OpenGL indirect drawing for ui quad

  (shader and vao)

1 files changed, 94 insertions, 0 deletions

diff --git a/src/OpenGL/VertexArrayObject.cs b/src/OpenGL/VertexArrayObject.cs
new file mode 100644
index 00000000..9b75af29
--- /dev/null
+++ b/src/OpenGL/VertexArrayObject.cs
@@ -0,0 +1,94 @@
+using System;
+using OpenTK;
+using OpenTK.Graphics.OpenGL;
+
+namespace go
+{
+	public class VertexArrayObject : IDisposable
+	{
+		public int vaoHandle,
+		positionVboHandle,
+		texVboHandle,
+		eboHandle;
+
+		Vector2[] positionVboData;
+		public int[] indicesVboData;
+		Vector2[] texVboData;
+
+		public VertexArrayObject (Vector2[] _positions, Vector2[] _texCoord, int[] _indices)
+		{
+			positionVboData = _positions;
+			texVboData = _texCoord;
+			indicesVboData = _indices;
+
+			CreateVBOs ();
+			CreateVAOs ();
+		}
+
+		void deleteVAOs()
+		{
+			GL.DeleteBuffer (positionVboHandle);
+			GL.DeleteBuffer (texVboHandle);
+			GL.DeleteBuffer (eboHandle);
+			GL.DeleteVertexArray (vaoHandle);
+		}
+
+		void CreateVBOs()
+		{
+			positionVboHandle = GL.GenBuffer();
+			GL.BindBuffer(BufferTarget.ArrayBuffer, positionVboHandle);
+			GL.BufferData<Vector2>(BufferTarget.ArrayBuffer,
+				new IntPtr(positionVboData.Length * Vector2.SizeInBytes),
+				positionVboData, BufferUsageHint.StaticDraw);
+
+			texVboHandle = GL.GenBuffer();
+			GL.BindBuffer(BufferTarget.ArrayBuffer, texVboHandle);
+			GL.BufferData<Vector2>(BufferTarget.ArrayBuffer,
+				new IntPtr(texVboData.Length * Vector2.SizeInBytes),
+				texVboData, BufferUsageHint.StaticDraw);
+			//
+			eboHandle = GL.GenBuffer();
+			GL.BindBuffer(BufferTarget.ElementArrayBuffer, eboHandle);
+			GL.BufferData(BufferTarget.ElementArrayBuffer,
+				new IntPtr(sizeof(uint) * indicesVboData.Length),
+				indicesVboData, BufferUsageHint.StaticDraw);
+
+			GL.BindBuffer(BufferTarget.ArrayBuffer, 0);
+			GL.BindBuffer(BufferTarget.ElementArrayBuffer, 0);
+		}
+
+		void CreateVAOs()
+		{
+			vaoHandle = GL.GenVertexArray();
+			GL.BindVertexArray(vaoHandle);
+
+			GL.EnableVertexAttribArray(0);
+			GL.BindBuffer(BufferTarget.ArrayBuffer, positionVboHandle);
+			GL.VertexAttribPointer(0, 2, VertexAttribPointerType.Float, true, Vector2.SizeInBytes, 0);
+
+			GL.EnableVertexAttribArray(1);
+			GL.BindBuffer(BufferTarget.ArrayBuffer, texVboHandle);
+			GL.VertexAttribPointer(1, 2, VertexAttribPointerType.Float, true, Vector2.SizeInBytes, 0);
+
+			GL.BindBuffer(BufferTarget.ElementArrayBuffer, eboHandle);
+
+			GL.BindVertexArray(0);
+		}
+			
+		public void Render(PrimitiveType _primitiveType){
+			GL.BindVertexArray(vaoHandle);
+			GL.DrawElements(_primitiveType, indicesVboData.Length,
+				DrawElementsType.UnsignedInt, IntPtr.Zero);	
+			GL.BindVertexArray (0);
+		}
+
+
+		#region IDisposable implementation
+		public void Dispose ()
+		{
+			deleteVAOs ();
+		}
+		#endregion
+	}
+}
+