//using Essgee.Graphics.Shaders;
//using System;
//using System.ComponentModel;
//using System.Diagnostics;
//using System.Drawing;

//namespace Essgee.Graphics
//{
//    public class GraphicsHandler : IDisposable
//	{
//		static readonly CommonVertex[] vertices = new CommonVertex[]
//		{
//			new CommonVertex() { Position = new Vector3(0.0f, 1.0f, 0.0f), TexCoord = new Vector2(0.0f, 1.0f), Color = Color4.White },
//			new CommonVertex() { Position = new Vector3(0.0f, 0.0f, 0.0f), TexCoord = new Vector2(0.0f, 0.0f), Color = Color4.White },
//			new CommonVertex() { Position = new Vector3(1.0f, 0.0f, 0.0f), TexCoord = new Vector2(1.0f, 0.0f), Color = Color4.White },
//			new CommonVertex() { Position = new Vector3(1.0f, 1.0f, 0.0f), TexCoord = new Vector2(1.0f, 1.0f), Color = Color4.White }
//		};

//		static readonly byte[] indices = new byte[] { 0, 1, 2, 2, 3, 0 };

//		public string GLRenderer { get; private set; }
//		public string GLVersion { get; private set; }

//		VertexBuffer vertexBuffer;
//		ShaderBundle shaderBundle;

//		Texture[] textures;
//		int lastTextureUpdate;

//		OnScreenDisplayHandler onScreenDisplayHandler;

//		(int Width, int Height) textureSize;
//		(int X, int Y, int Width, int Height) inputViewport, outputViewport;
//		Matrix4 projectionMatrix, modelviewMatrix;

//		bool refreshRendererAndShader;

//		Stopwatch stopwatch;
//		float deltaTime;

//		bool disposed = false;

//		public GraphicsHandler(OnScreenDisplayHandler osdHandler)
//		{
//			onScreenDisplayHandler = osdHandler;

//			if (AppEnvironment.EnableOpenGLDebug)
//				GL.Enable(EnableCap.DebugOutput);

//			GLRenderer = GL.GetString(StringName.Renderer);
//			GLVersion = GL.GetString(StringName.Version);

//			GL.Enable(EnableCap.Blend);
//			GL.BlendFunc(BlendingFactor.SrcAlpha, BlendingFactor.OneMinusSrcAlpha);

//			vertexBuffer = new VertexBuffer();
//			vertexBuffer.SetVertexData(vertices);
//			vertexBuffer.SetIndices(indices);

//			textures = new Texture[ShaderBundle.MaxNumSourceSamplers];

//			lastTextureUpdate = 0;

//			projectionMatrix = Matrix4.Identity;
//			modelviewMatrix = Matrix4.Identity;

//			stopwatch = Stopwatch.StartNew();

//			Application.Idle += (s, e) =>
//			{
//				if (LicenseManager.UsageMode == LicenseUsageMode.Designtime || GraphicsContext.CurrentContext == null) return;

//				stopwatch.Stop();
//				deltaTime = (float)stopwatch.Elapsed.TotalMilliseconds / 10.0f;
//				stopwatch.Reset();
//				stopwatch.Start();
//			};

//			onScreenDisplayHandler.EnqueueMessageSuccess($"Graphics initialized; {GLRenderer}, {GLVersion}.");
//		}

//		~GraphicsHandler()
//		{
//			Dispose(false);
//		}

//		public void Dispose()
//		{
//			Dispose(true);
//			GC.SuppressFinalize(this);
//		}

//		protected virtual void Dispose(bool disposing)
//		{
//			if (disposed) return;

//			if (disposing)
//			{
//				if (vertexBuffer != null) vertexBuffer.Dispose();
//				if (shaderBundle != null) shaderBundle.Dispose();
//			}

//			disposed = true;
//		}

//		public void LoadShaderBundle(string shaderName)
//		{
//			var lastShaderFilter = shaderBundle?.Manifest.Filter;
//			var lastShaderWrap = shaderBundle?.Manifest.Wrap;

//			shaderBundle = new ShaderBundle(shaderName, typeof(CommonVertex));

//			if ((lastShaderFilter != null && lastShaderFilter != shaderBundle.Manifest.Filter) || (lastShaderWrap != null && lastShaderWrap != shaderBundle.Manifest.Wrap))
//				CreateTextures();

//			FlushTextures();

//			refreshRendererAndShader = true;

//			onScreenDisplayHandler.EnqueueMessage($"Loaded shader '{shaderName}'.");
//		}

//		public void SetTextureSize(int width, int height)
//		{
//			textureSize = (width, height);

//			CreateTextures();

//			refreshRendererAndShader = true;
//		}

//		private void CreateTextures()
//		{
//			if (textureSize.Width == 0 || textureSize.Height == 0)
//				return;

//			for (int i = 0; i < textures.Length; i++)
//				textures[i] = new Texture(textureSize.Width, textureSize.Height, PixelFormat.Rgba8888, shaderBundle.Manifest.Filter, shaderBundle.Manifest.Wrap);

//			lastTextureUpdate = 0;
//		}

//		public void SetTextureData(byte[] data)
//		{
//			textures[lastTextureUpdate].SetData(data);
//			lastTextureUpdate++;
//			if (lastTextureUpdate >= shaderBundle.Manifest.Samplers) lastTextureUpdate = 0;
//		}

//		public void SetScreenViewport((int, int, int, int) viewport)
//		{
//			inputViewport = viewport;

//			lastTextureUpdate = 0;

//			refreshRendererAndShader = true;
//		}

//		public void FlushTextures()
//		{
//			for (int i = 0; i < shaderBundle.Manifest.Samplers; i++)
//				textures[i]?.ClearData();

//			lastTextureUpdate = 0;

//			refreshRendererAndShader = true;
//		}

//		public void Resize(Rectangle clientRectangle, Size screenSize)
//		{
//			GL.Viewport(0, 0, clientRectangle.Width, clientRectangle.Height);

//			projectionMatrix = Matrix4.CreateOrthographicOffCenter(0.0f, clientRectangle.Width, clientRectangle.Height, 0.0f, -10.0f, 10.0f);

//			switch (Program.Configuration.ScreenSizeMode)
//			{
//				case ScreenSizeMode.Stretch:
//					{
//						modelviewMatrix = Matrix4.CreateScale(clientRectangle.Width, clientRectangle.Height, 1.0f);

//						outputViewport = (clientRectangle.X, clientRectangle.Y, clientRectangle.Width, clientRectangle.Height);
//					}
//					break;

//				case ScreenSizeMode.Scale:
//					{
//						var multiplier = (float)Math.Min(clientRectangle.Width / (double)screenSize.Width, clientRectangle.Height / (double)screenSize.Height);

//						var adjustedWidth = screenSize.Width * multiplier;
//						var adjustedHeight = screenSize.Height * multiplier;
//						var adjustedX = (float)Math.Floor((clientRectangle.Width - adjustedWidth) / 2.0f);
//						var adjustedY = (float)Math.Floor((clientRectangle.Height - adjustedHeight) / 2.0f);

//						modelviewMatrix = Matrix4.CreateScale(adjustedWidth, adjustedHeight, 1.0f) * Matrix4.CreateTranslation(adjustedX, adjustedY, 1.0f);

//						outputViewport = (clientRectangle.X, clientRectangle.Y, clientRectangle.Width, clientRectangle.Height);
//					}
//					break;

//				case ScreenSizeMode.Integer:
//					{
//						var multiplier = (float)Math.Min(Math.Floor(clientRectangle.Width / (double)inputViewport.Width), Math.Floor(clientRectangle.Height / (double)inputViewport.Height));

//						var adjustedWidth = inputViewport.Width * multiplier;
//						var adjustedHeight = inputViewport.Height * multiplier;
//						var adjustedX = (float)Math.Floor((clientRectangle.Width - adjustedWidth) / 2.0f);
//						var adjustedY = (float)Math.Floor((clientRectangle.Height - adjustedHeight) / 2.0f);

//						modelviewMatrix = Matrix4.CreateScale(adjustedWidth, adjustedHeight, 1.0f) * Matrix4.CreateTranslation(adjustedX, adjustedY, 1.0f);

//						outputViewport = ((int)adjustedX, (int)adjustedY, (int)adjustedWidth, (int)adjustedHeight);
//					}
//					break;
//			}

//			onScreenDisplayHandler.SetViewport((clientRectangle.X, clientRectangle.Y, clientRectangle.Width, clientRectangle.Height));
//			onScreenDisplayHandler.SetProjectionMatrix(projectionMatrix);
//			onScreenDisplayHandler.SetModelviewMatrix(modelviewMatrix);

//			refreshRendererAndShader = true;
//		}

//		public void Render()
//		{
//			if (refreshRendererAndShader)
//			{
//				shaderBundle.SetTextureSize(new Vector2(textureSize.Width, textureSize.Height));
//				shaderBundle.SetInputViewport(new Vector4(inputViewport.X, inputViewport.Y, inputViewport.Width, inputViewport.Height));
//				shaderBundle.SetOutputViewport(new Vector4(outputViewport.X, outputViewport.Y, outputViewport.Width, outputViewport.Height));
//				shaderBundle.SetProjectionMatrix(projectionMatrix);
//				shaderBundle.SetModelviewMatrix(modelviewMatrix);

//				GC.Collect();

//				refreshRendererAndShader = false;
//			}

//			for (int i = 0; i < shaderBundle.Manifest.Samplers; i++)
//				textures[i]?.Activate(TextureUnit.Texture0 + ((lastTextureUpdate + i) % shaderBundle.Manifest.Samplers));

//			shaderBundle.Activate();
//			vertexBuffer.Render();

//			onScreenDisplayHandler.Render(deltaTime);
//		}
//	}
//}