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Written By John Wilson

Cover Art
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Loading Screen
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Opening Screen
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Game Screenshot

Cosmic Clash

John Wilson takes you on a voyage across the universe in his armed-to-the-teeth starship

Cosmic Clash is a games program for the BBC Micro Model B or Model A with 32K. The program is written in BBC Basic and machine code, to produce ultra fast, high resolution graphics in true perspective. Before I go into how the program works, I will give a brief description of how to play the game.

You take the controls of a starship within an enemy galaxy. You are surrounded by 30 alien craft, which attack your ship one at a time. Your starship is fitted with a number of special attachments, as follows:

  • Energy shield in front, back, left and right
  • Phaser weapon system
  • Photon torpedo launcher
  • Warp drive generator
  • Short range scanner

These systems can be used by pressing either one or two keys as required.

When the game starts, an alien craft will appear somewhere in the galaxy, which will probably be out of viewing range. Therefore, you must first your starship in order to face it, and then adjust your height until the alien is in the centre of the screen. While this is happening, the alien will probably be shooting at you. Therefore, before attempting combat, it is a good idea to put some energy into all the shields. This is accomplished by holding the two appropriate keys down. The energy for the shields is then removed from the main fuel energy. If your starship is hit and it has no protection, the starship will be destroyed.

You have a choice of two weapons systems available to you. Proton torpedoes automatically hit and destroy the target, but you only have a limited supply of these. The phasers must hit the center of the enemy ship, in order to destroy it. As it takes a finite time for the phaser blast to reach its target, the enemy could have moved and avoided the shot.

Alternatively, you can escape from the enemy by using your warpdrive generators to enter Hyperspace. Unfortunately, this wears out the engines, so can only be used a few times.

Alien Craft

Once all 30 aliens have been destroyed, or avoided, you must aim your starship into the centre of the stargate, and into the next galaxy. Your ship will then be refueled and you will receive some more photon torpedoes.

There are five different types of alien craft which attack, in waves of six. Each craft gets progressively more dangerous, as they fire more often. Therefore, you have to keep one eye on your shield indicator, to keep each shield topped up, and try to destroy the enemy at the same time. This is no easy task, as it requires a lot of manual dexterity to control 18 buttons simultaneously!

For those of you interesting in converting or modifying the program, I will give a brief description of what the main parts do.

Lines Use
20 Set up machine code
30 Define envelope for explosion
40 to 170 Define user characters for small numbers
180 Trap any errors in the program
200 Set up main variables for the game
210 Set up screen
220 Print title
230 to 270 Add all indicators to screen
280 to 290 Make an alien craft fly past screen
300 Delete title
320 to 360 Main program loop
370 to 390 Your starship has been destroyed
400 Print your final score
410 Update high score
420 to 430 Play another game if required
440 to 540 Read keyboard for keypress
550 Reset colours 8 to 15 to black
560 Set up stars
570 to 580 Move stars
590 Time delay
600 Define graphics window
610 Update score
620 Print in small numbers
630 to 690 Modify forward shield energy
700 to 760 Modify back shield energy
770 to 830 Modify left shield energy
840 to 900 Modify right shield energy
910 Update star date
920 to 940 Update fuel level indicator
950 to 1000 Fire and move phaser shot
1010 Rotate starship to left
1020 Rotate starship to right
1030 Move starship upwards
1040 Move starship downwards
1050 to 1160 Assemble machine code
1170 to 1250 Read in data for alien craft types
1260 to 1270 Set up alien craft position
1280 Plot alien craft
1290 to 1390 Move alien craft
1400 Check for alien fire
1410 to 1470 You are hit by alien fire
1480 to 1490 Check to see if alien craft is hit by phasers
1500 to 1540 Alien craft is destroyed
1550 to 1580 Short range scanner
1590 Calculate position of alien craft relative to the starship's direction
1660 Plot a square
1610 to 1650 Try to go through star gate
1660 to 1680 Go through to next galaxy
1690 to 1700 Fire photon torpedo
1710 to 1760 Hyperspace jump

To fit the program into the limited memory required, the loss of readability in the program. To save memory, I had to remove every unnecessary space, semi-colon and comma. Then, I also had to put as much on one single line as possible. Therefore, when typing in the program do not add any spaces, etc, or you will run out of memory.

Game Controls

The different keys are as follows:

A - Rotate Left, D - Rotate Right, W - Up, X - Down
S - Fire phaser banks, SPACE - Fire photon torpedo
Cursor Up/Down - Increase/Decrease energy level

f0 - Select front energy screen
f1 - Select back energy screen
f2 - Select left energy screen
f3 - Select right energy screen
f4 - Short range scan
f5 - Fire phasers
f6 - Fire photon torpedo
f7 - Increase screen energy level
f8 - Decrease screen energy level
f9 - Hyperspace jump