using System;
using OpenTK.Graphics;
using OpenTK;
using OpenTK.Graphics.OpenGL;
using System.Drawing;
using System.Drawing.Imaging;

namespace Moth
{
    public class MainWindow : GameWindow
    {
        static MainWindow Instance { get { return MainWindow.instance; } }
        static readonly MainWindow instance = new MainWindow();
        static void Main(string[] args) { instance.Run(); }

        public MainWindow()
            : base(256, 256, GraphicsMode.Default, "AlphaTest")
        {
            Keyboard.KeyDown += new EventHandler<OpenTK.Input.KeyboardKeyEventArgs>(Keyboard_KeyDown);
        }

        int textureID;

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

            GL.GenTextures(1, out textureID);
            GL.BindTexture(TextureTarget.Texture2D, textureID);

            Bitmap bitmap = Bitmap.FromFile("Texture.png") as Bitmap;

            for (int x = 0; x < bitmap.Width; x++)
            {
                for (int y = 0; y < bitmap.Height; y++)
                {
                    Color color = bitmap.GetPixel(x, y);
                    if (color.A == 0)
                    {
                        color = Color.FromArgb(0, 255, 255, 255);
                        bitmap.SetPixel(x, y, color);
                    }
                }
            }


            BitmapData bitmapData = bitmap.LockBits(new Rectangle(0, 0, bitmap.Width, bitmap.Height), ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);

            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.LinearMipmapLinear);
            GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);
            GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba, (int)bitmap.Width, (int)bitmap.Height, 0, OpenTK.Graphics.OpenGL.PixelFormat.Bgra, PixelType.UnsignedByte, bitmapData.Scan0);
            GL.GenerateMipmap(GenerateMipmapTarget.Texture2D);

            bitmap.UnlockBits(bitmapData);
            bitmap.Dispose();

            GL.Enable(EnableCap.Blend);
            GL.BlendFunc(BlendingFactorSrc.One, BlendingFactorDest.Zero);
        }

        void Keyboard_KeyDown(object sender, OpenTK.Input.KeyboardKeyEventArgs e)
        {
            switch (e.Key)
            {
                case OpenTK.Input.Key.A:
                    GL.BlendFunc(BlendingFactorSrc.SrcAlpha, BlendingFactorDest.OneMinusSrcAlpha);
                    break;

                case OpenTK.Input.Key.O:
                    GL.BlendFunc(BlendingFactorSrc.One, BlendingFactorDest.Zero);
                    break;
            }
        }

        protected override void OnRenderFrame(FrameEventArgs e)
        {
            //GL.ClearColor(Color4.Blue);
            GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);

            GL.Enable(EnableCap.DepthTest);

            GL.Enable(EnableCap.Texture2D);
            GL.BindTexture(TextureTarget.Texture2D, textureID);


            GL.Enable(EnableCap.AlphaTest);


            float alphaTest = (Environment.TickCount % 50000) / 25000.0f - 1;
            alphaTest = (float)Math.Sin(alphaTest * Math.PI * 2) / 2.0f + 0.5f;
            alphaTest = alphaTest * 0.8f + 0.1f;
            GL.AlphaFunc(AlphaFunction.Greater, alphaTest);


            GL.PushMatrix();

            for (int a = 0; a < 5; a++)
            {
                for (int i = 0; i < 4; i++)
                {
                    GL.PushMatrix();

                    GL.Translate(-0.7f, 0, 0);
                    float rotation = (Environment.TickCount % 20000) / 10000.0f - 1;
                    rotation = (float)Math.Sin(rotation * Math.PI * 2) * 10;
                    GL.Rotate(rotation, 0, 0, 1);
                    GL.Translate(0.7f, 0, 0);

                        GL.Begin(BeginMode.Quads);
                        {
                            //GL.Color4(Color4.Green);
                            GL.TexCoord2(0, 0);
                            GL.Vertex3(-0.6f, -0.8f, -0.1f);
                            GL.TexCoord2(1, 0);
                            GL.Vertex3(-0.2f, -0.8f, -0.1f);
                            //GL.Color4(Color4.Red);
                            GL.TexCoord2(1, 1);
                            GL.Vertex3(-0.2f, 0.8f, 0);
                            GL.TexCoord2(0, 1);
                            GL.Vertex3(-0.6f, 0.8f, 0);
                        }
                        GL.End();
                    GL.PopMatrix();

                    GL.Rotate(90, 0, 0, 1);
                }

                GL.Translate(0, 0, 0.1f);
                GL.Scale(0.7f, 0.7f, 1);
            }

            GL.PopMatrix();

            SwapBuffers();
        }
    }
}