XNA Tutorial I: Window settings and overall setup:
Before you start creating your game, even the logic behind it, it is very important that you have an understanding of the basic settings that can be applied to the window. Essentially these consist mainly of the window size, windowed and full screen modes, as well as the way sprites are drawn.
For the window resolution or size, in the class constructor, in Game1.cs, recognizable as “public Game1(){…}” you can see an object named graphics is created, of class GraphicsDeviceManager. You can consider this to be the cause of anything related to the above. Enter a new line and type “graphics.” with the dot, that should cause visual studio to show you a dropdown list to select elements of that object. From these elements you will select PreferredBackBufferWidth and PreferredBackBufferHeight for the window width and height correspondingly, in other words the resolution. These are measured in pixels of course, and you can assign them any positive value you wish. You may try to assign negative values, or change them during runtime later on, it would be interesting to see how that handles.
To make your game full screen you will similarly find the Boolean variable of graphics called IsFullScreen and assign it the value true. Note however that if for some reason your game crashes, it will be nearly impossible to convince windows to show you Visual Studio again without terminating the game. This means that you will either have to check the error log after you close it (Shift + F5 in visual studio, once you blindly get passed the popup box), or you will have to run in windowed mode for debugging.
A great convenience is the ToggleFullScreen() function, a member function of graphics, which you can call at any point of the code. You are probably not going to run into trouble before you add some game logic, for which you will have to read on to the tutorial on keyboard input –which is really short. By then you will be able to assign a hotkey for toggling full screen, typically it is Alt + Enter.
To exit during testing, whether in full screen or not, you can just hit Alt + F4, it is automatically implemented into the window by the framework.
The rendering modes are of great importance as the default mode is Immediate, which is of course theoretically fine, but I did happen to find thing rendered in the wrong order once. It is just good to know that in the Draw() function, when you call spriteBatch.Begin(), you can change the first parameter to BackToFront so sprites will be painted in the order you tell XNA to paint them. This of course means that you will manually paint them in inverse order of depth, from the farthest to the closest, you have to do it like that in XNA unless you wish to write a more sophisticated function which takes distance into account.
Some final tips, GraphicsDevice.Clear() will repaint the entire screen with the color passed to it before you draw anything, so you don’t get any mess in the background. The default is CornflowerBlue, but you might want something else. Do not remove the call to this function unless you are absolutely sure you will redraw the entire area. Unlike the GDI’s WM_ERASEBKGND message, this does not cause flickering and has no effect on the overall look, nor should it have any effect on the overall efficiency of the game.
In the next tutorial I will go through the basics of keyboard input, it is fast and easy to learn and that’s actually enough to make a game once you also read the tutorial on image rendering. However, the more you learn the better your game is, so keep on reading to cover subjects such as timing, randomness, spawning units and other elements of the language and techniques.
Not much to practice on just yet, but do take a minute to take a look around the XNA and familiarize with the classes, the members and the functionality.