Vectron

Manipulate atomic particle blasters and energy deflectors to destroy more targets than your opponent. This strategic marksmanship game is Antic's second offering from the author of Cliffhanger (Antic, Nouember 1986). The BASIC Program works on all 8-bit Atari computers of any memory size, with disk or cassette.

Your Atari starts Vectron by randomly placing a playfield of 50 energy deflectors (arrow-shaped targets) within a border of atomic containment gutters. Opposing atomic particle launchers are at the left and right sides of the field. These two launchers can move up or down. The scores of each player and the number of deflectors remaining are displayed at the bottom of the screen.

Arrangement of the energy deflectors is crucial to the game. Movement of launched projectiles is controlled by the directions in which deflector arrows point. For example, if your projectile is hurtling horizontally across the field and strikes a deflector arrow pointing up, the projectile starts moving upward. At the same time, it blows up the deflector and increases your score by one point.

You win by destroying more deflectors than your opponent. Naturally you want to keep your projectiles in play as long as possible. You do this by finding lengthy "chains" of targets, which will usually make your projectile change direction constantly.

Spend time analyzing the field's target setup before you do anything else during your turn. See which deflector directions and positions will do you the most good. Always look for a new chain, because the playfield is constantly changing. Don't rule out isolated deflectors--they just might get you into a chain that looked inaccessible.

FOUR PHASES

Each player's turn is divided into four phases. During the first phase, the message DEFLECTOR TYPE appears at the top of the screen. Push your joystick in the direction of an arrow that you want to put into play. That arrow direction will be displayed at the top of the screen. Press the joystick button to move to the second part of your turn.

You are now ready to position the deflector. An inverse image of your deflector appears in the middle of the playfield. Use your joystick to move the cursor to the desired position and press the joystick button. But only a buzzer will sound if you try to lay one deflector over another.

You only get to add one deflector during your turn, so you must make sure to place it where it will do you the most good.

Next, move the atomic particle blaster up or down with the joystick. When it is lined up properly, press the joystick button to launch a projectile. The projectile keeps moving in one direction until it hits a deflector.

If the projectile strikes a blaster it will reverse direction and the blaster disappears until the next turn. So don't hesitate to use your opponent's blaster (or even your own) to keep a chain going.

When the projectile hits a containment gutter, it will roll off the screen and your turn is over. Turns continue until there are no targets left. Whoever has the highest score gets a musical victory salute from Vectron.

TYPING VECTRON

Type in Listing 1, VECTRON.BAS, check it with TYPO II and SAVE a copy. If you have trouble typing in the special characters in lines 575 and 581, leave those lines out. Instead, Listing 2 will make a a disk or cassette file called LINES.LST that creates those lines for you. LIST a copy of Listing 2 after you check it with TYPO II. Now type NEW and LOAD Listing 1, then ENTER the file created by Listing 2. Make sure you SAVE a copy of the merged program before you RUN it.

To change the number of targets at the start of the game, change the 50 in line 540 to the number you want. Having more than 99 targets will slightly affect the second player's score display.

To increase the speed of the projectile, remove the FORNEXT loop from line 60. To decrease the speed, increase the number in that loop.

PROGRAM TAKE-APART

Lines 10-20--Jump to initialization routines.

40-100--Establish the initial posotion of projectile, add to the horizontal and vertical positions of projectile and check for collision with gutter or deflector.

120-140--Indicate player turn and adjust the variables accordingly.

160-180--Check trigger for projectile launch and joystick for launcher movement.

200-230--Check trigger for deflector type selection and display deflector options according to joystick input.

250-320--Check joystick for cursor movement and check trigger for selection of deflector location.

340-380--Display projectile rolling down gutter.

400--Display scores and targets left.

420-480--Display game over, scores and winner, play victory tune and display Play Again option.

500-540--Initialize the variables and create the playfield.

560-590--Display the title screen and redefine the characters.

610-630--DATA for shapes.

650---DATA for tune.

Heath Lawrence lives in Port Elgin, Ontario, and has been programming on his Atari 800 for nearly five years. His game Cliffhanger appeared in the November, 1986 issue of Antic.

Listing:VECTRON.BAS Download