I would like to try to proceed some experiment, where I give two inputs for reinforcement learning agents. As first input, I would like to provide him grid-like environment that would represent room-maze with some walls and reward in one of the maze rooms. And the second one would be a graph representation of this maze.
I'm still stuck at planning the experiment, because I'm not sure about creating sufficient way to create a proper graph structure of 2D-grid environment. For example, I was thinking about looking for some algorithms that is able to find modularities (e.g. modules could correspond to rooms).
Do you have any idea what would be worth recommending when it comes to building a graph? And maybe what RL algorithm would work fine on both?
A maze grid is often represented in a text file as "ASCII ART"
The * mark the cells that are in the path from the start to the end.
It is fairly straightforward to write code to read this text file and create a graph with links between adjacent cells. If there is a wall the link has "infinite" cost, if there is a door then the link cost can be small or zero. From this graph a standard path finding code will find the path through the maze.
Here is the result as visualized by graphviz
"cnrm" is the node representing the call at row m, column n and the path is highlighted in red.
You can look at C++ code for doing this at https://github.com/JamesBremner/PathFinder
specifically the code to read the ascii art and generate the graph is in https://github.com/JamesBremner/PathFinder/blob/main/src/cMaze.cpp
Related
I really like the functions of OSMnx, thank you! Nevertheless sometimes OSM-data is limited, especially for human powered modes like walking and cycling. I am working on a project for Zuerich, Switzerland and I am lucky that the city has a full walking network, including sidewalks, steps, paths, etc. At the moment this file is downloable as ESRI shapefile, gpkg or GEOjson. It just contains the lines but it would be easy to add nodes to them because edges are drawn until the next intersection point with another edge. For the 3D-layer it is accounted for, in such a way that lines on a different height aren't intersecting. I was wondering if it is possible to import a shape-file and work with it in OSMnx?
Did anyone did this before?
What would be a first step?
Does it make sense to try to convert the shapefile to "osm xml" in order to import it like this?
I have tried to first import it in networkx (https://gis.stackexchange.com/questions/227909/from-shapefile-to-python-networkx) but the syntax for nodes and edges is so different.
Thank you, I appreciate every hint.
The data can be found here: https://data.stadt-zuerich.ch/dataset/geo_fuss__und_velowegnetz/resource/80af45c0-835c-4e29-b99d-f8cd6dfefa11?inner_span=True (includes also bike-infrastructure which has to be removed)
I'm testing an algorithm that finds a shortest path between two certain vertexes in graph and gives a list of vertexes after each turn (actually it gives three paths - one of them is a shortest path in this graph and two others are some kind of extra paths that are also important for us and are used for further shortest path calculations). On each turn the weights of graph edges change somehow so every turn we get a new triple of lists (paths). I would like to visualize the evolving of these paths by drawing a graph (this graph is actually a grid that represents a city, e.g. New York) and each kind of path would be represented with certain colour (so on each turn there would be a grid with three coloured paths). One more time - on every turn the paths will be different so the picture will change. What is the best way to represent it? And one more question - sometimes there would be edges that belong to two or maybe even three of these pathes and I'd like to show it, so it would be nice if there is an opportunity to colour this edge with two/three colours at once. It would be perfect if it was possible to make it look like two/three thinner edges put along together, but I could only find a situation where we draw several lines of different colour that are being put together consecutively (like that: enter image description here). Is there a way to make it the first way?
I'm sorry for being discursive but I've never dealt with graphics in Python and I desperately need help. Thanks!
If you want to show the image in a GUI, it depends on the GUI toolkit that you want to use. In the Tkinter toolkit that comes with most Python distributions you could use the Canvas widget. There are several tutorials online [1], [2]. Most GUI toolkits have a similar functionality, but they can have different names.
If you want to save an image to a file, there are many graphics libraries you could use, depending on what kind of format you want to save it to.
For example the Python bindings to the Cairo library can save a picture as PDF or SVG vector formats.
The Pillow library on the other hand supports many bitmap formats.
There are many others; matplotlib, agg, gd are just some examples.
I would like to implement a Maya plugin (this question is independent from Maya) to create 3D Voronoi patterns, Something like
I just know that I have to start from point sampling (I implemented the adaptive poisson sampling algorithm described in this paper).
I thought that, from those points, I should create the 3D wire of the mesh applying Voronoi but the result was something different from what I expected.
Here are a few example of what I get handling the result i get from scipy.spatial.Voronoi like this (as suggested here):
vor = Voronoi(points)
for vpair in vor.ridge_vertices:
for i in range(len(vpair) - 1):
if all(x >= 0 for x in vpair):
v0 = vor.vertices[vpair[i]]
v1 = vor.vertices[vpair[i+1]]
create_line(v0.tolist(), v1.tolist())
The grey vertices are the sampled points (the original shape was a simple sphere):
Here is a more complex shape (an arm)
I am missing something? Can anyone suggest the proper pipeline and algorithms I have to implement to create such patterns?
I saw your question since you posted it but didn’t have a real answer for you, however as I see you still didn’t get any response I’ll at least write down some ideas from me. Unfortunately it’s still not a full solution for your problem.
For me it seems you’re mixing few separate problems in this question so it would help to break it down to few pieces:
Voronoi diagram:
The diagram is by definition infinite, so when you draw it directly you should expect a similar mess you’ve got on your second image, so this seems fine. I don’t know how the SciPy does that, but the implementation I’ve used flagged some edge ends as ‘infinite’ and provided me the edges direction, so I could clip it at some distance by myself. You’ll need to check the exact data you get from SciPy.
In the 3D world you’ll almost always want to remove such infinite areas to get any meaningful rendering, or at least remove the area that contains your camera.
Points generation:
The Poisson disc is fine as some sample data or for early R&D but it’s also the most boring one :). You’ll need more ways to generate input points.
I tried to imagine the input needed for your ball-like example and I came up with something like this:
Create two spheres of points, with the same center but different radius.
When you create a Voronoi diagram out of it and remove infinite areas you should end up with something like a football ball.
If you created both spheres randomly you’ll get very irregular boundaries of the ‘ball’, but if you scale the points of one sphere, to use for the 2nd one you should get a regular mesh, similar to ball. You can also use similar points, but add some random offset to control the level of surface irregularity.
Get your computed diagram and for each edge create few points along this edge - this will give you small areas building up the edges of bigger areas. Play with random offsets again. Try to ignore edges, that doesn't touch any infinite region to get result similar to your image.
Get the points from both stages and compute the diagram once more.
Mesh generation:
Up to now it didn’t look like your target images. In fact it may be really hard to do it with production quality (for a Maya plugin) but I see some tricks that may help.
What I would try first would be to get all my edges and extrude some circle along them. You may modulate circle size to make it slightly bigger at the ends. Then do Boolean ‘OR’ between all those meshes and some Mesh Smooth at the end.
This way may give you similar results but you’ll need to be careful at mesh intersections, they can get ugly and need some special treatment.
I'm planning to generate a flower in Maya2016 where the leafs are not flexible, but they are built up by 4-5 segments connected to each other. I already have the python script which gets a segment as an input parameter and generates the leaf. (And also generates multiple leafs in a circle.)
Now the question is, how to animate it. I'm new in maya animation. I've found a few example how to do basic things like rotation or transformation with python. But what I wish to have is a realistic movement where the segments are moving how they should be.
My idea is to generate a "skeleton" bone and joint point for every segment. And then I wish to animate the skeleton.
Do you think it's a good way of animating the leaf?
How can I set up the skeleton?
How can I animate a skeleton?
(For the last two, I expect a good source like a blogpost, but I also wish to know if my entire concept is good or not.)
Thanks!
It's a long one so you might want to get that cup of tea/coffee you've been holding off on ;)
I run a game called World of Arl, it's a turn based strategy game akin to Risk or Diplomacy. Each player has a set of cities, armies and whatnot. The question revolves around the display of these things. Currently the map is created using a background image with CSS positioning of team icons on top of that to represent cities. You can see how it looks here: WoA Map
The background image for the map is located here: Map background and created in Omnigraffle. It's not designed to draw maps but I'm hopelessly incompetent with photoshop and this works for my purposes just fine.
The problem comes that I want to perform such fun things as pathfinding and for that I need to have the map somehow stored in code. I have tried using PIL, I have looked at incorporating it with Blender, I tried going "old school" and creating tiles as from many older games and finally I tried to use SVG. I say this so you can see clearly that it's not through lack of trying that I have this problem ;)
I want to be able to store the map layout in code and both create an image from it and use it for things such as pathfinding. I'm using Python but I suspect that most answers will be generic. The cities other such things are stored already and easily drawn on, I want to store the layout of the landmass and features on the landmass.
As for pathfinding, each type of terrain has a movement cost and when the map is stored as just an image I can't access the terrain of a given area. In addition to pathfinding I wish to be able to know the terrain for various things related to the game, cities in mountains produce stone for example.
Is there a good way to do this and what terms should I have used in Google because the terms I tried all came up with unrelated stuff (mapping being something completely different most of the time).
Edit 2:
Armies can be placed anywhere on the map as can cities, well, anywhere but in the water where they'd sink, drown and probably complain (in that order).
After chatting to somebody on MSN who made me go over the really minute details and who has a better understanding of the game (owing to the fact that he's played it) it's occurring to me that tiles are the way to go but not the way I had initially thought. I put the bitmap down as it is now but also have a data layer of tiles, each tile has a given terrain type and thus pathfinding and suchlike can be done on it yet at the same time I still render using Omnigraffle which works pretty well.
I will be making an editor for this as suggested by Adam Smith. I don't know that graphs will be relevant Xynth but I've not had a chance to look into them fully yet.
I really appreciate all those that answered my question, thanks.
I'd store a game map in code as a graph.
Each node would represent a country/city and each edge would represent adjacency. Once you have a map like that, I'm sure you can find many resources on AI (pathfinding, strategy, etc.) online.
If you want to be able to build an image of the map programattically, consider adding an (x, y) coordinate and an image for each node. That way you can display all of the images at the given coordinates to build up a map view.
The key thing to realize here is that you don't have to use just one map. You can use two maps:
The one you already have which is drawn on screen
A hidden map which isn't drawn but which is used for path finding, collision detection etc.
The natural next question then is where does this second map come from? Easy, you create your own tool which can load your first map, and display it. Your tool will then let you draw boundaries around you islands and place markers at your cities. These markers and boundaries (simple polygons e.g.) are stored as your second map and is used in your code to do path finding etc.
In fact you can have your tool emit python code which creates the graphs and polygons so that you don't have to load any data yourself.
I am just basically telling you to make a level editor. It isn't very hard to do. You just need some buttons to click on to define what you are adding. e.g. if you are adding a polygon. Then you can just add each mouse coordinate to an array each time you click on your mouse if you have toggled your add polygon button. You can have another button for adding cities so that each time you click on the map you will record that coordinate for the city and possibly a corresponding name that you can provide in a text box.
You're going to have to translate your map into an abstract representation of some kind. Either a grid (hex or square) or a graph as xynth suggests. That's the only way you're going to be able to apply things like pathfinding algorithms to it.
IMO, the map should be rendered in the first place instead of being a bitmap. What you should be doing is to have separate objects each knowing its dimensions clearly such as a generic Area class and classes like City, Town etc derived from this class. Your objects should have all the information about their location, their terrain etc and should be rendered/painted etc. This way you will have exact knowledge of where everything lies.
Another option is to keep the bitmap as it is and keep this information in your objects as their data. By doing this the objects won't have a draw function but they will have precise information of their placement etc. This is sort of duplicating the data but if you want to go with the bitmap option, I can't think of any other way.
If you just want to do e.g. 2D hit-testing on the map, then storing it yourself is fine. There are a few possibilities for how you can store the information:
A polygon per island
Representing each island as union of a list rectangles (commonly used by windowing systems)
Creating a special (maybe greyscale) bitmap of the map which uses a unique solid colour for each island
Something more complex (perhaps whatever Omnigiraffe's internal representation is)
Asuming the map is fixed (not created on the fly) its "correct" to use a bitmap as graphical representation - you want to make it as pretty as possible.
For any game related features such as pathfinding or whatever fancy stuff you want to add you should add adequate data structures, even if that means some data is redundant.
E.g. describe the boundaries of the isles as polygon splines (either manually or automatically created from the bitmap, thats up to you and how much effort you want to spend and is needed to get the functionality you want).
To sum it up: create data structures matching the problems you have to solve, the bitmap is fine for looks but avoid doing pathfining or other stuff on it.