We Keep Coding

C# Monogame Performance when Drawing Thousands of SpriteBatch.DrawString()

I'm currently creating a large map, that consists of a lot of rectangles (33,844), that all have a unique name (label), which I'm drawing on top of them using a SpriteFont.
Drawing all of the rectangles takes no performance hit at all. But, as soon as I try to write all of their labels with DrawString(), my performance goes into the dumps.
In my head, I would like to draw all my rectangles and text to one texture all at once, and only have to keep redrawing that entire finished texture. My issue is, this is an enormous map, and some of the coordinates for the rectangles are very high (example: one slot's x is 14869 and y is 23622), and they're far bigger than a Texture2D allows.
Since this is a map, I really only need to draw the entire thing once, and then allow the user to scroll/move around it. There's no need for me to continually redraw all of the individual rectangles and their labels.
Does anyone have experience with this type of situation?

Try to only render the labels that you can see on the screen and if you can zoom back far enough, just don't render them.
Textrendering is expensive, since it is basically creating a rectangle to draw on for every character in the font and then applying the same RGBA texture to it. So depending on the number of characters you write, the number of rectangles increases. This means four new vertices per character.
Depending on what you write you could simply create a texture with the text already on it and render that, but it won't be very dynamic.
EDIT: I need to clarify something.
There's no need for me to continually redraw all of the individual rectangles and their labels.
This is wrong. You have to draw the whole thing every frame. Sure, it doesn't increase memorywise, but it still is a lot to render and you will need to render it every frame.
But as I said: Try to only render the labels and the rectangles that collide with the screenboundaries, then you should be fine.

There are two ways to solve your problem.
You can either render your map to a RenderTarget(2D/3D) or you can cull the rectangles/text that are offscreen. However, I am not 100% sure that RenderTargets can go as large as you would need, but you could always segment your map into multiple smaller RenderTargets.
From more information on RenderTargets, you might want to check out RB Whitaker's article on them, http://rbwhitaker.wikidot.com/render-to-texture
Culling, in case you are familiar with the term when used in this context, means to only render what is visible to the end-user. There are various ways that culling can be implemented. This does however require you to have already implemented a camera (or some type of view region) and you perform a basic axis-aligned bounding box collision (AABB collision, which MonoGame's Rectangle supports out of the box) of the rectangles against the camera's viewport and only render it if there is a collision.
A basic implementation of culling would look something like this:
Rectangle myRect = new Rectangle(100, 100, 48, 32);
public void DrawMapItem(SpriteBatch batch, Rectangle viewRegion)
{
if (viewRegion.Contains(myRect))
{
//Render your object here with the SpriteBatch
}
}
Where 'viewRegion' is the area of you world that the camera/end-user can actually see.
You can also combine the two methods, and render the map to multiple render targets, and then cull the render targets.
Hope this helps!

I got points on a map.Getting all independent inner polygons that are formed?

I got points on a map and lines connecting those points.
How do I get all independent inner polygons that are formed?
The linked picture describes the problem.
http://i.imgur.com/0LdA3ji.jpg
I'm supposing I need a tree search algorithm that enumerates all the points and connecting lines in a tree structure and then searches for cycles but this job is kinda over my head.
In a perfect world the example would be in C#.)
I found:
Finding all cycles in undirected graphs
but it does not mark independent polygons. It finds all possible polygons even overlapping ones.
I'm using google maps. The use case is: I detect clicks on map and draw points. I detect click on points and then get lines between points. Now I need to automaticaly generate polygons from the lines and points. Sure I can draw polygons. I just dont know which ones (what coordinates - or rather: what points to choose for a polygon)

I actually have no experience in graphics and how to actually colour a polygon once you've found it, but assuming:
You have the polygons themselves.
They do not patialy overlap or any other weird behaviour.
Then the colouring pseudo code could go something like this:
while listOfPolygons is not empty
temp <- find smallest polygon in listOfPolygons
colour temp
remove from listOfPolygons all polygons containing temp
remove temp from listOfPolygons
Notice that the part about finding the containing polygons might be tricky.
Edit:
Checking if polygon A is in polygon B can be done by checking if any corner (vertex?) of A is located inside B.

Dynamically Create and Destroy PictureBoxes

I am trying to make a simple tile-based turn based strategy-game.
So I made a test-map with different things like trees, rivers etc.
My next step is to make classes that I call Unit, that holds the X-Y position and other data. Since Unit will be created/destroyed dynamically during the game (in a List>), I also want PictureBox containing the Unit tile-icon to be created/destroyed as needed.
I want to be able to click on a PictureBox, the box will make a mouse event, the event will check which class is connected to the PictureBoxand perform action as needed.
Dynamically Create and Destroy PictureBox in C#? Or should I make a grid of PictureBox?

I would go a different route. Create one single PictureBox and draw everything in it's Paint event. Do a nested loop through your map's x and y coords for the visible tiles and draw out those tiles using Graphics.Draw commands. After you paint the background tiles you can loop though the unit list and paint those right on top. You can do a simple hit-test on mouse down to see what is being clicked on.
This will be less resource intensive and also allow you to do better animations and graphics later (think sprites crossing tile boundaries or tiles larger than a single physical tile).

Programmatically link all points

REWRITE: I wasn't getting much feedback on this question, I assume I did not write it properly and am attempting to clarify.
I am making a program that lets people created countries. The thick red lines in the picture below are the borders to said countries. I am trying to figure out how to generate a polygon that will fill the entire area inside of the "border" lines. I have the triangulation code that accepts the polygons working - I tested that out with a polygon I entered manually - now I'm trying to figure out how to generate the polygon from the lines/linked point.
For more info - all the red lines are how the yellow dots are linked together. The users drag the yellow dots together to link the lines. It is possible for the polygon to have a hole inside and be open - what I am trying to do is make code that handles open polygons and polygons with holes inside it and generates an output of all the yellow dot's locations (vector3's with x and z as it lies at 0 on the y plane) for my triangulation code.
I'm still looking up way to figure this out but I haven't come up with even where to start looking for solutions. Thanks for all the help.
OLD QUESTION BELOW
I'm trying to find a way to link points together to form an internal polygon. Basically, I'm creating a program that lets people link lines together. After a closed polygon is made, it is supposed to generate a new polygon object inside the lines.
I'm not too sure how to do this - I have made it so they can generate the lines and link them together, but how to do a closed polygon escapes me. I looked at convex hulls but this isn't the same, and tried looking or thinking up a few different things that don't seem to work. I'm curious if anyone can point me in the write direction/a tutorial or idea on how to continue on my creation.
I have two pictures uploaded to help show my point.
Above is what I am trying to do but not too sure how - basically, when the user finished a closed polygon (all the yellow dots are the polygon's external points), I want it to generate an internal polygon (marked by the black 1, 2 and 3).

You may be interessted in Polylines. This could help you to prevent lots of research on graph theory. Like the Polygon class, you can fill a Polyline object. The documentation says:
This object is similar to the Polyline object, except that this object must be a closed shape.
Since you want your shape to be "open", this could help you.
And the linked manual page even includes an example of how to create the Polyline programmatically:
// Add the Polyline Element
myPolyline = new Polyline();
myPolyline.Stroke = System.Windows.Media.Brushes.SlateGray;
myPolyline.StrokeThickness = 2;
myPolyline.FillRule = FillRule.EvenOdd;
System.Windows.Point Point4 = new System.Windows.Point(1, 50);
System.Windows.Point Point5 = new System.Windows.Point(10, 80);
System.Windows.Point Point6 = new System.Windows.Point(20, 40);
PointCollection myPointCollection2 = new PointCollection();
myPointCollection2.Add(Point4);
myPointCollection2.Add(Point5);
myPointCollection2.Add(Point6);
myPolyline.Points = myPointCollection2;
myGrid.Children.Add(myPolyline);
Your second requirement is, that your shape can have "holes".
Notice, that you don't have to take care of filling the Polyline. By setting myPolyline.FillRule you can have "holes" inside of your shape. See the Polyline.FillRule page on MSDN, which shows:
If you have further wishes on how to make "holes", have a look at the Geometry.Combine Method and especially the GeometryCombineMode.
An example that demonstrates GeometryCombineModes...
Have fun : )
Pictures and code are example content, provided by Microsoft and were extracted from MSDN. Please take care of the copyrights, which are available through the given links, when reusing it. For using those contents here, I want to refer to the Microsoft Limited Public License.

What about a derivative of Marching Quads? you could have something like this :
for each three points (grouped in creation order inside of the mesh) find the center of the polygon and let the user assign a bool value to it which will define if this polygon is inside or outside the mesh and then draw it or not

You can't create an open polygon. It's only becomes a polygon when it's closed. But, here is an approach that might serve your needs.
Create a closed polygon by connecting all of the available lines, and then calculate the final line that links the starting point with the end point while it's in an intermediate state.
Then,
Draw (not fill) the polygon with a different color than the
background.
Draw the final calculated line with the background color so it disappears.
That approach, or a modified version, will create the illusion of an open polygon.

Commenter #SamyS.Rathore is right. If your question is "How do I find the closed areas (polygons) in a planar graph given its vertices and edges?" then you want to look into Simple Circle algorithms like https://stackoverflow.com/a/14115627/642532 there.
However after finding those circles additional work is required to support holes. Basically what you want to do is to detect wether a polygon is inside another one and then geometrically subtract it.
Simple Circles doesn't deal with partially opened areas. But that shouldn't be a problem in your case, because those areas can only exist at the outer borders of the playing field and the user can easily close them at will.

I got this done by taking every point and linking it to a class that had a base vector3 that was the location of the point, as well as every linked line that went out from it. Basically.
class DoubleV3
Vector3 MiddleVector
List LinkedVectors
I also take care of people having accidentally or purposefully put the same entries multiple times right now by remove all redundant lines.
After that I go through the entire thing and check every doubleV3's linked vectors, I go from every linkedvector to the left-most vector beyond it (basically, I check the last vector and next vector of every linkedvectors list to a north vector 1 up from the middle and take the smallest angle). This gives me a bunch of closed polygons (yes, I know now the proper term is cycle, I now use that). This deals with open cycles (which I do not want). It won't deal with complex cycles that come from overlapping lines, but I deal with that in another method.
After that I simply remove all duplicate polygons and check to make sure no polygon in inside another (I also throw out all internal cycles that aren't part of the outer hull).
Thanks everyone for helping me ^.^ This is how I ended up doing it in case anyone else is in my situation.

Draw points along the surface of a cube

So for an assignment I have to morph a cube into a sphere. All that's required is to have a bunch of points along the surface of a cube (don't need to be connected or actually be on a cube, but has to form a cube, though connections would make it easier to look at) and have them smoothly translate into a sphere shape.
The main problem is I never learned how to make points in XNA 4.0 and from what I've seen it's very different to what we did in OpenGL (we learned the old one in a previous class).
Would anyone be able to help me figure out making the cube shape I need? Each side would have 10x10 points with the points on the edge shared by the surfaces of that edge. The structure would need to be easy to copy or modify since I would need to have the start state, end state, and the intermediate state to translate the points between the two states.
If I left out anything that could be important let me know.

First of all, you should familiarise yourself with the Primitives3D sample. It illustrates all of the rendering APIs that you need.
Here is how I would approach this problem (you can look up these classes and methods on MSDN and it will hopefully help you flesh out the details):
Create an array of Vector3[] that represents an appropriately tessellated unit cube around (0,0)
Create a second array of Vector3[] and and use Vector3.Normalize to copy in the vertices from your first array. This will create a unit sphere with vertices that match up with the original cube.
Create an array of VertexPositionColor[]. Fill in the colour data however you like.
Use Vector3.Lerp to loop through the first two arrays, interpolating each element to set positions in the third array. This gives you a parameter you can animate - you will have to do this each frame (in Update is probably best).
Create an array of indices (short[]) that describes a triangle list of the tessellated cube (and, in turn, the sphere and animation between the two).
Set up a BasicEffect for rendering. This involves setting its World, View and Projection matrices and maybe turning on VertexColorEnabled. If you want lighting, see the sample for details (you'll need to use a vertex type with normals, and animate those normals correctly).
The way to render with an effect is: foreach(EffectPass effectPass in effect.CurrentTechnique.Passes) { effectPass.Apply(); /* your stuff here */ }
You could create a DynamicVertexBuffer and IndexBuffer and draw with those. But for something simple like this, DrawUserIndexedPrimitives is much easier (here is a recent answer with some details, and here's another one with a complete example of BasicEffect).
Note that you should only create these objects at startup (LoadContent is a good place). During rendering you're simply using them.
If you have trouble with your 3D rendering, and you're drawing text or sprites, see this article for how to fix it.