I am using Jsy3d to draw a 3d scatter plot in Java. However, I noticed that the drawing order of the points seems to be based on the order of the given List of Points, not on the distance to the camera. Is there a way to fix this?
You are right, rendering is based on point declaration. Why would you change this?
To change the scatter rendering, simply override Scatter.draw(...)
You may use Camera.getDistance(coord) to get the distance to Camera. This method is already used by BarycenterOrderingStrategy in Graph to order the drawables (but this won't work for your scatter as it is a primitive Drawable).
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Can anyone share a code how to draw a rectangle like this?
(not vertical, not horizontal, somewhere between)
Because as I see you can only specify 4 ints to function DrawRect(), not 4 points.
The area of rectangle must be sensitive to touch (I use Contains() method)
As I tried, Matrix and Rotate() update only graphics, the rect's area remains the same it was
After transforming as #fortran suggested, you can use one of the Matrix.mapPoints overloads to find out what the new corners of your rectangle are. You'll probably have to find some fancy math and do hit testing yourself. Might be easier to call Matrix.mapPoints() on the inverse of the transformation used to draw the rectangle, passing the touched coordinates, and then hit test on the original rectangle.
Push a rotation transformation, draw the rectangle, pop it.
http://developer.android.com/reference/android/graphics/Canvas.html#rotate%28float,%20float,%20float%29
I found solution - the easiest way is to use Path class, make a free-turned rectangle by points and then create a region method, which has function Contains()
No need for math and hard work, pretty and easy.
I want to virtualize my network simulations and need to plot the nodes in the network. Each node has a pre-defined location and I need to plot the nodes into the correct coordination.
I am using JUNG: http://jung.sourceforge.net/applet/index.html
Any suggestions?
Thanks!
I recently solved this problem by writing my own rendering Layout for JUNG.
As base for my derived layout I used the Circle Layout, which is pretty simple. In there you will see that JUNG does a setLocation(Dimension d) for every Vertex, which is pretty much what you are looking for, I guess. Just take a look at the source of the CircleLayout.
Then you could use a custom Vertex object, which stores the coordinates you want the vertex to have, which is then read by your custom layout.
I'm looking to use the java2d API to make a graph in which users can manipulate certain features using their mouse - such as the scale used for an axis or move around the different points plotted on the graph.
So far all I have found is the drawX methods on a Graphics2D object, however there does not seem to be an easy way to capture a user clicking on one of these and moving it so that I can redraw the graph.
Can anyone suggest the best/easiest way to implement this? Just looking for a point in the right direction.
Not reinventing the wheel is always the best way, there are plenty of excellent libraries you can use: http://www.jfree.org/jfreechart/
If you are looking to implement this yourself, you would listen to mouse events on whatever component you're actually using to display your chart (say a JPanel), and then would have to convert between screen and chart coordinates to figure out what you need to change.
I'd like to be able to set a colour of every point (addressed by x&y, where x is a DateTime (of joda-time, actually) and y is a double) on a chart to represent a z=f(x,y) value. Is it possible with JFreeChart?
If I understood your needs correctly I think you want to use an XYPlot with an XYBlockRenderer.
Quoting the docs:
A renderer that represents data from an XYZDataset by drawing a color block at each (x, y) point, where the color is a function of the z-value from the dataset
Check the sample image in the docs for XYBlockRenderer: http://www.jfree.org/jfreechart/api/javadoc/org/jfree/chart/renderer/xy/XYBlockRenderer.html
I recommend http://www.jzy3d.org
Here are some example charts: http://www.jzy3d.org/gallery.php
And example code to plot a surface: https://github.com/jzy3d/jzy3d-api/tree/master/jzy3d-tutorials
As far as I remember that's not possible by default. You can set only one color for every plotted series. However, I think it's possible to extend AbstractRenderer and achieve what you need.
Of course there is possibility that I'm mistaking. Dont remember for sure. :P
I'm new to OpenGL. I'm using JOGL.
I would like to create a sky for my world that I can texture with clouds or stars. I'm not sure what the best way to do this is. My first instinct is to make a really big sphere with quadric orientation GLU_INSIDE, and texture that. Is there a better way?
A skybox is a pretty good way to go. You'll want to use a cube map for this. Basically, you render a cube around the camera and map a texture onto the inside of each face of the cube. I believe OpenGL may include this in its fixed function pipeline, but in case you're taking the shader approach (fixed function is deprecated anyway), you'll want to use cube map samplers (samplerCUBE in Cg, not sure about GLSL). When drawing the cube map, you also want to remove translation from the modelview matrix but keep the rotation (this causes the skybox to "follow" the camera but allows you to look around at different parts of the sky).
The best thing to do is actually draw the cube map after drawing all opaque objects. This may seem strange because by default the sky will block other objects, but you use the following trick (if using shaders) to avoid this: when writing the final output position in the vertex shader, instead of writing out .xyzw, write .xyww. This will force the sky to the far plane which causes it to be behind everything. The advantage to this is that there is absolutely 0 overdraw!
Yes.
Making a really big sphere has two major problems. First, you may encounter problems with clipping. The sky may disappear if it is outside of your far clipping distance. Additionally, objects that enter your sky box from a distance will visually pass through a very solid wall. Second, you are wasting a lot of polygons(and a lot of pain) for a very simple effect.
Most people actually use a small cube(Hence the name "Sky box"). You need to render the cube in the pre-pass with depth testing turned off. Thus, all objects will render on top of the cube regardless of their actual distance to you. Just make sure that the length of a side is greater than twice your near clipping distance, and you should be fine.
Spheres are nice to handle as they easily avoid distortions, corners etc. , which may be visible in some situations. Another possibility is a cylinder.
For a really high quality sky you can make a sky lighting simulation, setting the sphere colors depending on the time (=> sun position!) and direction, and add some clouds as 3D objects between the sky sphere and the view position.