sprint

Attribution

Original Python code


from time import time

WIDTH  = 800
HEIGHT = 300

ACCELERATION = 0.005
DECELERATION = 0.0008
# number of pixels representing 1m
SCALE = 75

# a function to display an image at a specific distance along the track
def displayAt(img, pos, y):
    screen.blit(img,(sprinter.x + (pos * SCALE) - (sprinter.distance * SCALE), y))

class Sprinter(Actor):
    def __init__(self, **kwargs):
        super().__init__(image='idle', pos=(200,220), **kwargs)
        self.startTime = time()
        self.finishTime = time()
        self.runFrames = ['run' + str(i) for i in range(1,16)]
        self.timeOnCurrentFrame = 0
        self.speed = 0
        self.lastPressed = None
        self.keyPressed = False
        self.distance = 0

    # advances the sprinter to the next frame
    def nextFrame(self):
        # start the running animation if currently idle
        if self.image == 'idle':
            self.image = self.runFrames[0]
        else:
            # find the next image in the list, wrapping back to the first image
            # when the end of the list is reached
            nextImageIndex = (self.runFrames.index(self.image) + 1) % len(self.runFrames)
            self.image = self.runFrames[nextImageIndex]

    # checks whether left and right arrow keys are
    # being pressed alternately
    def isNextKeyPressed(self):
        if keyboard.left and self.lastPressed is not 'left' and not keyboard.right:
            self.lastPressed = 'left'
            return True
        if keyboard.right and self.lastPressed is not 'right' and not keyboard.left:
            self.lastPressed = 'right'
            return True
        return False

    def update(self):
        # update sprinter's speed
        # accelerate on alternate key presses
        if self.isNextKeyPressed() and self.distance < 100:
            self.speed = min(self.speed + ACCELERATION, 0.15)
        # decelerate if no key pressed
        else:
            self.speed = max(0, self.speed-DECELERATION)
        # use the sprinter's speed to update the distance
        self.distance += self.speed
        # animate the sprinter in relation to its speed
        self.timeOnCurrentFrame += 1
        if self.speed > 0 and self.timeOnCurrentFrame > 10 - (self.speed * 75):
            self.timeOnCurrentFrame = 0
            self.nextFrame()
        # set to idle animation if not moving
        if self.speed <= 0:
            self.image = 'idle'


#--------

sprinter = Sprinter()

def update():
    # move and animate the sprinter
    sprinter.update()
    # add to the finish time if race is still in progress
    if sprinter.distance < 100:
        sprinter.finishTime = time()

def draw():
    screen.clear()
    # draw the track
    screen.blit('track', (0,0))
    # draw distance markers and finish line
    displayAt('25m', 25, 200)
    displayAt('50m', 50, 200)
    displayAt('75m', 75, 200)
    displayAt('finishline', 100, 230)
    # draw the sprinter
    sprinter.draw()
    # draw the current distance and time
    screen.draw.text('Distance (m): ' + str(int(min(100, sprinter.distance))), (20, 20), fontsize=32, color="white")
    screen.draw.text('Time (s): ' + str(round(sprinter.finishTime - sprinter.startTime, 2)), (250, 20), fontsize=32, color="white")