using System;
using Tao.OpenGl;
using Tao.FreeGlut;

// By Ben Woodhouse, translated to C# and Tao by Rob Loach.

namespace SimpleExample
{
	/// <summary>
	/// Summary description for Class1.
	/// </summary>
	public class SimpleExample
	{



		public static void Run()
		{
			Glut.glutMainLoop();
		}

		private static void Render()
		{
			Gl.glClear(Gl.GL_COLOR_BUFFER_BIT | Gl.GL_DEPTH_BUFFER_BIT);  //clears the colour and depth buffers

			Gl.glPushMatrix();         //saves the current matrix on the top of the matrix stack
			Gl.glTranslatef(0,0,-100); //translates the current matrix 0 in x, 0 in y and -100 in z

			Gl.glBegin(Gl.GL_TRIANGLES);  //tells OpenGL that we're going to start drawing triangles
			Gl.glColor3f(1,0,0);       //sets the current colour to red
			Gl.glVertex3f(-30,-30,0);  //specifies the first vertex of our triangle
			  
			Gl.glColor3f(0,1,0);       //sets the current colour to green
			Gl.glVertex3f(30,-30,0);   //specifies the second vertex of our triangle
			  
			Gl.glColor3f(0,0,1);       //sets the current colour to blue
			Gl.glVertex3f(-30,30,0);   //specifies the third vertex of our triangle
			Gl.glEnd();                //tells OpenGL that we've finished drawing

			Gl.glPopMatrix();          //retrieves our saved matrix from the top of the matrix stack
			Glut.glutSwapBuffers();      //swaps the front and back buffers
		}

		static SimpleExample()
		{
			Glut.glutInit();
			Glut.glutInitDisplayMode(Glut.GLUT_RGB | Glut.GLUT_DOUBLE | Glut.GLUT_DEPTH);   //sets up the display mode
			Glut.glutCreateWindow("My first GLUT program");                  //creates a window
			Glut.glutDisplayFunc(new Glut.DisplayCallback(Render));

			Gl.glMatrixMode(Gl.GL_PROJECTION);   //changes the current matrix to the projection matrix
			
			//sets up the projection matrix for a perspective transform
			Glu.gluPerspective(45,     //view angle
							1.0,    //aspect ratio
							10.0,   //near clip
							200.0); //far clip

			Gl.glMatrixMode(Gl.GL_MODELVIEW);   //changes the current matrix to the modelview matrix

		}

		public static void Main()
		{
			SimpleExample e = new SimpleExample();
			e.Run();
		}
	}
}