GUI example using OpenTK and OpenGL 1.1.
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// This code was written for the OpenTK library and has been released | |
// to the Public Domain. | |
// It is provided "as is" without express or implied warranty of any kind. | |
using System; | |
using System.Collections.Generic; | |
using System.Drawing; | |
using System.Text; | |
using OpenTK; | |
using OpenTK.Graphics; | |
using OpenTK.Graphics.OpenGL; | |
namespace Examples.Tutorial | |
{ | |
class TextRendering : GameWindow | |
{ | |
TextRenderer renderer; | |
Font serif = new Font(FontFamily.GenericSerif, 24); | |
Font sans = new Font(FontFamily.GenericSansSerif, 24); | |
Font mono = new Font(FontFamily.GenericMonospace, 24); | |
float angle; | |
/// <summary> | |
/// Uses System.Drawing for 2d text rendering. | |
/// </summary> | |
public class TextRenderer : IDisposable | |
{ | |
Bitmap bmp; | |
Graphics gfx; | |
int texture; | |
Rectangle dirty_region; | |
bool disposed; | |
#region Constructors | |
/// <summary> | |
/// Constructs a new instance. | |
/// </summary> | |
/// <param name="width">The width of the backing store in pixels.</param> | |
/// <param name="height">The height of the backing store in pixels.</param> | |
public TextRenderer(int width, int height) | |
{ | |
if (width <= 0) | |
throw new ArgumentOutOfRangeException("width"); | |
if (height <= 0) | |
throw new ArgumentOutOfRangeException("height "); | |
if (GraphicsContext.CurrentContext == null) | |
throw new InvalidOperationException("No GraphicsContext is current on the calling thread."); | |
bmp = new Bitmap(width, height, System.Drawing.Imaging.PixelFormat.Format32bppArgb); | |
gfx = Graphics.FromImage(bmp); | |
gfx.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias; | |
texture = GL.GenTexture(); | |
GL.BindTexture(TextureTarget.Texture2D, texture); | |
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.Linear); | |
GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear); | |
GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba, width, height, 0, | |
PixelFormat.Rgba, PixelType.UnsignedByte, IntPtr.Zero); | |
} | |
#endregion | |
#region Public Members | |
/// <summary> | |
/// Clears the backing store to the specified color. | |
/// </summary> | |
/// <param name="color">A <see cref="System.Drawing.Color"/>.</param> | |
public void Clear(Color color) | |
{ | |
gfx.Clear(color); | |
dirty_region = new Rectangle(0, 0, bmp.Width, bmp.Height); | |
} | |
/// <summary> | |
/// Draws the specified string to the backing store. | |
/// </summary> | |
/// <param name="text">The <see cref="System.String"/> to draw.</param> | |
/// <param name="font">The <see cref="System.Drawing.Font"/> that will be used.</param> | |
/// <param name="brush">The <see cref="System.Drawing.Brush"/> that will be used.</param> | |
/// <param name="point">The location of the text on the backing store, in 2d pixel coordinates. | |
/// The origin (0, 0) lies at the top-left corner of the backing store.</param> | |
public void DrawString(string text, Font font, Brush brush, PointF point) | |
{ | |
gfx.DrawString(text, font, brush, point); | |
SizeF size = gfx.MeasureString(text, font); | |
dirty_region = Rectangle.Round(RectangleF.Union(dirty_region, new RectangleF(point, size))); | |
dirty_region = Rectangle.Intersect(dirty_region, new Rectangle(0, 0, bmp.Width, bmp.Height)); | |
} | |
/// <summary> | |
/// Gets a <see cref="System.Int32"/> that represents an OpenGL 2d texture handle. | |
/// The texture contains a copy of the backing store. Bind this texture to TextureTarget.Texture2d | |
/// in order to render the drawn text on screen. | |
/// </summary> | |
public int Texture | |
{ | |
get | |
{ | |
UploadBitmap(); | |
return texture; | |
} | |
} | |
#endregion | |
#region Private Members | |
// Uploads the dirty regions of the backing store to the OpenGL texture. | |
void UploadBitmap() | |
{ | |
if (dirty_region != RectangleF.Empty) | |
{ | |
System.Drawing.Imaging.BitmapData data = bmp.LockBits(dirty_region, | |
System.Drawing.Imaging.ImageLockMode.ReadOnly, | |
System.Drawing.Imaging.PixelFormat.Format32bppArgb); | |
GL.BindTexture(TextureTarget.Texture2D, texture); | |
GL.TexSubImage2D(TextureTarget.Texture2D, 0, | |
dirty_region.X, dirty_region.Y, dirty_region.Width, dirty_region.Height, | |
PixelFormat.Bgra, PixelType.UnsignedByte, data.Scan0); | |
bmp.UnlockBits(data); | |
dirty_region = Rectangle.Empty; | |
} | |
} | |
#endregion | |
#region IDisposable Members | |
void Dispose(bool manual) | |
{ | |
if (!disposed) | |
{ | |
if (manual) | |
{ | |
bmp.Dispose(); | |
gfx.Dispose(); | |
if (GraphicsContext.CurrentContext != null) | |
GL.DeleteTexture(texture); | |
} | |
disposed = true; | |
} | |
} | |
public void Dispose() | |
{ | |
Dispose(true); | |
GC.SuppressFinalize(this); | |
} | |
~TextRenderer() | |
{ | |
Console.WriteLine("[Warning] Resource leaked: {0}.", typeof(TextRenderer)); | |
} | |
#endregion | |
} | |
#region Constructor | |
public TextRendering() | |
: base(800, 600) | |
{ | |
} | |
#endregion | |
#region OnLoad | |
protected override void OnLoad(EventArgs e) | |
{ | |
renderer = new TextRenderer(Width, Height); | |
PointF position = PointF.Empty; | |
renderer.Clear(Color.Transparent); | |
renderer.DrawString("The quick brown fox jumps over the lazy dog", serif, Brushes.White, position); | |
position.Y += serif.Height; | |
renderer.DrawString("The quick brown fox jumps over the lazy dog", sans, Brushes.White, position); | |
position.Y += sans.Height; | |
renderer.DrawString("The quick brown fox jumps over the lazy dog", mono, Brushes.White, position); | |
position.Y += mono.Height; | |
} | |
#endregion | |
#region OnUnload | |
protected override void OnUnload(EventArgs e) | |
{ | |
renderer.Dispose(); | |
} | |
#endregion | |
#region OnResize | |
protected override void OnResize(EventArgs e) | |
{ | |
GL.Viewport(ClientRectangle); | |
} | |
#endregion | |
#region OnUpdateFrame | |
protected override void OnUpdateFrame(FrameEventArgs e) | |
{ | |
if (Keyboard[OpenTK.Input.Key.Escape]) | |
{ | |
this.Exit(); | |
} | |
} | |
#endregion | |
#region OnRenderFrame | |
protected override void OnRenderFrame(FrameEventArgs e) | |
{ | |
GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit); | |
RenderCube((float)e.Time); | |
RenderGui(); | |
SwapBuffers(); | |
} | |
#endregion | |
#region RenderCube | |
void RenderCube(float time) | |
{ | |
Matrix4 projection = Matrix4.CreatePerspectiveFieldOfView( | |
MathHelper.PiOver2, Width / (float)Height, 1.0f, 128.0f); | |
Matrix4 modelview = Matrix4.LookAt(0, 3, 3, 0, 0, 0, 0, 1, 0); | |
GL.MatrixMode(MatrixMode.Projection); | |
GL.LoadMatrix(ref projection); | |
GL.MatrixMode(MatrixMode.Modelview); | |
GL.LoadMatrix(ref modelview); | |
GL.Rotate(angle, 0.0f, 1.0f, 0.0f); | |
angle += time * 100; | |
GL.Enable(EnableCap.DepthTest); | |
GL.Begin(BeginMode.Quads); | |
GL.Color3(Color.Red); | |
GL.Vertex3(-1.0f, -1.0f, -1.0f); | |
GL.Vertex3(-1.0f, 1.0f, -1.0f); | |
GL.Vertex3(1.0f, 1.0f, -1.0f); | |
GL.Vertex3(1.0f, -1.0f, -1.0f); | |
GL.Color3(Color.Green); | |
GL.Vertex3(-1.0f, -1.0f, -1.0f); | |
GL.Vertex3(1.0f, -1.0f, -1.0f); | |
GL.Vertex3(1.0f, -1.0f, 1.0f); | |
GL.Vertex3(-1.0f, -1.0f, 1.0f); | |
GL.Color3(Color.Blue); | |
GL.Vertex3(-1.0f, -1.0f, -1.0f); | |
GL.Vertex3(-1.0f, -1.0f, 1.0f); | |
GL.Vertex3(-1.0f, 1.0f, 1.0f); | |
GL.Vertex3(-1.0f, 1.0f, -1.0f); | |
GL.Color3(Color.Yellow); | |
GL.Vertex3(-1.0f, -1.0f, 1.0f); | |
GL.Vertex3(1.0f, -1.0f, 1.0f); | |
GL.Vertex3(1.0f, 1.0f, 1.0f); | |
GL.Vertex3(-1.0f, 1.0f, 1.0f); | |
GL.Color3(Color.Magenta); | |
GL.Vertex3(-1.0f, 1.0f, -1.0f); | |
GL.Vertex3(-1.0f, 1.0f, 1.0f); | |
GL.Vertex3(1.0f, 1.0f, 1.0f); | |
GL.Vertex3(1.0f, 1.0f, -1.0f); | |
GL.Color3(Color.Violet); | |
GL.Vertex3(1.0f, -1.0f, -1.0f); | |
GL.Vertex3(1.0f, 1.0f, -1.0f); | |
GL.Vertex3(1.0f, 1.0f, 1.0f); | |
GL.Vertex3(1.0f, -1.0f, 1.0f); | |
GL.End(); | |
GL.Disable(EnableCap.DepthTest); | |
} | |
#endregion | |
#region RenderGui | |
void RenderGui() | |
{ | |
GL.MatrixMode(MatrixMode.Projection); | |
GL.LoadIdentity(); | |
GL.Ortho(-1.0, 1.0, -1.0, 1.0, 0.0, 4.0); | |
GL.MatrixMode(MatrixMode.Modelview); | |
GL.LoadIdentity(); | |
GL.Disable(EnableCap.DepthTest); | |
GL.Enable(EnableCap.Blend); | |
GL.Enable(EnableCap.Texture2D); | |
GL.BlendFunc(BlendingFactorSrc.SrcAlpha, BlendingFactorDest.OneMinusSrcAlpha); | |
GL.BindTexture(TextureTarget.Texture2D, renderer.Texture); | |
GL.Begin(BeginMode.Quads); | |
GL.Color3(Color.White); | |
GL.TexCoord2(0.0f, 1.0f); GL.Vertex2(-1f, -1f); | |
GL.TexCoord2(1.0f, 1.0f); GL.Vertex2(1f, -1f); | |
GL.TexCoord2(1.0f, 0.0f); GL.Vertex2(1f, 1f); | |
GL.TexCoord2(0.0f, 0.0f); GL.Vertex2(-1f, 1f); | |
GL.End(); | |
GL.Disable(EnableCap.Texture2D); | |
GL.Disable(EnableCap.Blend); | |
GL.Enable(EnableCap.DepthTest); | |
} | |
#endregion | |
#region Main | |
public static void Main() | |
{ | |
using (TextRendering example = new TextRendering()) | |
{ | |
Utilities.SetWindowTitle(example); | |
example.Run(30.0); | |
} | |
} | |
#endregion | |
} | |
} |
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