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This example introduces a couple of new things starting on line 13:

float radius = dist(mouseX,mouseY,width/2,height/2);

Here the distance from the mouse pointer to the window center centre is determined (see Pythagoras).

radius = map(radius,0,width,1,4);

The original range is from 0 to the width of the window. The target range is from 1-4. Now radius is transformed from original range to the target range.

-atan2(mouseX - (width / 2),mouseY - (height / 2)); 

The atan2 function returns the angle in radians at a given coordinate from the 0 point. In this example we shift the 0 point to the centre of the screen by subtracting width/2 from X and height/2 from Y.

Image Added

Image Credit: wikipedia

Exercise 8

Create a new program where a simple car follows the mouse on the screen. The car should be drawn from the side, and include wheels that rotate. You may use the example code to get started.

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