This is a pretty good overview of the roots of (mostly) right-wing Internet subcultures and trolls with a little fair-and-balanced lip service given to SJWs too. I guess the main thesis here is that the Pepe crowd is the direct decedent of 60s left-wing transgressive counter-culture. The most extreme and abusive side of 4chan culture is on display and, as a reader, I was adequately repulsed by it. However, I feel there is a fun, creative side of the trolling culture wars that gets a little lost in her narrative.
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 leveraging machine code routines via
POKEs. To do this, first I simulate a cursor by placing a flashing underscore character at the bottom of the screen.
101 VTAB 24 : HTAB 1 : CALL -868 : PRINT ":"; : FLASH : PRINT "_"; : NORMAL : GOSUB 55
A lot is going on in this line. The
HTAB commands position the screen cursor at line 24 and character 1.
CALL -868 is a special machine code call that clears that single line of text. Now that we have an empty line we type a colon and then a flashing underscore. The result looks like this:
This looks like a user input prompt, but at this point it does nothing. The magic happens at the subroutine which is GOSUB’d at the end of that line.
55 KEY = PEEK (49152) : IF KEY < 128 THEN 55 56 IF KEY > 224 AND KEY < 251 THEN KEY = KEY - 32 : REM UPPERCASE 57 POKE 49168,0 : BUZZ = PEEK (49200) : RETURN
In line 55 we are creating a variable KEY and assigning to it the contents of memory location 49,152 to it ($C000 for you hex-heads). Turns out location 49,152 will read the keyboard and return the ASCII value of the currently pressed key. If that value is a character then we break out of the loop and go to line 56.
Line 56 insures that, if the ASCII value of the key denotes a lowercase key, it is converted to uppercase by shifting the ASCII value.
POKE 49168,0 clears the keyboard buffer so that the PEEK in 55 will work next time around and not just register the same value. Finally, that
BUZZ = PEEK (49200) bit triggers a speaker click so that the player’s keystroke has and audible sound.
When we return to the main game loop we now have a variable KEY which contains an ASCII value of the key pressed. I can then branch the program based on this value. I can also test if it’s a RETURN keypress and then toggle text display. Later in my program I can concatenate keypresses into a single string value by returning to that subroutine again and again until a return press is detected. That’s how I collect the OBJECT half of the VERB OBJECT pair.
Apocalyptic dystopia from a libertarian perspective. Biases confirmed! In this story it’s not war, plague or environmental catastrophe that brings the end times, it’s the devaluation of the U.S. dollar. This is a far more likely scenario than we’d like to think and the author does a great job in showing how it would gradually affect a regular family. In the early parts it feels like a tale of what happens to all the normal people in the world of Atlas Shrugged.
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:
One of the cooler things I have implemented is this text screen. If at any prompt you hit RETURN you turn off the hi-res graphics and can see this text screen. Here will be some valuable game info included the location’s name, exits and any TAKE-able objects. The code for this is rather simple:
58 IF GM = 1 THEN GM = 0 : TEXT : RETURN 59 GM = 1 : CALL -3100 : RETURN
GM is a flag which tracks where you are in graphics mode (1) or text mode (0).
CALL -3100 triggers the hi-res graphics screen without erasing its contents. So exciting, right!?!
Another one of these sub-culture documentaries which follows the formula: Identify sub-culture, show the originators, show the people who “took it to the next level”, and finally show how this sub-culture has infiltrated mass culture. This time it’s all about music that uses the Roland 808 drum machine. The big takeaway here is that, after an hour an a half, I don’t ever want to hear another 808 beat again.
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.
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.
The verb list is largely based on the options in Monkey Island. PUSH and PULL have been combined into MOVE. To move you must hit Go then enter either North, South, East, West, Up or Down. This is a little annoying, but there are only so many letters in on the keyboard and I needed that D, U and S elsewhere. Other commands require you to hit the keystroke, then type out an object NOUN and then hit Return. “Guess the verb” will no longer be an issue… welcome to 21st century “guess the noun” technology!
Each verb then get’s its own subroutine which contains the logic that triggers the various game actions (or provides a default message if nothing special happens). By assigning a number value VB to each verb, I can use the following to branch to the various subroutines:
ON VB GOSUB 1000,600,800,850, ...
The game data is set in the program by assigning strings and numbers to several arrays. In Applesoft you need to declare the size of an array by dimensioning it with the
DIM command. For the rooms I will set the size of the rooms array to the number of rooms RM by declaring
DIM RM$(RM). Then, near the start of my program I read data into the array by using
GOSUB to a loop like this:
5000 DATA "Room description 1","Room Description 2", [...] 5005 FOR I = 1 to RM : READ RM$(I) : NEXT 5010 RETURN
DATA can be listed anywhere in the code and it’s important to make sure that there are exactly as many data strings as
READ commands. Otherwise, you might get
OUT OF DATA errors.
This method of declaring rooms and object will eventually make your Applesoft program very long and hard to edit. I was pretty sure that I could figure out a way to read the data in from an external text file. But more on that later.
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, Applesoft BASIC it is! With emulation and modern computing I have been able to develop my code on a Windows PC and then quickly run it in emulation. My workflow isn’t nearly as fancy as some other retro-programmers. I type my Applesoft in a text editor, then in AppleWin I paste the entire code listing into an emulated apple using SHIFT+INSERT. The benefit of using emulation as a development environment is that you can throttle the emulation to run hundreds of times faster (hit ScrLK) than real hardware. This makes testing small changes a breeze.
My first task was to see if I could successfully load a Graphics Magician image into a program. The program itself is a bit of a UI nightmare. Without a manual or reference card, it’s nearly impossible to know what keys do what. On top of that, the program requires that you use a joystick to move the drawing cursor on the screen. Fortunately, the manual can be found online and you can use a PC mouse as a joystick within AppleWin. I managed to crank out a couple of silly images for testing and save them to my game disk.
I then used to code provided in the manual to write a simple Applesoft program that displays the image:
1 PRINT CHR$ (4);"MAXFILES1"5 HIMEM: 32768 10 PRINT CHR$ (4);"BLOAD PICDRAWH" 20 PRINT CHR$ (4);"BLOAD ROOM1.SPC,A32768" 30 HGR 40 A = 32768:HI = INT (A / 256):LO = A - HI * 256: POKE 0,LO: POKE 1,HI50 CALL 36096
In order for this code to work, you are required to copy PICDRAWH from the Graphics Magician disk to your disk. This is the machine code rendering engine that is loaded into memory at the top of this program. The
MAXFILES1 DOS command apparently frees up some memory by limiting the amount of open files. This command needs to be the first one in your code, before any string assignments, etc. I think
HIMEM does something similar with allocating memory locations. I have never written an Applesoft program so large that it required memory management so the purpose of these commands alludes me somewhat. As this project grows, I may have to familiarize myself with them.
You will see
CHR$(4) often in Applesoft programs.
CHR$() is a function that retrieves the keyboard character in assigned to the numerical value in then parenthesis. For example,
PRINT CHR$(65) prints the letter A. In this case, character number four is the equivalent of keying in CTRL+D. That instructs the computer that the next PRINTed string should be executed as a DOS command rather than PRINTed to the screen.
The Graphics Magician file is ROOM1.SPC.
BLOAD ROOM1.SPC,A32768 loads the drawing code into memory location 32768. That seems like a crazy random number but it is actually $8000 in hexidecimal.
HGR switches to high-resolution graphics mode and then line 40 stores the memory address of the picture into a location PICDRAWH will know to look. Finally, the
CALL 36096 triggers the PICDRAWH draw routines.
There’s a lot of fancy stuff going on here, but it does the job as advertised. The Graphics Magician manual also goes deeper with more code that shows how to string multiple images into slide shows and how to overlay objects over backgrounds. More on that when I get to my object code. For now, this proof-of-concept was enough to get a simple working prototype up and running.
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:
The Graphics Magician is something altogether different though. Instead of meticulously drawing each point on the screen, you create images programatically using a language of lines, fills and brushes. The end product is what today we would call vector art.
The advantage of vector art is that file sizes are small. The other advantage is that these drawing routines can be used within one’s own Apple ][ programs.
This gave me an idea for a project. Take the text-based adventure game I had made years ago, and use these routines to add graphics to the game. As I type this, I am already pretty far along in the project, but I will be going back and documenting my progress. Hopefully someone might find this informative and, if I am able to follow through, maybe I will have a releasable game in the end. It’s doing more than I ever imagined already:
Continue to Part II
He starts off with a typical comedian’s memoir and, after about three pages, Norm gives up and go total autofiction. There’s a grain of truth in every chapter, but each quickly descends into madness. It’s not just cheap jokes (there’s much of that, including the famous “Moth Joke”). Eventually, the fourth wall is broken and it becomes a smart, thrilling story.