WIP: Beginning to improve composition.

* Added code to change the windowing in Sample.Sprites to test
      composition and camera movements.
    * Added the ability to change the window title.

DotSDL/Graphics/SdlWindow.cs

@@ -11,6 +11,7 @@ namespace DotSDL.Graphics {
     public class SdlWindow : IResourceObject {
         private readonly SdlInit _sdlInit = SdlInit.Instance;
         private readonly ResourceManager _resources = ResourceManager.Instance;
+        private string _windowTitle;
 
         private readonly IntPtr _window;
         private readonly IntPtr _renderer;
@@ -39,6 +40,15 @@ namespace DotSDL.Graphics {
         /// <summary>Gets the height of this <see cref="SdlWindow"/>.</summary>
         public int WindowHeight { get; }
 
+        /// <summary>Gets or sets the title of this <see cref="SdlWindow"/>.</summary>
+        public string WindowTitle {
+            get => _windowTitle;
+            set {
+                _windowTitle = value;
+                Video.SetWindowTitle(_window, _windowTitle);
+            }
+        }
+
         /// <summary>Gets the width of the rendering target used by this <see cref="SdlWindow"/>.</summary>
         public int TextureWidth { get; }
         /// <summary>Gets the height of the rendering target used by this <see cref="SdlWindow"/>.</summary>
@@ -148,6 +158,7 @@ namespace DotSDL.Graphics {
         public SdlWindow(string title, Point position, int windowWidth, int windowHeight, int textureWidth, int textureHeight, ScalingQuality scalingQuality) {
             _sdlInit.InitSubsystem(Init.SubsystemFlags.Video);
 
+            _windowTitle = title;
             _window = Video.CreateWindow(title, position.X, position.Y, windowWidth, windowHeight, Video.WindowFlags.Hidden);
             _renderer = Render.CreateRenderer(_window, -1, Render.RendererFlags.Accelerated);
 

DotSDL/Interop/Core/Video.cs

@@ -103,6 +103,14 @@ namespace DotSDL.Interop.Core {
         [DllImport(Meta.CoreLib, EntryPoint = "SDL_GetWindowID", CallingConvention = CallingConvention.Cdecl)]
         internal static extern uint GetWindowId(IntPtr window);
 
+        /// <summary>
+        /// Sets the title of an SDL window.
+        /// </summary>
+        /// <param name="window">The window to set the title of.</param>
+        /// <param name="title">The string to set the window title to.</param>
+        [DllImport(Meta.CoreLib, EntryPoint = "SDL_SetWindowTitle", CallingConvention = CallingConvention.Cdecl)]
+        internal static extern void SetWindowTitle(IntPtr window, string title);
+
         /// <summary>
         /// Shows an SDL window.
         /// </summary>

Samples/Sample.Sprites/Player.cs

@@ -39,7 +39,6 @@ namespace Sample.Sprites {
 
                 // Increase the brightness and alpha as we move further inside.
                 _color.A = (byte)(baseAlpha + ((float)Radius - x + 1) / Radius * (255 - baseAlpha));
-                System.Console.WriteLine(_color.A);
 
                 var newR = (short)(_color.R * 1.1);
                 _color.R = (byte)(newR > 255 ? 255 : newR);

Samples/Sample.Sprites/Window.cs

@@ -155,6 +155,31 @@ namespace Sample.Sprites {
             _player1.Move(_player1Delta);
             _player2.Move(_player2Delta);
 
+            var x1 = _player1.Position.X <= _player2.Position.X
+                         ? _player1.Position.X - (_player1.Width * _player1.Scale.X)
+                         : _player2.Position.X - (_player2.Width * _player2.Scale.X);
+            var x2 = _player1.Position.X >= _player2.Position.X
+                         ? _player1.Position.X + (_player1.Width * _player1.Scale.X)
+                         : _player2.Position.X + (_player2.Width * _player2.Scale.X);
+            var y1 = _player1.Position.Y <= _player2.Position.Y
+                         ? _player1.Position.Y - (_player1.Height * _player1.Scale.Y)
+                         : _player2.Position.Y - (_player2.Height * _player2.Scale.Y);
+            var y2 = _player1.Position.Y >= _player2.Position.Y
+                         ? _player1.Position.Y + (_player1.Height * _player1.Scale.Y)
+                         : _player2.Position.Y + (_player2.Height * _player2.Scale.Y);
+
+            x1 = x1 < 0 ? 0 : x1;
+            x2 = x2 >= Background.Width ? Background.Width : x2;
+            y1 = y1 < 0 ? 0 : y1;
+            y2 = y2 >= Background.Height ? Background.Height : y2;
+
+            Background.Clipping.Position.X = (int)x1;
+            Background.Clipping.Position.Y = (int)y1;
+            Background.Clipping.Size.X = (int)(x2 - x1);
+            Background.Clipping.Size.Y = (int)(y2 - y1);
+
+            WindowTitle = $"({(int)x1} {(int)y2}), ({(int)(x2 - x1)}, {(int)(y2 - y1)}) / ({Background.Width}, {Background.Height})";
+
             /*_camX += _deltaX;
             _camY += _deltaY;