Canvas Games: Part I - HTML5 Canvas - page 698

case case 3 :

this

this . width = 16 ;
this

this . height = 16 ;
break

break ;

}

}

Rock . prototype . update = function function ( xmin , xmax , ymin , ymax ) {

this this . x += this this . dx ;

this this . y += this this . dy ;

this this . rotation += this this . rotationInc ;

iif ( this this . x > xmax ) {

this this . x = xmin - this this . width ;

} else else iif ( this this . x < xmin - this this . width ){

this this . x = xmax ;

}

iif ( this this . y > ymax ) {

this this . y = ymin - this this . width ;

} else else iif ( this this . y < ymin - this this . width ){

this this . y = ymax ;

}

}

Rock . prototype . draw = function function ( context ) {

var var angleInRadians = this this . rotation * Math . PI / 180 ;

var var halfWidth = Math . floor ( this this . width * . 5 ); //used to find center of object

var var halfHeight = Math . floor ( this this . height * . 5 ) // used to find center of object

context . save (); //save current state in stack
context . setTransform ( 1 , 0 , 0 , 1 , 0 , 0 ); // reset to identity
// translate the canvas origin to
// the center of the player

context . translate ( this this . x + halfWidth , this this . y + halfHeight );

context . rotate ( angleInRadians );
context . strokeStyle = '#ffffff' ;

context . beginPath ();

// draw everything offset by 1/2. Zero Relative 1/2 is if .5*width −1.
// Same for height

context . moveTo ( - ( halfWidth - 1 ), - ( halfHeight - 1 ));
context . lineTo (( halfWidth - 1 ), - ( halfHeight - 1 ));
context . lineTo (( halfWidth - 1 ),( halfHeight - 1 ));