Michael Bayne
834d9099d6
sprite was following a path is going to scroll; fixed bug in getDirection(); added setDuration() which computes the path velocity based on the time that the sprite should spend following the path. git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@1252 542714f4-19e9-0310-aa3c-eee0fc999fb1
65 lines
2.5 KiB
Java
65 lines
2.5 KiB
Java
//
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// $Id: Path.java,v 1.3 2002/04/15 23:09:10 mdb Exp $
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package com.threerings.media.sprite;
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import java.awt.Graphics2D;
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/**
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* A path is used to cause a sprite to follow a particular path along the
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* screen. The sprite will call into the path every time it is ticked by
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* the animation manager and the path is responsible for updating the
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* position of the sprite based on the time that has elapsed since the
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* sprite started down the path. The animation manager attempts to tick
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* once per frame at the desired frame rate, but may tick less often if
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* CPU resources are limited, thus paths should not rely on tick counts
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* but instead use elapsed time to determine progress.
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*
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* <p> The path should call back to the sprite (via {@link
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* Sprite#pathCompleted}) to let it know when the path has been completed.
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*/
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public interface Path
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{
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/**
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* Called once to let the path prepare itself for the process of
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* animating the supplied sprite.
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*/
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public void init (Sprite sprite, long timestamp);
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/**
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* Called to request that this path update the position of the
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* specified sprite based on the supplied timestamp information. A
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* path should record its initial timestamp and determine the progress
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* of the sprite along the path based on the time elapsed since the
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* sprite began down the path.
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*
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* @return true if the sprite's position was updated, false if the
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* path determined that the sprite should not move at this time.
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*/
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public boolean updatePosition (Sprite sprite, long timestamp);
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/**
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* Sets the velocity of this sprite in pixels per millisecond. The
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* velocity is measured as pixels traversed along the path that the
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* sprite is traveling rather than in the x or y directions
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* individually. Note that the sprite velocity should not be changed
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* while a path is being traversed; doing so may result in the sprite
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* position changing unexpectedly.
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*
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* @param velocity the sprite velocity in pixels per millisecond.
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*/
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public void setVelocity (float velocity);
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/**
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* Called when the view that contains the sprite following this path
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* is scrolling by the specified amount. Gives the path an opportunity
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* to adjust its internal coordinates by the scrolled amount.
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*/
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public void viewWillScroll (int dx, int dy);
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/**
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* Paint this path on the screen (used for debugging purposes only).
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*/
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public void paint (Graphics2D gfx);
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}
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