A simple 2D Java Renderer (incomplete example implemenation)

renderer.java

/* An example implemenation of data structures to support a 2D Renderer in (semi) Java... */

class abstract Body {
    public Vector2f posNext;
    public Vector2f posPrev;
    
    /**
     * The actual position of the object at time t = t0 + dt * alpha.
     */
    protected Vector2f pos = new Vector2f(0f, 0f);
    
    protected void interpolatePos(float alpha) {
        // Maybe everything should be converted to double and then back to float?
        // Not sure if that will help precision.. I don't even think the precision really matters here, though.
        pos.x = posPrev.x + alpha * (posNext.x - posPrev.x);
        pos.y = posPrev.y + alpha * (posNext.y - posPrev.y);
    }
    
    public abstract void draw(double alpha);
}

/**
 * A Particle is a simple colored polygon.
 */
class Particle {
    
}

class Sprite {
}

class Mesh {
}