Added the ability to use a pointer to represent the background of an SdlWindow.

DotSDL/Graphics/SdlWindow.cs

@@ -105,6 +105,7 @@ namespace DotSDL.Graphics {
         /// <param name="windowHeight">The height of the window.</param>
         /// <param name="textureWidth">The width of the window's texture.</param>
         /// <param name="textureHeight">The height of the window's texture.</param>
+        /// <param name="updateType">The method used to update the canvas.</param>
         public SdlWindow(string title, Point position, int windowWidth, int windowHeight, int textureWidth, int textureHeight) {
             _sdlInit.InitSubsystem(Init.SubsystemFlags.Video);
 
@@ -135,15 +136,10 @@ namespace DotSDL.Graphics {
         /// <summary>
         /// Handles calling the user draw function and passing the CLR objects to SDL2.
         /// </summary>
-        private unsafe void BaseDraw() {
+        private void BaseDraw() {
             if(IsDestroyed || IsMinimized) return;
-            OnDraw(ref _canvas);  // Call the overridden Draw function.
-
-            fixed(void* pixelsPtr = _canvas.Pixels) {
-                var ptr = (IntPtr)pixelsPtr;
-                Render.UpdateTexture(_texture, IntPtr.Zero, ptr, TextureWidth * 4);
-            }
-
+            
+            Render.UpdateTexture(_texture, IntPtr.Zero, GetCanvasPointer(), TextureWidth * 4);
             Render.RenderCopy(_renderer, _texture, IntPtr.Zero, IntPtr.Zero);
             Render.RenderPresent(_renderer);
         }
@@ -173,6 +169,21 @@ namespace DotSDL.Graphics {
             IsDestroyed = true;
         }
 
+        /// <summary>
+        /// Gets an <see cref="IntPtr"/> that points to what should be displayed on the window's background. You usually
+        /// do not need to override this method.
+        /// </summary>
+        /// <remarks>If an invalid <see cref="IntPtr"/> is generated by this method, your application may
+        /// crash with a segmentation fault. When in doubt, override <see cref="OnDraw"/> instead!</remarks>
+        /// <returns>An <see cref="IntPtr"/> containing the contents of the window's background.</returns>
+        public unsafe virtual IntPtr GetCanvasPointer() {
+            OnDraw(ref _canvas); // Call the overridden Draw function.
+
+            fixed(void* pixelsPtr = _canvas.Pixels) {
+                return (IntPtr)pixelsPtr;
+            }
+        }
+
         /// <summary>
         /// Retrieves the SDL resource ID for this <see cref="SdlWindow"/>.
         /// </summary>
@@ -254,7 +265,7 @@ namespace DotSDL.Graphics {
         /// </summary>
         /// <param name="canvas">The active canvas for the window.</param>
         protected virtual void OnDraw(ref Canvas canvas) { }
-
+        
         /// <summary>
         /// Called before the window is shown.
         /// </summary>