I am working on a Project in which I have to create an editor, which can create and transform ellipses. I understand all the necessary programming to do it with a GUI for the transformations, but it looks and feels better when all the Ellipses can be transformed by mouse. I know how to drag them, so that shouldn't be a problem, but for the transformation of the 2 radii and the rotation I have no clue.
An sketch of what I'm looking for:
If the grabbing points are visible or not doesn't matter. Do any of you have a knowledge of how to do this easily or if there already is code out there?
I didn't find anything on Google(may be my average search skills though).
Every Node in JavaFX has convenience methods to set transformations. So all you have to do is to register your desired input handlers aplly some transforms based on the mouse position.
ellipse.setRadiusY( radiusY );
ellipse.setRadiusX( radiusX );
ellipse.setRotate( angle );
See a full example.
Related
I've been asked to build something similar to this so that customers can draw basics shapes of kitchen tops. Similar to that in the image below but also have dimensions.
It looks like konva has support for basic shapes like rectangle and circle etc and it also includes a transformer which allows for resizing. However, I think if I want to build a custom shape like the one in green and have individual sizing i.e. resize each individual line. I am going to have to build something myself.
I was hoping someone could point me in the right direction. I have seen an example where someone has used a "line" class which takes a series of points and then sets the attribute to closed which fills in the shape. Obviously I would need to extend this to allow the custom resizing. However, Im not sure this is the correct path to head down?
Any suggestions?
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How about using rectangles and having an option to snap them together. It should be fairly simple to do the edge detection and snapping. Then show the result as a Konva.Line around the perimeter.
Then you can show all the control handles for the rectangles except those on the sides where another Rect has joined.
Using three.js am trying to create a floor that reflects the objects that sit upon it. Preferably the floor material should reflect not like a mirror but in a more 'matte' or diffused way.
To achieve this I looked to Jaume Sanchez Elias who has made a great example using a cube camera: Look for the "smooth material" example on this page:
http://www.clicktorelease.com/blog/making-of-cruciform
Here is my attempt using the same technique. But as you see the reflections are misplaced, they do not appear underneath the mountain objects as expected.
http://dev.udart.dk/stackoverflow_reflections/
I am looking to correct this or to use any other technique that will achieve a more correct diffused reflection.
There are three.js examples using the cube camera technique but they all create mirror-like effects not a soft reflection.
Vibber. Parallax-corrected cubemaps, the technique used in cru·ci·form, only works for closed volumes, like cubes. It works really well to simulate correct reflections inside a room, but not so much for outdoors or open/large scenes. They also can't reflect anything that it's inside the cubemap, you'd have to split the volume in many sub-volumes.
I can think of a couple of solutions for what you want to achieve:
SSR: Screen-space reflections, you can find more info in many places on the internet. It's not the most trivial of effects to implement, and you might have to change the way you render your scene.
Simpler post-processing approach: since you have a flat floor, render the mountains vertically flipped on a framebuffer object, blur it, and render the regular scene on top. For extra effect, render the depth of the flipped mountains, and use that value as the blur radius, to get diffuse reflections.
As always, there's a ton of ways to achieve the (un)expected result :)
I'm using the excellent code provided in threex to allow me to capture clicks on various objects in my scene, which allows me to select them. This works with no issue.
I'd like to extend the selection functionality, where the user can draw a selection box(working), and I can detect all the objects in the scene which are rendered in this selection.
Looking at threex / three, the general onclick algorithm seems to be:
project mouse co-ords to Ray
using ray.intersectObjects(scene), it tests each object in the scene for ray
intersection
This works for a single '1D' ray in the system, but there doesn't seem to be an easy way to modify it to work with a selection box.
Before I attempt to extend this mechanism to work with a selection frustum, is there an alternate / existing facility?
The answer to your question is no, there is no such existing facility.
I would not use Raycaster.intersects() for this.
Probably the easiest thing to do is to assign a 2D screenCoords property to each object, and set it equal to the screen projection of the object's world position. Search this site for how to do that.
Then, consider as selected, those objects whose screenCoords are inside the selection box in screen space.
If you need complete containment, then you have to either do the above for each vertex, or use something like a bounding sphere as an approximation.
three.js r.58
I currently have a FBX animation model of a biped moving slightly forward (positive Z axis), turning around 180 degrees, and starting to run in the opposite direction (negative Z axis).
However, I would like to completely mirror such animation, in other words, start heading the negative Z axis, and the turning forward the positive Z axis. This, preferably through 3dsMax.
I know what you must be thinking, "Why the hell doesn't he just rotate the transform component/object of his animation character??". Well, unfortunately the current code I am working on depends that the characters movement should be independent of the actual animation, among other limitations.
Apparently, according to our 3d designer here, there is no trivial "Rotate Animation" option in 3dsMax (does that check?), so I am looking for possible scripts that could help me out. Anyone ever heard of such solution? Thanks in advance.
Create a dummy aligned to the root of your model.
Link the root of the model to that dummy.
With only the dummy selected, click the mirror button on the maintoolbar.
This will create a mirror image of the bones along with the animation on those bones. The only caveat is the names of the bones will also be mirrored. eg. the arm called 'right_arm' is now now on the left side.
If you need to preserve the animations to the original bones, look into using the animation mixer. This allows loading and saving animations onto characters. But it also has object mapping feature that allows objects of different names to load on saved animations.
So create a mapping. Save the mirrored animation. And load it back onto the original bones with that mapping.
I'd like to implement a dragging feature where users can drag objects around the workspace. That of course is the easy bit. The hard bit is to try and make it a physically correct drag which incorporates rotation due to torque moments (imagine dragging a book around on a table using only one finger, how does it rotate as you drag?).
Does anyone know where I can find explanations on how to code this (2D only, rectangles only, no friction required)?
Much obliged,
David
EDIT:
I wrote a small app (with clearly erroneous behaviour) that I hope will convey what I'm looking for much better than words could. C# (VS 2008) source and compiled exe here
EDIT 2:
Adjusted the example project to give acceptable behaviour. New source (and compiled exe) is available here. Written in C# 2008. I provide this code free of any copyright, feel free to use/modify/whatever. No need to inform me or mention me.
Torque is just the applied force projected perpendicular to a vector between the point where the force is applied and the centroid of the object. So, if you pull perpendicular to the diameter, the torque is equal to the applied force. If you pull directly away from the centroid, the torque is zero.
You'd typically want to do this by modeling a spring connecting the original mouse-down point to the current position of the mouse (in object-local coordinates). Using a spring and some friction smooths out the motions of the mouse a bit.
I've heard good things about Chipmunk as a 2D physics package:
http://code.google.com/p/chipmunk-physics/
Okay, It's getting late, and I need to sleep. But here are some starting points. You can either do all the calculations in one coordinate space, or you can define a coordinate space per object. In most animation systems, people use coordinate spaces per object, and use transformation matrices to convert, because it makes the math easier.
The basic sequence of calculations is:
On mouse-down, you do your hit-test,
and store the coordinates of the
event (in the object coordinate
space).
When the mouse moves, you create a
vector representing the distance
moved.
The force exterted by the spring is k * M, where M is the amount of distance between that initial mouse-down point from step 1, and the current mouse position. k is the spring constant of the spring.
Project that vector onto two direction vectors, starting from the initial mouse-down point. One direction is towards the center of the object, the other is 90 degrees from that.
The force projected towards the center of the object will move it towards the mouse cursor, and the other force is the torque around the axis. How much the object accelerates is dependent on its mass, and the rotational acceleration is dependent on angular momentum.
The friction and viscosity of the medium the object is moving in causes drag, which simply reduces the motion of the object over time.
Or, maybe you just want to fake it. In that case, just store the (x,y) location of the rectangle, and its current rotation, phi. Then, do this:
Capture the mouse-down location in world coordinates
When the mouse moves, move the box according to the change in mouse position
Calculate the angle between the mouse and the center of the object (atan2 is useful here), and between the center of the object and the initial mouse-down point. Add the difference between the two angles to the rotation of the rectangle.
This would seem to be a basic physics problem.
You would need to know where the click, and that will tell you if they are pushing or pulling, so, though you are doing this in 2D, your calculations will need to be in 3D, and your awareness of where they clicked will be in 3D.
Each item will have properties, such as mass, and perhaps information for air resistance, since the air will help to provide the motion.
You will also need to react differently based on how fast the user is moving the mouse.
So, they may be able to move the 2 ton weight faster than is possible, and you will just need to adapt to that, as the user will not be happy if the object being dragged is slower than the mouse pointer.
Which language?
Here's a bunch of 2d transforms in C