I have seen how I can place points on a VTK object using seed widget from : http://www.vtk.org/Wiki/VTK/Examples/Cxx/Widgets/vtkSeedWidget
I have also seen how I can rotate an object from : http://www.cmake.org/Wiki/VTK/Examples/Cxx/Qt/SideBySideRenderWindows
I am wondering how I can combine this so I can rotate the object when I drag, and place points when I click
Usually to do something like this you will have to subclass an interactor style (like this: http://www.vtk.org/Wiki/VTK/Examples/Cxx/Interaction/MouseEvents). Then you can store an instance of something like the seed widget in that class, and pass along events to it that you don't want to handle, and handle the ones that you do want to handle (or let the defaults of the style handle them).
Related
I would like to know if it's possible to 'ignore' transparent objects.
The idea is that if I draw over another object, the drawing path will group with the underlying object (this works). Now I want the free drawing path only visible inside the object itself. See picture below for reference.
What I have:
https://pasteboard.co/IqSuu4Y.png
What I would like to have:
https://pasteboard.co/IqSwxfv.png
I was thinking that the 'perPixelTargetFind' options could step in, but I can't get it to work.
As I understand it, if I create a vtk render window, then I can add different renderers to it and for each renderer renders from a different perspective. No to actually render the scene I use the vtk render window method render() to render all renderers in parallel. Now there is a vtk render window method called GetZbufferData which apparently returns an array containing the zbuffer. So my question is, to which renderer does this zbuffer correspond to?
Thanks for any clarification.
If you have all renderers in the same window, then they will share the same framebuffer, so also the same z-buffer. So a simple answer to your question is "to all of them". To get the individual z-values, it depends on what you are exactly doing with the renderers.
If you are doing some kind of a "tiled view", you want to assign different viewports (vtkRenderer::SetViewport(), like here) to each of the renderers. Then you can access the z data for a given "tile" (renderer) by passing appropriate x,y coordinates to the GetZBufferData function. For example, to get the whole part of the z buffer that belongs to renderer ren1 of vtkRenderWindow renWin:
double x1 = ren1->GetViewport()[0] * (renWin->GetSize()[0] - 1);
double y1 = ren1->GetViewport()[1] * (renWin->GetSize()[1] - 1);
double x2 = ren1->GetViewport()[2] * (renWin->GetSize()[0] - 1);
double y2 = ren1->GetViewport()[3] * (renWin->GetSize()[1] - 1);
float *ren1Z = renWin->GetZbufferData(
static_cast<int>(x1),static_cast<int>(y1),static_cast<int>(x2),
static_cast<int>(y2));
If you have the same viewport, it would be more complicated. You can have a renderwindow with multiple "layers", by setting vtkRenderWindow::SetNumberOfLayers(int) and then you can assign each renderer to a different layer (vtkRenderer::SetLayer(0-based layer index)). The window then renders from layer 0 to the last layer over each other. If you are interested in getting only one specific renderer's z-data, you should get it if you have it render in the last layer. However, I am not sure if the z-buffer is cleaned in between individual renderer's renders, I would actually bet on that it is not, so you might also get some inconsistent mess.
I would like to complement tomj answer:
Any of the vtkRenderWindow::GetZbufferData() methods query the framebuffer for Z-values, which is contained in the vtkRenderWindow, but there is a slight remark:
You need to set this in your renderers: vtkRenderer::PreserveDepthBufferOn(). This is because as the documentation says:
"By default, the depth buffer is reset for each renderer.
If this flag is true, this renderer will use the existing depth buffer for its rendering."
So, that bring us to the vtkRenderers. There is a layering of vtkRenderers, which tells which "chain" or "precedence order" to make the drawing. Check the method vtkRenderer::SetLayer().
So, you first need to set up your layered vtkRenderers, attach them to the vtkRenderWindow, and then set up correctly if you want to preserve some depth buffers or not.
Notice that if the z-buffer has not been set (first draw of the first vtkRenderer), it will return 1.0. I'm still figuring out why, but currently that is the situation.
I've a layer with multiple markers with rather big icons, so they overlap. Via the list on the side of the map users can select a marker and the map will pan (and zoom) to it. But it will still be behind some other makers.
How do I get a individual makers z-index and set it? I would be useful to get the highest used z-index and just add one. (another solution is to add the total number of markers to the z-index)
The markers (or features) are in a myLib.features array. The console doesn't show any z-index type functions.
I can't find a appropriate example or api function for this.
EDIT:
I found this example: http://dev.openlayers.org/examples/ordering.html
I don't really understand it. Somehow the created feature takes the next z-index given by the layer via somekind of symbolizer. I have no idea how to work this static sort into a dynamic one.
Try this:
First of all, make sure you are using a OpenLayers.Layer.Vector layer, not a OpenLayers.Layer.Markers layer. Apparently the Markers layer is old news and all new development is done in the Vector layer. It has more features. (I wasted a pile of time with the Markers layer myself).
Then, each of your markers needs to be a OpenLayers.Feature.Vector object. The constructor takes three arguments, the third of which is called the style. The style is where you set your image attributes, the background shadow, the mouse-over text, and the z-index, which has the property name "graphicZIndex". I think that's what you're looking for.
http://dev.openlayers.org/releases/OpenLayers-2.12/doc/apidocs/files/OpenLayers/Feature/Vector-js.html#OpenLayers.Feature.Vector.OpenLayers.Feature.Vector.style
Add your "markers" (which are Vector's) to your Vector layer with the addFeatures function. And just ignore the "options" argument.
http://dev.openlayers.org/releases/OpenLayers-2.12/doc/apidocs/files/OpenLayers/Layer/Vector-js.html#OpenLayers.Layer.Vector.addFeatures
I found that example page too, and I found it confusing too. It was setting all the markers' styles in the Vector layer's constructor (as default values to be used if the marker style was omitted) instead of the marker's constructor. I think it makes more sense to set the marker style in the marker constructor.
To change the style in real-time, take one of your OpenLayers.Feature.Vector markers, called "marker" and do this. And let's call the Vector Layer "layer".
marker.style.graphicZIndex = 13;
layer.redraw();
Any suggestions for a good way to do this?
I want to be able to draw lots of 2D things in XNA- often in offset position. eg if something is in position (X,Y) then ideally I'd like to be able to pass it a modified SpriteBatch which, when Draw(X,Y) is called would take account of the offset and draw the thing at (X+OffsetX, Y+OffsetY).
I don't want to pass this offset to the children and have to deal with it separately in each child- that could screw up and would also screw up my interfaces!
Firstly I thought of having a Decorator to a SpriteBatch which if I call Decorator.Draw for something in position (X,Y) would route this to the original SpriteBatch as (X+offsetX, y+offsetY). But then I can't override the Draw methods in the SpriteBatch class, and even if I created my own "Decorator.DrawOffset", the Decorator seems to need "SpriteBatch.Begin()" called and stuff which seems to break... :(
I then thought of Extension Methods, but I think they'd need the offset passed to them as a variable each time draw() is called? Which still requires me to pass the offset down through the children...
Another option would be to draw the children to a RenderTarget (or whatever they are in XNA4) and then render this to the screen in an offset position... but that seems hideously inefficient?
Thanks for any comments!
you should use a Transformation Matrix.
Matrix Transform = Matrix.CreateTranslation(offsetX, offsetY, 0);
SpriteBatch.Begin(...,...,...., Transform);
I'm using JUNG2 to draw some graphs.
This is the image I get:
http://img841.imageshack.us/img841/205/graphvizkk3312164f020b4.png
I'd like to:
1) change the rendering order (labels should be the last objects to be drawn);
2) add a semi-transparent background to the labels.
3) change background color of the whole image.
Any idea on how to do this?
The JUNG2 documentation is not very extensive on these issues.
Mulone
(1) To do this you'd have to hack the rendering code; I don't believe that we support this at the moment.
UPDATE: I took a closer look. Actually JUNG does support this without hacking the existing libraries; the easiest way is perhaps to subclass BasicRenderer and then override the render() method so that things happen in the order that you want. (I recommend that you render vertices after edges.) Once you do that, you create an instance of your custom Renderer, and call VisualizationViewer.setRenderer(customRenderer).
(2) The labels respect HTML code (i.e., surround your label with <html></html> and then put whatever tags you like in it).
(3) BasicVisualizationServer (and its subclasses, e.g. VisualizationViewer) inherit from JComponent, which defines setBackground(Color).