linear functions
Let's start with a simple one:
int simple(int x) {
return x;
}
And this just means make y equal to whatever x is.
If we want y to change at the same speed as x but not have the same value, we can do something like this:
int fiveMore(int x) {
return (x + 5);
}
which means make y equal to whatever x is plus 5. + 5 is referred to as a constant term.
We can also make y change at a different speed than x:
int twice(int x) {
return (x * 2);
}
which means make y equal to double what x is. 2 is referred to as a coefficient.
We can also combine these, and that's what we'll do in the following applet. Note that the move(...) function's x parameter has nothing to do with horizontal coordinates.
//----------------------------
// variables
float currY;
int currTime;
//----------------------------
void setup() {
// set up the applet
size(300, 300);
smooth();
frameRate(30);
// reset the animation independent variable (time)
currTime = 0;
// set the ball color
noStroke();
fill(#FF6F00);
}
//----------------------------
void draw() {
// clear the screen
background(0);
// move the ball
currY = move(currTime);
// draw the ball
ellipse(width/2, currY, 20, 20);
currTime++;
}
//----------------------------
void mousePressed() {
// reset the animation independent variable (time)
currTime = 0;
}
//----------------------------
float move(float x) {
return (0.8 * x + 10);
}
That's a bit lame, but that's because this function is pretty simple.