TestTriangle.cs

/*
 * Created by SharpDevelop.
 * User: NCDyson
 * Date: 7/31/2017
 * Time: 4:17 AM
 * 
 * To change this template use Tools | Options | Coding | Edit Standard Headers.
 */
using System;
using OpenTK;
using OpenTK.Graphics.OpenGL;
using System.Runtime.InteropServices;
using System.Diagnostics;

namespace StudioCCS
{
	/// <summary>
	/// Description of TestTriangle.
	/// </summary>
	public class TestTriangle
	{
		int ProgramID;
		int AttribPos;
		int AttribColor;
		int UniMatrix;
		
		int VAOIndex = -1;
		int VBOIndex = -1;
		
		public Vector3 Position = new Vector3();
		
		public bool WasInit = false;
		
		[StructLayout(LayoutKind.Sequential)]
		public struct TriangleVertex
		{
			public Vector3 Position;
			public Vector3 Color;
		}
		
		private TriangleVertex[] Vertices;
		
		
		public TestTriangle()
		{
			Vertices = new TriangleVertex[3];
			//Vertices[0].Position = new Vector3(-0.8f, -0.8f, 0.0f);
			Vertices[0].Position = new Vector3(0.374f, 2.792f, 0.186f);
			Vertices[0].Color = new Vector3(1.0f, 0.0f, 0.0f);

			//Vertices[1].Position = new Vector3(0.8f, -0.8f, 0.0f);
			Vertices[1].Position = new Vector3(0.28f, 2.792f, 0.186f);
			Vertices[1].Color = new Vector3(0.0f, 1.0f, 0.0f);

			//Vertices[2].Position = new Vector3(0.0f, 0.8f, 0.0f);
			Vertices[2].Position = new Vector3(0.28f, 2.792f, 0.411f);
			Vertices[2].Color = new Vector3(0.0f, 0.0f, 1.0f);			
		}
		
		public bool Init()
		{
			ProgramID = Scene.LoadProgram("Triangle");
			if(ProgramID != -1)
			{
				AttribPos = GL.GetAttribLocation(ProgramID, "vPosition");
				AttribColor = GL.GetAttribLocation(ProgramID, "vColor");
				UniMatrix = GL.GetUniformLocation(ProgramID, "modelView");
				
				if(AttribPos == -1 || AttribColor == -1 || UniMatrix == -1)
				{
					Debug.WriteLine("TestTriangle::Init(): Error binding Vertex Attribs:");
					Debug.WriteLine(string.Format("\taPos: {0}, aColor: {1}, uMatrix: {2}", AttribPos, AttribColor, UniMatrix));
					return false;
				}
				
				VAOIndex = GL.GenVertexArray();
				GL.BindVertexArray(VAOIndex);
				
				int VertexSize = Marshal.SizeOf(Vertices[0].GetType());
				Type VertexType = Vertices[0].GetType();
				
				VBOIndex = GL.GenBuffer();
				GL.BindBuffer(BufferTarget.ArrayBuffer, VBOIndex);
				GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(VertexSize * 3), Vertices, BufferUsageHint.StaticDraw);
				
				GL.EnableVertexAttribArray(AttribPos);
				GL.VertexAttribPointer(AttribPos, 3, VertexAttribPointerType.Float, false, VertexSize, Marshal.OffsetOf(VertexType, "Position"));
				
				GL.EnableVertexAttribArray(AttribColor);
				GL.VertexAttribPointer(AttribColor, 3, VertexAttribPointerType.Float, false, VertexSize, Marshal.OffsetOf(VertexType, "Color"));
				
				
				GL.BindVertexArray(0);
				GL.BindBuffer(BufferTarget.ArrayBuffer, 0);
				
				WasInit = true;
			}
			return WasInit;
		}
		
		public void DeInit()
		{
			if(ProgramID != -1) GL.DeleteProgram(ProgramID);
			ProgramID = -1;
			
			if(VBOIndex != -1) GL.DeleteBuffer(VBOIndex);
			VBOIndex = -1;
			if(VAOIndex != -1) GL.DeleteVertexArray(VAOIndex);
			VAOIndex = -1;
		}
		
		public void Render(Matrix4 ViewMtx)
		{
			if(WasInit)
			{
				Matrix4 modelViewMtx = Matrix4.CreateTranslation(-Position) * ViewMtx;
				GL.UseProgram(ProgramID);
				
				GL.UniformMatrix4(UniMatrix, false, ref modelViewMtx);
				
				GL.BindVertexArray(VAOIndex);
				GL.BindBuffer(BufferTarget.ArrayBuffer, VBOIndex);
				
				GL.EnableVertexAttribArray(AttribPos);
				GL.EnableVertexAttribArray(AttribColor);
				
				GL.DrawArrays(PrimitiveType.Triangles, 0, 3);
				
				GL.DisableVertexAttribArray(AttribPos);
				GL.DisableVertexAttribArray(AttribColor);
				
				GL.BindVertexArray(0);
				GL.BindBuffer(BufferTarget.ArrayBuffer, 0);
				GL.UseProgram(0);
			}
		}
	}
}