using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using System.Text;

namespace StgSharp.Graphics
{
    public partial class Form
    {
        /// <summary>
        /// Create a set of <see cref="VertexArray"/>.
        /// </summary>
        /// <param name="count">Amount of VAO to be crated.</param>
        /// <returns></returns>
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        protected VertexArray CreateVertexArray(uint count)
        {
            return new VertexArray(count, gl);
        }
    }

    public unsafe class VertexArray : IBufferObject
    {
        internal VertexArray(uint n, IglFunc gl)
        {
            _bufferID = new uint[n];
            GL = gl;
            fixed (uint* id = _bufferID)
            {
                GL.GenVertexArrays(n, id);
            }
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public sealed override void Bind(int index)
        {
            GL.BindVertexArray(_bufferID[index]);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public void BindNull()
        {
            GL.BindVertexArray(0);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public void SetVertexAttribute(uint index, int vertexLength, Type dataType, bool isNomalized, uint stride, int pointer)
        {
            GL.SetVertexAttribute(
                index, vertexLength, dataType,
                isNomalized,
                stride, pointer);
        }

        protected sealed override void Dispose(bool disposing)
        {
            if (disposing)
            {
                GL.DeleteVertexArrays((uint)_bufferID.Length, _bufferID);
            }
        }
    }
}