P4P2010-05-27
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Programming for Poets, class 5/27
We went through varibles and functions again, and introduced conditionals ("if") statements. We updated our pongball program to bounce!
int ballx = 0; // start at left int bally = 200; // and halfway down int pballx = 0; int pbally = 200; int speed = 5; // the ball moves this number of pixels between frames int deltax = speed; // start with positive x speed (right) int deltay = speed; // start with positive y speed (down) void setup() { // size of our drawing window size(400, 400); // set the background color to gray background(128); } void draw() { // draw over the previous ball location stroke(128); // gray fill(128); drawball(pballx,pbally); // update the ball location ballx = ballx + deltax; bally = bally + deltay; // check that ball is on the screen if(ballx>400) { println("right bounce x"); deltax = -speed; // move left } if(bally>400) { println("bottom bounce y"); deltay = -speed; // now move up } if(ballx<1) { println("left bounce x"); deltax = speed; // now move right } if(bally<1) { println("top bounce y"); deltay = speed; } // now draw ball in new location stroke(255); fill(255); //white drawball(ballx,bally); // save the new location for next time pballx = ballx; pbally = bally; } // draw a paddle-shaped box at the given coordinates void drawbox(int x, int y) { rect(30,y,10,40); } // draw a ball at the given coordinates void drawball(int foo, int bar) { ellipse(foo,bar,10,10); } int myadd(int A, int B) { return (A+B); }