# Tagged Questions

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

7k 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 ...
3k 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 ...
1k 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 ...
289 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: 1 ['2', '4', '5', '7', '17', '10'] 2 ['1', '3', '4'] ...
1k 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 ...
1k 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 ...
152 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 ...
6k 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 are good one available). I could consider using a path finding library ...
169 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 ...
287 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 ...
995 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 ...
363 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 ...
187 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 ...
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 ...
61 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: <v_0, v_1 ... v_n-1, v_n> where if v_i == v_j then i == j Great! now the simple question appears: How ...
718 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 ...
531 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-...
49 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. ...
244 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,...
240 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 ...
1k 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 ...
2k 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....
1k 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 ....
66 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 ...
125 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 ...
146 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 ...
76 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 ...
185 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 ...
282 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 ...
306 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-...
96 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 ...
163 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 ...
224 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....
118 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 ...
39 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. ...
64 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 degree of a node as a height value at position x and y of a height map. I ...
241 views

### Bubble shooter clone, structure for storing/adding of bubbles

Im having a few issues trying to figure out what the best data structure to use for storing bubbles on the grid, and how to connect new bubbles to the grid when a moving ball collides with a ball on ...
106 views

### Path smoothing while path following

I can't find a nice way to do path smoothing while i'm following a path. I have tried this piece of code but aparently it doesn't work as suspected. The idea of how it should work is: Edge 1 (the ...
384 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 ...
273 views

### Code sample on how to implement Lee's visibility graph

In my recent search, I've been amazed about how difficult it is to find code examples or information on how to build visibility graphs. Considering its importance on video-game development for AI path-...
57 views

### Camera (pole cam) implementation problem

In my project I have simple scene graph to render whole scene and Bullet physics SDK to provide physics simulation. Each rendered object is represented as scene node. Camera always has target and ...