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Engine/Renderer/Buffer/VertexArray.cs

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+using System.Reflection;
+using System.Runtime.InteropServices;
+using Engine.Renderer.Buffer.Vertex;
+using OpenTK.Graphics.OpenGL;
+using Serilog;
+
+namespace Engine.Renderer.Buffer;
+
+public class VertexArray : OpenGlObject
+{
+    // private IndexBuffer? _boundIndexBuffer;
+    // private readonly Dictionary<int, VertexBuffer<IVertex>> _boundVertexBuffers = new();
+    
+    public VertexArray()
+    {
+        GL.CreateVertexArrays(1, out int handle);
+        Handle = handle;
+    }
+
+    public void BindIndexBuffer(IndexBuffer buffer)
+    {
+        GL.VertexArrayElementBuffer(Handle, buffer.Handle);
+        
+        Log.Debug("Vertex array {Handle} bound to index buffer {Buffer}", Handle, buffer.Handle);
+    }
+
+    public void BindVertexBuffer<T>(VertexBuffer<T> buffer, int bindingIndex = 0, int divisor = 0)
+        where T : struct, IVertex
+    {
+        if (bindingIndex < 0)
+            throw new ArgumentException("Binding index must be greater than 0");
+
+        if (divisor < 0)
+            throw new ArgumentException("Divisor must be greater than 0");
+
+        var stride = Marshal.SizeOf<T>();
+        var fields = IVertex.GetFields<T>();
+
+        GL.VertexArrayVertexBuffer(Handle, bindingIndex, buffer.Handle, 0, stride);
+
+        var location = 0;
+        foreach (var field in fields)
+        {
+            var attribute = field.GetCustomAttribute<VertexAttribute>()!;
+
+            var offset = Marshal.OffsetOf<T>(field.Name).ToInt32();
+            SetupAttribute(attribute, location, offset, bindingIndex);
+
+            location += attribute.RepeatCount;
+        }
+
+        GL.VertexArrayBindingDivisor(Handle, bindingIndex, divisor);
+
+        Log.Debug(
+            "Vertex array {Handle} bound to vertex buffer {Buffer} at {BindingIndex} binding with {Divisor} divisor",
+            Handle, buffer.Handle, bindingIndex, divisor);
+    }
+
+    private void SetupAttribute(VertexAttribute attribute, int baseLocation, int baseOffset, int bindingIndex)
+    {
+        var size = attribute.ComponentCount * IVertex.AttributeSize(attribute.Type);
+
+        for (var i = 0; i < attribute.RepeatCount; i++)
+        {
+            var location = baseLocation + i;
+            var offset = baseOffset + i * size;
+
+            GL.EnableVertexArrayAttrib(Handle, location);
+            GL.VertexArrayAttribFormat(Handle, location, attribute.ComponentCount, attribute.Type, attribute.Normalized,
+                offset);
+            GL.VertexArrayAttribBinding(Handle, location, bindingIndex);
+        }
+    }
+
+    internal override void Bind()
+    {
+        GL.BindVertexArray(Handle);
+    }
+
+    internal override void Unbind()
+    {
+        GL.BindVertexArray(0);
+    }
+
+    protected override void Destroy()
+    {
+        GL.DeleteVertexArray(Handle);
+    }
+}