Racing the Beam: The Atari Video Computer System by Nick Montfort & Ian Bogost

Author:Nick Montfort & Ian Bogost [SPi]
Language: eng
Format: epub, mobi
Tags: History, Videogames, Atari, 80s
ISBN: 9780262012577
Google: m1WlngEACAAJ
Amazon: 026201257X
Goodreads: 5435210
Publisher: Mit Press
Published: 2009-01-09T00:00:00+00:00

Building on Star Castle

The object of Star Castle is to repeatedly destroy the rotating cannon in the center of the screen, with one’s triangular, rotating ship, a vessel that looks and moves like the ones in Asteroids and Space Wars. The enemy cannon appears behind colored overlays and is surrounded by three concentric, rotating shields, each of which is made of line segments. The segments can be destroyed by fire from the player’s ship, but whenever an entire ring is shot away, it regenerates. Whenever the player clears a path to the cannon, creating a chance to shoot at it to destroy it, the cannon fires a large missile toward the player’s ship. As the player is trying to break down the shield rings, three mines also move out and seek the player’s ship. They can be avoided or shot, although shooting them does not increase the score and they soon reappear. After a central cannon is finally successfully destroyed, another one quickly appears with three intact rings around it.

In Yars’ Revenge, the player’s "ship" or "man" is the Yar, a "fly simulator" that is controlled with the joystick. Yars’ Revenge replaces the pivoting of the ship about a point, which could easily be done by the vector graphics display system of Star Castle, with movement in the standard eight directions—up, down, left, right, and diagonally. The latter is a form of movement that was fairly easy for the Atari VCS: translation while facing in one of eight directions. The Yar sprite is animated, requiring an additional frame for each direction, but its appearance facing right is a reflection of what it looks like facing left, allowing for some savings. As was mentioned in the discussion of the VCS Pac-Man, up/down reflection is not as straightforward as left/right reflection. For this reason, the Yar sprites for up and down are both laid out in ROM. Switching between the two requires reading a different bitmap. The insect appearance of the Yar was simply based on what Warshaw could draw and animate in an interesting way within a player sprite.11 The name "Yar" has a more definite referent—it was devised by spelling Atari CEO Ray Kassar’s first name backward. Figure 5.1 compares screens from Star Castle and Yars’ Revenge.

The objective in Yars’ Revenge is the Qotile, which moves up and down along the right side of the screen and is protected by a shield. All of the levels are similar in form, but the first one (and all the odd-numbered levels) have a stationary, somewhat rounded shield around the Qotile, while the other levels (all the even-numbered ones) feature a block of shield whose pieces move left-to-right, down a space, right-to-left, down a space, and then right-to-left again through the block. The motion of the pieces mimics that of the CRT’s electron gun as it sweeps across and back while moving down the screen.

Defeating the Qotile is a somewhat complex process. Initially, the Yar is in a mode where it fires shots

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