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New Release: KWEEPOUT

Posted: Sun Jun 17, 2012 6:01 pm
by Kweepa
Image
Image

http://www.kweepa.org/step/vic20/kweepout.prg

A version of Breakout (oops!) written in BASIC for the unexpanded VIC.
This was an experiment to see how much I could fit into a BASIC program.
Loosely inspired by this presentation:
http://www.youtube.com/watch?v=Fy0aCDmgnxg
Let me know what you think!

Posted: Mon Jun 18, 2012 2:30 am
by TBCVIC
Very nice! Though that's not Pong, that's Breakout.

Posted: Mon Jun 18, 2012 8:00 am
by Kweepa
TBCVIC wrote:Though that's not Pong, that's Breakout.
DOH!

Posted: Mon Jun 18, 2012 9:48 am
by Mayhem
Kweepout sounds a bit wrong though ;)

Posted: Mon Jun 18, 2012 10:32 am
by Jeff-20
Mayhem wrote:Kweepout sounds a bit wrong though ;)
HAHAHA! That would get my attention a bit faster though!

I look forward to playing this!

Posted: Mon Jun 18, 2012 6:05 pm
by tokra
Nice one! Always pleasantly surprised by your versatility! Action (Doom), Text Adventure (Cometfall), Jump & Run (Blue Star) and now you even rival the Jeff's BASIC skills!

I managed to finish level one but in level two the screen started going crazy. The blanks in the background were replaced with another char, and after a few minutes even the ball was gone. Probably string-variables creeping into the character definitions (since those are written from the top down). Looks like you did not protect your character-definition by something like

Code: Select all

POKE56,28:CLR
like most programs do.

Posted: Mon Jun 18, 2012 6:26 pm
by Kweepa
Gah!
I deliberately didn't do that, because I needed all the space below for the program and variables.
I'm only using one string variable, A$, and during gameplay it's only used to hold the score, so I'm not sure how it keeps growing... Any ideas? There should be 248 bytes free between the space character and the screen.

Posted: Mon Jun 18, 2012 7:20 pm
by GreyGhost
Could you use some of that free space to save the score there. Then read it like you would a low byte - high byte. I haven't played the game yet so I'm not sure how high the score can go, but 3 bytes can hold a number over 15 million.

score = peek(byte 1)+peek(byte 2)*256+peek(byte 3)*65536

Of course it will take a bit of memory to calculate.

if byte 1>256 then byte 2 = byte 2 + 1
if byte 2 >256 then byte 3 = byte 3 + 1

Posted: Tue Jun 19, 2012 12:49 am
by Ghislain
I really should get an sd2iec device so I can try these new games that are coming out. A couple of years ago I made it a point to transfer all of the 'New Releases' via USB to 1541 cable. Emulation is fine, but when you have a real hardware setup, you tend to just want to actually play the games on real hardware.

So I'm going to order an sd2iec device right now. Maybe a second one for my C64 as well. I'm sort of tired of always trying to keep track of what game or program is on which disk, etc.

Posted: Tue Jun 19, 2012 1:49 am
by matsondawson
tokra wrote: I managed to finish level one but in level two the screen started going crazy. The blanks in the background were replaced with another char, and after a few minutes even the ball was gone.
Ah, on my emulator it's immediately broken. Must be because I launch the program by loading it into ram, then sys'ing it.

http://www.mdawson.net/vic20chrome/vic2 ... neType=pal

Posted: Tue Jun 19, 2012 2:49 am
by tokra
Kweepa wrote:I'm only using one string variable, A$, and during gameplay it's only used to hold the score, so I'm not sure how it keeps growing... Any ideas?
Yes, I see the problem. You use:

Code: Select all

A$=STR$(K)
However, this will always reserve new space in memory for A$, until the memory is full and the garbage collection kicks in. To avoid this you can force a garbage collection by caling the FRE(0) function:

Code: Select all

F=FRE(0)
I also noticed you poke the new character set into RAM with your program. You may just include the character set with the file and start with

Code: Select all

POKE45,x:POKE46,y:CLR
where x and y are the true ending of the program. However this might go against your "pure" BASIC agenda

Posted: Tue Jun 19, 2012 6:06 am
by GreyGhost
Also, if you change:

Code: Select all

1 v=36874:fori=.to5:readx:pokev+i,x:next
76 data0,0,0,0,15,14
to:

Code: Select all

1 v=36874:pokev,0:pokev+1,0:pokev+2,0:pokev+3,0:pokev+4,15:pokev+5,14
You will save 10 bytes. Unless their is another reason you did it like that.

You can also put the new character data starting at location 7424.

Then:

Code: Select all

poke52,29:poke56,29:clr
Your first character defined would have to be a space character, and your custom characters will start with the value 32(space), but it will save 256 bytes. And you still have the regular set when reversed.

Hope that is explained ok.

EDIT:
2 more bytes, you have "thengoto" in lines 63 & 64.

Posted: Tue Jun 19, 2012 7:36 am
by Kweepa
Thanks for the detailed analysis!
I had no idea there was lazy garbage collection! You (I) live and learn!
Including the character set definitely goes against my "true" agenda which is a single, type-in-able, file.
For setting the sound and border, unless I'm miscounting, using a loop and data statement (which I combined with existing data) takes 4 bytes less than 6 pokes.
I tried moving the character set further up in memory but without the FRE(0) the definitions got massacred instantly. I know how to fix it now though :)
THENGOTO? Oops! Amateur hour!
I'll knock up a new version soon.

Oh, and for the emulated version, I realize now that I'm using the space character undefined, so it's liable to end up garbage. In VICE it seemed to be ok.

Posted: Tue Jun 19, 2012 9:08 am
by Jeff-20
Ghislain wrote:I really should get an sd2iec device so I can try these new games that are coming out.
You should! For me, everything is straight to a real Vic now. It's great!

Posted: Tue Jun 19, 2012 1:35 pm
by GreyGhost
Kweepa wrote:For setting the sound and border, unless I'm miscounting, using a loop and data statement (which I combined with existing data) takes 4 bytes less than 6 pokes.
Opps. guess early morning hours must be to blame. I am getting a different result than I did last night.

Anyway, gratz on getting it working correctly.