MagPi31-single

25, 75 75, 75
MAKE GAMES WITH PYTHON
Tutorial
pygame.draw.circle(window,(255,255,0),(250,200),20,1)
while True:
250,200
20px
#Just like before to help us remember
#pygame.draw.circle(WHERE TO DRAW, (RED, GREEN,
BLUE), (X COORDINATE, Y COORDINATE), RADIUS, HEIGHT,
WIDTH)
pygame.draw.circle(window, (255,255,0),
(250, 200), 20, 0)
pygame.display.update()
Above Here’s how the variables affect the drawing of a circle
while True:
pygame.draw.rect(window, (255,0,0),
(0, 0, 50, 50))
#pygame.draw.rect(window, (0,255,0),
#(40, 0, 50, 50)) FROM HERE
pygame.draw.rect(window, (0,0,255),
(80, 0, 50, 50))
pygame.draw.rect(window, (0,255,0),
(40, 0, 50, 50)) #TO HERE
Just like drawing a rectangle, we tell Pygame on which
surface we want to draw our circle, what colour we want it to
be, and where it should go. The radius is specific to drawing
this particular shape. You might have noticed that we put
a 0 after our radius; this is a value used to determine the
width of the line that draws our circle. If we pass 0, the circle
is filled; but if we pass 2, for instance, we get a 2-pixel-wide
line with an empty centre:
Rectangles are awesome, but
Pygame lets us draw all kinds
of other shapes too
pygame.display.update()
while True:
Now we get rectangle, square, rectangle. This is
because the red and blue squares were drawn first
and then the green square was drawn over the top of
them. We still got squares but we just can’t see all of
them, so they look like rectangles.
But enough with rectangles. Rectangles are awesome
and we can build many things with them, but Pygame
lets us draw all kinds of other shapes too. We can draw
circles, ellipses and paths (which are made up of many
lines between multiple points).
Drawing circles
Drawing a circle is much like drawing a square except
instead of passing a width and a height, we pass a
radius and a point, around which we draw our circle. If
we wanted to draw a yellow circle in the middle of our
window with a diameter of 40 pixels, we would use the
following code to replace the while loop in hello.py:
#Filled
pygame.draw.circle(window,(255,255,0),
(200, 200), 20, 0)
#Not filled
pygame.draw.circle(window,(255,255,0),
(300, 200), 20, 2)
pygame.display.update()
What about ellipses? They are a slightly strange
cross between drawing rectangles and circles. It’s
the same as drawing a rectangle: we pass an X
coordinate, a Y coordinate, a width, and a height,
but we end up with a circle(ish) shape. Let’s draw an
ellipse or two…
raspberrypi.org/magpi March 2015 53