Loadstar 128 #41

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Text File | 1993-01-01 | 11.3 KB | 289 lines

M u l t i P l o t 1 2 8 v1.2 Program and text by Brian Crosthwaite noesis0@rmci.net Back in the early 1980s I was working on a program on an HP-3000 Mainframe when a gentleman asked if I needed any assistance. While there is a long story that fits in about here, it has been told often and is well known within the Commodore community. This guy was excited about getting a computer called the Commodore 64. A month later I was programming my new C64. I did some of my homework assignments on it, transcribed the programs from the screen by hand and typed them in on the HP over at the University. One of the first things I did was get into graphics. I loved (and still do) plotting points on a screen. While teachers were saying the most powerful command on the computer was PRINT, I was using PLOT. Well, okay, I was calculating and setting a POKE to plot a dot. To me, THAT was the most powerful command a computer had. One of the first mathematical pictures I ever concocted was a Nexus design called SnailSkin. It was so named because it resembled a snail-shell with a rattlesnake's skin texture. The Nexus design is a simple one. In this case, it is achieved by an arch made on the screen with several dots. The arch is repeated with a greater radius with more dots. It looks like the side would get flat, eventually, but that would be no flatter than the earth itself is as is a perfect curve. The perfect curve, however, is not perfect as the pixels on the 64/128 screen are not square, so I've fudged the curve of the arch to make it look round -- and it is not the outside roundness but the actual Nexus curve that I've fudged. Several years later, a group of many of the graphics modules I had written were published. I then grouped the MODs into one place, within GEOS it was called geoGraphs. The next version was the Amiga version called MultiPlot. This version was unique in that you could suspend any of the plots and enter a new one, and another one and another one, and so on, plus it had music (something I had originally planned to add to this version before my back went south) and I incorporated geoMandelbrot and 3D-Run (an Atari ST originating Graph) as two of the Graphs. The Cir MOD became Zebra. On the Mac, it appeared as MacGraphs. The program was a strange black and white version with no pulldown menus. It programmed well onto the Atari ST (no music, although the ST and GEOS versions are the only ones that print). It finally landed on the Commodore 128. It does not require anything other than a stock 128 to run. The menu is on the 80-column screen while drawing takes place on the 40-column screen. I have two monitors hooked up to my 128D, a TV can be used for 40 column as well. However, the program can also be run, switching the monitor mode from the 80-column to 40-column modes with the video mode switch. There is a limit (10) as to how many MODs or Plots you can run at the same time, but once one Plot has finished you can initiate another. Many of the variables are shared by different Plots, so the results can be...not quite as expected. If you want to see each plot played out as it was originally written to be, simply clear the screen and reset the variables before selecting a Plot. With this version (v1.2) of MultiPlot comes a new Plot called Invortex. (As if a vortex isn't weird enough!) Pictures from Lightning (LOADSTAR 128 #38) can be loaded in for further processing. This can add some real strange effects to some already weird pictures. In this version you can't readily exit any of the plots, except the Fractal II routine. Because the Fractal II takes a long time to render out, it can be painful waiting when you have changed your mind. Aside from the Plots and the Exit Fractal II feature, the remaining menu items are the same as in Lightning. THE MENUS --------- Menu items are selected by pressing the highlighted (reverse video) letter. PROJECT ------- About ----- Pressing <A> will bring up the About Screen. This is the same screen you see when you first load the program. If you missed it, you didn't miss much. There are two About Screens: 80- and 40-column. The 40-column one appears at any time this is selected, the 80-column only appears if no plots are rendering. Load ---- Loads the files that make up a picture. A directory will appear on the right hand side of the 80 column screen (also known as the menu screen). Files that have .PIC and .COL are the ones you are looking for here. If all you want is a directory, simply hit <RETURN> without entering anything. To pause the directory scrolling, press the <NO SCROLL> key at the top center of your computer. NOTE: On JiffyDOS CMD equipment only the .PIC files will show up on screen when the directory is called up. Save ---- Saves the picture as a set of files. A directory will appear on the right hand side of the menu screen. The .PIC and .COL are added automatically. If you change your mind and don't want to save, simply press <RETURN> without entering anything. To pause the directory scrolling, press the <NO SCROLL> key at the top center of your computer. Logged dr ( / ) --------------- Pressing the slash </> key will change the logged drive. MultiPlot V1.2 supports up to 30 drives. Send dr cmd ( @ ) ----------------- Pressing the AT key (@) will allow you to send drive commands for navigation on hard drives and RAMLinks and such. To check the drive status, press RETURN without entering anything. Quit ---- Zips you out of MultiPlot when you decide you have really had enough. PLOT ---- Fractal II F1 ------------- This is actually a new version, but since it looks the same as Fractal II, I didn't change the name. Once again I shrunk the code, but it didn't speed up much. This was originally uploaded onto QLink (and written) by Fractalle. I wrote a GEOS version of it with some minor tweaking, it was tweaked again on the Amiga & ST versions and then a final big tweak here. This one has the longest rendering time and can be aborted by pressing <X>. SnailSkin F2 ------------ One of my first, and still my most favorite graphics to date is the SnailSkin. This is a Nexus formed by a simple perfect arch. It is distorted here to preserve the pure Nexus shape. The formula used is a simple circle plot formula: x=INT(xc+v*xf*SIN(N/(c/2)*PI) y=INT(yc-v*yf*COS(N/(c/2)*PI) where x and y are coordinates (x,y); v and N are loop values (v=1 to usually the yc and N=degrees 0 to what ever v is at in a given loop); xc and yc are the center of the screen; the following + or - simply determines the direction of the circular plot (from a control perspective); xf is about 1 and yf is 1.3 (included to round out the screen). Normally, in a standard circle, the rest of the equation would be the sine of the number that represents degrees and since the computer does RADs we convert it thus: DEG/180*PI. But here, we are changing the rules a bit. 180 degrees is half a circle and we want to change the laws of Euclidean Geometry a tad so we will start off with a different number, .05, and each time we come by to calculate, it will be incremented by .05. Sine Morae F3 ------------- Pronounced as it is written in the menu, SIN More is the actual spelling, but it looks like something else. This is also a Nexus but it folds out from infinity to an origin, while it is a 2-dimensional plot using only x and y coordinates, it plots a 3-dimensional image (with a little imagination). This is an inside out variation on the Snail. In this case we add a twist to the base circle by dividing the c factor by 4 in x and 5 in y forcing the plot to apparently leave the 2-dimensional constraints of our plotting field. The inverse is achieved by counting down from the xc to 0. Zebra F4 -------- This was the Cir MOD of long ago. Zebra has changed slightly from the last few computer platforms, but the mathematics has remained pretty much the same. The second longest running Plot, this one plots screen color as well as a plot color, blocking, erasing, and leaving what is on the screen all at the same time while making progressively larger circles. This is a simple circle that either plots, skips or unplots as it gets larger. Crystal C F5 ------------ Crystal Cracker has changed to a simplified version here, mainly to make it easier to see on the smaller resolution screen. It is back to the way it was originally written, before it became a Nexus. It is a cross between the SnailSkin and SIN More in that it gets larger and leaves the traditional Euclidean plotting plane. Cracker 2 F6 ------------ Cracker II is a variant on Crystal Cracker. The Crystal Crackers found here are somewhat odd in that they are inverse Nexus with the c factors changed to bring them out of sync with a normal 2 dimensional plane. Invortex F7 ----------- This one was originally called What. A Nexus, much like a cross between the SnailSkin and SIN More, with a twist. It has the Crystal Cracker effect. Sort of a Meta-Plot: x=INT(xc+v*xf*SIN(N/(c/.4)*PI)) y=INT(yc-v*yf*SIN(N/(c/.5)*PI)) ^ ^ ^ ^ +--------+---------SnailSkin/Sine Morae +--+---Crystal Cracker 3D-Run F8 --------- This is a random plot that either plots -1, 0 or +1 relative to its previous plot. It starts at 0. The 3D effect is simply that, an effect. The dots are extended up to the left to make it look 3D. CONTROL ------- Clear screen ------------ Does just that. Reset variables --------------- Resets many, but not all, of the variable shared by many of the plots to the state they were at the first of run. Now is a good place to talk about one of the Major aspects of the program. Many of the variables used by the Plots are shared, so when one Plot runs and changes the values and another Plot is selected, the results will be different. While control is rather close to random, there is some control. Exit Fractal II --------------- Only want half a Fractal? Seen one too many Mandelbrot sets? Hit X and move on. The Fractal II does take a while to render, so I thought it (or you) could use an escape. Under plot ---------- This will make whatever is plotting plot only on a clean screen and avoid any plot already on screen. The 3D-Run is immune to this control. Over plot --------- Will only plot where dots are already plotted. The 3D-Run is immune to this control as well. Under and Over plot do not toggle each other on or off, so if both are on nothing will plot. Turbo (go!) ----------- Press G and swing into high gear. The screen will blank and the C128's 2 MHz mode will kick in. This is useful when you want to speed things up a little. It has an auto off feature, so the screen appears when nothing is plotting. Experimentation is encouraged. WRAP-UP ------- This program allows you to start new plots inside of present plots, to plot on top of old plots, to miss old plots while adding new plots. Some really amazing pictures can come about. The pictures can be plotted and view for the sake of seeing them as the were originally written, or they can be intermixed to make something completely new. With that, enjoy! \\\\\ R - Run RETURN - Menu \\\\\