I really hate asking this since this question has be answered several times. The problem is... well, it's not working for me.

I'm calling this during my draw():
Code:

if(_rotation!=0){ //only use transform on rotating objects;
	float offsetX = -this._x-(this._width/2);
	float offsetY = -this._y-(this._height/2);
	pushMatrix();
	rotate(_rotation);
	translate(offsetX,offsetY);
	image(b,_x,_y,_width,_height);
	popMatrix(); 
    }  

Okay, so walking through this... we calculate the center point of the image. That's my two floats, returning a float in the middle of the image. pushMatrix(), then rotate on another float, translate, blit, pop.

Now earlier I tried to translate then rotate, but that doesn't seem to work. Also I have to image() before popping, otherwise that doesn't work either.

So what I have is the image is drawn with the center point on the origin (0,0) of the screen rotating in place.

If I try to move the image back with:

image(b,_x+100,_y+100,_width,_height);

or whatever, it'll still rotate around the origin.

It's kinda sad I got collision detection working but I'm struggling on this.

TAB1: Code:

ArrayList Sprites; // build an array of all the sprites, leave this above the class declarion
class bSprite { //Blaine sprite Class
  PImage b;
  float _x;
  float _y;
  float _yspeed;
  float _xspeed;
  float _width;
  float _height;
  float _rotation;

  bSprite (String img, float tempXpos, float tempYpos, float tempXspeed, float tempYspeed){
    // EXAMPLE:  guy = new bSprite("buster.jpg", 10, 10, 1 ,1);
    b = loadImage(img);
    _x = tempXpos;
    _y = tempYpos;
    image(b,_x,_y);
    _xspeed = tempXspeed;
    _yspeed = tempYspeed;
    _width = b.width;
    _height = b.height;
    _rotation = 0;
    Sprites.add(this); // every bSprite is added to the Sprites array

  }
  void move(){
    _x = _x+_xspeed;
    _y = _y+_yspeed;
  }
  void display(){
    if(_rotation!=0){ //only use transform on rotating objects;
	float offsetX = -this._x-(this._width/2);
	float offsetY = -this._y-(this._height/2);
	pushMatrix();
	rotate(_rotation);
	translate(offsetX,offsetY);
	image(b,_x,_y,_width,_height);
	popMatrix(); 
    } 
    else{ // unless rotating, draw image;
	image(b,_x,_y,_width,_height);
    }
  }

  boolean isHit(bSprite target){

    float AX1 =  this._x;
    float AY1 =  this._y;
    float BX1 =  target._x;
    float BY1 =  target._y;
    float AX2 = this._x+this._width;
    float AY2 = this._y+this._height;
    float BX2 = target._x+target._width;
    float BY2 = target._y+target._height;
    //AX1<AX2||AY1<AY2||BX1<BX2||BY1<BY2||
    if(BY2<AY1||AY2<BY1||BX2<AX1||AX2<BX1){
	//if any of these are true, then no collision is possible
	return false;
    } 
    else {
	//additional collision detecting can be added in here
	return true;
    }
  }

}







 

TAB2: Code:

// declare all the sprites

bSprite guy;
bSprite moon;
bSprite dude;
bSprite title;

void setup(){
  smooth();
  Sprites = new ArrayList();
  size(700,500);
  title = new bSprite("dodgeMaulTitle.png", 90,90,0,.5);
  moon = new bSprite("roll.png", 40,40,.2,.2);
  guy = new bSprite("buster.jpg", 300, 300, 0 ,0);
  dude = new bSprite("moon.png", 100,100,0,0);


}
void draw(){
  guy._rotation+=.02;
  background(125);
  for (int i = Sprites.size()-1; i>=0; i--){
    bSprite blit=(bSprite)Sprites.get(i);
    ;
    blit.display();
  }

  for (int i = Sprites.size()-1; i>=0; i--){
    bSprite blit=(bSprite)Sprites.get(i);
    ;

    if(blit._x>width){
	blit._x=0-blit._width;

    }
    else if (blit._y>height){
	blit._y=0-blit._height;
    }


    else{
	blit.move();

    }
  }
  // print(guy.isHit(moon));

}



 

That's 3 questions in as many days... I'll try and take a few off.

Thanks!!

If you want to rotate around the center, you must translate first, rotate, then translate back.

A generic solution is to translate to where you want the centre of the image to be, rotate by the angle you want, then translate -image.width,-image.height