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jPCT - a 3d engine for Java => Support => Topic started by: theFALCO on December 12, 2006, 08:24:21 pm
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I'm rotating my cube like so:
if(right) {
cube.rotateY(0.01f);
cube.translate(cube.getYAxis());
}
when I rotate it, it moves down (while rotating), and when I rotate it the similar way with the X axis it moves right (while rotating).
any idea why it acts like that and how to fix it?
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If you just want it to rotate, I am pretty sure you dont need
the last line of code.
Maybe I don't get what your trying to do;)
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yes but then it rotates very strange... from the begining while rotating up/down it behaves as it shoul - it changes it's pitch, when i turn it 90 deg to the right/left then up/down makes it to roll (become like up side down)
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Hee hee, cyberkilla is right. Translating is when you want to move.
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So it rotates but not around its center of origin?
Is this the problem?
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Object3D does have a function called setOrigin(SimpleVector)... Maybe you need to do that first... I am not sure~~ Maybe cube.setOrigin(new SimpleVector(0,0,0)); But then again, I always thought that this origin should be the default...
[edit]Oh right! I remember looking at your code, you did change the origin of your cube after creation... Maybe you should remove that line from your code and see what happens? I still do not know why you would have that problem since you did set it to 0,0,0
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Well, im guessing thats the problem.
When the object is created, the center of the bounding box appears to be set
as the origin.
Thats the assumption im working on anyway;)
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i have created 4 balls: up, down, left and right to visualize it better
what i see is that it seems like it's rotating around the same unchangable axis... what I mean is when the cube rotates, the pivot, axis or whatever it is, doesn't (the cube rotates using some global axis, not it's local) so when it becomes "from the left side" it is rotated as thought it's side was the front... or like so
maybe I forgot something like: cube.recalculateThePivotAndOtherRotationStuffSoThatYouDontHaveProblemsRotatingThisCubeThatYouWasSoHappyAbout();
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I am very clueless on the reply, but anyway! I think that this may help?
Object3D.rotateMesh()
Rotates the raw mesh data using the rotation matrix specified for this object.
You use that after you set the rotation.. There is also a translateMesh(), but that's out of topic...
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First of all, there's a method called setRotationPivot() to set the...rotation pivot :wink: By default, this is set to the calculated center of the object, which is the average of its vertices. For a cube, it's the center.
The rotate?-methods are rotating around a fixed axis, that's correct. If you don't want that, you may use the rotateAxis()-method instead and feed it with the axis you want to rotate around. That should work.
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The god has spoken and now I am enlightened... I know that someday, whenever I get serious with game programming, I will need to know that... Thanks..
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oh, yes I see it in the FPS example
if (left) {
camera.rotateAxis(camera.getBack().getYAxis(), -TURN_SPEED);
playerDirection.rotateY(-TURN_SPEED);
}
if (right) {
camera.rotateAxis(camera.getBack().getYAxis(), TURN_SPEED);
playerDirection.rotateY(TURN_SPEED);
}
I'll try it
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nope, still have problems :(
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Of which kind?
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this is the starting position:
(http://img440.imageshack.us/img440/3977/1am8.jpg)
this shows that from this orientation the up/down rotation is good:
(http://img335.imageshack.us/img335/4695/2sd1.jpg)
but when I turn left (the ball is one of those four balls which I added for better orientation):
(http://img335.imageshack.us/img335/40/3zh7.jpg)
the up/down rotation looks like this:
(http://img72.imageshack.us/img72/322/4tn5.jpg)
(http://img335.imageshack.us/img335/3231/5ro7.jpg)
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I see...so how does the code that does this looks exactly?
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cube init:
private Object3D cube = Primitives.getCube(1);
...
cube.setOrigin(new SimpleVector(0, 0, 0));
cube.setBaseTexture("teks");
cube.setTexture("teks");
cube.setTranslationMatrix(new Matrix());
... // then goes the theWorld.add(cube); and buildAll();
private void gameLoop() {
World.setDefaultThread(Thread.currentThread());
buffer=new FrameBuffer(width, height, FrameBuffer.SAMPLINGMODE_NORMAL);
buffer.enableRenderer(IRenderer.RENDERER_SOFTWARE);
buffer.setBoundingBoxMode(FrameBuffer.BOUNDINGBOX_NOT_USED);
buffer.optimizeBufferAccess();
Timer timer = new Timer(25);
timer.start();
while(!exit) {
if(!isIdle) {
buffer.clear();
theWorld.renderScene(buffer);
theWorld.draw(buffer);
buffer.update();
poll();
camera.setPosition(cube.getTransformedCenter());
camera.align(cube);
if(right) {
cube.rotateAxis(camera.getBack().getYAxis(), 0.01f);
cube.rotateY(0.01f);
}
if(left) {
cube.rotateAxis(camera.getBack().getYAxis(), 0.01f);
cube.rotateY(-0.01f);
}
if(up) {
cube.rotateAxis(camera.getBack().getXAxis(), 0.01f);
cube.rotateX(0.01f);
}
if(down) {
cube.rotateAxis(camera.getBack().getXAxis(), -0.01f);
cube.rotateX(-0.01f);
}
camera.setPosition(cube.getTransformedCenter());
camera.align(cube);
//camera.moveCamera(Camera.CAMERA_MOVEOUT, 10);
buffer.display(gFrame, leftBorderWidth, titleBarHeight);
Thread.yield();
}
}
if (openGL) {
buffer.disableRenderer(IRenderer.RENDERER_OPENGL);
} else {
if (fullscreen) {
device.setFullScreenWindow(null);
}
}
System.exit(0);
}
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Rotate one entity, not a mixture of cube and camera...that may work somehow, but seems to be too confusing to me. Try to change
if(right) {
cube.rotateAxis(camera.getBack().getYAxis(), 0.01f);
cube.rotateY(0.01f);
}
to
if(right) {
cube.rotateAxis(cube.getYAxis(), 0.01f);
}
and the other rotations accordingly.
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cool, it works
thanks :D