Question

I don’t know if this is the correct website, but you guys have been so helpful before, I wanted to get your advice on a problem I’m having with Python and Pygame.

I am making a simple game, and only recently begun learning Python (loving it so far) and at the moment, I having a sprite constructor which I am using. This constructor will manage my objects, but I want it to draw either an ellipse or a rectangle based on an argument passed to it.

#My code
class Block(pygame.sprite.Sprite):
    #Variables!
    speed = 2
    indestructible = True
    #Constructor
    def __init__(self, color, width, height, name, shapeType):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.Surface([width,height])
        self.image.fill(color)
        #Choose what to draw
        if shapeType == "Ellipse":
            pygame.draw.ellipse(self.image,color,[0,0,width,height])
        elif shapeType == "Rect":
            pygame.draw.rect(self.image,color,[0,0,width,height])
        elif shapeType == "":
            print("Shape type for ",name," not defined.")
            pygame.draw.rect(self.image,color,[0,0,width,height])
        #Init the Rect class for sprites
        self.rect = self.image.get_rect()

The coding I am using for drawing a square is below:

#Add 'white star' to the list
for i in range(random.randrange(100,200)):
    whiteStar = Block(white, 1, 1, "White Star", "Rect")
    whiteStar.rect.x = random.randrange(size[0])
    whiteStar.rect.y = random.randrange(size[1])
    whiteStar.speed = 2
    block_list.add(whiteStar)
    all_sprites_list.add(whiteStar)

This works wonderfully. It draws a perfect little white square for me. But this doesn’t work:

#Create Planet
planet = Block(green, 15,15, "Planet", "Ellipse")
planet.rect.x = random.randrange(size[0])
planet.rect.y = 30
planet.speed = 1
block_list.add(planet)
all_sprites_list.add(planet)

The ‘planet’ spawns correctly, but it does so as a square. Why is this happening? And how can I fix it? Should I use a bitmap to correct this? Or is my coding wrong?

Just to clarify, I know for a fact that self.rect = self.image.get_rect() does work to draw an ellipse, because the coding below works.

#Not the code I'm using, but this works and proves self.rect = self.image.get_rect() is not the cause
# Call the parent class (Sprite) constructor
    pygame.sprite.Sprite.__init__(self) 

    # Create an image of the block, and fill it with a color.
    # This could also be an image loaded from the disk.
    self.image = pygame.Surface([width, height])
    self.image.fill(white)
    self.image.set_colorkey(white)
    pygame.draw.ellipse(self.image,color,[0,0,width,height])

    # Fetch the rectangle object that has the dimensions of the image
    # image.
    # Update the position of this object by setting the values 
    # of rect.x and rect.y
    self.rect = self.image.get_rect()

Thankyou for your help. 🙂

Answer 1

In the Block constructor, you call self.image.fill(color). That will fill the sprite’s entire image with that color, so you get a rectangle.

The example code you have calls self.image.set_colorkey(white) after doing the fill, so that when it gets drawn, the background fill is transparent. That’s probably the fastest solution.