recrownedgtk/RecrownedGTK/Graphics/VertexAttributesArrayHandle.cs

using System;
using OpenTK.Graphics.OpenGL;
using OpenTK;
using RecrownedGTK.Graphics.Render.Shaders;
namespace RecrownedGTK.Graphics {
    /// <summary>
    /// The attributes of the vertex.
    /// Handle for openGL.
    /// </summary>
    public class VertexAttributesArrayHandle : IDisposable {
        private bool disposed;
        private int handle;

        /// <summary>
        /// Generates an openGL vertex array.
        /// </summary>
        public VertexAttributesArrayHandle() {
            handle = GL.GenVertexArray();
        }

        /// <summary>
        /// Tells openGL to bind this vertex attributes array.
        /// </summary>
        public void Bind() {
            GL.BindVertexArray(handle);
        }

        /// <summary>
        /// Creates a basic vertex attributes object handle that takes in vertices, texture coordinates, and a color.
        /// First 3 values are normalized vertex position (x, y, z), second two are texture coordinates, and last 4 are color values.
        /// </summary>
        /// <param name="shader">The shader program used. Default is the one created from <see cref="RecrownedGTK.Graphics.Render.Shaders.Shader.CreateBasicShader"/>.</param>
        /// <param name="positionAttribName">The name of the attribute for the vertex's position in the shader. Default is "aPosition".</param>
        /// <param name="textureAttribName">The name of the attribute for the texture's coordinate. Default is "aTexture".</param>
        /// <param name="colorAttribName">The name of the attribute for color mixture. Default is "aColor".</param>
        /// <returns>The built <see cref="RecrownedGTK.Graphics.VertexAttributesArrayHandle"/>.</returns>
        public static VertexAttributesArrayHandle CreateBasicVA(ref Matrix4 transformMat, Shader shader, string positionAttribName = "aPosition", string textureAttribName = "aTexture", string colorAttribName = "aColor", string transformUnifName = "transform") {
            VertexAttributesArrayHandle vertexAttribs = new VertexAttributesArrayHandle();
            vertexAttribs.Bind();
            GL.UniformMatrix4(shader.GetAttribLocation(transformUnifName), true, ref transformMat);
            
            GL.VertexAttribPointer(shader.GetAttribLocation(positionAttribName), 3, VertexAttribPointerType.Float, false, 9 * sizeof(float), 0);
            GL.EnableVertexAttribArray(shader.GetAttribLocation(positionAttribName));

            GL.VertexAttribPointer(shader.GetAttribLocation(textureAttribName), 2, VertexAttribPointerType.Float, false, 9 * sizeof(float), 3 * sizeof(float));
            GL.EnableVertexAttribArray(shader.GetAttribLocation(textureAttribName));

            GL.VertexAttribPointer(shader.GetAttribLocation(colorAttribName), 4, VertexAttribPointerType.Float, false, 9 * sizeof(float), 5 * sizeof(float));
            GL.EnableVertexAttribArray(shader.GetAttribLocation(colorAttribName));
            return vertexAttribs;
        }

        public void Dispose() {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing) {
            if (disposed) return;
            if (disposing) {

            }
            GL.DeleteVertexArray(handle);
            disposed = true;
        }
        ~VertexAttributesArrayHandle() {
            Dispose(false);
        }
    }
}