292 lines
11 KiB
C#
292 lines
11 KiB
C#
// This code was written for the OpenTK library and has been released
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// to the Public Domain.
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// It is provided "as is" without express or implied warranty of any kind.
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#region --- Using Directives ---
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using System;
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using System.Collections.Generic;
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using System.ComponentModel;
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using System.Drawing;
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using System.Text;
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using System.Windows.Forms;
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using System.Threading;
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using System.Diagnostics;
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using System.IO;
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using OpenTK;
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using OpenTK.Graphics;
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using OpenTK.Graphics.OpenGL;
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#endregion --- Using Directives ---
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namespace Examples.Tutorial
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{
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/// <summary>
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/// Demonstrates how to load and use a simple OpenGL shader program. Example is incomplete (documentation).
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/// </summary>
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[Example("First shader", ExampleCategory.OpenGL, "2.x", Documentation = "SimpleGLSL")]
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public class T10_GLSL_Cube : GameWindow
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{
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#region --- Fields ---
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static float angle = 0.0f, rotation_speed = 3.0f;
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int vertex_shader_object, fragment_shader_object, shader_program;
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int vertex_buffer_object, color_buffer_object, element_buffer_object;
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Shapes.Shape shape = new Examples.Shapes.Cube();
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#endregion
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#region --- Constructors ---
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public T10_GLSL_Cube()
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: base(800, 600, GraphicsMode.Default)
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{ }
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#endregion
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#region OnLoad
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/// <summary>
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/// This is the place to load resources that change little
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/// during the lifetime of the GameWindow. In this case, we
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/// check for GLSL support, and load the shaders.
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/// </summary>
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/// <param name="e">Not used.</param>
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protected override void OnLoad(EventArgs e)
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{
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base.OnLoad(e);
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// Check for necessary capabilities:
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Version version = new Version(GL.GetString(StringName.Version).Substring(0, 3));
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Version target = new Version(2, 0);
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if (version < target)
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{
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throw new NotSupportedException(String.Format(
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"OpenGL {0} is required (you only have {1}).", target, version));
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}
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GL.ClearColor(Color.MidnightBlue);
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GL.Enable(EnableCap.DepthTest);
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CreateVBO();
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using (StreamReader vs = new StreamReader("Data/Shaders/Simple_VS.glsl"))
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using (StreamReader fs = new StreamReader("Data/Shaders/Simple_FS.glsl"))
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CreateShaders(vs.ReadToEnd(), fs.ReadToEnd(),
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out vertex_shader_object, out fragment_shader_object,
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out shader_program);
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}
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#endregion
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#region CreateShaders
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void CreateShaders(string vs, string fs,
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out int vertexObject, out int fragmentObject,
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out int program)
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{
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int status_code;
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string info;
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vertexObject = GL.CreateShader(ShaderType.VertexShader);
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fragmentObject = GL.CreateShader(ShaderType.FragmentShader);
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// Compile vertex shader
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GL.ShaderSource(vertexObject, vs);
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GL.CompileShader(vertexObject);
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GL.GetShaderInfoLog(vertexObject, out info);
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GL.GetShader(vertexObject, ShaderParameter.CompileStatus, out status_code);
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if (status_code != 1)
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throw new ApplicationException(info);
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// Compile vertex shader
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GL.ShaderSource(fragmentObject, fs);
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GL.CompileShader(fragmentObject);
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GL.GetShaderInfoLog(fragmentObject, out info);
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GL.GetShader(fragmentObject, ShaderParameter.CompileStatus, out status_code);
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if (status_code != 1)
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throw new ApplicationException(info);
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program = GL.CreateProgram();
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GL.AttachShader(program, fragmentObject);
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GL.AttachShader(program, vertexObject);
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GL.LinkProgram(program);
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GL.UseProgram(program);
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}
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#endregion
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#region private void CreateVBO()
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void CreateVBO()
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{
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int size;
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GL.GenBuffers(1, out vertex_buffer_object);
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GL.GenBuffers(1, out color_buffer_object);
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GL.GenBuffers(1, out element_buffer_object);
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// Upload the vertex buffer.
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GL.BindBuffer(BufferTarget.ArrayBuffer, vertex_buffer_object);
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GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(shape.Vertices.Length * 3 * sizeof(float)), shape.Vertices,
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BufferUsageHint.StaticDraw);
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GL.GetBufferParameter(BufferTarget.ArrayBuffer, BufferParameterName.BufferSize, out size);
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if (size != shape.Vertices.Length * 3 * sizeof(Single))
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throw new ApplicationException(String.Format(
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"Problem uploading vertex buffer to VBO (vertices). Tried to upload {0} bytes, uploaded {1}.",
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shape.Vertices.Length * 3 * sizeof(Single), size));
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// Upload the color buffer.
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GL.BindBuffer(BufferTarget.ArrayBuffer, color_buffer_object);
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GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(shape.Colors.Length * sizeof(int)), shape.Colors,
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BufferUsageHint.StaticDraw);
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GL.GetBufferParameter(BufferTarget.ArrayBuffer, BufferParameterName.BufferSize, out size);
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if (size != shape.Colors.Length * sizeof(int))
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throw new ApplicationException(String.Format(
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"Problem uploading vertex buffer to VBO (colors). Tried to upload {0} bytes, uploaded {1}.",
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shape.Colors.Length * sizeof(int), size));
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// Upload the index buffer (elements inside the vertex buffer, not color indices as per the IndexPointer function!)
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GL.BindBuffer(BufferTarget.ElementArrayBuffer, element_buffer_object);
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GL.BufferData(BufferTarget.ElementArrayBuffer, (IntPtr)(shape.Indices.Length * sizeof(Int32)), shape.Indices,
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BufferUsageHint.StaticDraw);
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GL.GetBufferParameter(BufferTarget.ElementArrayBuffer, BufferParameterName.BufferSize, out size);
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if (size != shape.Indices.Length * sizeof(int))
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throw new ApplicationException(String.Format(
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"Problem uploading vertex buffer to VBO (offsets). Tried to upload {0} bytes, uploaded {1}.",
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shape.Indices.Length * sizeof(int), size));
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}
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#endregion
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#region OnUnload
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protected override void OnUnload(EventArgs e)
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{
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if (shader_program != 0)
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GL.DeleteProgram(shader_program);
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if (fragment_shader_object != 0)
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GL.DeleteShader(fragment_shader_object);
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if (vertex_shader_object != 0)
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GL.DeleteShader(vertex_shader_object);
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if (vertex_buffer_object != 0)
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GL.DeleteBuffers(1, ref vertex_buffer_object);
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if (element_buffer_object != 0)
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GL.DeleteBuffers(1, ref element_buffer_object);
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}
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#endregion
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#region OnResize
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/// <summary>
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/// Called when the user resizes the window.
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/// </summary>
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/// <param name="e">Contains the new width/height of the window.</param>
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/// <remarks>
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/// You want the OpenGL viewport to match the window. This is the place to do it!
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/// </remarks>
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protected override void OnResize(EventArgs e)
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{
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GL.Viewport(0, 0, Width, Height);
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float aspect_ratio = Width / (float)Height;
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Matrix4 perpective = Matrix4.CreatePerspectiveFieldOfView(MathHelper.PiOver4, aspect_ratio, 1, 64);
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GL.MatrixMode(MatrixMode.Projection);
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GL.LoadMatrix(ref perpective);
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}
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#endregion
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#region OnUpdateFrame
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/// <summary>
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/// Prepares the next frame for rendering.
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/// </summary>
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/// <remarks>
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/// Place your control logic here. This is the place to respond to user input,
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/// update object positions etc.
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/// </remarks>
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protected override void OnUpdateFrame(FrameEventArgs e)
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{
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if (Keyboard[OpenTK.Input.Key.Escape])
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this.Exit();
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if (Keyboard[OpenTK.Input.Key.F11])
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if (WindowState != WindowState.Fullscreen)
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WindowState = WindowState.Fullscreen;
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else
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WindowState = WindowState.Normal;
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}
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#endregion
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#region OnRenderFrame
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/// <summary>
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/// Place your rendering code here.
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/// </summary>
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protected override void OnRenderFrame(FrameEventArgs e)
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{
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GL.Clear(ClearBufferMask.ColorBufferBit |
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ClearBufferMask.DepthBufferBit);
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Matrix4 lookat = Matrix4.LookAt(0, 5, 5, 0, 0, 0, 0, 1, 0);
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GL.MatrixMode(MatrixMode.Modelview);
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GL.LoadMatrix(ref lookat);
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angle += rotation_speed * (float)e.Time;
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GL.Rotate(angle, 0.0f, 1.0f, 0.0f);
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GL.EnableClientState(ArrayCap.VertexArray);
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GL.EnableClientState(ArrayCap.ColorArray);
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GL.BindBuffer(BufferTarget.ArrayBuffer, vertex_buffer_object);
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GL.VertexPointer(3, VertexPointerType.Float, 0, IntPtr.Zero);
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GL.BindBuffer(BufferTarget.ArrayBuffer, color_buffer_object);
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GL.ColorPointer(4, ColorPointerType.UnsignedByte, 0, IntPtr.Zero);
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GL.BindBuffer(BufferTarget.ElementArrayBuffer, element_buffer_object);
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GL.DrawElements(BeginMode.Triangles, shape.Indices.Length,
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DrawElementsType.UnsignedInt, IntPtr.Zero);
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//GL.DrawArrays(GL.Enums.BeginMode.POINTS, 0, shape.Vertices.Length);
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GL.DisableClientState(ArrayCap.VertexArray);
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GL.DisableClientState(ArrayCap.ColorArray);
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//int error = GL.GetError();
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//if (error != 0)
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// Debug.Print(Glu.ErrorString(Glu.Enums.ErrorCode.INVALID_OPERATION));
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SwapBuffers();
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}
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#endregion
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#region public static void Main()
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/// <summary>
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/// Entry point of this example.
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/// </summary>
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[STAThread]
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public static void Main()
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{
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using (T10_GLSL_Cube example = new T10_GLSL_Cube())
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{
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// Get the title and category of this example using reflection.
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ExampleAttribute info = ((ExampleAttribute)example.GetType().GetCustomAttributes(false)[0]);
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example.Title = String.Format("OpenTK | {0} {1}: {2}", info.Category, info.Difficulty, info.Title);
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example.Run(30.0, 0.0);
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}
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}
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#endregion
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}
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}
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