Added SansSerif font.

Source/Examples/Tutorial/Fonts.cs

@@ -19,12 +19,16 @@ using OpenTK.Math;
 
 namespace Examples.Tutorial
 {
+    /// <summary>
+    /// Tests Font loading and rendering.
+    /// </summary>
     class Fonts : GameWindow, IExample
     {
         public Fonts() : base(new DisplayMode(800, 600), String.Format("OpenTK | Tutorial {0}: Fonts", order))
         { }
 
-        ITextPrinter text = new TextPrinter();
+        ITextPrinter printer = new TextPrinter();
+        const string text = "Hello, world!";
 
         // Load some different TextureFont sizes to compare their quality.
         TextureFont[] fonts = new TextureFont[]
@@ -39,25 +43,70 @@ namespace Examples.Tutorial
             new TextureFont(new Font(FontFamily.GenericSerif, 20.0f)),
             new TextureFont(new Font(FontFamily.GenericSerif, 22.0f)),
 
-            new TextureFont(new Font(FontFamily.GenericSerif, 24.0f)),
+            new TextureFont(new Font(FontFamily.GenericSerif, 24.0f, FontStyle.Bold)),
             new TextureFont(new Font(FontFamily.GenericSerif, 26.0f)),
             new TextureFont(new Font(FontFamily.GenericSerif, 28.0f)),
             new TextureFont(new Font(FontFamily.GenericSerif, 30.0f)),
 
-            new TextureFont(new Font(FontFamily.GenericSerif, 32.0f)),
+            new TextureFont(new Font(FontFamily.GenericSerif, 32.0f, FontStyle.Italic)),
             new TextureFont(new Font(FontFamily.GenericSerif, 34.0f)),
             new TextureFont(new Font(FontFamily.GenericSerif, 36.0f)),
             new TextureFont(new Font(FontFamily.GenericSerif, 38.0f)),
+
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 8.0f)),
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 10.0f)),
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 12.0f)),
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 14.0f)),
+
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 16.0f)),
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 18.0f)),
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 20.0f)),
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 22.0f)),
+
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 24.0f, FontStyle.Bold)),
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 26.0f)),
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 28.0f)),
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 30.0f)),
+
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 32.0f, FontStyle.Italic)),
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 34.0f)),
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 36.0f)),
+            new TextureFont(new Font(FontFamily.GenericSansSerif, 38.0f)),
         };
         TextHandle[] handles;       // Used to cache the strings we want to print.
 
+        /// <summary>
+        /// To maintain high rendering performance, we need to cache the text
+        /// we wish to draw, for each font we want to draw it with. To achieve
+        /// this, we use the TextPrinter.Prepare() method, which returns a
+        /// TextHandle - i.e. a handle to the cached text.
+        /// <para>
+        /// We can use these TextHandles with the TextPrinter.Draw() method
+        /// to draw text with very high performance.
+        /// </para>
+        /// </summary>
+        /// <param name="e"></param>
         public override void OnLoad(EventArgs e)
         {
             GL.ClearColor(Color.SteelBlue);
 
             handles = new TextHandle[fonts.Length];
             for (int i = handles.Length; --i >= 0; )
-                text.Prepare("Hello, world!", fonts[i], out handles[i]);
+                printer.Prepare(text, fonts[i], out handles[i]);
+        }
+
+        /// <summary>
+        /// It is important that we need to call the Dispose() methods to reclaim of
+        /// each and every TextHandle and TextureFont to reclaim the unamanged
+        /// (OpenGL) resources they are using.
+        /// </summary>
+        /// <param name="e"></param>
+        public override void OnUnload(EventArgs e)
+        {
+            foreach (TextHandle h in handles)
+                h.Dispose();
+            foreach (TextureFont f in fonts)
+                f.Dispose();
         }
 
         protected override void OnResize(OpenTK.Platform.ResizeEventArgs e)
@@ -71,6 +120,21 @@ namespace Examples.Tutorial
                 this.Exit();
         }
 
+        /// <summary>
+        /// To render pixel-perfect text, we have to setup a 2d display projection
+        /// with a width/height that corresponds to our current Viewport.
+        /// In OpenGL this can be easily achieved using the GL.Ortho method.
+        /// <para>
+        /// It is still possible to render text in a 3d projection, but it will
+        /// be very hard to achieve pixel-perfect precision.
+        /// </para>
+        /// <para>
+        /// To achieve the highest possible performance, render your 3d scene first.
+        /// At the end of the RenderFrame call, setup a 2d projection and render all
+        /// text in one go.
+        /// </para>
+        /// </summary>
+        /// <param name="e"></param>
         public override void OnRenderFrame(RenderFrameEventArgs e)
         {
             GL.Clear(ClearBufferMask.ColorBufferBit);
@@ -82,10 +146,21 @@ namespace Examples.Tutorial
             GL.MatrixMode(MatrixMode.Modelview);
             GL.LoadIdentity();
 
-            // Font size test:
+            // Print using the first font.
-            for (int i = 0; i < handles.Length; i++)
+            for (int i = 0; i < handles.Length / 2; i++)
             {
-                text.Draw(handles[i]);
+                printer.Draw(handles[i]);
+                GL.Translate(0, fonts[i].Height, 0);
+            }
+
+            // Move to the right, and print using the second font.
+            float width, height;
+            fonts[handles.Length / 2 - 1].MeasureString(text, out width, out height);
+            GL.LoadIdentity();
+            GL.Translate(width + 32.0f, 0, 0);
+            for (int i = handles.Length / 2; i < handles.Length; i++)
+            {
+                printer.Draw(handles[i]);
                 GL.Translate(0, fonts[i].Height, 0);
             }