#region Using Statements
using System;
using System.Collections.Generic;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Storage;
#endregion

namespace BlogExample01
{
    
    public class BlogExample : Microsoft.Xna.Framework.Game
    {
        GraphicsDeviceManager m_graphics;
        ContentManager m_content;
        GraphicsDevice m_device;

        private Effect m_effect;
        private VertexPositionColor[] m_vertices;
        private VertexDeclaration m_vd;

        private Matrix m_matView;
        private Matrix m_matProj;
        private Matrix m_matWorld;

        public BlogExample()
        {
            m_graphics = new GraphicsDeviceManager(this);
            m_content = new ContentManager(Services);            
        }

        protected override void Initialize()
        {
            base.Initialize();
        }

        protected override void LoadGraphicsContent(bool loadAllContent)
        {
            if (loadAllContent)
            {
                m_device = m_graphics.GraphicsDevice;
                m_effect = m_content.Load<Effect>("simpleshader");  

                m_vertices = new VertexPositionColor[3];

                m_vertices[0].Position = new Vector3(-0.5f, -0.5f, 0f);
                m_vertices[0].Color = Color.Red;
                m_vertices[1].Position = new Vector3(0, 0.5f, 0f);
                m_vertices[1].Color = Color.Green;
                m_vertices[2].Position = new Vector3(0.5f, -0.5f, 0f);
                m_vertices[2].Color = Color.Yellow;

                m_vd = new VertexDeclaration(m_device, VertexPositionColor.VertexElements);

                m_matView = Matrix.CreateLookAt(new Vector3(0.0f, 0.0f, 2.0f), new Vector3(0.0f, 0.0f, 0.0f), new Vector3(0.0f, 1.0f, 0.0f));
                m_matProj = Matrix.CreatePerspectiveFieldOfView(
                    MathHelper.PiOver4,
                    (float)m_device.Viewport.Width / (float)m_device.Viewport.Height,
                    1.0f, 100.0f);
                m_matWorld = Matrix.Identity;
            }
        }

        protected override void UnloadGraphicsContent(bool unloadAllContent)
        {
            if (unloadAllContent)
            {
                m_content.Unload();
            }
        }

        protected override void Update(GameTime gameTime)
        {
            base.Update(gameTime);
        }

        protected override void Draw(GameTime gameTime)
        {
            m_graphics.GraphicsDevice.Clear(Color.CornflowerBlue);

            m_device.RenderState.CullMode = CullMode.None;
            m_device.RenderState.FillMode = FillMode.Solid;
            m_effect.CurrentTechnique = m_effect.Techniques["Simplest"];
            m_effect.Parameters["xViewProjection"].SetValue(m_matView * m_matProj * m_matWorld);
            m_effect.Begin();
            foreach (EffectPass pass in m_effect.CurrentTechnique.Passes)
            {
                pass.Begin();

                m_device.VertexDeclaration = m_vd;                
                m_device.DrawUserPrimitives(PrimitiveType.TriangleList, m_vertices, 0, 1);

                pass.End();
            }
            m_effect.End();

            base.Draw(gameTime);
        }
    }
}