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MegaBounce shows how actual framerate (displayed in the
browser's status bar) varies depending on the number
of balls and whether pixel perfect collision detection
is used. Note that since each ball is checked against
every other ball for a possible collision, the number
of ball to ball comparisons is the number of balls
squared, divided by two.
Use the up and down arrow keys, or the mouse wheel, to control the number of balls, and use the space bar to toggle pixel perfect collision detection. The goal framerate is higher than most monitors' refresh rate, which means that some invocations of draw() will not get to the screen. The value sent to framerate() also controls the typematic or auto-repeat frequency. At the high level of 100, even the quickest press of the up arrow key would result in multiple additional balls; therefore, typematic is turned off for MegaBounce. Class Ball extends Sprite. It's an inner class, so that the code can use the canvas object and the random method, which are part of the Ucigame class. |
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MegaBounce.java
import ucigame.*;
public class MegaBounce extends Ucigame
{
final int MAX_BALLS = 150;
final int GOAL_FRAMERATE = 100;
boolean usePixelPerfect = true;
int numBallsDisplayed = 25;
Ball[] balls = new Ball[MAX_BALLS];
Sprite display;
public void setup()
{
window.size(250, 250);
window.title("MegaBounce");
framerate(GOAL_FRAMERATE);
window.showFPS();
keyboard.typematicOff();
canvas.background(200, 200, 200);
randomSeed(100);
Image ballImage = getImage("images/bouncing-ball.png", 0, 0, 0);
for (int i=0; i<MAX_BALLS; i++)
balls[i] = new Ball(ballImage);
display = makeSprite(getImage("images/border.png", 255, 0, 0));
display.position(canvas.width()/2 - display.width()/2,
canvas.height() - display.height() - 5);
String myFont;
if (isAvailableFont("Georgia"))
myFont = "Georgia";
else
myFont = arrayOfAvailableFonts()[0]; // just choose first one
println("MegaBounce using font " + myFont);
canvas.font(myFont, PLAIN, 40, 0, 150, 50);
}
public void draw()
{
canvas.clear();
canvas.putText("FPS: " + actualFPS(), 60, 80);
for (int i=0; i<numBallsDisplayed; i++)
balls[i].move();
for (int i=0; i<numBallsDisplayed; i++)
{
balls[i].bounceIfCollidesWith(TOPEDGE, BOTTOMEDGE, LEFTEDGE, RIGHTEDGE);
for (int j=i+1; j<numBallsDisplayed; j++)
{
if (usePixelPerfect)
balls[i].bounceIfCollidesWith(balls[j], PIXELPERFECT);
else
balls[i].bounceIfCollidesWith(balls[j]);
}
}
for (int i=0; i<numBallsDisplayed; i++)
balls[i].draw();
display.draw();
display.font("Arial", BOLD, 11, 255, 100, 100);
display.putText("Num Balls: " + numBallsDisplayed, 33, 48);
display.font("Arial", BOLD, 11, 0, 0, 128);
if (usePixelPerfect)
display.putText("Pixel Perf: On", 33, 68);
else
display.putText("Pixel Perf: Off", 33, 68);
}
public void onKeyPress()
{
if (keyboard.isDown(keyboard.UP) && numBallsDisplayed < MAX_BALLS)
numBallsDisplayed = numBallsDisplayed + 1;
if (keyboard.isDown(keyboard.DOWN) && numBallsDisplayed > 1)
numBallsDisplayed = numBallsDisplayed - 1;
if (keyboard.isDown(keyboard.SPACE))
usePixelPerfect = !usePixelPerfect;
}
public void onMouseWheelMoved()
{
numBallsDisplayed = numBallsDisplayed - mouse.wheelClicks();
if (numBallsDisplayed < 1)
numBallsDisplayed = 1;
if (numBallsDisplayed > MAX_BALLS)
numBallsDisplayed = MAX_BALLS;
}
class Ball extends Sprite
{
double rotationIncrement;
double rotationAmount;
int thisBallsNumber;
Ball(Image image)
{
super(image);
position(random(0, canvas.width() - width()),
random(0, canvas.height() - height()));
motion(random(-5, 5), random(-5, 5));
rotationAmount = 0;
rotationIncrement = random(-15, 15);
}
public void draw()
{
rotationAmount = rotationAmount + rotationIncrement;
rotate(rotationAmount);
super.draw();
}
}
}
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