Questions tagged [graph]

A graph is a data structure for a set of objects where some pairs of the objects are connected by links.

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36
votes
6answers
21k views

Why is the origin in computer graphics coordinates at the top left?

From what I've seen almost all things use coordinates where (0, 0) is at the top left and the positive Y-axis goes in the downwards direction of your screen. Why is it like this? Why not the ...
12
votes
6answers
3k views

Efficient Algorithm for the boundary of a set of tiles

I have a grid of tiles of a known finite size that forms a map. Some of the tiles inside the map are put into a set known as a territory. This territory is connected, but nothing is known about its ...
10
votes
1answer
4k views

To scene graph or not to scene graph?

I've been struggling with a decision regarding whether or not to implement a scene graph in my game. I have some use cases that call for such a tool, but I haven't been able to get through some of the ...
9
votes
3answers
4k views

Determine if a set of tiles on a grid forms an enclosed shape

Given a set of tiles on a grid, I want to determine: If the tiles make an enclosed figure If the tiles make an enclosed figure when you count the sides of the board as an edge of the figure If either ...
8
votes
2answers
2k views

How to create a map from graph

I want to draw a 2d polygon map based on data provided by another source to ease analysing actions on the map. The data has the following format: ...
7
votes
1answer
3k views

Delaunay triangulation. Where to start?

I'm trying to learn procedural generation technique's. Specifically for dungeons. I started off with a 2D array and I generate my rooms fine. Each room contains wall tiles as seen in the screenshot ...
7
votes
1answer
9k views

C# graph library to be used from Unity3D [closed]

I'm looking for a C# graph library to be used inside Unity3D script. I'm not looking for pathfinding libraries (I know there ...
6
votes
3answers
2k views

How to find path in graph without crossing the walls?

I would like to know how to find path in a graph while having the edges "double-sided". Consider this scenario: I have list of the line segments. These represents "walls" or rather impassable edges (...
6
votes
4answers
175 views

Evenly distributed checkpoints in a procedurally generated world?

Got a procedurally generated world. It's succinctly described as an undirected acyclic graph where vertices are junctions and edges weights/length note the amount of time/effort guesstimated to be ...
6
votes
1answer
972 views

A* for non grid network

For my specific case, I am trying to find a path finding implementation similar to what described here. I could see reference implementation for A* and HPA*, but I wonder how to extend A* to simple ...
6
votes
3answers
286 views

Graph search with a high number of actions

I have implemented A* to reach a goal state from a start state. My state is position X,Y, angle and others state variable. I have a number of actions. What I call actions is : A* on a grid has 4/8 ...
5
votes
1answer
191 views

trapped inside a Graph : Find paths along edges that do not cross any edges

This is a graph based platformer level and the round shapes are creatures. I am looking for a path traveling along edges that does not cross other edges(To simulate the creature crawling on the ...
5
votes
1answer
2k views

Find sub-graphs in a graph

The initial problem I'm trying to solve is for pac-man, but of course there must be thousands of other situations with the same problem. I consider the pac-man grid to be a graph (two ways of doing ...
5
votes
1answer
327 views

How to randomly create a fair maze for a multiplayer game?

I am creating a 2d multiplayer RTS game which happens inside a maze. I have used Growing Tree algorithm to randomly generate the maze. I thought that the maze would be fair for each team as long as ...
5
votes
4answers
1k views

Dynamic Dijkstra

I need dynamic dijkstra algorithm that can update itself when edge's cost is changed without a full recalculation. Full recalculation is not an option. I've tryed to "brew" my own implemantion with no ...
5
votes
1answer
419 views

Triangulating a partially triangulated mesh (2D)

Referring to the above exhibits, this is the scenario I am working with: starting with a planar graph (in my case, a 2D mesh) with a given triangulation, based on a certain criterion, the graph nodes ...
4
votes
2answers
325 views

How would I go about updating my electronic circuit simulator's 'electricity'?

I have made an application which allows the user to place down wires, power sources, and inverters on a virtual circuit board. All connections between tiles are automatic, as shown here: As you can ...
4
votes
1answer
166 views

Convert 2d generated level to graph or analyze

Do you have any idea how to extract graph data from this type of procedurally generated level? Well, actually we need to analyze only top level (gray). Background (black) does not matter. What I am ...
4
votes
1answer
71 views

Lazy way to figure out the two sides of a border?

We have a 3d model. There is a simple path on that model's surface graph G of the form: ...
4
votes
0answers
136 views

Procedurally generated paths with intersections

The Problem I've been attempting to create some procedurally generated paths for a while now, but I've reached a problem when it comes to generating the intersections of the paths. The paths are ...
3
votes
2answers
176 views

What algorithm can I use to distribute energy between connected nodes?

I'm creating a game where every user has a network of connected nodes that each have a specific amount of energy. The nodes will try to distribute energy evenly amongst themselves. If a node has more ...
3
votes
1answer
893 views

Better data structure for a game like Bubble Witch

I'm implementing a bubble-witch-like game (http://www.king.com/games/puzzle-games/bubble-witch/), and I was thinking on what's the better way to store the "bubbles" and to work with. I thought of ...
3
votes
1answer
855 views

Placing nodes in a graph in a random but readable way

I'd like to create a simple map from vertices and lines - you know, like a usual graph. A tree, to be precise. To select the location of the next point that comes from one, I use a simple circle-...
3
votes
1answer
965 views

Procedurally generating dungeons using predefined rooms

Most attempts at procedurally generating dungeons I have stumbled upon do space out areas that will be rooms and connect them will corridors and hallways but what about instances where you have a ...
3
votes
1answer
976 views

How to choose and scale heuristics for A-star on a graph?

I am trying to find the best and scale my cost function for my algorithm. I am following amit blog which explain that (http://theory.stanford.edu/~amitp/GameProgramming/Heuristics.html#manhattan-...
3
votes
1answer
744 views

How to implement visibility graph pathfinding in Unity/C# to detect paths (i.e. visibility connections) efficiently?

I am struggling with implementing continuous path-finding trough visibility graphs. Notice, I know that grids can be used even when movement is not trough grids (e.g. Theta*). But for my current needs,...
2
votes
2answers
277 views

State propagation in modern OpenGL

When last I dabbled in game development, I managed my geometry in a tree. Every node would call the render method on it's children, prior to resetting it's transformations, thus allowing the ...
2
votes
1answer
2k views

Moving sprites on a graph in libGDX

In my game I'd like to move sprites on a fixed path. Until this point I was trying to stick with the tools already provided by libGDX, like the Tiled map renderer classes so I'm looking for a solution ...
2
votes
2answers
3k views

Data structure for bubble shooter game

I'm starting to make a bubble shooter game for a mobile OS. Assume this is just the basic "three or more same-color bubbles that touch pop" and all bubbles that are separated from their group fall/pop....
2
votes
3answers
2k views

Integrating Scene Graphs and Physics Engines

For some specific reasons, i will have to use a graphic engine based on Scene Graphics with a Physic Engine without this concept. I was thinking about a clear way to integrate both representation but ....
2
votes
2answers
363 views

Find extreme points of a rotated ellipse function on a given axis

How to find the points where it is most extreme on the X and Y axis? For example lets say I have an equation that describes an ellipse that is rotated: ...
2
votes
1answer
252 views

HeightMap from a graph

This is just a toy experiment. I laid out a graph in 2d space, so that every node has x and y coordinates. I'm considering ...
2
votes
1answer
228 views

Storing visibility graph for path-finding: do redundant and non-visible pairs of points have to be saved?

Using C# in Unity, I have recently implemented an algorithm that determines during run-time the visibility graph of a given scene in my game project (visibility between corners of obstacles). Now I am ...
2
votes
1answer
247 views

Voronoi / Delaunay Graph - Triangle Circumcenter error

I have written a Delaunay Graph script that given a set of points (voronoi cell/region) will generate the Delaunay triangles with their edges. Considering that the Voronoi diagram is complimentary to ...
2
votes
1answer
428 views

Algorithms for positioning rectangles evenly spaced with unknown connecting lines

I'm new to game development, but I'm trying to figure out a good algorithm for positioning rectangles (of any width and height) in a given surface area, and connecting them with any variation of lines....
2
votes
2answers
257 views

How can I test if a point is behind a polygon in 2D?

In order to improve the performance of my visibility graph generator I am trying to figure out the following. Given the image below; is there a way to find out if a point is 'behind' the polygon? For ...
2
votes
1answer
87 views

How can I cut a graph representing 2D positions into two sub-graphs?

I have a graph where each node is associated with a 2D position. I would like to use a finite line to "cut" this graph into two halves, as shown below: Note that the cutting line does have a ...
2
votes
2answers
257 views

Splitting Graph into distinct polygons in O(E) complexity

If you have seen my last question: trapped inside a Graph : Find paths along edges that do not cross any edges How do you split an entire graph into distinct shapes 'trapped' inside the graph(like ...
2
votes
1answer
425 views

Is finding graph minors without single node pinch points possible?

Is it possible to robustly find all the graph minors within an arbitrary node graph where the pinch points are generally not single nodes? I have read some other posts on here about how to break up ...
2
votes
1answer
141 views

Multilevel 2D grid graph and A*

I've coded up a little grid based dungeon game. Everything working quite nicely in a Tile[,]. The AI uses basic GOAP for tasks and A* for moving around. Tile reachability is done using a floodfill. ...
2
votes
0answers
196 views

Graph Isomorphism > What kind of Graph is this? [closed]

Essentially, this is a variation of Comparing Two Tree Structures, however I do not have "trees", but rather another type of graph. I need to know what kind of Graph I have in order to figure out if ...
1
vote
1answer
221 views

Electronic circuit simulator four-way flood-filling issues

I've made an electronic circuit board simulator which has simply 3 types of tiles: wires, power sources, and inverters. Wires connect to anything they touch, other than the sides of inverters; ...
1
vote
1answer
67 views

Snake AI - Is a Hamiltonian approach valid for all grid sizes?

So, as has been done many times before, I am designing an AI that can play Snake as effectively as possible. It didn't take me long to find this extremely useful thread here: How to find a safe path ...
1
vote
2answers
118 views

What graph Search algorithm (s) that can simulate the behaviour of a human searching in a forest

We are building a game , where a group of humans(AI agents) have to wander seperatly throughout the forest looking for a collectable item. The forest is represented as a 2d graph with the item ...
1
vote
1answer
198 views

What's an optimal procedure to create a connected cyclic grid of nodes and edges for A* pathfinding

like the title says, I'm trying to create a grid of nodes that hold edges or connections to each other so I can perform A* algorithm to have objects traverse across them as seen in your standard RTS. ...
1
vote
1answer
267 views

Understanding Scene Graphs and Graph Edges

So I'm trying to getting to grips with using Scene graphs and nodes in my code (game coding in C++) and I think I understand the basics of them and how they are used (and I can definitely see the ...
1
vote
1answer
121 views

More Precise PathSmoothing

I'm reading a book about AI - Path planning and path smoothing. Yet this book is using c++ code. And i'm coding in c# with the XNA framework. I have a path smoothing working, yet the book says it can ...
1
vote
2answers
446 views

Partial recalculation of visibility on a 2D uniform grid

Problem Imagine that we have a 2D uniform grid of dimensions N x N. For this grid we have also pre-computed a visibility look-up table, e.g. with DDA, which answers the boolean query is cell X visible ...
1
vote
1answer
334 views

Line of Sight Check Theta* Algorithm

I am looking at implementing the Theta* algorithm in a 2D NavMesh. I have A* working, and I need to add a line of sight check to turn it into Theta*, this seems relatively easy in a uniform grid but a ...
1
vote
0answers
528 views

Shadow & sorting issues with vertex colored PBR Shader Graph

I'm working on a custom shader using Unity 2018's new shader graph feature. Previously, I was using this shader, which worked great for awhile, but it ended up constantly breaking for seemingly no ...