question: void render ( GraphicsContext g , Point2D viewportOrigin ) { g . setGlobalAlpha ( life ) ; g . setGlobalBlendMode ( blendMode ) ; if ( image != null ) { g . save ( ) ; g . translate ( x - viewportOrigin . getX ( ) , y - viewportOrigin . getY ( ) ) ; g . scale ( radiusX * 2 / image . getWidth ( ) , radiusY * 2 / image . getHeight ( ) ) ; g . drawImage ( image , 0 , 0 ) ; g . restore ( ) ; } else { g . setFill ( color ) ; g . fillOval ( x - viewportOrigin . getX ( ) , y - viewportOrigin . getY ( ) , radiusX * 2 , radiusY * 2 ) ; } }
target:  Renders particle to g context. Takes into account the viewport origin, so if particle XY is outside the viewport it will not be seen.