2 * Sixth 3D engine. Author: Svjatoslav Agejenko.
3 * This project is released under Creative Commons Zero (CC0) license.
5 package eu.svjatoslav.sixth.e3d.gui;
7 public interface ViewRenderListener {
10 * Notifies that it is about time (to keep constant framerate) to render next frame and
11 * allows listener to do any related processing that it needs to.
13 * Each {@link ViewRenderListener} will be notified exactly once before every frame is rendered.
15 * {@link ViewRenderListener} can determine if frame repaint is actually
16 * needed from its perspective. Frame will be rendered only if at least one listener says yes.
17 * This mechanism allows to save computing power and energy by skipping frame rendering when possible.
19 * @return <code>true</code> if underlying view shall be re-rendered. If at least one of the view update listeners
20 * returns <code>true</code>, view is re-rendered.
22 boolean beforeRender(ViewPanel viewPanel, final int millisecondsSinceLastFrame);