Internal animation function. If you want your program to vary with time, use
the frame() function to update variables. This function is called
approximately 24 times a second.
This is an internal function used by vroom. All internal functions are optional. However, if they are defined in your application they will be called automatically. A list of all internal vroom functions can be found here.
usage
def frame(): # animation (simulation) code goes here...
example
The following program demonstrates usage of the frame() to animate a
bouncing ball. Each time the function is called it updates the global
height variable. The display() function simply draws a sphere at
whatever the current height is.
from math import sqrt def init(): Global.height = 15.0 # height of the ball Global.velocity = 0.0 # ball starts with no velocity Global.gravity = 0.05 # strength of gravity (try changing this # value and see what happens). # In this simple example we will ignore damping effects. Global.max_velocity = sqrt(2.0 * Global.gravity * Global.height) Global.radius = 1.0 # radius of the ball sphereDetail(20) # increase the resolution of the sphere def frame(): # Each time frame() is called we increase (or decrease) the velocity # due to gravity and then update the position of the ball. Global.velocity -= Global.gravity Global.height += Global.velocity # The ball "bounces" when it falls through the floor (when its height # becomes negative). if Global.height < 0.0: Global.height = 0.0 Global.velocity = Global.max_velocity def display(): # Draw the ball. Note that we do not update any variables in the display() # function. All changes related to the animation (simulation) are done in # frame(). material(green) draw(sphere, Global.radius, style='solid').at(0, 0, Global.height) # Draw a grid for the floor. lighting(False) color(0.3) draw(grid, 20, 20, 10, 10).at(-10, -10, -Global.radius)