#region --- License ---
/* Copyright (c) 2006, 2007 Stefanos Apostolopoulos
 * See license.txt for license info
 */
#endregion

using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using System.Threading;

using OpenTK;
using OpenTK.OpenGL;
using System.Diagnostics;
using OpenTK.Input;

namespace Examples.Tutorial
{
    /// <summary>
    /// Demonstrates Vertex Arrays (in system memory).  Example is incomplete (documentation).
    /// </summary>
    class T02_Vertex_Arrays : GameWindow, IExample
    {
        float rotation_speed = 3.0f;
        float angle = 0.0f;

        Shapes.Shape shape = new Examples.Shapes.Plane(16, 16, 2.0f, 2.0f);

        #region Constructor

        public T02_Vertex_Arrays() : base(new DisplayMode(800, 600), "OpenTK Tutorial 2: Vertex Arrays")
        {
            this.VSync = VSyncMode.On;
            this.Keyboard.KeyUp += new KeyUpEvent(Keyboard_KeyUp);
        }

        void Keyboard_KeyUp(KeyboardDevice sender, Key key)
        {
            // F4 cycles between available VSync modes.
            if (key == Key.F4)
            {
                if (this.VSync == VSyncMode.Off)
                    this.VSync = VSyncMode.On;
                else if (this.VSync == VSyncMode.On)
                    this.VSync = VSyncMode.Adaptive;
                else
                    this.VSync = VSyncMode.Off;
            }
        }

        #endregion

        #region OnLoad

        public override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);

            GL.ClearColor(Color.CadetBlue);
            GL.Enable(GL.Enums.EnableCap.DEPTH_TEST);
            
            GL.EnableClientState(GL.Enums.EnableCap.VERTEX_ARRAY);
            //GL.EnableClientState(GL.Enums.EnableCap.COLOR_ARRAY);
            GL.VertexPointer(3, GL.Enums.VertexPointerType.FLOAT, 0, shape.Vertices);
            //GL.ColorPointer(4, GL.Enums.ColorPointerType.UNSIGNED_BYTE, 0, shape.Colors);
        }

        #endregion

        #region OnResize

        /// <summary>
        /// Called when the user resizes the window.
        /// </summary>
        /// <param name="e">Contains the new width/height of the window.</param>
        /// <remarks>
        /// You want the OpenGL viewport to match the window. This is the place to do it!
        /// </remarks>
        protected override void OnResize(OpenTK.Platform.ResizeEventArgs e)
        {
            base.OnResize(e);

            GL.Viewport(0, 0, Width, Height);

            double ratio = e.Width / (double)e.Height;

            GL.MatrixMode(GL.Enums.MatrixMode.PROJECTION);
            GL.LoadIdentity();
            Glu.Perspective(45.0, ratio, 1.0, 64.0);
        }

        #endregion

        #region OnUpdateFrame

        /// <summary>
        /// Prepares the next frame for rendering.
        /// </summary>
        /// <remarks>
        /// Place your control logic here. This is the place to respond to user input,
        /// update object positions etc.
        /// </remarks>
        public override void OnUpdateFrame(UpdateFrameEventArgs e)
        {
            // Escape quits.
            if (Keyboard[Key.Escape])
            {
                this.Exit();
                return;
            }

            // Alt+Enter toggles fullscreen mode.
            if ((Keyboard[Key.AltLeft] || Keyboard[Key.AltRight]) && Keyboard[Key.Enter])
            {
                Fullscreen = !Fullscreen;
            }

            // Plus/Minus change the target render frequency.
            // PageUp/PageDown change the target update frequency.
            if (Keyboard[Key.Plus] || Keyboard[Key.KeypadAdd]) TargetRenderFrequency++;
            if (Keyboard[Key.Minus] || Keyboard[Key.KeypadSubtract]) TargetRenderFrequency--;
            if (Keyboard[Key.PageUp]) TargetUpdateFrequency++;
            if (Keyboard[Key.PageDown]) TargetUpdateFrequency--;

            // Right/Left control the rotation speed and direction.
            if (Keyboard[Key.Right]) rotation_speed += 0.5f;
            if (Keyboard[Key.Left]) rotation_speed -= 0.5f;
        }

        #endregion

        #region OnRenderFrame

        /// <summary>
        /// Place your rendering code here.
        /// </summary>
        public override void OnRenderFrame(RenderFrameEventArgs e)
        {
            GL.Clear(GL.Enums.ClearBufferMask.COLOR_BUFFER_BIT | GL.Enums.ClearBufferMask.DEPTH_BUFFER_BIT);

            GL.MatrixMode(GL.Enums.MatrixMode.MODELVIEW);
            GL.LoadIdentity();
            Glu.LookAt(
                0.0, 5.0, 5.0,
                0.0, 0.0, 0.0,
                0.0, 1.0, 0.0
            );

            angle += rotation_speed * (float)e.ScaleFactor;

            if (angle >= 360.0f)
                angle -= 360.0f;
            GL.Rotate(angle, 0.0f, 1.0f, 0.0f);

            GL.DrawElements(GL.Enums.BeginMode.TRIANGLES, shape.Indices.Length,
                GL.Enums.All.UNSIGNED_INT, shape.Indices);

//            GL.DrawArrays(GL.Enums.BeginMode.LINES, 0, shape.Vertices.Length);

            GL.Begin(GL.Enums.BeginMode.TRIANGLES);

            GL.Vertex3(-1.0, -1.0, 5.0);
            GL.Vertex3(1.0, -1.0, 5.0);
            GL.Vertex3(1.0, 1.0, 5.0);

            GL.End();
            
            SwapBuffers();
        }

        #endregion

        #region public void Launch()

        /// <summary>
        /// Launches this example.
        /// </summary>
        /// <remarks>
        /// Provides a simple way for the example launcher to launch the examples.
        /// </remarks>
        public void Launch()
        {
            // Lock UpdateFrame rate at 30Hz and RenderFrame rate 85Hz.
            //Run(60.0, 85.0);
            Run(30.0);
        }

        #endregion

        public static readonly int order = 2;
    }
}