I'm creating a 2D game in Unity which has procedurally placed tiles. I want to simplify the collision geometry using Angus Johnson's Clipper library (specifically the union function), but I'm running into an issue with the library returning empty solutions and I'm not sure why.
For reference, here are the Polygon Colliders I've been using to test.
And here is a simplified version of the function I'm using to combine the geometry:
List<List<Vector2>> unitedPolygons = new List<List<Vector2>>();
Clipper clipper = new Clipper();
Paths solution = new Paths();
ClipperOffset offset = new ClipperOffset();
//Use a scaling factor for floats and convert the Polygon Colliders' points to Clipper's desired format
int scalingFactor = 10000;
for (int i = 0; i < polygons.Count; i++)
{
Path allPolygonsPath = new Path(polygons[i].points.Length);
for (int j = 0; j < polygons[i].points.Length; j++)
{
allPolygonsPath.Add(new IntPoint(Mathf.Floor(polygons[i].points[j].x * scalingFactor), Mathf.Floor(polygons[i].points[j].y * scalingFactor)));
}
bool succeeded = clipper.AddPath(allPolygonsPath, PolyType.ptSubject, true);
}
//Execute the union
bool success = clipper.Execute(ClipType.ctUnion, solution);
Debug.Log("Polygons after union: " + solution.Count);
//Offset the polygons
offset.AddPaths(solution, JoinType.jtMiter, EndType.etClosedPolygon);
offset.Execute(ref solution, 5f);
//Convert back to a format Unity can use
foreach (Path path in solution)
{
List<Vector2> unitedPolygon = new List<Vector2>();
foreach (IntPoint point in path)
{
unitedPolygon.Add(new Vector2(point.X / (float)scalingFactor, point.Y / (float)scalingFactor));
}
unitedPolygons.Add(unitedPolygon);
}
return unitedPolygons;
What I've discovered through debugging is that the first Execute (for the union) is returning an empty solution. I've figured out that the "BuildResult" function in the "Clipper" class is indeed running, and "m_PolyOuts" has data in it, but the "Pts" property of the "OutRec"s in that list are all null. I can't figure out where this happens or if they were ever set in the first place.
I'm convinced this is proper behavior and I'm just using the library wrong, but I can't find any documentation or examples explaining what I need to change to make the union succeed.
Thanks.
EDIT: I've narrowed it down a bit more. During "ExecuteInteral" in the Clipper class, the "Pts" lists aren't null until the "FixupOutPolygon" function is run. After that, all of the lists are null. "JoinCommonEdges" also makes a couple of the lists null, but not all of them.
I've been working on my own game project as well and stumbled upon similar problem with Clipper. What worked for me in this case was instead of writing this:
clipper.Execute(ClipType.ctUnion, solution);
... I specified PolyFillType for Execute method:
clipper.Execute(ClipType.ctUnion, solution, PolyFillType.pftNonZero, PolyFillType.pftNonZero);
I'm not sure why it worked for me but I think it's due to the fact that some Paths can share common edges so with the default pftEvenOdd filling rule it gets cut out.
Related
I'm working on creating a building generator, and am trying to combine all walls of the building into a single mesh. The building itself is made of quite a lot of individual gameobjects, all parented under one gameobject. In play mode, the constructed building looks like this.
I can export the gameobjects as a prefab just fine.
The issue arises when I attempt to combine everything to a single mesh. It shows like this, with a great deal of vertices appearing to be missing. I've already considered that I could be running up against the vertice limit, but even after raising that limit, the issue remains unresolved. Recalculating the normals hasn't helped, either. Code below.
MeshFilter[] filters = building.GetComponentsInChildren<MeshFilter>();
Mesh finalMesh = new Mesh();
finalMesh.indexFormat = UnityEngine.Rendering.IndexFormat.UInt32;
Debug.Log("Filters " + filters.Length);
CombineInstance[] combiners = new CombineInstance[filters.Length];
for (int i = 0; i < filters.Length; i++)
{
Debug.Log(filters[i].gameObject.name);
combiners[i].subMeshIndex = 0;
combiners[i].mesh = filters[i].sharedMesh;
combiners[i].transform = filters[i].transform.localToWorldMatrix;
}
finalMesh.CombineMeshes(combiners);
finalMesh.RecalculateNormals();
building.AddComponent<MeshFilter>();
building.GetComponent<MeshFilter>().sharedMesh = finalMesh;
string localPath2 = buildingFolderPath + "/Building.asset";
AssetDatabase.CreateAsset(finalMesh, localPath2);
GameObject finalBuilding = PrefabUtility.SaveAsPrefabAsset(building, localPath);
I have no clue what could be happening. I've considered that it could be automatically removing intersecting polygons (unsure if that's even a factor with CombineMesh(), the documentation doesn't say anything about it) but even changing the gameobjects involved to very small sizes, to the point where intersection would be impossible, hasn't helped a bit.
A possible clue is that the mesh is only displaying T-junction walls, which are the largest of the walls. Could there be a connection between size and this issue?
As it stands, I've exhausted all of my possible ideas. What could be going on here? For reference, the models in question are simple blender models, more or less just planes, exported in fbx with read/write enabled.
EDIT: As suggested by shingo, I have counted the vertices in the building using the following code.
MeshFilter[] filters = building.GetComponentsInChildren<MeshFilter>();
Mesh finalMesh = new Mesh();
finalMesh.indexFormat = UnityEngine.Rendering.IndexFormat.UInt32;
CombineInstance[] combiners = new CombineInstance[filters.Length];
long count = 0;
for (int i = 0; i < filters.Length; i++)
{
combiners[i].subMeshIndex = 0;
combiners[i].mesh = filters[i].sharedMesh;
combiners[i].transform = filters[i].transform.localToWorldMatrix;
count += filters[i].sharedMesh.vertexCount;
}
Debug.Log("Final count is " + count);
In one experimental example, the final count given by the code was 39174 vertices, while the vertices recorded in the inspector of the corresponding mesh counted 28372. So there's a significant disparity, meaning that the vertices are actually being deleted, instead of just not displaying properly.
I am new to Unity as well as C#. Yet, I am trying to make a simple 2D platform game where I made a prefab of an object called Block. What I want to be able to do is to create an array tile map with 0s and 1s where the 1s are blocks and 0s are nothing. Also, I don't want the tile map to be random. I want the blocks to be instantiated from another object called GameController. A perfect example of what I would like to achieve is something like this.
But I don't really know how to do this with an array. I want to keep things simple since I am trying to learn how unity and c# work. Any help would be appreciated.
So you can use some assets from the asset store( for example: https://www.assetstore.unity3d.com/en/#!/list/2965-procedural-generation) This is a pretty hard challange. I would recomand this video: https://www.youtube.com/watch?v=k1pWpYEt2UE , but the closest one to what you want to achieve is this one: https://www.youtube.com/watch?v=gIUVRYViG_g
Hope it helped.
You can make a 2 dimensional array, e.g. int[40, 100] and loop through it twice, and if the number in the array is one, multiply your position in the array by the length or width of your block respectively. For example:
int[,] positions = new int[40,100];
for (int i = 0; i < 41; i++) {
for (int j = 0; j < 100; j++) {
if (positions[i,j] = 1) {
GameObject temp = Instantiate(block, new Vector3(j * blockWidth, i * blockHeight, 0), Quaternion.identity) as GameObject;
}
}
}
It would take a long while to set all of the coordinates for an array this large, but you could loop through with parameters, or just do it the hard way if it is smaller. Otherwise, I would just try doing it without a script.
Okay so, I have looked at a lot of question from people like my self who are beginners in programming. And most of the time their questions are hard to answer or understand what the question really is. I will do my best to be as specific as possible about my problems so the above mentioned doesn't happen.
First off I have been following the tutorials over at http://xnagpa.net/xna4rpg.php. And my tile engine is based off the one that Jamie McMahon makes in his rpg tutorial series. Just so you know what the general structure of my tile engine is like.
Secondly I will try to explain what I'm trying to do inside the tile engine. I recently found an article about how the original Civilization generated their maps. http://forums.civfanatics.com/showthread.php?t=498630
And I rather like this approach to generating a "world" style map if you will. ie: oceans, continents, islands ect. So I decided to try to take this and implement it into my tile engine. It works for the most part. The parts that I added to the tile engine are supposed to randomly pick a location in the specified map layer (y,x) and then from that location generate a chunk of land(or tiles) and then replace the tiles in the map layer with the tiles created in the chunk of land. (ill show the code in a minute) and then do that for a desired amount of either number of landmasses(chunks) or continue creating chunks of land until the number of land tiles is equal to a desired amount of land tiles.
My Problem:
My program does what its supposed to (as mentioned above) except it only ever makes one landmass.(Chunk of land tiles) It does everything else just fine but it for some reason will not make more than one landmass. Now I suspect that it actually is making the other landmasses but somehow the way the tile engine is set up to display map layers is causing the landmass's to be covered up with water. Maybe its a layering issue. But It shouldn't be because the landmass's are all part of the same layer. So I'm completely baffled as to why its doing this.
public void GenerateLandChunks(MapLayer layer)
{
Tile tile = new Tile(0, 3);
Random random = new Random();
int x = random.Next(8, layer.Width - 10);
int y = random.Next(10, layer.Height - 20);
int length = random.Next(10, 70);
for (int i = 0; i < length; i++)
{
if (length != 0 && x > 8 || x < layer.Width - 10 && y > 10 || y < layer.Height - 20)
{
layer.SetTile(y, x, tile);
layer.SetTile(y, x + 1, tile);
layer.SetTile(y + 1, x, tile);
}
x = random.Next(x - 1, x + 2);
y = random.Next(y - 1, y + 2);
}
}
This is my method for generating the actual chunks it does what I want it to. (ABOVE)
MapLayer randomLayer = new MapLayer(100, 100);
for (int y = 0; y < randomLayer.Height; y++)
{
for (int x = 0; x < randomLayer.Width; x++)
{
Tile tile = new Tile(1, 3);
randomLayer.SetTile(x, y, tile);
}
}
int landMasses = 5;
for (int i = 0; i < landMasses; i++)
{
randomLayer.GenerateLandChunks(randomLayer);
}
This is where I create the map layer. I initially set the entire map to water tiles(tile (1,3)) then I tell it to generate 5 landmasses.
It seems like this should work. And it does but like I said only for the first one. It doesn't display the other 4 land masses.
My Question:
Is there anything you can see here that I'm doing wrong in order to accomplish what I'm trying to do?
If you need more of the code to understand whats going on let me know and ill post what ever you need. And like I said everything other than what I have posted is the exact same as it is in Jamie McMahon's tile engine.
I'm sorry if I have come off as unclear or if my question is hard to answer. I tried to make it as straight forward as possible. Thank you for your time.
So much text for such a simple answer. The problem is that a new Random object is generated every time, and so the "random" values are the same every time. That is how random number generators work, the numbers are not actually random, but "pseudorandom", and if you use the same random function and the same seed you will get the same progression of seemingly random numbers.
Default Random constructor seeds the generator with some value based on time, but if two generators are created with very small time period then that time value will be the same.
Move the Random object outside the function, so that it is used for all random generations, or move the loop inside (but Random outside the loop).
Okay, so yesterday at school i was presented with a task in c#, which was create a program to build a Matrix and multiply that matrix by another one. so far i have done this:
List<List<double>> translacao = new List<List<double>>();
translacao[0][0] = 0;
translacao[0][1] = 0;
translacao[0][2] = 4;
translacao[1][0] = 0;
translacao[1][1] = 1;
translacao[1][2] = 6;
translacao[2][0] = 0;
translacao[2][1] = 0;
translacao[2][2] = 8;
I tried with normal arrays like double [,] , but my problem is always the same. From here, how can i multiply this Matrix by another ?? (I know how to multiply matrixes (in paper) but isnt there any method in c# that does that for me ?) the only Matrix classes i found were only able to multiply 3x3 matrixes.
I would say you are gonna have to write your own funciton, maybe even a few overloads for different sizes depending on how crafty your function is.
I am not very good at matrix math but here is somewhat of a process
also this is not c#:
matrix Multiply[][] (matrix a[][], matrix b[][])
{
//check the sizes, i remeber its something that must be done but dont remember the specifics
if (a.width != b.height)
throw WrongSizeException;
matrix result[][];
//do the math:
result[0][0] = a[0][0] * b[0][0]; //again, I don't remeber this stuff
...
...
return result;
}
I hope this gets the right gears turning
I have a canvas where there are several polygons, what I want to do is try detect whether the polygons are overlapping. I'v looked around on various websites and most of what i'v found is to do with object collision - this for example, my polygons aren't moving so that's not going to be an issue.
I was wondering if someone could point me in the right direction on how to detect if they are overlapping. Is there a method that can calculate the space that's used on screen? or the region of the Polygon to compare the two?
So for example like the mock up here, the red shape overlaps the green one.
essentially all i want is to say yes they are overlapping or no they are not.
http://peterfleming.net84.net/Slice%201.png
Thanks in advance.
Pete
This library here (free and open source) will show polygon clipping: http://www.angusj.com/delphi/clipper.php
That said, if by polygons overlapping you mean at least one point of one is inside the other, you can test each polygon's point against the others by either looking at the point in point polygon problem or checking each polygons lines to see if it cuts across another polygon.
These methods will all work with different efficiency, try and see what's best for your situation.
However, your diagram seems to suggest you want to see if these polygons are 'side by side' or something similar. It would help to get clarification on this. Overlapping generally needs some coordinate plan to determine overlap against.
Assuming that each polygon is a Shape (either Path or Polygon) you could use the FillContainsWithDetail method of their RenderedGeometry to pairwise check interscetion.
I was having the same problem too and I used this implementation (which is heavenly inspired by this: C# Point in polygon ):
bool DoesPolygonsOverlap(IList<Point> firstPolygon, IList<Point> secondPolygon)
{
foreach (var item in firstPolygon)
{
if (IsPointInPolygon(secondPolygon, item))
{
return true;
}
}
foreach (var item in secondPolygon)
{
if (IsPointInPolygon(firstPolygon, item))
{
return true;
}
}
return false;
}
bool IsPointInPolygon(IList<Point> polygon, Point testPoint)
{
bool result = false;
int j = polygon.Count() - 1;
for (int i = 0; i < polygon.Count(); i++)
{
if (polygon[i].Y < testPoint.Y && polygon[j].Y >= testPoint.Y || polygon[j].Y < testPoint.Y && polygon[i].Y >= testPoint.Y)
{
if (polygon[i].X + (testPoint.Y - polygon[i].Y) / (polygon[j].Y - polygon[i].Y) * (polygon[j].X - polygon[i].X) < testPoint.X)
{
result = !result;
}
}
j = i;
}
return result;
}
Attention: The function was not very much tested and has a big potential for improvement. Please tell me if you find a bug/problem.