PVector follow mouse - weird jumping...

Programming Questions

cdaein

PVector follow mouse - weird jumping...

in Programming Questions • 8 months ago

I'm having trouble with this game program I'm making. you can control the spaceship with your mouse, and it will ease in to your mouse location. But sometimes, there is a random position jump. The default renderer is quite slow, so I'm using P2D. My target framerate is 60fps.

I'm guessing my update() function inside Spaceship class may have a problem, but it's been inconsistent. The default renderer seems fine and it's worse on my MacBook Air than my Macbook Pro with Retina.(I don't know if this is relevant.)

I attached a video that shows this strangeness.

Any help would be appreciated!

              
               Spaceship player;
               int life = 10;
               int score = 0;
               

               ArrayList<Asteroid> asteroids;
               int numAsteroids = 70;
               

               boolean gameOver = false;
               

               

               void setup() {
                 size(800, 600, P2D);
                 frameRate(60);
               

                 player = new Spaceship(life);
                 asteroids = new ArrayList<Asteroid>();
                 for (int i=0; i<numAsteroids; i++) {
                   asteroids.add(new Asteroid());
                 }
               

                 mouseX = width/2;
                 mouseY = height/2;
               }
               

               void draw() {
                 background(0);
               

                 for (int i = 0; i < asteroids.size(); i++) {
                   Asteroid a = (Asteroid) asteroids.get(i);
                   a.update();
                   a.display();
               

                   if (player.isHitBy(a)) {
                     asteroids.remove(a);
                     fill(255, 0, 0);
                     rect(0, 0, width, height);
                     if (player.life <= 0) {
                       gameOver = true;
                     }
                   }
                 }
               

                 if (!gameOver) {
                   player.display();
                   player.update();
                 }
               

                 drawHUD();
                 debug();
               }
               

               void keyPressed() {
                 if (key == ' ') {
                   //shoot a bullet
                 }
               }
               

               void debug() {
                 println("FPS: " + frameRate + " | " + "Life: " + player.life);
               }
               

               void drawHUD() {
                 if (gameOver) {
                   noStroke();
                   fill(0, 150);
                   rect(0, 0, width, height);
               

                   fill(255, 0, 0);
                   textSize(80);
                   textAlign(CENTER);
                   text("GAME OVER", width/2, height/2);
                   textSize(30);
                   text("Your Score is " + score, width/2, height/2+40);
                 } 
                 else {
                   fill(255, 255, 0);
                   textSize(24);
                   textAlign(LEFT);
                   text("life: " + player.life, 30, 30);
                   text("Score: " + score, 30, 50);
                 }
               }

class Asteroid {
PVector loc = new PVector();
PVector vel = new PVector();
float mass;
color c;
float timeFactor = 1;
Asteroid() {
c = color(random(100, 150), random(100, 150), 0);
reset();
}
void reset() {
timeFactor += .1;
mass = random(1, 4);
float r = random(1);
if (r < .25) {
loc.x = random(-10, 0);
loc.y = random(height);
vel.x = timeFactor * (2/mass) * random(0.5, 2);
}
else if (r < .5) {
loc.x = random(width, width+10);
loc.y = random(height);
vel.x = timeFactor * (2/mass) * random(-2, -0.5);
}
else if (r < .75) {
loc.x = random(width);
loc.y = random(-10, 0);
vel.y = timeFactor * (2/mass) * random(0.5, 2);
}
else {
loc.x = random(width);
loc.y = random(height, height+10);
vel.y = timeFactor * (2/mass) * random(-2, -0.5);
}
}
boolean isOffscreen() {
if (loc.x > width+10 || loc.x < -10 || loc.y > height+10 || loc.y < -10) {
return true;
}
else {
return false;
}
}
void update() {
vel.limit(10);
loc.add(vel);
if (this.isOffscreen() && !gameOver) {
score += 10;
reset();
}
}
void display() {
pushMatrix();
translate(loc.x, loc.y);
noStroke();
fill(c);
ellipse(0, 0, mass*10, mass*10);
popMatrix();
}
}

class Spaceship {
PVector loc;
PVector vel;
PVector acc;
int life;
float topspeed = 6.0;
float easing = 0.2;
Spaceship(int _life) {
loc = new PVector(width/2, height/2);
vel = new PVector();
acc = new PVector();
life = _life;
}
boolean isHitBy(Asteroid a) {
if (dist(loc.x, loc.y, a.loc.x, a.loc.y) < 10.0) {
life--;
return true;
}
else {
return false;
}
}
void update() {
PVector mouse = new PVector(mouseX, mouseY);
PVector dir = PVector.sub(mouse, loc);
acc.add(dir);
vel.add(acc);
vel.limit(topspeed);
dir.mult(easing);
loc.add(dir);
acc.mult(0);
}
void display() {
float theta = vel.heading2D();
pushMatrix();
translate(loc.x, loc.y);
rotate(theta);
noStroke();
fill(0, 200, 100);
triangle(20, 0, -10, -10, -10, 10);
popMatrix();
}
}

Replies(5)

GoToLoop

Re: PVector follow mouse - weird jumping...

8 months ago

You haven't published your class Item.
And you have a
ConcurrentModificationException @ line #38.
Like the post here -> http://forum.processing.org/topic/wth-with-arraylist-cocurrentmodificationexception

cdaein

Re: PVector follow mouse - weird jumping...

8 months ago

Sorry..I just fixed the code. Now Item class problem is gone.

And I'm going to look at your link.

Thank you.

cdaein

Re: PVector follow mouse - weird jumping...

8 months ago

I removed all the unnecessary parts in my program, and there is only Spaceship class now and I still have the same problem - spaceship position jumps from time to time.

Spaceship player;
int life = 10;
int score = 0;
boolean gameOver = false;
void setup() {
size(800, 600, P2D);
frameRate(60);
player = new Spaceship(life);
}
void draw() {
background(0);
if (!gameOver) {
player.display();
player.update();
}
drawHUD();
}
void keyPressed() {
if (key == ' ') {
//shoot a bullet
}
}
void drawHUD() {
if (gameOver) {
noStroke();
fill(0, 150);
rect(0, 0, width, height);
fill(255, 0, 0);
textSize(80);
textAlign(CENTER);
text("GAME OVER", width/2, height/2);
textSize(30);
text("Your Score is " + score, width/2, height/2+40);
}
else {
fill(255, 255, 0);
textSize(24);
textAlign(LEFT);
text("life: " + player.life, 30, 30);
text("Score: " + score, 30, 50);
}
}
class Spaceship {
PVector loc;
PVector vel;
PVector acc;
int life;
float topspeed = 6.0;
float easing = 0.2;
Spaceship(int _life) {
loc = new PVector(width/2, height/2);
vel = new PVector();
acc = new PVector();
life = _life;
}
void update() {
PVector mouse = new PVector(mouseX, mouseY);
PVector dir = PVector.sub(mouse, loc);
acc.add(dir);
vel.add(acc);
vel.limit(topspeed);
dir.mult(easing);
loc.add(dir);
acc.mult(0);
}
void display() {
float theta = vel.heading2D();
pushMatrix();
translate(loc.x, loc.y);
rotate(theta);
noStroke();
fill(0, 200, 100);
triangle(20, 0, -10, -10, -10, 10);
popMatrix();
}
}

GoToLoop

Re: PVector follow mouse - weird jumping...

8 months ago

Dunno if it fixes for you. But I've made some tweaks here and it's working on Processing 1.5.1 for me.

// Main Sketch:

/**
 * Asteroids (v2.52)
 * by cdaein (2013/Feb)
 *
 * http://forum.processing.org/topic/pvector-follow-mouse-weird-jumping
 */

boolean gameOver;
int score, life  = 10;

final Spaceship player = new Spaceship(life);

final static byte numAsteroids = 100;
final static List
               
                <Asteroid> asteroids = 
                new 
                ArrayList(numAsteroids);


                void 
                setup() {
  
                size(800, 600, 
                P2D);
  
                frameRate(60);
  
                noStroke();

  
                mouseX = 
                width>>1;
  
                mouseY = 
                height>>1;

  
                for (
                int i=0; i!=numAsteroids; i++)  asteroids.
                add( 
                new Asteroid() );
}


                void 
                draw() {
  
                background(0);  

  
                for (
                int i=asteroids.
                size(); i!=0;)
    
                if ( asteroids.
                get(--i).action() )    asteroids.remove(i);

  
                if (player.life <= 0)   gameOver = 
                true;

  
                if (!gameOver) {
    player.display();
    player.update();
  }

  drawHUD();
  debug();
}  


                void 
                keyPressed() {

                 int k = keyCode;

               
                
  
                if (k == 
                ' ') {
    
                //shoot a bullet
  }
}


                void debug() {
  
                print( 
                "FPS: " + 
                round(
                frameRate) + 
                " | Life: " + player.life );
  
                println( 
                " | Asteroids: " + asteroids.
                size() );
}


                void drawHUD() {
  
                if (gameOver) {
    
                fill(0, 150);
    
                rect(0, 0, 
                width, 
                height);

    
                fill(#FF0000);
    
                textSize(80);
    
                textAlign(
                CENTER);
    
                text(
                "GAME OVER", 
                width>>1, 
                height>>1);

    
                textSize(30);
    
                text(
                "Your Score is " + score, 
                width>>1, 
                height/2 + 40);
  } 
  
                else {
    
                fill(#FFFF00);
    
                textSize(24);
    
                textAlign(
                LEFT);
    
                text(
                "life: " + player.life, 30, 30);
    
                text(
                "Score: " + score, 30, 50);
  }
}

// Class Asteroid:

final class Asteroid extends PVector {
  final PVector vel = new PVector();

  float mass, timeFactor = 1;

  final static byte maxSize = 15, topSpeed = 10;
  final int w, h;
  final color c;

  Asteroid() {
    c = color(random(100, 150), random(100, 150), 0);
    w = width;
    h = height;
    
    reset();
  }

  void reset() {
    timeFactor += .1;
    mass  = random(1, 4);

    float factor =  2/mass * timeFactor;
    float r = random(1);

    if (r < .25) {
      x = random(-maxSize);
      y = random(h);
      vel.x = factor * random(.5, 2);
    }
    else if (r < .5) {
      x = random(w, w+maxSize);
      y = random(h);
      vel.x = factor * random(-2, -.5);
    }
    else if (r < .75) {
      x = random(w);
      y = random(-maxSize, 0);
      vel.y = factor * random(.5, 2);
    }
    else {
      x = random(w);
      y = random(h, h+maxSize);
      vel.y = factor * random(-2, -.5);
    }
  }

  boolean isOffscreen() {
    return x > w+maxSize | x < -maxSize | 
      y > h+maxSize | y < -maxSize;
  }

  void update() {
    vel.limit(topSpeed);
    add(vel);

    if (isOffscreen() & !gameOver) {
      score += 10;
      reset();
    }
  }

  void display() {
    pushMatrix();
    translate(x, y);
    fill(c);
    ellipse(0, 0, mass*maxSize, mass*maxSize);
    popMatrix();
  }

  boolean checkHit() {
    if ( player.isHitBy(this) ) {
      --player.life;

      fill(#FF0000);
      rect(0, 0, w, h);

      return true;
    }

    return false;
  }

  boolean action() {
    update();
    display();
    return checkHit();
  }
}

// Class Spaceship:

final class Spaceship extends PVector {
  final PVector vel = new PVector();
  final PVector dir = new PVector();

  final static float topSpeed = 6f;
  final static float easing = .2;

  final static byte  shipSize = 10;
  final static color c = #00C864;

  int life;

  Spaceship(int lives) {
    super(width>>1, height>>1);
    life = lives;
  }

  boolean isHitBy(Asteroid a) {
    return dist(a) < shipSize<<1;
  }

  void update() {
    dir.set(mouseX, mouseY, 0);
    dir.sub(this);

    vel.add(dir);
    vel.limit(topSpeed);

    dir.mult(easing);
    add(dir);
  }

  void display() {
    fill(c);

    pushMatrix();

    translate(x, y);
    g.rotate( vel.heading2D() );

    triangle(shipSize<<1, 0, -shipSize, 
    -shipSize, -shipSize, shipSize);

    popMatrix();
  }
}

cdaein

Re: PVector follow mouse - weird jumping...

8 months ago

Thank you very much for taking your time on this.

As you said, it works really good on Processing 1.5.1 but it still has the same problem on 2.0b7. I'll just stick with 1.5.1 for this project..

Regardless of that, your code optimization definitely leaves me a lot to play with and learn from.

Thank you again!

Top Reply