programming

Take a computer and make it do what you want. Does not apply to VCRs.

Apple ][ Graphic Adventure Part V

Now that my memory issues are seemingly under control, let's take a look at my modifications to the parser. Normally, in these types of graphical adventures the player enters two words in the form of VERB OBJECT. My interface limits the number of verb choices and allows the player to enter a verb with a single keystroke.

In Applesoft you can prompt for user input in two ways. First there is INPUT A$ which will display a question mark on the screen and await user input followed by a RETURN. That user response then fills the variable A$. Similarly there is GET A$ which also displays a question mark but GET will only accept a single keypress as user input. My main problem with both of these is an aesthetic one: that darn question mark.

The solution is to write your own input routine…

Apple ][ Graphic Adventure Part IV

Previously I discussed the overall structure of my soon-to-be hit adventure game. Well, last night was a milestone. I managed to write an Applesoft program so epic that it overwrote the high-resolution graphics page. Compared to other programs I have seen, mine isn't that huge. Around 250 lines isn't that huge, right? Transylvania clocks in at 464 lines.

I think the issue is the number of arrays that I am defining. For now I think I have a fix. I have set LOMEM: 24576 at the top of my program. Supposedly, this will force the interpreter to define variables in a memory location after the hi-res pages. We shall see.

In any event, the game is back and running again. And the text screen now has some text formatting enhancements:

Text Adventures in Text Adventures

One of the cooler things I have implemented is this text screen. If…

Apple ][ Graphic Adventure Part III

The previous post in this series explained how to get Graphics Magician images to display from Applesoft. Now, I'd like to go over the structure of the program listed in Write your Own Adventure Programs. The bulk of the program listing consists of the game data including objects, room descriptions, verbs and state flags. Most of the remaining code is comprised of a series of conditions that check how the player's actions affect the objects in the game world.

Verbs

Haunted House used a simple, two-word input parser: VERB NOUN. But I wanted this new game to simplify the number of verb choices in the same way the LucasArts adventures streamlined the interface of Sierra-style adventure games. The player will be limited to around a dozen verbs that are entered with a single keystroke.

Verb List

The verb…

Apple ][ Graphic Adventure Part II

In my previous post I wrote about the impetus behind this project. To start, I knew that my code was going to be structured around the Haunted House program in the excellent book Write your Own Adventure Programs for your Microcomputer. As I have written before, this book was crucial in my development as a programmer (I haven't developed much beyond it). I would love to do this project in 6502 machine code and I have been trying very hard to learn 6502 assembly programming. But, although I've gotten a better understanding of machine code, there's serious lack of noob-friendly practical learning exercises available out there. Sure I can draw pixels at lightning speed, but, after reading most of Assembly Lines, I still have no idea how to do a simple INPUT command or mimic an array.

So…

Apple ][ Graphic Adventure Part I

Having recently played the Apple ][ game Transylvania and its sequel, I was inspired to mess with the art program which those games used. The Graphics Magician was a huge hit for Penguin Software, but I never actually had a chance to use it when we had an Apple ][. I just remember it being advertised in every computer magazine I had.

My go to art program back in the day was always Alpha Plot from Beagle Bros. It wasn't the easiest software to use. In fact, it came bundled with a cardboard overlay for your keyboard so you had an immediate reference as to what the various keys did. Still, I managed to draw pixel by pixel and create masterpieces like this:

GROSS by Robert William Gomez

The Graphics Magician is something altogether different though. Instead of meticulously drawing each point on the screen, you create images…

Apple ][ Assembly Language Programming

The past few weeks I have been diving into the world of assembly language programming on the Apple ][ computer. My interest in the topic stems from the recent book release of a compilation of articles on assembly language programming called Assembly Lines: The Complete Book. The articles were written by Roger Wagner and originally published in Softalk magazine back in the early eighties. This edition was edited by Chris Torrence and is available for download and purchase from a number of locations.

Now, I am pretty familiar with Applesoft Basic programming, but I was always in awe of commercially released software on the Apple ][ that ran so fast, had fancy hi-res graphics and used sounds other than the system beep. What was the secret of these mythical programs that required you to type…

My First Foray into SASS

As I mentioned a few posts ago, this site has received a major theme overhaul. Aside from a couple form element styles, this change was mostly structural and behind-the-scenes. The new theme is my first foray into using the SASS CSS preprocessing language. Let me tell you, it was a revelation. SASS allows you to write CSS using a super-clean tabbed coding style and (finally) allows the use variables and expressions in styles. I mean, look at this OCD coder's dreamscape:

Behold the beauty of SASS!

Gone are curly brackets and semi-colons. Now elements can be nicely nested within each other and there's lots of neat shorthand to make code more portable.

Now, I am very late to this party and it turns out much of the SASS code you find on the net is written in a more standard CSS syntax (those sass files are saved as .SCSS…

Haunted House Text Adventure

"Dippy Golf" - Another Apple ][ Game I Wrote as a Kid

After posting Malfunction, my text adventure game for the Apple ][, I have been spending a whole bunch of time tinkering with my old Apple ][ software creations. Another one of my better creations was a golf game that I titled, Dippy Golf. This game featured nine holes which were loaded in from external graphics files and, even more impressive, was the use of audio samples of my voice! The game worked but still felt somewhat unfinished, so I decided to complete the game and post it here on the Pages of Fun!