#region File Description
//-----------------------------------------------------------------------------
// Quad.cs
//
// Microsoft XNA Community Game Platform
// Copyright (C) Microsoft Corporation. All rights reserved.
//-----------------------------------------------------------------------------
#endregion

using System;
using System.Collections.Generic;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Content;

namespace TexturedQuad
{
    public struct Quad
    {
        public Vector3 Origin;
        public Vector3 UpperLeft;
        public Vector3 LowerLeft;
        public Vector3 UpperRight;
        public Vector3 LowerRight;
        public Vector3 Normal;
        public Vector3 Up;
        public Vector3 Left;

        public VertexPositionNormalTexture[] Vertices;
//        public int[] Indexes;
        public short[] Indexes;


        public Quad( Vector3 origin, Vector3 normal, Vector3 up, 
            float width, float height )
        {
            Vertices = new VertexPositionNormalTexture[4];
            Indexes = new short[6];
            Origin = origin;
            Normal = normal;
            Up = up;

            // Calculate the quad corners
            Left = Vector3.Cross( normal, Up );
            Vector3 uppercenter = (Up * height / 2) + origin;
            UpperLeft = uppercenter + (Left * width / 2);
            UpperRight = uppercenter - (Left * width / 2);
            LowerLeft = UpperLeft - (Up * height);
            LowerRight = UpperRight - (Up * height);

            FillVertices();
        }
        
        private void FillVertices()
        {
            // Fill in texture coordinates to display full texture
            // on quad
            Vector2 textureUpperLeft = new Vector2( 0.0f, 0.0f );
            Vector2 textureUpperRight = new Vector2( 1.0f, 0.0f );
            Vector2 textureLowerLeft = new Vector2( 0.0f, 1.0f );
            Vector2 textureLowerRight = new Vector2( 1.0f, 1.0f );

            // Provide a normal for each vertex
            for (int i = 0; i < Vertices.Length; i++)
            {
                Vertices[i].Normal = Normal;
            }

            // Set the position and texture coordinate for each
            // vertex
            Vertices[0].Position = LowerLeft;
            Vertices[0].TextureCoordinate = textureLowerLeft;
            Vertices[1].Position = UpperLeft;
            Vertices[1].TextureCoordinate = textureUpperLeft;
            Vertices[2].Position = LowerRight;
            Vertices[2].TextureCoordinate = textureLowerRight;
            Vertices[3].Position = UpperRight;
            Vertices[3].TextureCoordinate = textureUpperRight;

            // Set the index buffer for each vertex, using
            // clockwise winding
            Indexes[0] = 0;
            Indexes[1] = 1;
            Indexes[2] = 2;
            Indexes[3] = 2;
            Indexes[4] = 1;
            Indexes[5] = 3;
        }
    }
}