Animations Demonstrates more animation techniques

More Animation Examples The Animations.zip program demonstrates additional animation methods. The opening form, featuring the old Michigan Stadium (without luxury boxes or a losing team), demonstrates using an array of points to define a path for an object to follow. The Shapes form demonstrates have to build a picture in layers (this technique would be simple to apply to the drawings you are creating for assignment 8). The Velocity form demonstrates how to apply some simple physics (the constant downward acceleration of gravity) to objects. The Multiball form demonstrates how to manage numerous objects at the same time.

The Punt Return The punt return (frmAnimationExamples) uses a pre-defined set of points:

Punt Return When the timer ticks, the ball moves to the next point on the curve:

Adding Some Physics The Velocity and Multiball forms in the Animations example demonstrate incorporating some simple physics into a class. The ball.vb class has a velocity variable (mv) which is a Structure consisting of x and y components. Since these balls will be flying close to ground, they will obey the simplified law of gravity— gravity is a constant downward acceleration (g). The program assumes no air resistance, so the x velocity will remain constant.

Coding Gravity Here’s the code: Every tick of the timer, the object moves a distance equivalent to its velocity in each direction (assuming velocity is in units of pixels/tick). The y velocity is then reduced by the value of gravity, so it will be less the next time the timer ticks. By varying the x and y velocities and the value of gravity, we get different trajectories for the balls.

The football class The football class inherits from the ball class, overriding only how it is drawn. The constructor simply calls ball’s constructor (VB requires that you do this if you want a custom constructor in a derived class).