Proposal: SPACE DESTROYER!

by : LINUS OKOTH and Maximos Xu

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About

Space destroyer is a hybrid version of the classic arcade games Asteroids and Space Invaders.

Synopsis

Elements

The game will have four elements that will be factored from different sections as listed below:

• SpaceObject

  This is a Abstract class that defines the general attributes and behavior of any of my objects floating in space. It comprises of the following listed elements;

  • Falcon

    A horizontally and vertically movable rectangle that produces rectangles at the upper tip that we refer to as missiles. It inherits the abstract class Space Object, and is controlled by the user.

  • Destroyer

    Horizontally movable rectangles located at the top of the screen. Their movement is predefined and the speed varies depending on the level. They also randomly shoot straight missiles downwards. They are inherited from the abstract class Space Object.

    • DeathStar

      This is a bigger horizontally movable object that shoots missiles at a faster rate than other Destroyers. It also moves faster than other destroyers and disappears on one part of the screen and reappears on the other side of the screen. It also has a longer life span (3 lives) than other destroyers. It inherits the Destroyer class.

  • Asteroids

    These are circular objects randomly floating on the screen. They are inherited from the Abstract Space Object class.

• Missile

  These are vertically mobile rectangles that originate from some members of Space Object. The velocity and size are determined by which type of object produced them.

Goal

The players goal is to control the falcon to shoot and manoeuvre the Asteroids to eventually destroy the Destroyers and the DeathStar in the Boss level.

Game play

The game starts in a frozen state with the falcon stationary at the center bottom with three bars at the left corner of the screen showing the player lives left. Asteroids are positioned in the middle of the screen and the destroyers are stationary at the top of the screen. When spacebar is pressed the game starts and the asteroids start randomly floating and the Destroyers begin moving horizontally at the top sporadically firing missiles downwards. To complete the level the player has to navigate by using the directional keys and fire missiles at the Destroyers and asteroids with the space bar while dodging any approaching missiles or asteroids. If the player (falcon) hits any edge of the screen or any screen object then their life is reduced by one. If the player loses all their lives then the game ends and the game is reset.

If the player manages to destroy all the destroyers then the boss stage begins with every other screen object being cleared and the boss replacing the destroyers at the top. The player will strictly have their number of lives from the previous level.

Functional requirements

1. The destroyers are placed stationary in a row at the top when the game starts. The player is placed at the center of the x plane above the bottom of the screen when the game start. The Asteroids are placed starting from the top 1/4 down to the bottom 3/4 end and stationary in a frozen state. Verification Observe when starting the game
2. The player can launch the game by pressing the space bar and this makes the Asteroids begin random motion while the destroyers move uniformly horizontally towards the right. Verification Observe by presing the space bar
3. When the player presses the up or down key, the Falcon moves up or down with a predefined velocity. On release of the up or down key the Falcon resets to a velocity of zero and stops. Verification Observe by pressing up and down arrow keys
4. When a side key is pressed, the Falcon surges towards that side with a predefined velocity. On release of a side key, the falcon stops. When the player presses F, the Falcon fires a missile vertically upwards. Verification Observe by pressing side keys and by pressing F
5. If the falcon hits any of the sides it loses one life. If the Falcon hits any of the screen elements or is hit by an element or missile, it loses one life and is reset to a frozen state, and all the asteroids are also recreated and reset to a frozen state. The remaining destroyers are reset to a frozen state awaiting user to press the space bar. Verification Second test case in screenObject_test Can also be verified by playing the game and losing a life
6. If the Falcon loses all lives the game is over and thus the game resets completely; back to frozen mode with the player having 3 lives. Verification First test in model_test Can also be verified by dieing three times
7. If any of the other space objects on the screen is hit by a asteroid except the Falcon, the asteroid is reflected both vertically and horizontally and it then continues with its random motion. Verification Second test in model_test Can be observed by seeing asteroids bounce off each other
8. If an Asteroid is hit by a missile it is immediately destroyed. If a destroyer is hit by any missile then they are removed. Verification 4th test case in screenObject_test and 3rd test case in model_test Can be observed by shooting an asteroid/destroyer with a missile
9. If a destroyer hits any of the sides, all the destroyers velocity are reflected horizontally. Verification 4th test case in model_test Observe by starting the game, the destroyers constantly sway left and right
10. Destroyers fire a missile straight down periodically Verification Can be observed in game
11. If the player destroy all destroyers the boss stage begins with the boss behaving directly as other destroyers except with a higher velocity, faster shooting pace, and three lives. All the asteroids are reset. Verification Observe by destroying all the destroyers
12. If a missile hits any of the windows sides its destroyed. If it hits a spaceObject, both the object and the space missile are destroyed. If it hits the Falcon, the falcon loses a life and is reset. Verification 5th test in model_test and First test in model_test Can be observed by firing a missiles
13. If the Falcon kills the boss or vice versa, the game is completely reset to the beginning frozen state. Verification Can be observed by hitting the deathstar with 3 missiles
14. There is an asteroid field that begins immediately below the destroyers. The asteroids will bounce off the field, reflecting its velocity vertically. Verification 6th test in model_test Can be observed by seeing the asteroids bounce off invisible field