While I was trying to rotate Spark TitleWindow using the following code
<s:Rotate id="rotate" angleBy="360" autoCenterTransform="true" target="{targtObj}"></s:Rotate>
it rotates around z-axis. How can I rotate by x-axis or y-axis maintaining the autoCenterTransform="true".
There is also a Spark Rotate3D effect, which enables one to rotate about the other axes. Unfortunately, it doesn't seem to have an equivalent angleBy property, only angleFrom and angleTo for each of the axes. If you are rotating 360°, then that isn't that big of a problem, since you would be ending at the starting point:
<s:Rotate3D id="rotate3D" target="{targtObj}"
angleYFrom="0" angleYTo="360"
autoCenterTransform="true" />
Even if you weren't ending at the starting point, getting the same effect as the angleBy is still a rather simple matter. Here is a 30° rotation about the Y-Axis:
<fx:Number id="lastAngle">0</fx:Number>
<s:Rotate3D id="rotate3D" target="{targtObj}"
angleYFrom="{lastAngle}" angleYTo="{lastAngle+30}"
autoCenterTransform="true" effectEnd="lastAngle+=30"/>
Related
I am trying to create a 3D Visualization of an RC airplane in Threebox. The RC plane sends live telemetry, including:
GPS Coordinates
Gyro sensor data, showing the pitch, roll and heading of the plane.
I have now loaded a Model of an airplane in Threebox, no problems with that.
My problem comes down to the rotation of the plane. I want the plane object to represent the current orientation of the RC plane. Since I have the live telemetry from the flight controller, this should be possible.
In the Documentation, I have found this method, which seemed like exactly what i needed:
plane.setRotation({x: roll, y: pitch, z: yaw/heading})
And it basically works. I can rotate the Plane around its axes. But things get messed up when I combine the rotations.
For example: When I just update the roll axis, the Object behaves just like I want it to. However, when i change the heading of the plane by 90 degrees, the roll axis suddenly becomes the pitch axis. It seems to me, that the axes of the Plane object don't rotate with the plane itself.
I've prepared a recreation of the issue on jsfiddle. You can change the heading of the plane using the slider in the bottom right.
I've been stuck on this for days, would be super happy for any help!
There are lots of issues with your jsfiddle that prevent it from running. To isolate an issue and make it easier to test you should eliminate as many variables as possible - you're using two third-party libraries that will play a big hand in how transformations behave, particularly threebox.
I would recommend sticking with three.js's built in transformation tools unless you specifically need some lat/lng transformations, or other transformations to move between a local cartesian space and a global coordinate system. In this case, a very basic plane.setRotationFromEuler(new THREE.Euler(yaw, pitch, roll)) should do the trick. Be aware of how much order in euler rotations can affect the outcome, and that three.js uses radians for all its rotations, not degrees.
I am using the PerspectiveCamera in three.js. I want to move the camera forward and backward, so I try to use translates and it works well.
I also need to get the camera's position. But the translateZ doesn't change the position of the camera. So what does translateZ change?
All Three.js objects have a translateX, translateY, translateZ method, which changes the position along the axis by the given units. translateZ() moves it along the Z-axis. If you're not seeing any change in the camera, try using larger values, maybe you're just not noticing it because moving forward/backward is a little less obvious than moving up/down or left/right.
Having fun with D3 geo orthographic projection to build an interactive globe, based on all the great examples I found.
You can see my simple mockup at http://bl.ocks.org/patricksurry/5721459
I want the user to manipulate the globe like a trackball (http://www.opengl.org/wiki/Trackball). I started with one of Mike's examples (http://mbostock.github.io/d3/talk/20111018/azimuthal.html), and improved slightly to use canvas coordinates and express the mouse locations in 'trackball coordinates' (i.e. rotation around canvas horizontal and vertical axes) so that a fixed mouse movement gives more rotation near the edges of the globe (and works outside the globe if you use the hyberbolic extension explained above), rather than Mike's one:one correspondence.
It works nicely when the globe starts at an unrotated position (north pole vertical), but when the globe is already rotated (manipulate the example so the north pole is facing out of the page) then the trackball controls become non-intuitive because you can't simply express a change in trackball coordinates as a delta in the d3.geo.rotate lat/lon coordinates. D3's 3-axis rotation involves applying a longitude rotation (spin around north pole), then a latitude rotation (spin around a horizontal axis in the canvas plane), and then a 'yaw' rotation (spin around an axis perpendicular to the plane) - see http://bl.ocks.org/mbostock/4282586.
I guess what I need is a method for composing my two rotation matrices (the one currently in the projection, with a new one to rotate the trackball slightly), but I can't see a way to do that in D3, other than digging into the source (https://github.com/mbostock/d3/blob/master/src/geo/rotation.js) and trying to do the math to define the rotation matrix. The code looks elegant but comment-free and I'm not sure I can correctly decipher the closures with the orthographic projection instance.
On the last point, if someone knows the rotation matrix form of d3.geo.projection that would probably solve my problem too.
Any ideas?
There is an alternative solution to patricksurry's answer, by using quaternion representations, as inspired by Jason Davies. I, too, thought D3 would've already supported this composition natively! And hoped Jason Davies posted his code...
Took sometime to figure out the math. A demo is uploaded here, with an attempt to explain the math too. http://bl.ocks.org/ivyywang/7c94cb5a3accd9913263
With my limited math knowledge, I think, one of the advantages quaternion over Euler is the ability to compound multiple rotations over and over, without worrying about coordinate references. So it would always work, no matter where your north pole faces, and no matter how many rotations you'll have. (Someone please correct me, if I got this wrong).
I decided that solving for the combined rotation matrix might not be so hard. I got http://sagemath.org to do most of the hard work, so that I could express the composition of the original projection rotate() orientation plus a trackball rotation as a single equivalent rotate().
This gives much more natural behavior regardless of the orientation of the globe.
I updated the mockup so that it has the improved version - see http://bl.ocks.org/patricksurry/5721459
The sources are at http://bl.ocks.org/patricksurry/5721459 which include an explanation of the math - cool that you can use proper greek letters in javascript for almost readable math sourcecode!
It would still be good if D3 supported composition of rotate operations natively (or maybe it does already?!)
I'm a fresh in cocos3d, now I have a problem.
In cocos3d, I want to rotate a node. I got the angles in x axis, y axis, z axis, then I used the property:rotation to rotate, like this:
theNodeToBeRotated.rotation = cc3v(x,y,z);
But I found out it didn't rotate as I expected, because the document said the rotate order is y-x-z.
I want to change the order to x-y-z. Can anyone let me know how?
You might need to clarify further regarding the following: "it didn't rotate as I expected"
OpenGL ES (and ergo, cocos3D) uses the y-axis as up so the rotation order is still x-y-z. If you are importing a model, you then need to take into account the 3D editor's co-ordinate system and adapt accordingly.
If you are not used to working with three-dimensional representations, the leap from 2D to 3D can be a significant hurdle. Within Cocos3D:
the x-axis is positive on the right and negative on the left
the y-axis is positive upwards and negative downwards
the z-axis is positive moving towards you and negative moving away from you
Envisage those three lines of axis, or even better, a piece of string.
If you are rotating around the x-axis, hold the string horizontally from left to right: the object would rotating towards you or away from you.
If you are rotating around the y-axis, hold the string vertically from feet to head: the object would rotate as if like a revolving door.
If you are rotating around the z-axis, hold one end close to your chest and the other end as far away as possible: the object would rotate similar to a clock face.
-- Update
I heavily wouldn't recommend changing the rotation order as it is the OpenGL standard to use Y-X-Z. If you wish to modify it, take a look at CC3GLMatrixMath and look for kmMat4RotationYXZ - there is also kmMat4RotationZYX. If you want to have X-Y-Z, you would need to construct your own rotation matrix and update accordingly in CC3GLMatrix and CC3GLMatrixMath.
As a reference, you also have the OpenGL Red book - it should have some suggestions for you.
Context: trying to take THREE.js and use it to display conic sections.
Method: creating a mesh of vertices and then connect face4's to all of them. Used two faces to produce a front and back side so that when the conic section rotates it won't matter from which angle the camera views it.
Problems encountered: 1. Trying to find a good way to create a intuitive mouse rotation scheme. If you think in spherical coordinates, then it feels like just making up/down change phi and left/right change phi would work. But that requires that you can move the camera. As far as I can tell, there is no way to change actively change the rotation of anything besides the objects. Does anyone know how to change the rotation of the camera or scene? 2. Is there a way to graph functions that is better than creating a mesh? If the mesh has many points then it is too slow, and if the mesh has few points then you cannot easily make out the shape of the conic sections.
Any sort of help would be most excellent.
I'm still starting to learn Three.js, so I'm not sure about the second part of your question.
For the first part, to change the camera, there is a very good way, which could also include zooming and moving the scene: the trackball camera.
For the exact code and how to use it, you can view:
https://github.com/mrdoob/three.js/blob/master/examples/webgl_trackballcamera_earth.html
At the botton of this page (http://mrdoob.com/122/Threejs) you can see the example in action (the globe in the third row from the bottom).
There is an orbit control script for the three.js camera.
I'm not sure if I understand the rotation bit. You do want to rotate an object, but you are correct, the rotation is relative.
When you rotate or move your camera, a matrix is calculated for that position/rotation, and it does indeed rotate the scene while keeping the camera static.
This is irrelevant though, because you work in model/world space, and you position your camera in it, the engine takes care of the rotations under the hood.
What you probably want is to set up an object, hook up your rotation with spherical coordinates, and link your camera as a child to this object. The translation along the cameras Z axis relative to the object should mimic your dolly (zoom is FOV change).
You can rotate the camera by changing its position. See the code I pasted here: https://gamedev.stackexchange.com/questions/79219/three-js-camera-turning-leftside-right
As others are saying OrbitControls.js is an intuitive way for users to manage the camera.
I tackled many of the same issues when building formulatoy.net. I used Morphing Geometries since I found mapping 3d math functions to a UV surface to require v little code and it allowed an easy way to implement different coordinate systems (Cartesian, spherical, cylindrical).
You could use particles instead of a mesh I suppose but a mesh seems best. The lattice material is not too useful if you're trying to understand a surface mathematically. At this point I'm thinking of drawing my own X,Y lines on the surface (or phi, theta lines etc) to better demonstrate cross-sections.
Hope that helps.
You can use trackball controls by which you can zoom in and out of an object,rotate the object,pan it.In trackball controls you are moving the camera around the object.Object still rotates with respect to the screen or renderer centre (0,0,0).