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LIFE, an interactive version, 15.0 generations per second. by Dave Storer, with unknowing contributions from Tomas Rokicki and Charlie Heath. This version of the LIFE program is placed in the public domain and may be freely distributed, in the hopes that someone else will build on this the way I have built on the work of Tomas Rokicki and Charlie Heath. LIFE is a form of cellular automaton invented (discovered?) by the mathe- matition John Horton Conway. The life universe is a rectangular array of cells. Each cell is either alive (white) or dead (blue), and has eight neighboring cells. What happens to a cell in the next generation depends on the number of its living neighbors. Zero, one, or four through eight living neighbors cause a cell to become or remain dead. Two living neighbors cause the cell to remain in the same state, living or dead, as in the previous generation. Three living neighbors cause the cell to become or remain living in the next generation. These simple rules generate complex interactions which are wonderful to watch at high speed. This version owes its speed to Tomas Rokicki, who wrote the original blitter program which I found on Amicusdisk 31 (also Fred Fish disk 31). I've added interactive capability, as an exercise in learning C and the Amiga internals. This version does NOT run at 19.8 generations per second, because of the extra stuff in the main loop. With Depth 1, it runs at 15.0 generations per second. For depth 3, it runs at about 13.5 g/s, quick enough for most of us. This version does not "wrap-around" as some other LIFE programs do. The active display area is 318 cells by 188 cells. Rokicki's original doc files, POSTER, WARNING, and WARNING2 are included, as the blit.c file has not changed. The file requestor is a slightly modified version of the GetFile example by 'cheath' in the Manx C (3.4a) SYS3:Examples directory. I have included the object files only. Controls. This version of LIFE is controlled by the mouse, the keypad keys, the control keys on the regular keyboard, and the letters and special char- acter keys. ESCape. This key terminates the program. Left-Amiga-n. This switches to the LIFE HELP display. Left-Amiga-m. This switches back to the LIFE display. Letter, number, and special character keys. These may be assigned to any pattern of cells from 1x1 up to 16x16. These assignments are specified in the file, LIFE.KEY. By pressing one of the assigned keys, (unassigned keys flash) the cursor changes to the shape from the LIFE.KEY file. The key assignments and the accompanying text strings are displayed on the HELP screen. Left mouse button. This is used to place the cursor shape on the display. At the left and bottom edges, you may not get a complete copy, as the cursor shape is clipped to fit on the screen. You may place a shape onto a running display. Gliders placed this way give interesting effects. Right mouse button. Clicking this rotates the cursor shape 90 degrees. If the shape has four-fold symmetry, you won't see anything happen. Either-Amiga-left-alt. Same as left mouse button. Either-Amiga-right-alt. Same as right mouse button. Either-Amiga-arrow-key. Useful for moving the cursor very precisely. These three combinations are good for setting up complex displays where the positioning of adjacent shapes is critical. Return and Tab. These keys cause the cursor shape to change to its mirror image shape. If the shape has two-fold symmetry, you have a 50-50 chance that the shape will change. Spacebar. Toggles between RUN and STOP state. When in the STOP state, the title bar shows the generation number. By holding down the spacebar, you can run LIFE at one-half the repeat rate of the keyboard. This can be altered from Preferences. Backspace. Causes the display to advance to the next generation and then stop. It does this from either the RUN or the STOP state. Holding the backspace down to rapidly single step the display is probably better than using the spacebar, as you will always be stopped when you release the backspace. DEL. This key causes the display to back up one generation. However, see keypad controls '1', '2', and '3'. Normally only useful when stopped. Keypad controls. Kp Enter. This key brings up a file requestor. You can read predefined patterns into the display. All of the patterns provided end with the .pat suffix. Reading also makes a copy in the quick restore buffer (see Kp '7' and Kp '9') and sets the generation number to zero. By selecting the WRITE gadget, you may save interesting patterns to disk. (Mnemonic: Enter a pattern into the display from disk.) Note that if you specify a directory (drawer) on a disk, you must end with '/', as the drawer name and file name are concatenated to form the full name. E. g. 'df1:life/' for the drawer and 'box.pat' for the file name. Kp '-'. Toggle erase mode. In erase mode, the cursor will erase any live cells under it. The eraser is actually the size of the smallest rectangle containing the cursor shape. (Mnemonic: You are subtracting something from the display.) Kp '.'. This places the display into tile mode. In tile mode, whichever cursor you have selected is used to fill the entire display. This can yield some interesting effects. In the file LIFE.KEY, some of the colony names start with * and end in "farm." These shapes have enough extra space around them so that in tile mode, they are not too cramped to be interesting. (Mnemonic: The display is filled with a PERIODic ((ouch)) pattern.) Kp '0'. This key causes the display to be cleared. To prevent acci- dental erasure, you must hold down the right shift key at the same time. Generation number is set to zero. The quick restore buffer is NOT cleared. (Mnemonic: Clearing a calculator puts Zero on the display.) Kp '1', '2', '3'. This is the depth of the screen display. This controls how many previous generations are saved. When Kp '1' is pressed, one bitplane is used, and no previous generations are saved. In this case the DEL key has no effect, and LIFE runs at its maximum speed. When Kp '2' or '3' is pressed, you may back up at most one or two generations, respectively, and the display runs a little slower. Kp '4'. Restore the backgound grid. Unfortunately, placing a colony on the display by clicking the left mouse button erases the grid under the cursor. I can't find a simple way to avoid this, hence the requirement for the Kp '4'. (Mnemonic: the '4' has a cross in the middle like the ticks on some grids.) Kp '5'. Remove the background grid. Kp '6'. Generate a random display of live cells. Set generation number to zero, and save the random display in the quick restore buffer. (Mnemonic: A six sided die is often used as a randomizing tool.) Kp '7'. This restores the display from the quick restore buffer. It may be used both while running and stopped. The generation number is reset to zero. Kp '9'. Saves the current display to the quick restore buffer. It may be used both while running and stopped. (Mnemonic: "A stitch in time saves nine.") Key assignments from file 'LIFE.KEY'. The names I have chosen are probably not the names in common use among those who have studied LIFE in depth. '0'=Blob Stable. '1'=*Small glider farm '4'=Block Stable. '7'=7 gliders Simple pattern which explodes and throws off seven gliders before becoming a still-life. '8'=Big flipper Generates a large three-cycle oscillator. '#'=Line+dashes3 A series of these, end to end leaves behind an array of blocks. '^'=Hat A building block. Upshift of '6' key. '-'=Small flipper Simplest two-cycle oscillator. '+'=Four cells Like block but rotated 45 degrees. '='=Line+dashes2 Like # but leaves nothing behind. '|'=15 step oscillator Longest period oscillator I've found. 'b'=Brick Stable. '^B'=*Big Bang ^B means press CTRL key and B key together. In tile mode, generates a stable densely packed array of blocks, which is stable. A single dot added will either do little or will cause a major catastrophy. 'c'=Little c Not stable by itself. Back to back with itself, with one or two spaces between, yields a stable pattern or a two-cycle oscillator. 'C'=Big C Can be used to build stable patterns, like 'c'. 'D'=Big D Stable pattern. Can be packed with itself on a diagonal and still be stable. 'f'=Edge Galumpfer In the center of the screen this is not stable. Along an edge, or back-to-back with itself, it forms a peculiar 14-cycle oscillator. '^F'=*Flipper farm For tiling the screen with small flippers. See Big Bang. 'g'=Small glider This pattern moves along a diagonal. 'G'=Big glider This pattern moves horizontally or vertically. '^G'=*Glider farm Useful for tile pattern of Big Gliders. 'i'=Little I-beam Interesting small explosion. 'I'=Big I-beam Ditto. Both I-beams are good for building interesting larger patterns. 'L'=Corner Useful building block. Changes to block in one generation if by itself. 'o'=Little o Stable. 'O'=Big O Not stable. '^O'=*O'Farm Interesting failure. 's'=S septomino Stable. Good building block. Will "eat" small gliders if everything is just right. 'r'=R pentomino Small, 5-cell pattern which explodes grandly. '^Z'=*Diag line farm Long diagonal lines are interesting when some small colony is tacked on at an end. '.'=Single dot Use this for building things. Especially useful in erase mode for fixing goofs. '/'=3-dot diagonal line Building block. Notes on LIFE.KEY file. The LIFE.KEY file is an ASCII file and can be modified as you like, provided the format is correct. Some words of warning about the format of the LIFE.KEY file. This file defines all of the cursor forms and their key assignments. You may have up to 100 colony forms in this file. The format must match the examples already in the file. Each colony has the format: <name># k w h definitionarray where name may be up to 18 characters long and must end with #. The key assignment is given by k, which may be upper or lower case, or a ctrl-key, if your editor can do that. The width (w) and the height (h) of the definition array come next, followed by a series of space-separated zeros and ones to define the colony pattern. Ones are living cells, zeros are dead cells. Maximum value for w and h is 16. Notes on some '.pat' files. hline.pat A horizontal line. This gives an interesting recursive explosion. hline1.pat Like hline.pat, but with live-live-dead-dead pattern repeated along one side. Does not behave at all like hline.pat. hline2.pat Like hline1.pat, but the added pattern is two live and three dead cells adjacent to the line. Try it to see what happens. vline.pat Single vertical line. box.pat A large rectangle of single lines. box1.pat Like box, but with two diagonals added. Start.pat A little of everything in this one. The lower left corner is the thing to watch. A 14-cycle edge galumpfer and a 15-cycle oscillator eventually reach a phase relationship where they interfer with each other and trigger the "fuse" which ultimately destroys almost everything. Finally settles down at about generation 2500. Enjoy. I think this beats 100,000 dominoes any day. Dave Storer 2916 Mansfield Ave. SE Cedar Rapids, IA 52403 Compuserve 71420,2672 P.S. Things which this program needs to improve. 1. A lens system. After an hour of building patterns, you get retina raster burn. 2. A glider gun pattern. I know these exist, but I haven't had time time find one.