itch.io

For my game "Revisiting the Exit" from last years contest, control codes were used extensively just to squeeze it into the PUR-120 category and for my code explanation I took screenshots with the code, explained what the standard command was for the most part (don't know why I didn't have it for the SYMBOL data though), and just had comments following that. I explained below how the Control Codes were obtained via keyboard, as well as the condensed characters through the use of CHR$() and Cursor Copy.  Magazines wouldn't have appreciated such a listing back in the day due to the control codes, though for this contest every keystroke matters.

Cheers, Ross.

Cool, initially I was hoping to squeeze it into 8 Lines, though had to go the full 10, still managed to get your Program Remarks in, though had to go on the same line. 

Apart from the Grid, everything else is PRINTed in using Redefined Symbol DATA (240..247), TAG & TAGOFF, using a Control Code to switch on the Graphics Write mode (prevents damage to the Grid). The initial Knight is Placed and Filled in using Redefined Symbol DATA (248..255). I would have got away with Drawing the Knight shape as your example shows, though needed to extract the Shape of the Knight to work out where the FILL needed to occur. Once I had that and worked out where the Number '1' was placed, I had the shape to Redefine Chars 248 to 255. In your version I noticed the FILL didn't reach behind the lower half of the Knight and the Number '1', though decided to hit that area anyway.

With all the Redefined Characters though, I had to Compact it right in to make it fit, CHR$(0) is used quite a bit which Cursor Copy cannot extract and CHR$(128), which Cursor Copy confuses as CHR$(32) needed to be defined as z$ and b$, while Redefining the Characters (hence the reason for their presence in those initial lines).

Cheers, Ross.

Hi Jason,

I've been working on your Knights Tour to produce an All CPCs counterpart. Guess I'll be in touch though your website.

Ross.

Hi, unfortunately there's a Syntax Error in Line 47:

Change: 

IF xnuage1=<4 THEN sensnuage1=1

To:

IF xnuage1<=4 THEN sensnuage1=1

BASIC 1.0 won't accept 'xnuage1=<4' reporting it as Syntax Error.

The problem has been corrected in BASIC 1.1.

No Worries, Sunday 22nd March 6pm Central European Time is the deadline just in case you're able to find some time to update and Gunnar is usually happy to receive new updates.

Thanks, it uses lots of abbreviated control codes in abbreviated print statements to get the job done, a nightmare to type-in if published in a magazine.

In your game, I got it down to one TEST from working out the top pixel of your alien critter. So TEST obviously uses Graphical Coordinates, the game is in MODE 0, x=10 and y=5. So I do the sums initially:-

-32+(10*32) =288

398-(5*16)=318

This gives the top-left hand corner of the next line below your Spaceship, however the point tested won't register with the Alien because it's using the next point along, so to TEST that spot simply 

288+4 =292 (I'm adding 4 because it's MODE 0), so with those values in play, I can simply say:

gx=292:gy=318 - which can go after the x & y declared in line 20.

In line 40 which deal with your controls I have to now put gx=gx+32 after x=x+1 and gx=gx-32 after x=x-1, I actually changed this line from INKEY$ to INKEY(), INKEY$ unfortunately is slower than INKEY(), though in my code I'm limited to Moving my Space craft Left & Right. I have written an alternative 4 way directional movement which is used in my Finding the Exit games, Revisiting the Exit uses JOY(), which is also acceptable for this style of game. My version actually removes the FRAME.

In Line 70 where the Collision Test is carried out I've simply got p=TEST(gx,gy):IF p<>0 THEN 100 - so now if an Alien has been detected TEST picks up that and since the Scenery is a Solid Block, that's detected as well.

Here's a program I made back in 2020,:

https://www.cpc-power.com/index.php?page=detail&num=17284

Of a character moving across the screen over some scenery and how much time it takes between COPYCHR$(#0), the 2 examples using TEST - one using Formulas and other more Direct values as well as the Array. The Array comes out the fastest, though isn't practical for fast moving games like this, though as I mentioned earlier TEST can either be slower or faster than COPYCHR$(#0), depending on how it's applied, the simpler the equation works better in that case, which is how I've approached it here.

I did some small changes because the game seems to end in a very narrow cavern unable to progress into. I changed the width variable in line 60 to: w=w+(w>2 AND RND>0.8)-(w<8 AND RND>0.95) which presents some tricky cavities to negotiate, though presented some larger Scores, so I had to end up moving the High score to the  Opening Page and just show the Score at the top of screen.

Anyway, there just some suggestions.

Yes, it's not Compulsory to write it in BASIC 1.0 and in the past entries weren't rated based on which BASIC they could or couldn't work on unless someone said "Here's my Game it's for the Amstrad CPC 464/664/6128 and Plus Range", though I don't know that for sure.

It's simply a view I hold that Games should be able to run on any machine, though Get some of those things become difficult when 10 Lines is concerned - normally it's the extra parameters in the graphical commands which leaves BASIC 1.0 behind in the amount of space saved. 

Though take a look at my game "Revisiting the Exit" from the 2025 contest, it's PUR-120 though had to work hard to get it like that and it was a reworked version between "Find The Exit" from the 2022 in the PUR-80 and "Find the Exit Red" from the same year in the PUR-120.

Thanks for the update, I did some poking around so feel free contact me at "out_bush at hotmail dot com", I made some changes to the control system and my version only needs one TEST, depending on how TEST is used, it can either be faster or slower than COPYCHR$(#0).

Locomotive BASIC 1.1 Only :(

It's a nice game, though on a few occasions Your player is placed next to the Big Bad Stupid Diamond Eater and that it's following your every movement! 

Perhaps Move the Player and Nasty opponent to the opposite ends of the Maze and make the Diamond placement in a random spot starting from more the Players side and move it further towards the Nasty opponents end as the game progresses?

I wasn't sure if Vice would run on my new Mac System, though it looks like this is running fine and Munchy plays as described in the notes. Unsure how fast the game speeds up, I got it to 148 when it was nearly a wall of Red Mushrooms.

Yeah I think it's a nice game too! 

Wants me want to try something on my CPC, though the MSX has some advantages in the coding here.

It's Frogger for the MC10! 

Thanks Marco!

Hi folks, I'm the author of this entry and I just wanted to say if finding an emulator to play my game is too difficult, I found another emulator available for Windows, Linux and MacOS which I was able to Download and play my game on.

I'm using the latest MacOS version of CPCemu v2.5, which is available here:

https://cpc-emu.org/download.html

After the file is downloaded and initially executed it will ask which language you want and what keyboard, I just select English, though the Amstrad CPC computers did come in QWERTY keyboards (English nations) as well as AZERTY (other European Countries).

Any key can be pressed when this screen appears.

Now the Blue Amstrad Opening Screen Appears, we now need to Pull Up a Menu, I do this on my Computer with the Command Key with the Hash Symbol which displays the Mouse Arrow, followed by clicking the Mouse Button:

the menu appears, now use your mouse pointer to select the 3rd Icon of the Disk that I've selected with the Red Box.

A Box Appears, you can now select Insert Disk A:

A DOS style Directory Box now appears to allow you to select a DSK image with a Directory Path in Red below. On my computer I have the Emulator in my Downloads as well as my Folder to my game. To get to it select the ".." to take you to the previous directory, you may need to do this several times before you see something like 'path = /Users/<username>/Downloads/', if 'Revisiting the Exit' is in there select that and then select the 'dsk' image (as pictured).

Selecting that the game now starts, though it won't work until Joystick is selected.

To do this press the Command key and use the Mouse to Select the "Spanner/ Soldering Iron" Icon.

A long list of items then appears, the one I found that works best is Cursor Keys as joystick 0:

this value needs to change to 1 which can be adjusted using the right arrow key, once that's done Okay can be selected with the changes in place ready to play the game.

Enjoy!

I had something similar in the CPC version which just Freezes. 

Unfortunately the CPC DSK image isn't working for CPCBox:

https://retroshowcase.gr/cpcbox-master/index.html

returning: "[DSK Parser] Error: Invalid DSK id"