OpenGL in C# with OpenTK Guide

Using OpenGL in C# typically requires the use of an OpenGL library, such as OpenTK. OpenTK is an open-source cross-platform OpenGL library that makes it easy to program OpenGL in C#.

Here is a simple example code in C# using the OpenTK library to draw a triangle.

using System;
using OpenTK;
using OpenTK.Graphics;
using OpenTK.Graphics.OpenGL;

class Program : GameWindow
{
    public Program() : base(800, 600, GraphicsMode.Default, "OpenGL Example") { }

    protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);
        GL.ClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    }

    protected override void OnRenderFrame(FrameEventArgs e)
    {
        base.OnRenderFrame(e);
        GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);

        GL.Begin(PrimitiveType.Triangles);
        GL.Color3(1.0f, 0.0f, 0.0f);
        GL.Vertex2(-0.5f, -0.5f);
        GL.Color3(0.0f, 1.0f, 0.0f);
        GL.Vertex2(0.5f, -0.5f);
        GL.Color3(0.0f, 0.0f, 1.0f);
        GL.Vertex2(0.0f, 0.5f);
        GL.End();

        SwapBuffers();
    }

    static void Main()
    {
        using (Program program = new Program())
        {
            program.Run(60.0);
        }
    }
}

In this example code, we created a Program class that inherits from the GameWindow class and overrides the OnLoad and OnRenderFrame methods. In the OnLoad method, we set the clear color to black. In the OnRenderFrame method, we used functions from the GL library to draw a colorful triangle. Finally, in the Main method, we created a Program object and ran the game window. This way, we can do graphics programming in C# using OpenGL.