Processing: Creative Coding and Computational Art

This linear motion would plot as a straight line, as its rate of change is constant. If, however,
I initially move a ball 30 pps, and then I keep doubling the rate at which I move the
ball (1 second equals 30 pps, 2 seconds equals 30 pps, 3 seconds equals 120 pps, 4 seconds
equals 240 pps, etc.) based on a geometric progression, I end up with acceleration. Here’s
the same sketch converted from linear motion to accelerated motion. However, to keep
the speed down, rather than continuously doubling the rate, I continuously increase it by
10 percent—which still gets the rectangle cruising. Don’t worry if you can’t follow the
code yet—I’ll be going over this again later in the book, in painstaking detail.
//Example 1: accelerated motion using multiplication
int w = 20;
int h = 10;
int x = 0;
int y;
float speed = 1;
void setup(){
size(400, 400);
y = height/2;
frameRate(30);
}
void draw(){
background(255);
speed*=1.1;
rect(speed, y, w, h);
}
There is another simple way to code acceleration, which uses addition and double implementation.
I’ve included it here for your viewing pleasure:
// Example 2:
// accelerated motion using addition
int w = 10;
int h = 10;
int x = 0;
int y;
float speed;
float acceleration = .1;
void setup(){
size(400, 400);
y = height/2;
}
void draw(){
background(255);
speed += acceleration;
rect(x+=speed, y, w, h);
}
COMPUTER GRAPHICS, THE FUN, EASY WAY
129
4