So I have to create a project in java and I need steps on how to consider thinking about the problem.
Its a GUI related project. What is required is that there are two objects that a user would place on the screen window(imagine them like rectangles on the screen).
And these rectangle objects have connector points. One point on the middle of each side of the rectangle(Hope that made sense). And the user will choose one point in each rectangle and my program will have to find a path between those two connector points. There could be obstacles like other rectangles between those two rectangles or walls.
So I am thinking I could use a path finding algorithm(like A*) to find a path between the two points but that's all I could figure out till now.
I need help on how to think about this problem especially with the GUI part.
Also the problem also requires that the number of turns be minimum. But I think I could work on that later. But if you've got an idea please share it here
Thank you so much in advance
Related
I've not found anything here or on google. I'm looking for a way to identify shapes (circle, square, triangle and various other shapes) from a image file. Some examples:
You get the general idea. Not sure if BoofCV is the best choice here but it looks like it should be straightforward enough to use, but again I know nothing about it. I've looked at some of the examples and I though before I get in over my head (which is not hard to do some days), I thought I would ask if there is any info out there.
I'm taking a class on Knowledge Based AI solving Ravens Progressive Matrix problems and the final assignment will use strictly visual based images instead of the text files with attributes. We are not being graded on the visual since we only have a few weeks to work on this section of the project and we are encouraged to share this information. SOF has always been my go to source for information and I'm hoping someone out there might have some ideas on where to start with this...
Essentially what I want to do is detect the shapes (?? convert them into 2D geometry) and then make some assumptions about attributes such as size, fill, placement etc, create a text file with these attributes and then using that, send it through my existing code based that I wrote for my other projects to solve the problems.
Any suggestions????
There are a lot of ways you can do it. One way is to find the contour of the shape then fit a polygon to it or a oval. If you git a polygon to it and there are 4 sides with almost equal length then its a square. The contour can be found with binary blobs (my recommendation for the above images) or canny edge.
http://boofcv.org/index.php?title=Example_Fit_Polygon
http://boofcv.org/index.php?title=Example_Fit_Ellipse
So I'm doing the project of an introduction to Java course and it seems that I chose something that goes way beyond what I'm able to do. :P
Any help would be greatly appreciated. This is what I'm having problems with:
You have a cursor that is controlled by a player (goes forward or
turns 90°) which leaves a colored line as it goes. If you manage to go
over your own line and close a polygon of any shape (only right angles
though), its surface changes color into the color of your line.
I can detect when this situation arises but I am kind of lost as how to actually fill the correct polygon just closed. I can't seem to imagine an algorithm that would cover any case possible.
I looked at the Scanline fill algorithm but I think it would start having problems by the time there are already some polygons already filled in the map.
The Floodfill algorithm would be perfect if I had a way of finding a point inside the polygon, but, as there are many different possibilities, I can't think of a general rule for this.
I'm using an array 2x2 of integers where each color is represented by a number.
Does anyone have an idea on how to approach this problem?
If you can detect the situation then this can be solved in very simple manner. The question is which point to choose as start point for floodfill. The simple answer is: try all of them. Of course it makes a sense to start only with points adjacent to the one where your cursor is located. In this case you will have at most 8 points to check. Even better - at least 2 of them are definitely painted already if current point forms a polygon.
So you have 8 points to check. Launch floodfill 8 times starting from each of those points.
Two things which you probably should keep in mind:
You should try filling the area in cloned version of your field in order to be able to get back if floodfill will not find a polygon.
Launching floodfill second time and later you should reuse this cloned version of your field to see whether it was filled there. This will allow you to check every point at most once and this will make your 8 floodfills almost as fast as 1 floodfill.
Check this question, using Graphics2 and Polygon to fill an arbitrary polygon: java swing : Polygon fill color problem
Finding out whether a point is inside or outside a polygon: http://en.wikipedia.org/wiki/Point_in_polygon
Make sure you use double buffering. If you set individual pixels and don't use double buffering the component may redraw after every pixel was set.
I am trying to draw an interactive planar straight line graph (PSLG) on a JApplet. I am using mouse-clicks to determine the vertices of the PSLG.
Here is the algorithm which I am following for drawing edges of the PSLG
1. The point where user performs a mouse-click is added as a vertex of the PSLG.
2. If he clicks a second point,an edge is directly created among the point and the previously clicked-point
Here are certain flaws which I observed due to the use of this algorithm:
Inability to create disjoint-planar sets like say just a line segment
A closed polygon is only created if the user clicks at the exact location where the start point was [Essentially, if the user clicks very close to the start point, there is no way to tell that this point is actually the start point since it appears within a certain tolerance range from the point].
I've checked out some similar questions over here and people suggest to use the JFreeChart library. But as far as I get, the scenario in those questions was that the points of the PSLG were already known. I do not know whether JFreeChart can be used for creating interactive PSLG's
I thought about adding points and having a button which would say add edges among points,but if that's the case selecting the 2 points will still involve the proximity problem encountered in 2.
I was wondering if anybody could suggest me a better approach on how to handle this situation.
Thanks in advance
GraphPanel could be adapted to this task, although it might benefit from a more advanced edge model for faster searching. Also consider JGraph.
Yesterday I tried to solve a Problem I had the entire Day and it is still unsolved. I searched for every combinations of words I could imagine to find solutions on Google etc. But without success. :(
The Problem consists of following idea:
I started programming GLES20 (Not GLES10!) on Android. There are many other ways how to compute matrixes and objects. So there aren't any methods like "Pop" or "push" Matrix.
I want to rotate a globe/sphere only by touching and moving my fingers. Touching functions etc works fine but the rotation itself never does. Everytime I first rotate by x-axis and then rotating by y-axis the rotation is still computed by local space axis of the object and Not two global axis. This happens whatever I do... :/
There are some people searching the solution for the Same Problem, but mostly GLES10 or completly different programming languages, never GLES20 and Java.
I will also post some Code parts later, when I get access to a Computer.
perhaps someone already understands what my Problem is.
Thank you so much! :)
Chrise
In OpenGL ES 2.0 there aren't any of the matrix functions and you're supposed to take care of your own matrices. So, for pushing and popping matrices what you need to do is when you're drawing you copy your matrix to a temporary one, do whatever transformation on it and pass the temporary matrix to the vertex shader.
I have just started learning basics about Graphics2D class, So far I am able to draw different objects and implements ActionListener to actually move them on screen by onKeyPress. So far so good, While I thought of doing something more complicated. I want to give a path to my object and animate it on that particular path only.
Something like, I will draw a line on sky and a plane should stick with that drawn line and keep it self to fly on that particular line. Now is it possible?
I don't need any sort of code, But few different method or ideas will let me get started working on this. A visualise elaboration of my idea is as below.
Start Point :
End Point :
Now as shown above, my yellow box(in future plane) should stick with given path while animating(path grey line)
My research so far,
I have searched my buzz words such as path in java, and found Path2D and GeneralPath classes, Does anyone know if I can use that to solve this.
Thanks
Great !
It reminds me of my first steps in IT. How much I enjoyed all this simple math stuff but that make things move on screen. :)
What you need is actually a linear interpolation . There are other sorts of interpolation and some api offer a nice encapsulation for the concept but here is the main idea, and you will quite often need this stuff :
you must rewrite your path
y = f (x )
as a function of time :
at time 0 the item will be on start position, at time 1 it will reach the end. And then you increment time (t) as you wish (0.001 every ms for instance).
So here is the formula for a simple linear path :
x = xstart + (xend-xstart) * t
y = ystart + (yend-ystart) * t
when t varies, you object will just move linearly along the path, linearly has speed will be constant on all the path. You could imagine some kind of gravtity attraction at end for instance, this would be modeled by a quadratic acceleration (t^2 instead of t) ...
Regards,
Stephane
First, make the ability to move from point a to point b. This is done with simple algebra.
Second, make the ability to take a path and translate it into points. Then when you're going to do curves, you're really just moving from point to point to point along that curve.
This is the most elementary way to do it and works for most instances.
What your talking about is simple 2D graphics and sprites. If that is all you need then for Java take a look at Java 2D Sprites If your leaning more towards or will eventually go with camera perspectives and wanting to view the animation from diferent angles the go with Java 3D from the OpenSource Java 3D.org. Either way what you want is a simple translating of the object along a line, pretty simple in either 2D or 3D.
You can try going trough the code of my open source college project - LANSim. It's code is available in Code menu. It does similar to what you are trying to do.