be. I've now written code for dynamically allocated TESTXY, SETXY, and RESETXY; it's not yet fully debugged. It conceptually uses 3 65byte...

I rewrote the input code, added custom graphics, and even added a "transporter" special effect. 8) http://members.cox.net/mechdan/vic/robovic2.prg The source code could be tightened up a bit, now that I realize that it's okay to simply set bx and mx to zero. The references to "pc"...

Slick! I just tested, and you can place more statements after an ON ... GOTO. That sure opens up more possibilities.

You can tighten it up slightly by replacing ABS(A$="") with -(A$=""). Another option if the opposite logic is requires is to use ONLEN(A$)GOTO{keyroutine}.

Thanks for the compliments and comments! I really appreciate it. I've made another improvement, changing the enemies with each level. Even though it's only a graphics change, it's a really important touch. It feels a lot better getting to the next level when the enemies look different. Here's the pr...