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Text File | 1993-03-13 | 32KB | 786 lines

Solar System Wars -- Version 1.14 Copyright © 1992 James Cleverdon. All Rights Reserved. The binary copy of THIS version of SSW and its other files may be freely distributed for non-commercial purposes, including and especially by Fred Fish's wonderful collection of software. More legal garbage and disclaimers below. New Features for Version 1.14 * First public release! * All new support for two-button joysticks! * Everyone now gets Hyperspace all the time, as well as an extra weapon from the Options menus! * Double-thick shields for EXTRA protection! * Improved color register handling for superior performance without the earlier glitching problems! * Much smoother motion, because now SSW does one game cycle (complete with all gravity calculations) for every screen frame, even on standard A1000 and A500 machines! Yes, that's 50Hz for PAL and 60Hz for NTSC. The only exception is for cycles involving sprite collisions, which take two screen frames per game cycle. * All of the gravity and update subroutines have been redone in hand-optimized assembly code for extra speed, plus the added bonus of now fitting entirely in the instruction caches of 68020 and 68030 CPUs! * Tested on A1000 (OS 1.3), A500 (OS 1.3), and A3000 (OS 2.04). Should run under OS 2.1. Will almost certainly break on an AGA chip machine. Is free of Enforcer hits on A3000. * Multi-tasks. (SSW should be the highest priority CPU-intensive task for smoothest game play.) Throw away any older versions of SSW that may have escaped earlier! This is the latest and greatest! Requirements * Runs under OS 1.3 or 2.0X, and probably 2.1, but not 3.X. * Needs 195K of Fast RAM and 39K of Chip RAM, in fairly large pieces. (Fragmented memory may prevent SSW from running, even if there is enough chip and fast ram listed by the Avail command.) * Only needs 4K of stack space, but I'm keeping SAS/C's default of 8K in SSW.info. * Requires all of the hardware sprites and all 4 audio channels. * Works with one-button digital joysticks (standard Amiga joysticks), but two-button digital joysticks are strongly advised. Instructions for joystick re-wire are included below. Does not support analog joysticks. Quick Start-up * Install SSW. + If SSW isn't compressed and came on a floppy, either run it from the floppy, or just drag the SSW drawer to RAM or onto your hard drive. + If SSW came compressed, or was downloaded, create a drawer named SSW and decompress the archive file in the usual way: * Make a new drawer (directory) named SSW * open up a shell and CD SSW If you have SSW.lha: lha -x -a -m x SSW.lha If you have SSW.zoo: zoo -extract SSW.zoo * If operating under OS 1.3, then: - delete SSW.info - rename SSW.1.3.info SSW.info Otherwise, if operating under OS 2.0 or greater: - delete SSW.1.3.info * Hook up a joystick to Joyport 1, and either be ready to plug in a second joystick into Joyport 0, or familiarize yourself with the keyboard control keys. If you have two-button digital joysticks now is the time to use them! Or, you can use ordinary one-button joysticks and some keys on the keyboard. * Start up SSW. Use either the Workbench or the Shell. Be sure that either its files are in the drawer with SSW, or else enter in the Shell: assign SSW: drawer_containing_files * Select any desired options from the menu with the mouse or keyboard. (See below for a list of menu command keys. Also, a file named Menu.keys has been provided for easy reference and printing.) An especially fun option is the Random Game (RightAmiga-R), which will randomly select solar systems for each round, along with a random extra weapon for each player. There are also menus for torpedo velocity, torpedo life, ship thrust, etc. * If you will be playing with two joysticks, then replace the mouse with the second one now. Then press RightAmiga-1 to switch to joystick control. * Enjoy! The first player to reach 20 points wins! Joystick and Keyboard Control Joystick control: Button : Fire photon torpedo Left/Rght: Turn Left/Right Forward : Thrust Back : Hyperspace Button2 : Extra weapon (If you do not have two-button joysticks, the keyboard Extra keys: port 0: ENTER, RSHIFT port 1: LSHIFT) Keyboard control: (the numbers are on the keypad, not above the keyboard) DOWN, 5: Fire photon torpedo RETURN, 0: Hyperspace LEFT, 4: Turn Left RIGHT, 6: Turn Right UP, 8: Thrust RSHIFT, 2: Extra weapon 7 : Left & Thrust 9 : Right & Thrust Program control: ESC, Q: Quit P : Pause HELP : Displays Help requester Common Gotchas * Make sure the file named SSW.grv is in the current directory, or located at the SSW: assignment. Otherwise, SSW will complain and die. * You may need to adjust the screen position Preferences in order to see the seventh sprite. In other words, if the purple ship's plasma bolt and seeker don't show up on the screen, do the following: + quit SSW -- type 'Q', followed by 'Y' + open the Preferences program for OS 1.3, or for OS 2.X and beyond, run the Overscan program in the Prefs drawer and select Edit Standard Overscan + shift the default screen position a little bit to the right + leave via the Use gadget + run SSW again Keep trying this until you find a screen position that allows the 7th sprite to appear, and best fits your monitor. Once you have this, either save this setting in Preferences, or use one of the public domain Preferences savers to save this setting in a file for easy recall later. (Prefs savers are available on Fred Fish disks and many BBSs.) * If you've forgotten to press RightAmiga-1, then a joystick plugged into the mouse joyport won't do anything useful. Menus Explained A = Right Amiga Key, C = Control Key, other keys such as ESC are named Project Pause? A-P Pause the game New A-N Start a New game About... HELP, AC-A Screen To Front A-[ Move the SSW screen to the front Screen To Back A-] Push the SSW screen to the back Quit... A-Q Leave SSW System No Primaries A-0 No stars at all One Primary Your ship orbits one star Red Dwarf A-E Yellow Star A-Y Blue Giant A-B Small Black Hole A-T Medium Black Hole A-U Large Black Hole A-I Two Primaries Your ship orbits two stars Red Dwarves A-O Red / Yellow A-{ Red / Blue A-} Red / Sml BH A-D Red / Med BH A-F Red / Lrg BH A-G Yellow Stars A-H Yellow / Blue A-J Yellow / Sml BH A-K Yellow / Med BH A-; Yellow / Lrg BH A-: Blue Giants A-' Blue / Sml BH A-" Blue / Med BH A-Z Blue / Lrg BH A-X Small Black Holes A-C Sml BH / Med BH A-V Sml BH / Lrg BH A-, Medium Black Holes A-< Med BH / Lrg BH A-. Large Black Holes A-> Three Primaries Your ship orbits three stars Red / Yel / Yel A-/ Yel / Blue / Blue A-? Yel / SBH / SBH A-DEL Blue / MBH / MBH A-ESC BH: S / M / M AC-B BH: M / L / L AC-G Misc. Systems Other solar systems Black Ellipse A-BackSpace Wide Red Binary AC-J Wide Yellow Binary A-) Wide Blue Binary A-` Wide Sml BH Binary A-~ Wide Med BH Binary A-Space Wide Lrg BH Binary A-Tab Asteroid? A-A Add an asteroid to 0/1 star games Random Game? A-R Random system/weapons every round Options Ship Thrust Pick ship thrust Low A-_ Medium A-+ High A-| Torp Velocity Pick photon torpedo velocity Low A-- Medium A-= High A-\ Torp Lifetime Pick photon torpedo lifetime Short A-S Medium A-M Long A-L Screen Wrap? A-W Pick screen wrap/bounce Green Ship Opts Joyport 0 A-1 Control from mouse port Joyport 1 A-2 Control from joystick port Keyboard A-3 Control from keyboard Full Shields A-4 Be immune to photon torpedoes Flip Ship A-5 Do 180 degree flip Cloaking A-6 Become invisible Plasma Bolt A-7 Shoot ball of electric death Quad Thrust A-8 Accelerate with quadruple thrust Seeker A-9 Fire seeker missile Purple Ship Opts Joyport 0 A-! --Ditto-- Joyport 1 A-@ Keyboard A-# Full Shields A-$ Flip Ship A-% Cloaking A-^ Plasma Bolt A-& Quad Thrust A-* Seeker A-( Weapons, etc. * Photon Torpedo -- shoot a simple missile in the direction your ship is currently pointing. A torpedo's initial velocity and lifetime are controlled by Options sub-menus. You may only have nine torpedoes in flight at one time, but torpedoes are otherwise unlimited. * Regular Shields -- a gray ring around your ship that absorbs Photon Torpedos, Plasma Bolts, and Seekers, as well as providing limited protection from collisions with asteroids and stars. Torpedos erode holes in your shields, exposing your ship to sudden destruction. Contact with a star, opponent, asteroid, Plasma Bolt, or Seeker will overload and destroy your shield generator. * Regular thrust -- accelerates your ship in the direction it points. The thrust level is controlled by an Options sub-menu. Fuel is unlimited. * Hyperspace -- activated by pulling directly back on a joystick (no diagonals!) or by pressing the RETURN key or 0 on the keypad. Hyperspace will teleport your ship to a random location on the screen. It takes time for Hyperspace to warp you out and back. Your controls will be frozen during this time. Also, the hyperspace field generator takes about two seconds to recharge and be available for use again. * Full Shields -- when activated, your ship becomes a gray octagon, totally immune to photon torpedoes. Full shields are lost under any circumstances that would overload your regular shields. Your regular shields are lost whenever the Full Shields are lost. Your other controls are frozen while the shields are up. Full Shields only stay up for a maximum of about two seconds before dropping. There is an about one-half second full shield generator recharge delay. * Flip Ship -- do a 180 degree flip. There is a short recharge delay. * Cloaking -- your ship becomes invisible, except for a slight wavering in the background stars. You may turn and accelerate while cloaked, at the cost of becoming partly visible, but may not fire any weapons. Cloaked ships are not tracked by Seekers. There is an about one-half second cloaking device recharge delay. * Plasma Bolt -- shoots a large, writhing ball of energy. Has a limited range, and will be detonated by "just one" photon torpedo. You may not fire another bolt until the first is gone. * Quad Thrust -- accelerates your ship with four times its normal acceleration. Note that SSW does have a maximum allowed speed for all objects (the "speed of light"), which is easy to reach using Quad Thrust. * Seeker -- fires a missile which will seek out and hit your opponent. In fairness to the other player, Seekers are very simple-minded. Seekers can not track Cloaked ships (despite S.T. 6), but will keep their last acceleration vector. You may not fire another seeker until the first is gone. Known Offences Against the OS 2.0 Style Guide * Topaz 8 is hard-coded into the menus, requesters, and opening screen. * Not Internationalized. * Uses raw key events without proper mapping. * Turns off the mouse when a player is using Joyport 0. * SSW's screen does not have drag or depth gadgets. (See the Screen To Back and Screen To Front menu entries for a replacement.) * The Quit and About requesters are not draggable or depth arrangable, and do not set a "Wait" pointer in the main window when activated. * Game settings cannot be saved or loaded. * Doesn't read Tool Types from icon files. * Pays no attention to Shell command line arguments. Known Deficiencies * The use of keyboard screen dragging will misalign the sprites with SSW's screen. * Uses hardware collision detection for all collisions except between photon torpedoes -- the Twilight Zone on Wrap games is a safety zone from all collisions. Also, because there are no detection bits for collisions between members of a sprite pair, your own Plasma Bolts and Seekers won't kill you. (Twilight Zone: the off-screen part of the game playfield.) * I can find no easy way of knowing whether the SSW screen is in the foreground, at least not without digging deep into private Intuition data. This makes it hard for the Copper interrupt routine to know whether to consume the Copper interrupt, or not. So I play around with the ScreenToFront and ScreenToBack functions and window activation events to try to insure that either SSW's screen is in front of all others, or that it is in back and the game is paused. * Because of the fact that SSW jams its own values into the posctldata fields of sprites, and uses several low-level hardware registers, SSW has no chance of working with the AGA chip set. * Since SSW uses a quick-and-dirty approximation for faster gravity calculations, some star systems are unstable. Trinary systems will hit the screen edge after about 10 to 13 minutes. This is almost never a problem, since most rounds last under two minutes. * Uses ADCMD_LOCKs on the audio device, so it will release a requested channel, then attempt to reallocate it. All this is according to the rules in the RKM, which allow sharing of audio channels. However, some program's attempts to allocate an audio channel don't wait long enough for SSW's locks to be released, and fail. Potential Portability Problems * The ScreenToBack menu selection uses a probably non-portable kludge to activate the foremost window in the Workbench screen. * Uses hardware registers for sprite/playfield collision detection, and changes the POTGO register to use two button joysticks. * Directly modifies the posctldata fields of sprites, so anything that shifts SSW's view origin will confuse the sprite positioning. * Reads hardware for both joysticks. * Uses RAWKEY events for the keyboard, so no keymap translations, or localization. * Installs its own Copper interrupt, and may not work well with other Copper interrupts. * Assumes that Intuition screens use standard BitMaps. * Bypasses the graphics library to read and write photon torpedoes, but uses MENUVERIFY and REQVERIFY to synchronize with Intuition. * The structure used by the copper interrupt handler isn't in PUBLIC memory, as per the manuals. This won't matter until virtual memory is attempted by Commodore. * Sets and clears the CHECKED flag directly in MenuItems, although protected by Disable/Enable. Implementation Details * Sets up a Low-Res Dual Playfield screen with two bit-planes in either PAL or NTSC mode, based on presence of the PAL bit in GfxBase. This means that a NTSC A3000 will display a NTSC screen, even if it is displaying a PAL Workbench. Sorry, I couldn't find a legal way to override this, since any attempt to use NTSC/PAL Display IDs is set back to DEFAULT_MONITOR when doing the MakeScreen/RethinkDisplay after attaching the Dual Playfield. Maybe this will change for OS 2.1. * Installs a Copper interrupt Server and adds a Copper interrupt to the screen. * Adds a high-priority (126) Input Event handler to the food chain to eat RAWMOUSE events when a joystick is plugged into joyport 0. Otherwise, the menus would appear every time joystick 0's second button was pressed. This also keeps DMouse and other screen/mouse blankers or other Commodities from sometimes doing the wrong thing, like pushing the current screen to the back. The handler is turned on whenever a player is using joyport 0, and the game isn't paused. * Sorry, can't use AutoRequest or any other window-based requesters for the few requesters SSW uses. I need the WINDOWACTIVATE and deactivate events to tell me when SSW has been pushed into the background. This means using layer-based requesters that don't seem to be draggable. Yet another offense against the Style Guide. * Allocates audio channels at priority -50, the highest standard level for sound effects. Ask Capt'n Quirk And now that grizzled and grouchy, veteran of Solar System Wars, Captain Quirk -- one who deals out insults, death, and run-on sentences in all directions, will answer some of your questions about game strategy! Thank you, worthless pandering announcer. There's a big backlog today, so let's go right to the first member of the audience: Q: How can I keep from getting blown out of the sky whenever my opponent gets Seeker and I get something wimpy like Cloaking? A: What! You've got Cloaking against Seeker and you come whining to me? Get yer pathetic rear-end back out in the arena and USE Cloaking! Once you are cloaked, Seekers can't track your ship! However, they will keep their last heading, so if you uncloak to fire off a burst of torpedoes, then recloak after a Seeker is coming your way, be sure to accelerate away from your last course. That will fool 'em every time. Q: Suppose I don't have Cloaking, but have Flip instead? A: Do I have to do all your thinking for you? Haven't you noticed how totally stupid Seekers are? Just get something massive, like a star or an asteroid between you and it and the Seeker will mindlessly ram into it. What's more, Seekers never consider gravity in their tracking, programs and are easily confused by Black Hole's, or even Yellow Star's gravity. Q: I try all that and still get fried. Now what? A: Get out of here! <draws and waves blaster menacingly> I haven't even mentioned shooting Seekers with torps, warping out of danger with Hyperspace, outrunning them with Quad Thrust, or blasting them with Plasma Bolts. Next questioner. Q: If my ship can Cloak, why can't it fire Plasma Bolts when uncloaked? I saw that very move on an old episode of Star T<<ZZAAPP!!>> A: <blowing on blaster barrel> Sorry, sonny! You tried to say the "S.T." phrase, which is a registered trademark of Paramount Corporation. Don't even THINK of saying it on my show. Speaking of things we don't mention, <points blaster at camera> I don't want six hundred of you weekend-SSW geeks out there writing in and telling me that on S.T. 6 they had a modified torpedo track a cloaked ship. <blasts nearby table> I know that, and thought it was a stupid plot gimmick when I saw the movie. Typical lazy screenwriters! <burns a microphone cable in two> <takes a sheath of papers from a trembling stagehand> Our next question is from a fax: Q: I have a hard time reaching the keyboard to use my Extra weapon. How do you manage? A: Now that's a fair question. Either get into the habit of reaching for a shift key on the keyboard, or buy or build yourself some two button digital joysticks. If you can locate a nine wire joystick cable and find some joysticks that have enough room inside to install a normally open push-button, then its easy to rewire an existing joystick. One more thing: take the usual precautions when dealing with hot solder, connecting anything homemade up to your Amiga, etc. If some pitiful excuse for a lawyer shows up on my doorstep, trying to serve me a lawsuit because I didn't warn you not to do something truly stupid, then I'll burn the lawyer down where he stands and spit on the ashes. <waves blaster, picture bounces as cameraman dives for cover> But, I've already been warned twice that I'm over my Lawyer limit for this season -- so don't screw up, OK? Now a question from the audience. Q: Why are the orbits around Blue / Medium, Small / Medium, Yellow / Large, Red / Medium, and Medium / Large Binaries unstable, especially in a Bounce game? A: Good question -- I won't kill you. <vaporizes an innocent bystander instead> Those orbits have resonances with those of their primaries. That, along with the crude approximation that passes for gravity in SSW does the rest. Anyway, what do you care about orbits? Are you a pilot, or what? Here's another fax: Q: Cap'n Quirk, just what is Flip Ship good for? Maybe nothing? A: Maybe you've never found yourself around a Wide Large Black Hole Binary, doing an orbit once every second? Maybe you've never had to suddenly thrust in the opposite direction because you were coming too close to a Blue Giant? Maybe you've never had an enemy warp in directly behind you? No doubt you've never had to handicap yourself when playing against a novice player! <throws fax into air, blasts it> What is the younger generation coming to? For Zelkor's sake, use some imagination, will you? This will be our last question today. From the audience: Q: I had just about peeled all the shields from my opponent while only taking one or two hits myself, and was coming back in from the Twilight Zone to finish him off, when I blew up for no reason at all. What happened? A: At last, a question worth answering. Remember that while you are in the Twilight Zone the Amiga hardware collision detection circuitry isn't checking for collisions. In the Twilight Zone, everyone and every torpedo is safe. However, that also means that a torpedo that ordinarily would be absorbed by your shields has a chance of drifting inside your shields, and may still be there when you emerge from the Twilight Zone. If that happens to you -- BOOM! <Blasts an off-camera object> To avoid this you can use Full Shields on every entrance or exit from the Twilight Zone. Otherwise, just be very careful out there. That's all for today, but be sure to listen to the next exciting episode of "Ask Capt'n Quirk!" <fade to black as the SWAT team tackles Captain Quirk> Legal Garbage and Disclaimers, In Plain English Solar System Wars will not cure world hunger. It will not bring global peace. I do not even guarantee that it is fun to play, or does anything more useful than waste CPU cycles. If you run this software and your disk drive bursts into flames, or your 1000 page dissertation on "Why Entropy Is Politically Incorrect" gets corrupted, or something else goes drastically wrong, you will get my sympathy but nothing else. I will not provide any money or other kind of compensation, no matter how valuable the hardware, software, or data that you believe SSW, or SSW's interaction with some other piece of software, has destroyed. If you, or whoever you got SSW from, has hacked, patched, or otherwise modified this package, then there is no telling what it will do, and I will not be responsible for any part of any problems such changes cause. If you don't like these limitations on my liability, then do not run Solar System Wars. If you do run SSW, then you have agreed to these limitations. Moreover, while I retain the copyright to Solar System Wars, this version of SSW may be freely copied for non-commercial purposes, as thanks for all the fine public domain and freely distributable software that I have used over the years. No one may charge more for your copy of SSW than Fred Fish charges for one Fish disk. SSW may eventually go Shareware, in which case there may be registration fees. (Aaarrrggghhhh! I hate the paranoid attitude such legalisms require.) Source Code Availability and Bug Fixes I'm not making the source code available until I decide if I want to make SSW shareware or not. Enjoy this copy entirely guilt-free, without any nagging requests to register, to send money anywhere, or to make Molotov Cocktails in your basement for the Revolution (any Revolution). The only thing I ask is that you mail to me any bug reports, great ideas, and general impressions you have about SSW. If I do decide to release the source code, I'd like all the obvious bugs fixed first. My address is: James Cleverdon 16465 S.W. Estuary Dr., Apt. 101 Beaverton, OR 97006 USA Bug fixes will be released via Fred Fish, and the other usual methods. Ports for other machines, especially IBM PC clones? Get real! SSW relies too heavily on the Amiga custom chips. Acknowlegements Thanks to my play testers: Clark MacDonald who had the 9-wire cables and let me crash his A3000, David Roemer for lots of good ideas (especially the random game option), Stewart Boutcher for deadly fire and French Vanilla ice cream, and all the others including the Bush Harbor Day gang. File Manifest Here are the files you should have received: Name Size What Menu.keys 2019 (menu keys text) Menu.keys.info 734 (its icon) SSW 62208 (the program) SSW.1.3.info 450 (the OS 1.3 icon) SSW.info 463 (the OS 2.X icon) SSW.doc 31590 (this document) SSW.doc.info 734 (its icon) SSW.grv 123904 (the gravity table) Instructions for Two-Button Joysticks First, a crude ASCII picture of the end of a joystick cable. This is the DB-9 that plugs into your Amiga, taken from the Hardware Guide: _____________________ / \ The numbers are pin numbers. | 5 4 3 2 1 | \ / Viewed as you would look into \ 9 8 7 6 / its end. Note: female pins. \_______________/ Pin Joystick Mouse * = optional button 1 forward V-pulse 2 back H-pulse 3 left VQ-pulse 4 right HQ-pulse 5 --- middle button* 6 button1 left button 7 --- +5V 8 GND GND 9 button2* right button All you have to do is add a normally-open push-button with one of the button's terminals connected to pin 8 (ground), and the other connected to pin 9 (button2). Push the button, which will ground pin 9, and fire a plasma bolt. Easy? Maybe. Standard joystick cables don't include pin 9. I was lucky enough to have a friend who had a bundle of premade DB-9 cables with all 9 wires left over from a previous job. You may not be so fortunate. Check electronic surplus stores. Look carefully to make sure that there are pins in all nine holes. Get a continuity tester and verify that every wire you need is really there. Another problem is finding a joystick that has enough room to allow an extra button. Also, it is hard to find a small push-button that is both reliable and durable, plus has a button large enough not to leave an imprint in your thumb at the end of a difficult game. I'm assuming that you have at least some skill at electronics. If not, check with someone who is skilled, or read the basic-technique articles in an electronics hobby magazine. If you've done all that, then I won't need to tell you: * Don't burn yourself. * Be sure to insulate all your solder joints with electrician's tape or heat-shrink tubing. * Test the finished product with a continuity tester. Connect it between pin 9 and pin 8 on the joystick DB-9 connector. The light should come on, the buzzer should buzz, or the ohmmeter should go to a low resistance value when the new button is pushed. When it is released, the light should go out, the buzzer will be quiet, or the ohmmeter will read very high (or infinite) resistance. About the only way you can damage your Amiga is by somehow connecting the +5V line (pin 7) to ground (pin 8). Since you won't even be working with pin 7, this shouldn't happen. Test for this mistake anyway. Be happy by being paranoid about Murphy's Laws. References "Space Wars, or Turning Your Oscilloscope into a Telescope," Byte, way long ago. Thoughts for the Future * Since I have to install an Input Event handler that eats RAWMOUSE events, then Intuition can't be moving the mouse pointer while the handler is turned on (unless someone uses the keyboard mouse mover). If so, why can't I use sprite 0? How about four-star solar systems? (There are only two sets of color registers, so there could only be as many 4-star systems as 2-star.) * Many analog joysticks have two buttons. Since I already have to go directly to the hardware for digital joysticks, maybe I can support analog as well..... * Can the Planet Cruncher be worked in somehow? How about a Tholian web? * What about a "Death Blossom" kind of weapon that shoots torpedos in eight different directions? Or, maybe an Ack-ack weapon that shoots a sprite which explodes into a spray of torpedos. * Maybe Flip Ship will go away. * Would a Tractor Beam be useful? Or, a Pressor Beam? * I would like to do a laser beam, except that there is a 16 pixel width limit on sprites, and the underlying code expects that only point sources and spherically symmetric objects will be experiencing gravity. (E.g. no provisions for bending an extended light beam around a black hole.) * Maybe some way to repair your shields, like don't push a button for 30 seconds per pixel repaired. * Maybe add more sounds, or allow IFF 8SVX sound files. * Get a real image of an asteroid for the asteroid sprite. * There's another line on the joyport that is used for the middle mouse button. How about 3-button joysticks? And, what about that rumor on comp.sys.amiga.games that some Sega game pads are compatible with Amigas and already come with three buttons? Suppose I assigned Full Shields to the third button? * Would it be worthwhile to allow customized space ships? Can I afford the CPU cycles? * Maybe go from a shield erosion model, to a shield heating model, like in "The Mote In God's Eye" or E. E. Smith's Lensman series. Of course, to do that right I would have to include heating from stars. This should be roughly proportional to the sum of the magnitudes of the gravitational force vectors, except for black holes. And what happens when you finally do blow the shields? BOOM? Or just lose them?