glbackend tests, copy first try from hg reposglbackend

1 files changed, 887 insertions, 0 deletions

diff --git a/src/OpenGL/GLBackend/Context.cs b/src/OpenGL/GLBackend/Context.cs
new file mode 100644
index 00000000..51d5d86b
--- /dev/null
+++ b/src/OpenGL/GLBackend/Context.cs
@@ -0,0 +1,887 @@
+#define	MPERF
+//#define GPU_TIME_MSR
+
+using System;
+using OpenTK.Graphics.OpenGL;
+using OpenTK;
+using System.Collections.Generic;
+using System.Linq;
+using System.Diagnostics;
+using System.Drawing.Imaging;
+
+
+
+namespace go.GLBackend
+{
+	public class Context : IDisposable
+	{
+		#region CTOR
+		public Context (Surface _surf)
+		{
+			surf = _surf;
+
+			saveGLConfig ();
+
+			createStencilTexture ();
+
+			fboId = createFbo (surf.texId);
+				
+			projectionMatrix = Matrix4.CreateOrthographicOffCenter 
+				(0, surf.width, surf.height, 0, 0, 1);
+			modelviewMatrix = Matrix4.Identity;
+
+			if (shader == null)
+				shader = new Shader ();
+			if (texturedShader == null)
+				texturedShader = new TexturedShader ();
+			if (clipShader == null)
+				clipShader = new ClipShader ();
+			if (fontShader == null)
+				fontShader = new FontShader ();
+
+
+			GL.Viewport (0, 0, surf.width, surf.height);
+			GL.PrimitiveRestartIndex (int.MaxValue);
+			GL.Enable (EnableCap.PrimitiveRestart);
+			GL.Enable (EnableCap.Blend);
+			GL.BlendFunc (BlendingFactorSrc.SrcAlpha, BlendingFactorDest.OneMinusSrcAlpha);
+
+			//GL.BindFramebuffer(FramebufferTarget.Framebuffer, fboId);
+
+			//			GL.ClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+			//			GL.Clear(ClearBufferMask.ColorBufferBit);
+		}
+		#endregion
+
+		#if (DEBUG && MPERF)
+		Stopwatch sw_fill = new Stopwatch ();
+		Stopwatch sw_stroke = new Stopwatch ();
+		#endif
+
+		#if GPU_TIME_MSR
+		ulong gpuTime = 0;
+		ulong gpuTimeCpt = 0;
+		#endif
+
+		public float coef1 = 1.0f;
+		public float coef2 = 0.5f;
+		public float coef3 = 0.0f;
+		public float coefA = 1.0f;
+
+		static Shader shader;
+		static Shader clipShader;
+		static Shader texturedShader;
+		static FontShader fontShader;
+
+		static List<glFont> fontsCache = new List<glFont>();
+
+		#region Private Fields
+		Surface surf;
+		Surface sourceSurface;//should be a pattern object from which surf would be derrived
+
+		double lineWidth = 1.0;
+		Color color = Color.White;
+		LineCap lineCap = LineCap.Butt;
+		LineJoin lineJoint = LineJoin.Miter;
+
+		FontFace fontFace;
+		uint fontSize = 10;
+		//path building temp fields
+		Vector2 curPos = new Vector2(0f,0f);
+		List<Path> pathes = new List<Path> ();
+		Path cpath;//current path
+
+		int fboId;
+		int stencilTexId;
+		VertexArrayObject vao;
+
+		Matrix4 projectionMatrix, 
+				modelviewMatrix;
+
+		bool stencilTest = false;
+
+		VertexArrayObject paint_vao; //quad used to paint source on context
+
+		//path limits used in fill
+		float	minX,maxX,minY,maxY,
+				polyWidth, polyHeight;
+
+		#endregion
+
+		#region Public properties
+		public double LineWidth {
+			get { return lineWidth; }
+			set { lineWidth = value; }
+		}
+		public Color Color {
+			get { return color; }
+			set { color = value; }
+		}
+		public LineCap LineCap {
+			get { return lineCap;}
+			set {lineCap = value;}
+		}
+		public LineJoin LineJoint {
+			get {return lineJoint;}
+			set {lineJoint = value;}
+		}
+		#endregion
+
+		#region Private functions
+		int createFbo(int texID)
+		{
+			//GL.BindFramebuffer(FramebufferTarget.Framebuffer, 0);
+			int fbo;
+			GL.GenFramebuffers(1,out fbo);
+			GL.BindFramebuffer(FramebufferTarget.Framebuffer, fbo);
+			GL.FramebufferTexture2D(FramebufferTarget.Framebuffer, 
+				FramebufferAttachment.ColorAttachment0,
+				TextureTarget.Texture2D,texID,0);
+
+			//GL.BindFramebuffer(FramebufferTarget.Framebuffer, 0);
+			FramebufferErrorCode fbErr = GL.CheckFramebufferStatus (FramebufferTarget.Framebuffer);
+
+			switch (fbErr) {
+			case FramebufferErrorCode.FramebufferUndefined:
+				break;
+			case FramebufferErrorCode.FramebufferComplete:
+				//Debug.WriteLine ("FBO complete");
+				break;
+			case FramebufferErrorCode.FramebufferIncompleteAttachment:
+				Debug.WriteLine ("FBO incomplete attachment");
+				break;
+			case FramebufferErrorCode.FramebufferIncompleteMissingAttachment:
+				Debug.WriteLine ("FBO missing attachment");
+				break;
+			default:
+				Debug.WriteLine ("FBO error");
+				break;
+			}
+			return fbo;
+		}
+		public int copyCurentSurfaceToTexture()
+		{
+			//create a new fbo to blit to with an empty texture
+			Surface tmp = surf.CreateSimilar ();
+			int dstFbo = createFbo (tmp.texId);//we are binded to new fbo (read&write)
+			//bind read to Context fbo;
+			GL.BindFramebuffer (FramebufferTarget.ReadFramebuffer, fboId);
+			GL.BindFramebuffer (FramebufferTarget.DrawFramebuffer, dstFbo);
+
+			GL.BlitFramebuffer (0, 0, surf.width, surf.height, 0, 0, surf.width, surf.height,
+				ClearBufferMask.ColorBufferBit,BlitFramebufferFilter.Nearest);
+
+			//bind write fbo to Context
+			GL.BindFramebuffer (FramebufferTarget.Framebuffer, fboId);
+			//delete temp fbo
+			GL.DeleteFramebuffer (dstFbo);
+			return tmp.texId;
+		}
+		void createStencilTexture(){
+			stencilTexId = GL.GenTexture();
+			GL.BindTexture(TextureTarget.Texture2D, stencilTexId);
+			GL.TexImage2D(TextureTarget.Texture2D,0,
+				PixelInternalFormat.R8, surf.width, surf.height,0,
+				OpenTK.Graphics.OpenGL.PixelFormat.Red, PixelType.UnsignedByte,IntPtr.Zero);
+
+			GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.Linear);
+			GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);
+			GL.BindTexture(TextureTarget.Texture2D, 0);
+		}
+		void clear_path()
+		{
+			pathes.Clear ();
+			curPos = new Vector2 (0f, 0f);
+			cpath = null;
+		}
+		void addPath(Path _path){
+			if (_path == null)
+				return;
+			if (_path.Count > 1)
+				pathes.Add (_path);
+		}
+		//TODO: 360° will fail
+		double NormalizeAngle(double a)
+		{
+			double res = a % (2*Math.PI);
+			return res < 0 ? res + 2*Math.PI : res;
+		}
+		#endregion
+
+		#region Public functions
+		#region Main drawing functions
+		public void Stroke()
+		{
+			stroke_internal ();
+			clear_path ();
+		}
+		public void StrokePreserve()
+		{
+			stroke_internal ();
+		}
+		public void Fill()
+		{
+			fill_internal ();
+			clear_path ();
+		}
+		public void FillPreserve()
+		{
+			fill_internal ();
+		}
+		public void Paint()
+		{
+			if (paint_vao == null)
+				return;
+			texturedShader.Enable ();
+			//shader.LineWidth = lineWidth;
+			texturedShader.ProjectionMatrix = projectionMatrix;
+			texturedShader.ModelViewMatrix = modelviewMatrix;
+			texturedShader.Color = new Vector4(1f,1f,1f,1f);
+
+			GL.ActiveTexture (TextureUnit.Texture0);
+			GL.BindTexture (TextureTarget.Texture2D, sourceSurface.texId);
+
+			paint_vao.Render (PrimitiveType.TriangleStrip);
+
+			GL.BindTexture (TextureTarget.Texture2D, 0);
+
+			texturedShader.Disable ();
+		}
+		public void SetSourceSurface (Surface _source, int x, int y)
+		{
+			sourceSurface = _source;
+
+			if (paint_vao != null)
+				paint_vao.Dispose ();
+
+
+			paint_vao = new QuadVAO (x,y,sourceSurface.width,sourceSurface.height);
+		}
+		#region Clipping
+		public void Clip()
+		{
+			clip_internal ();
+			clear_path ();
+		}
+		public void ClipPreserve()
+		{
+			clip_internal ();
+			clear_path ();
+		}
+		public void ResetClip()
+		{
+			stencilTest = false;
+
+			GL.FramebufferTexture2D(FramebufferTarget.Framebuffer, 
+				FramebufferAttachment.ColorAttachment0,
+				TextureTarget.Texture2D,stencilTexId,0);
+
+
+			GL.Clear (ClearBufferMask.ColorBufferBit);
+
+			GL.FramebufferTexture2D(FramebufferTarget.Framebuffer, 
+				FramebufferAttachment.ColorAttachment0,
+				TextureTarget.Texture2D,surf.texId,0);
+		}
+		#endregion
+
+		#region Fonts & text handling
+		public void SelectFontFace(string _fontName, FontSlant _slant, FontWeight _weight){
+			Font tmp = _fontName;
+			switch (_slant) {
+			case FontSlant.Italic:
+				tmp.Style |= FontStyle.Italic;
+				break;
+			case FontSlant.Oblique:
+				tmp.Style |= FontStyle.Oblique;
+				break;
+			}
+			if (_weight == FontWeight.Bold)
+				tmp.Style |= FontStyle.Bold;
+
+			fontFace = FontFace.SearchFont (tmp);
+		}
+		public void SetFontSize(uint _fontSize){
+			fontSize = _fontSize;
+			if (!fontFace.glyphesCache.ContainsKey(fontSize))
+				fontFace.buildGlyphesTextures (fontSize, 0, 0xFF);
+		}
+		public FontExtents FontExtents {
+			get {
+				return fontFace.originalFontExtents;
+			}
+		}
+		public TextExtents TextExtents(string s)
+		{
+			TextExtents te = new go.GLBackend.TextExtents ();
+
+			int penX = 0,
+				penY = 0;
+
+			for (int i = 0; i < s.Length; i++) {
+				uint c = (uint)s [i];
+				glGlyph g = fontFace.glyphesCache [fontSize] [c];
+				penX += (int)g.advanceX;
+				penY += (int)g.advanceY;
+			}
+
+			te.XAdvance = penX;
+			te.YAdvance = penY;
+			return te;
+		}
+		public void FillText(string text, Point _pt)
+		{
+			buildTextVAO (text,_pt);
+
+			int backTex = copyCurentSurfaceToTexture ();
+
+			fontShader.Enable ();
+			//shader.LineWidth = lineWidth;
+			fontShader.ProjectionMatrix = projectionMatrix;
+			fontShader.ModelViewMatrix = modelviewMatrix;
+			fontShader.Color = new Vector4(
+				(float)color.R,
+				(float)color.G,
+				(float)color.B,
+				(float)color.A);
+			fontShader.Resolution = new Vector2 (surf.width, surf.height);
+			fontShader.coef1 = coef1;
+			fontShader.coef2 = coef2;
+			fontShader.coef3 = coef3;
+			fontShader.coefA = coefA;
+//			shader.StencilTest = stencilTest;
+//
+//			if (stencilTest) {
+//					shader.Resolution = new Vector2 (surf.width, surf.height);
+//				GL.ActiveTexture (TextureUnit.Texture0);
+//				GL.BindTexture (TextureTarget.Texture2D, stencilTexId);
+//			}
+
+			GL.ActiveTexture (TextureUnit.Texture0);
+			GL.BindTexture (TextureTarget.Texture2D, curFontTex);
+			GL.ActiveTexture (TextureUnit.Texture1);
+			GL.BindTexture (TextureTarget.Texture2D, backTex);
+
+			vao.Render (PrimitiveType.TriangleStrip);
+			vao.Dispose ();
+
+			//			#if DEBUG
+			//			ErrorCode err = GL.GetError ();
+			//			if (err != ErrorCode.NoError)
+			//				Debug.WriteLine ("Stroke_internal error: " + err.ToString ());
+			//			#endif
+
+			fontShader.Disable ();
+
+			GL.BindTexture (TextureTarget.Texture2D, 0);
+			GL.ActiveTexture (TextureUnit.Texture0);
+			GL.BindTexture (TextureTarget.Texture2D, 0);
+
+			//destroy background texture
+			GL.DeleteTexture (backTex);
+			//GL.Enable (EnableCap.Blend);
+		}
+		#endregion
+
+		#endregion
+
+
+
+		#region Path handling functions
+		public void MoveTo(double x, double y)
+		{
+			addPath (cpath);
+			cpath = new Path ();
+			curPos = new Vector2 ((float)x, (float)y);
+		}
+		public void LineTo(double x, double y)
+		{
+			if (cpath==null)
+				cpath = new Path ();
+			if (cpath.Count == 0)
+				cpath.Add (curPos);
+			curPos = new Vector2 ((float)x, (float)y);
+			cpath.Add (curPos);
+		}
+		public void Rectangle(Rectangle r)
+		{
+			MoveTo (r.X, r.Y);
+			LineTo (r.Right, r.Y);
+			LineTo (r.Right, r.Bottom);
+			LineTo (r.X, r.Bottom);
+			ClosePath ();
+		}
+		public void Arc(double xc, double yc, double radius, double angle1, double angle2)
+		{
+			angle1 = NormalizeAngle (angle1);
+			angle2 = NormalizeAngle (angle2);
+
+			if (angle1 > angle2)
+				angle2 += Math.PI * 2.0;
+			double 	a = angle1,
+			//step = Math.PI/16;
+			step =Math.PI * 2/(radius+20);
+
+			Vector2 v = new Vector2 ((float)(Math.Cos (a) * radius + xc), (float)(Math.Sin (a) * radius + yc));
+			if (v!=curPos)
+				cpath.Add (v);
+			int cpt = 0;
+			while(true){
+				if (a<angle2){
+					a+=step;
+					if (a > angle2)
+						break;
+						//a = angle2;
+				}else
+					break;
+				cpt++;
+//				if (a == angle2) {//add a point very close to a to get good termination angle
+//					v = new Vector2 ((float)(Math.Cos (a-0.001) * radius + xc), (float)(Math.Sin (a-0.001) * radius + yc));
+//					cpath.Add (v);
+//				}
+
+				v = new Vector2 ((float)(Math.Cos (a) * radius + xc), (float)(Math.Sin (a) * radius + yc));
+				cpath.Add (v);
+
+			}
+			curPos = cpath [cpath.Count - 1];
+		}
+		public void ClosePath()
+		{
+			if (cpath == null)
+				return;
+			if (cpath.Count < 3)//cannot close path with less than 3 points
+				return;
+				
+			cpath.IsClosed = true;
+
+			MoveTo (cpath [0].X, cpath [0].Y);
+		}
+		#endregion
+
+		#region Transformations
+		public void Translate(double tx, double ty)
+		{
+			modelviewMatrix *= Matrix4.CreateTranslation ((float)tx, (float)ty, 0f);
+		}
+		public void Scale(double sx, double sy)
+		{
+			modelviewMatrix *= Matrix4.CreateScale ((float)sx, (float)sy, 0f);
+		}
+		public void Rotate(double angle){
+			modelviewMatrix *= Matrix4.CreateRotationZ ((float)angle);
+		}
+		#endregion
+		#endregion
+
+		//temp Lists used to build arrays for vao
+		List<Vector2> vertices = new List<Vector2> ();
+		List<int> indices = new List<int> ();
+		List<Vector2> texCoords = new List<Vector2> ();
+		int idxOffset = 0;	//offset in vertices array between pathes
+
+
+		void initVAOsCache()
+		{
+			if (vertices != null)
+				return;
+			vertices = new List<Vector2> ();
+			indices = new List<int> ();
+			texCoords = new List<Vector2> ();
+			idxOffset = 0;
+		}
+		void flush(){
+			vao = new VertexArrayObject (
+				vertices.ToArray (),
+				texCoords.ToArray (), 
+				indices.ToArray ());
+
+			vertices = null;
+			indices = null;
+			texCoords = null;
+		}
+
+		void stroke_internal()
+		{
+			buildStrokeVAOs ();
+
+			#if GPU_TIME_MSR
+			ulong gpuTimeStart, gpuTimeStop;
+			gpuTimeStart = (ulong)GL.GetInteger64 (GetPName.Timestamp);
+			#endif
+
+			shader.Enable ();
+			//shader.LineWidth = lineWidth;
+			shader.ProjectionMatrix = projectionMatrix;
+			shader.ModelViewMatrix = modelviewMatrix;
+			shader.Color = new Vector4(
+				(float)color.R,
+				(float)color.G,
+				(float)color.B,
+				(float)color.A);
+			shader.StencilTest = stencilTest;
+				
+			if (stencilTest) {
+				shader.Resolution = new Vector2 (surf.width, surf.height);
+				GL.ActiveTexture (TextureUnit.Texture0);
+				GL.BindTexture (TextureTarget.Texture2D, stencilTexId);
+			}
+
+			vao.Render (PrimitiveType.TriangleStrip);
+			vao.Dispose ();
+
+//			#if DEBUG
+//			ErrorCode err = GL.GetError ();
+//			if (err != ErrorCode.NoError)
+//				Debug.WriteLine ("Stroke_internal error: " + err.ToString ());
+//			#endif
+
+			shader.Disable ();
+
+			GL.BindTexture (TextureTarget.Texture2D, 0);
+
+			#if GPU_TIME_MSR
+			gpuTimeStop = (ulong)GL.GetInteger64 (GetPName.Timestamp);
+			Debug.WriteLine(gpuTimeStop - gpuTimeStart);
+			#endif
+		}
+		void fill_internal()
+		{
+			buildFillVAOs ();
+
+			shader.Enable ();
+			//shader.LineWidth = lineWidth;
+			shader.ProjectionMatrix = projectionMatrix;
+			shader.ModelViewMatrix = modelviewMatrix;
+			shader.Color = new Vector4(
+				(float)color.R,
+				(float)color.G,
+				(float)color.B,
+				(float)color.A);
+			shader.StencilTest = stencilTest;
+
+			if (stencilTest) {
+				shader.Resolution = new Vector2 (surf.width, surf.height);
+				GL.ActiveTexture (TextureUnit.Texture0);
+				GL.BindTexture (TextureTarget.Texture2D, stencilTexId);
+			}
+
+			vao.Render (PrimitiveType.Triangles);
+			vao.Dispose ();
+
+			shader.Disable ();
+
+			GL.BindTexture (TextureTarget.Texture2D, 0);
+		}
+		void clip_internal()
+		{
+			GL.FramebufferTexture2D(FramebufferTarget.Framebuffer, 
+				FramebufferAttachment.ColorAttachment0,
+				TextureTarget.Texture2D,stencilTexId,0);
+
+			if (!stencilTest)
+				GL.Clear (ClearBufferMask.ColorBufferBit);
+			stencilTest = true;
+
+			buildFillVAOs ();
+
+			clipShader.Enable ();
+			//shader.LineWidth = lineWidth;
+			clipShader.ProjectionMatrix = projectionMatrix;
+			clipShader.ModelViewMatrix = modelviewMatrix;
+
+			vao.Render (PrimitiveType.Triangles);
+			vao.Dispose ();
+
+			clipShader.Disable ();
+
+			GL.FramebufferTexture2D(FramebufferTarget.Framebuffer, 
+				FramebufferAttachment.ColorAttachment0,
+				TextureTarget.Texture2D,surf.texId,0);
+		}
+
+		void buildFillVAOs()
+		{
+			#if (DEBUG && MPERF)
+			sw_fill.Start();
+			#endif
+
+			addPath (cpath);
+
+			initVAOsCache ();
+
+			float hlw = (float)lineWidth / 2.0f;//half line width
+
+			Vector2 vDir,vDir2;
+			bool genTexCoords = false;
+
+			for (int j = 0; j < pathes.Count; j++) {
+				Path path = new Path(pathes[j]);
+				//keep an array containing real vertex indice
+				List<int> vertIdx = new List<int> (Enumerable.Range(0,path.Count));
+
+				#region get polygon bounds for texture mapping
+				if (genTexCoords){
+					minX = float.MaxValue;
+					maxX = float.MinValue;
+					minY = float.MaxValue;
+					maxY = float.MinValue;
+
+					foreach (Vector2 p in path) {
+						if (p.X < minX)
+							minX = p.X;
+						if (p.Y < minY)
+							minY = p.Y;
+						if (p.X > maxX)
+							maxX = p.X;
+						if (p.Y > maxY)
+							maxY = p.Y;
+					}
+					polyWidth = maxX - minX;
+					polyHeight = maxY - minY;
+				}
+				#endregion
+
+				vertices.AddRange (path);//we only play on indices
+				int ptrS = 0, ptrS1, ptrS2; //index du sommet dans le path
+				while (path.Count > 3) {
+					if (ptrS == path.Count)
+						ptrS = 0;
+
+					if (ptrS < path.Count - 2) {
+						ptrS1 = ptrS + 1;
+						ptrS2 = ptrS + 2;
+					} else if (ptrS < path.Count - 1) {
+						ptrS1 = ptrS + 1;
+						ptrS2 = 0;
+					} else {
+						ptrS1 = 0;
+						ptrS2 = 1;
+					}
+
+					//should test only concavity points if any
+					vDir = Vector2.NormalizeFast (path [ptrS1] - path [ptrS]);
+					vDir2 = Vector2.NormalizeFast (path [ptrS2] - path [ptrS]);
+
+					float dotP = Vector2.Dot (vDir.PerpendicularLeft, vDir2);
+					//double angle = Math.Acos((double)dotP);
+//
+//					Debug.WriteLine (dotP);
+//					Debug.WriteLine (angle);
+
+					if (dotP <= 0) {
+						//triangle is invalid
+						ptrS++;
+						continue;
+					}
+						
+					//check if no other points of path is inside tri
+//					bool triangleIsValid = true;
+//					int i = ptrS + 3;
+//					if (i >= path.Count)
+//						i -= path.Count;
+//					while (i != ptrS) {
+//						if (PointInTriangle (path [i],path [ptrS] , path [ptrS1], path [ptrS2])) {
+//							ptrS++;
+//							triangleIsValid = false;
+//							break;
+//						}
+//						i++;
+//						if (i == path.Count)
+//							i = 0;
+//					}
+//					if (!triangleIsValid)
+//						continue;
+					//triangle is valid, add tri to primitive to draw
+					//and remove middle sommet from path[];
+					addFillTriangle (j, vertIdx [ptrS], vertIdx [ptrS1], vertIdx [ptrS2]);
+
+					path.RemoveAt (ptrS1);
+					vertIdx.RemoveAt (ptrS1);
+				}
+				if (path.Count == 3)
+					addFillTriangle (j, vertIdx [0], vertIdx [1], vertIdx [2]);
+
+				if (j < pathes.Count - 1) {				
+					idxOffset += pathes[j].Count;
+				}
+			}
+			flush ();
+
+			#if (DEBUG && MPERF)
+			sw_fill.Stop();
+			#endif
+		}
+
+		int curFontTex;
+		void buildTextVAO(string text, Point pt)
+		{
+			initVAOsCache ();
+
+			int penX = pt.X,
+			penY = pt.Y + (int)fontFace.originalFontExtents.Ascent;
+
+			for (int i = 0; i < text.Length; i++) {
+				uint c = (uint)text [i];
+				glGlyph g = fontFace.glyphesCache [fontSize] [c];
+				curFontTex = g.texId;
+				vertices.Add (new Vector2(penX + g.bmpLeft, penY - g.bmpTop));
+				vertices.Add (new Vector2(penX + g.bmpLeft, penY - g.bmpTop + g.dims.Height));
+				vertices.Add (new Vector2(penX + g.bmpLeft + g.dims.Width, penY - g.bmpTop));
+				vertices.Add (new Vector2(penX + g.bmpLeft + g.dims.Width, penY - g.bmpTop + g.dims.Height));
+				indices.Add (int.MaxValue);//primitive restart
+				indices.Add (i*4);
+				indices.Add (i*4 + 1);
+				indices.Add (i*4 + 2);
+				indices.Add (i*4 + 3);
+				texCoords.Add (new Vector2(g.texX,g.texY));
+				texCoords.Add (new Vector2(g.texX,g.texY + g.texHeight));
+				texCoords.Add (new Vector2(g.texX + g.texWidth,g.texY));
+				texCoords.Add (new Vector2(g.texX + g.texWidth,g.texY + g.texHeight));
+
+				penX += (int)g.advanceX;
+				penY += (int)g.advanceY;
+			}
+
+			flush ();
+		}
+		void buildStrokeVAOs()
+		{
+			addPath (cpath);
+
+			initVAOsCache ();
+
+			float hlw = (float)lineWidth / 2.0f;//half line width
+
+			Vector2 vDir,vDir2, vPerp;
+			float lPerp;
+			int i;
+			//current offset in index
+			for (int j = 0; j < pathes.Count; j++) {
+				Path path = pathes[j];	
+				for (i = 0; i < path.Count; i++) {
+					lPerp = hlw;
+					vDir2 = Vector2.Zero;
+
+					if (i < path.Count - 1) {
+						vDir = Vector2.Normalize (path [i + 1] - path [i]);
+						if (i > 0) {
+							vDir2 = Vector2.Normalize (path [i] - path [i - 1]);
+						} else if (path.IsClosed)
+							vDir2 = Vector2.Normalize (path [0] - path [path.Count - 1]);
+					} else {
+						vDir = Vector2.Normalize (path [i] - path [i - 1]);
+						if (path.IsClosed)
+							vDir2 = Vector2.Normalize (path [0]-path [i]);
+					}
+
+					vPerp = Vector2.Normalize(vDir+vDir2).PerpendicularLeft;
+
+					if (vDir2 != Vector2.Zero) {
+						double dotP = Vector2.Dot (vDir.PerpendicularLeft, vPerp);
+						double angle = Math.Acos(dotP);
+						double x = Math.Tan (angle) * hlw;
+
+						if (dotP == 0)
+							lPerp = hlw;
+						else
+							lPerp = (float)Math.Sqrt (Math.Pow (x, 2) + Math.Pow (hlw, 2));
+					}
+
+					vertices.Add (path [i] + vPerp * (float)lPerp);
+					vertices.Add (path [i] - vPerp * (float)lPerp);
+					indices.Add (idxOffset + i*2);
+					indices.Add (idxOffset + i*2 + 1);
+					texCoords.Add (Vector2.Zero);
+					texCoords.Add (Vector2.One);
+				}
+				if (path.IsClosed) {
+					indices.Add (idxOffset);
+					indices.Add (idxOffset+1);
+					texCoords.Add (Vector2.Zero);
+					texCoords.Add (Vector2.One);
+				}
+				if (j < pathes.Count - 1) {
+					indices.Add (int.MaxValue);	//restart primitive idex
+					idxOffset += path.Count * 2;
+				}
+			}
+			flush ();
+		}
+			
+		void addFillTriangle(int pathIdx, int vx1, int vx2, int vx3){
+			addFillVertex (pathIdx, vx1);
+			addFillVertex (pathIdx, vx2);
+			addFillVertex (pathIdx, vx3);
+		}
+
+		void addFillVertex(int pathIdx, int vx){
+			Vector2 p = pathes [pathIdx] [vx];
+			indices.Add (idxOffset + vx);
+			//texCoords.Add (new Vector2(1.0f/polyWidth*(p.X-minX),1.0f/polyHeight*(p.Y-minY)));
+		}
+
+		float sign (Vector2 p1, Vector2 p2, Vector2 p3)
+		{
+			return (p1.X - p3.X) * (p2.Y - p3.Y) - (p2.X - p3.X) * (p1.Y - p3.Y);
+		}
+		bool PointInTriangle (Vector2 pt, Vector2 v1, Vector2 v2, Vector2 v3)
+		{
+			bool b1, b2, b3;
+
+			b1 = sign(pt, v1, v2) < 0.0f;
+			b2 = sign(pt, v2, v3) < 0.0f;
+			b3 = sign(pt, v3, v1) < 0.0f;
+
+			return ((b1 == b2) && (b2 == b3));
+		}
+
+		#region GL Ctx Save and restore
+		int savedFbo,
+		savedPriRstIdx,
+		savedBlendSrc,
+		savedBlendDst;
+		int[] viewport = new int[4];
+		float[] savedClsColor = new float[4];
+		bool savedBlend,savedPriRstCap;
+		void saveGLConfig(){
+			GL.GetInteger (GetPName.FramebufferBinding, out savedFbo);
+			GL.GetInteger ((GetPName)All.PrimitiveRestartIndex, out savedPriRstIdx);
+			GL.GetBoolean ((GetPName)All.PrimitiveRestart, out savedPriRstCap);
+			GL.GetInteger(GetPName.Viewport, viewport);
+			GL.GetFloat (GetPName.ColorClearValue, savedClsColor);
+			GL.GetBoolean (GetPName.Blend, out savedBlend);
+			GL.GetInteger (GetPName.BlendSrc, out savedBlendSrc);
+			GL.GetInteger (GetPName.BlendDst, out savedBlendDst);
+		}
+		void restoreGLConfig(){
+			GL.BindFramebuffer(FramebufferTarget.Framebuffer, savedFbo);
+
+			GL.Viewport (viewport[0],viewport[1],viewport[2],viewport[3]);
+			GL.PrimitiveRestartIndex (savedPriRstIdx);
+			GL.ClearColor (savedClsColor [0], savedClsColor [1], savedClsColor [2], savedClsColor [3]);
+			if (!savedBlend)
+				GL.Disable (EnableCap.Blend);
+			if (!savedPriRstCap)
+				GL.Disable (EnableCap.PrimitiveRestart);
+			GL.BlendFunc ((BlendingFactorSrc) savedBlendSrc,(BlendingFactorDest)savedBlendDst);
+		}
+		#endregion
+
+		#region IDisposable implementation
+
+		public void Dispose ()
+		{
+			restoreGLConfig ();
+
+			if (GL.IsFramebuffer (fboId))
+				GL.DeleteFramebuffer (fboId);
+			if (GL.IsTexture(stencilTexId))
+				GL.DeleteTexture(stencilTexId);
+		}
+
+		#endregion
+
+	}
+}
+