9.5: Describing the Data Structures
- Page ID
- 13615
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This program has three data structures to represent the player, enemy squirrels, and grass background objects. The data structures are dictionaries with the following keys:
Keys used by all three data structures:
'x' - the left edge coordinate of the object in the game world (not a pixel coordinate on the screen)
'y' - the top edge coordinate of the object in the game world (not a pixel coordinate on the screen)
'rect' - the pygame.Rect object representing where on the screen the object is located.
Player data structure keys:
'surface' - the pygame.Surface object that stores the image of the squirrel which will be drawn to the screen.
'facing' - either set to LEFT or RIGHT, stores which direction the player is facing.
'size' - the width and height of the player in pixels. (The width & height are always the same.)
'bounce' - represents at what point in a bounce the player is in. 0 means standing (no bounce), up to BOUNCERATE (the completion of the bounce)
'health' - an integer showing how many more times the player can be hit by a larger squirrel before dying.
Enemy Squirrel data structure keys:
'surface' - the pygame.Surface object that stores the image of the squirrel which will be drawn to the screen.
'movex' - how many pixels per frame the squirrel moves horizontally. A negative integer is moving to the left, a positive to the right.
'movey' - how many pixels per frame the squirrel moves vertically. A negative integer is moving up, a positive moving down.
'width' - the width of the squirrel's image, in pixels
'height' - the height of the squirrel's image, in pixels
'bounce' - represents at what point in a bounce the player is in. 0 means standing (no bounce), up to BOUNCERATE (the completion of the bounce)
'bouncerate' - how quickly the squirrel bounces. A lower number means a quicker bounce.
'bounceheight' - how high (in pixels) the squirrel bounces
Grass data structure keys:
'grassImage' - an integer that refers to the index of the pygame.Surface object in GRASSIMAGES used for this grass object
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The comments from lines 1 [37] to 25 [61] are in one large, multi-line string. They describe the keys in the player squirrel, enemy squirrel, and grass objects. In Python, a multi-line string value by itself works as a multi-line comment.