|
Hello all,
I)
I've been trying to use
view.setMinimumFrameCycleTime( ) to set the frame rate in game engine that
we have written, but I haven't been able to get satisfying results. I
wrote a small behavior that demonstrates this problem:
here are the results of
my test app:
ms
fps should be
------
-------- ---------
100 ms
~9.5 10
50 ms
~16.6
20
20 ms
~33.3 50
10 ms
~66.6 100
As you will be able to see in
FramesPerSecondBehavior.java I get the avarage frame rate over 50
frames.
II)
In addition, my other concern is that even if this
method works properly, I wont able to set the frame rate to lock at 30 or 60 Hz
because the parameter that I have to pass in the method is of type
"long" and not double/float. Take the following case as an
example:
ms
fps
------
-------- 16.67 60
(since the argument needed is a "long" we cannot use
16.67) 16 62.5
(if we round down or up, the resulting frame rates are unreasonably
off) 17
58.82 In visual simulations, locking
to a certain frame rate is considered a standard feature, and in gaming, this
problems can cause difficulty when trying to add frame-based
intergrations such as animation sequences, etc.
please let me know if the timing problem (1st
section of this e-mail) is a known bug or if there is a work arroud. I am also
wodering if there is any plans regarding fixing setMinimumFrameCycleTime()
inaccuracies (such as being able to set cycle time in microsecond's instead of
milisecond's).
----------------------------------------------------------------------------------------------
Syrus
Mesdaghi
Full Sail Real World Education
3D Gaming Course
Instructor 3300 University BLVD
[EMAIL PROTECTED]
Winter Park FL 32792
---------------------------------------------------------------------------------------------- |
import java.util.* ;
import javax.media.j3d.*;
public class FramesPerSecondBehavior extends Behavior {
private static FramesPerSecondBehavior instance = new FramesPerSecondBehavior();
private WakeupCondition wakeupCondition;
private WakeupCriterion wakeupCriterion;
int frameCount = 0;
long time = 0;
private FramesPerSecondBehavior(){}
public static FramesPerSecondBehavior getInstance(){
return instance;
}
public void initialize(){
wakeupCriterion = new WakeupOnElapsedFrames(0);
wakeupOn( wakeupCriterion );
}
public void processStimulus(Enumeration criteria){
if (frameCount++ == 1)
time = System.currentTimeMillis();
if (frameCount == 50){
float delta = (float)((System.currentTimeMillis() - time)/1000.0f);///(long)100.0;
float fps = ((float)frameCount)/(delta);
System.out.println(">> Fps: " + fps + " Hz");
frameCount = 0;
}
wakeupOn( wakeupCriterion );
}
}
/*
* @(#)HelloUniverse.java 1.48 00/02/10 13:14:09
*
* Copyright (c) 1996-2000 Sun Microsystems, Inc. All Rights Reserved.
*
* Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
* modify and redistribute this software in source and binary code form,
* provided that i) this copyright notice and license appear on all copies of
* the software; and ii) Licensee does not utilize the software in a manner
* which is disparaging to Sun.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
* IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
* NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
* LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
* OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
* LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
* INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
* CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
* OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*
* This software is not designed or intended for use in on-line control of
* aircraft, air traffic, aircraft navigation or aircraft communications; or in
* the design, construction, operation or maintenance of any nuclear
* facility. Licensee represents and warrants that it will not use or
* redistribute the Software for such purposes.
*/
import java.applet.Applet;
import java.awt.BorderLayout;
import java.awt.event.*;
import java.awt.GraphicsConfiguration;
import com.sun.j3d.utils.applet.MainFrame;
import com.sun.j3d.utils.geometry.ColorCube;
import com.sun.j3d.utils.universe.*;
import javax.media.j3d.*;
import javax.vecmath.*;
public class HelloUniverse extends Applet {
public BranchGroup createSceneGraph() {
// Create the root of the branch graph
BranchGroup objRoot = new BranchGroup();
// Create the transform group node and initialize it to the
// identity. Enable the TRANSFORM_WRITE capability so that
// our behavior code can modify it at runtime. Add it to the
// root of the subgraph.
TransformGroup objTrans = new TransformGroup();
objTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
objRoot.addChild(objTrans);
// Create a simple shape leaf node, add it to the scene graph.
objTrans.addChild(new ColorCube(0.4));
// Create a new Behavior object that will perform the desired
// operation on the specified transform object and add it into
// the scene graph.
Transform3D yAxis = new Transform3D();
Alpha rotationAlpha = new Alpha(-1, Alpha.INCREASING_ENABLE,
0, 0,
4000, 0, 0,
0, 0, 0);
RotationInterpolator rotator =
new RotationInterpolator(rotationAlpha, objTrans, yAxis,
0.0f, (float) Math.PI*2.0f);
BoundingSphere bounds =
new BoundingSphere(new Point3d(0.0,0.0,0.0), 100.0);
rotator.setSchedulingBounds(bounds);
objTrans.addChild(rotator);
// Have Java 3D perform optimizations on this scene graph.
objRoot.compile();
return objRoot;
}
public HelloUniverse() {
setLayout(new BorderLayout());
GraphicsConfiguration config =
SimpleUniverse.getPreferredConfiguration();
Canvas3D c = new Canvas3D(config);
add("Center", c);
// Create a simple scene and attach it to the virtual universe
BranchGroup scene = createSceneGraph();
SimpleUniverse u = new SimpleUniverse(c);
// This will move the ViewPlatform back a bit so the
// objects in the scene can be viewed.
u.getViewingPlatform().setNominalViewingTransform();
u.addBranchGraph(scene);
}
//
// The following allows HelloUniverse to be run as an application
// as well as an applet
//
public static void main(String[] args) {
new MainFrame(new HelloUniverse(), 256, 256);
}
}
