I have several geometry meshes in my Viewport3D, these have bounds of (w:1800, h:500, d:25).
When a user clicks in the middle of the mesh, I want the Point3D of (900, 500, 25)...
How can I achieve this?
Thanks!
Mark
Just use VisualTreeHelper.HitTest with the callback.
If you have a Viewport3D containing the model, you can just pass in a PointHitTestParameters containing the mouse location.
If you need to operate directly on a Visual3D, pass in a RayHitTestParameters computed from your camera parameters and the mouse location.
In either case your callback will be called with a RayTestHitResult, and if you hit a mesh it will be a RayMeshGeometry3DHitTestResult. This includes a Point3D property telling you the 3D point in space that was hit, and also the mesh and triangle that was hit.
See 3D Hit testing for more details.
Related
I have an ellipse which is drew on a window. I want to show a message when the pointer is on it (on the ellipse). How I do it? Is there any event for shapes? Like WM_MOVE or WM_SIZE.
I use TDM-GCC and C language.
When you draw on a device context, all knowledge of what shape you draw is lost, and the system just retains the pixel by pixel information of that device context. So there is no way for the system to give you any information about the shapes that you draw because it knows nothing of those shapes.
In order to do what you want you need to keep track in your program of the high level logic of where your shapes are. Then when you handle mouse messages you can map them onto your own data structures that represent the shapes.
There are no events for mouse activity over drawings. You are expected to remember where you draw, and then map the mouse coordinates to the drawing coordinates yourself. To help with this, have a look at the PtInRegion() function. Create an elliptical HRGN via CreateEllipticRgn() or CreateEllipticRgnIndirect() that matches your drawing (in fact, you can use the same HRGN to help facilitate the drawing, see the FillRgn() function), and when you want to test if the mouse is currently inside the drawing, such as in a WM_MOUSEMOVE handler, you can use PtInRegion() for that.
In SceneKit, you can add a lookAtConstraint constraint to your SceneView's Point Of View, to make Camera look at a certain node.
Is there a standard way of doing the same but for a specific face of a geometry?
So that, if I touch a specific face of a cube, camera would move so that the Z axis of the camera node gets in line with the normal of the touched face? So that the cube would look like a plane form the new perspective.
No.
That would require movement of the camera, in addition to re-aiming it.
Imagine I'm in front of my house. I have a great view of the front and can just barely see the side to my left. In my Scene I tap the side of the house. A LookAt constraint would merely change the angle of the camera. It would not be aligned with the normal of that barely visible side.
To align with the normal, I'd have to walk around the house until I can stare at the house and be perpendicular to the side I tapped. At what radius? What path? You have to figure that out yourself.
Depending on what effect you're trying for, you might want to rotate the model instead of moving the camera. Rotate the tapped node locally (or as a child of an invisible parent) so that its minus-Z axis points out the tapped face, and keep a lookAtConstraint on the node, not the camera. This approach will change the look of the object, though: you will see it rotating, and the shading changing appropriately.
So that, if I touch a specific face of a cube, camera would move so that the Z axis of the camera node gets in line with the normal of the touched face?
Supposing you are using hit-testing to determine what object got touched, a SCNHitTestResult will give you both localCoordinates and localNormal from which it should be fairly easy to derive a camera transform.
One easy way would be to have the camera as a child node of the box, compute a position that would look like localCoordinates + distance * localNormal and finally a transform using GLKMatrix4MakeLookAt and SCNMatrix4FromGLKMatrix4.
Note that you can also use worldCoordinates, worldNormal, as well as conversion utilities such as SCNNode.convertTransform(_:from:).
mutating on mnuages answer, use a hit test or ray trace to find where the user tapped on the mesh, then add a node at that location, and constrain the camera to lookAt that node.
I have drawing program that the user can draw either an ellipse or a line, which both derive from shape. I am creating one rubber band, and depending on what the user is drawing i say
rubberBand = new Ellipse();
//or
rubberBand = new Line();
but if i set the rubber band to line, I cannot access the x1 x2 etc, it says shape does not contain a definition of X1. I tried creating an Ellipse and the casting it to a line but still same issue. How do I resolve this?
This sounds like a basic polymorphism question to me. Think about what are you actually trying to do- for instance, a line has 2 points (X1/Y1, and X2/Y2). An ellipse (an oblong circle) has no such property- it has a width, maybe, and a height, and possibly an X and Y coordinates (or a position property).
I am guessing that you are attempting to adjust the bounds and/or location of the shape when the user is dragging it with the mouse. In this case, the operations that you need to define for the shape depend on what kind of shape it is. For a line, you need to write a method that adjusts X2 and Y2 (or whatever). For an ellipse, you will probably need another method that adjusts shapes that have width, height, left, and top properties. Then you just need to determine which one to call depending on which kind of shape you are dealing with.
You need to think about Liskov Substitution Principle:
http://www.objectmentor.com/resources/articles/lsp.pdf
http://www.oodesign.com/liskov-s-substitution-principle.html
I have a Viewport3D with a 3D model composed of multiple smaller components centered at the origin. I'm animating the PerspectiveCamera to rotate about the Y-axis using an AnimationClock created from a DoubleAnimation to create a rotating effect on the model. In addition, I have another rotateTransform3D assigned to the camera's transformgroup to enable the user to orbit around and zoom in-out of the model using the mouse.
I want to be able to translate each component as it is being selected to move in front of the rotating camera. However, I don't know how to get the position of the camera relative to the 3D model because the coordinate system of camera is being animated and transformed by the user's input.
Is there a way to get the offset between two coordinate systems?
Any help or suggestions would be appreciated.
Thanks,
I have some problems with implementing autoscrolling in WPF (I think I could call it that way).
I have a canvas placed inside a scrollviwer. On my canvas I can dynamicly add different shapes. The position of this shapes can be changed with mouse. Everytime I add new shape on canvas or change position of shape I fire measureOverride function.Thanks to this scrollview "know" the real size of canvas and the scrollbars appear. However even if scrolbars appear, the view doesn't "follow" shape which I currently move. I mean if I reach visible part of canvas I would like canvas to srcoll.
I was trying to use this function
ScrollToHorizontalOffset()
However I have problem with proper use of that function. I was trying to use (as a parameter) canvas actualwidth but it didn't work well. I also was trying to use as a parameter current position of shape (which I move) but it works only one way. I the viewer follow the moving element if I was moving this element to right side of canvas. However if I move shape back(to the left) the view don't follow the shape.
I hope somebody will understand this :) It is hard to explain my problem.
I also was trying to use as a
parameter current position of shape
That is the correct way to implement. Waht you need is a converter, which will returns the position according to the direction you move the object.