From 88ea2f1f0814fdb48b3dfe090c1db885bb5dc775 Mon Sep 17 00:00:00 2001
From: Nickolas McDonald <43690021+n77y@users.noreply.github.com>
Date: Fri, 8 Sep 2023 21:50:46 -0400
Subject: [PATCH] created MeshExtensions

---
 Raylib-cs/types/Mesh.cs           | 35 +++++++-----
 Raylib-cs/types/MeshExtensions.cs | 90 +++++++++++++++++++++++++++++++
 Raylib-cs/types/Raylib.Utils.cs   |  6 +++
 3 files changed, 118 insertions(+), 13 deletions(-)
 create mode 100644 Raylib-cs/types/MeshExtensions.cs

diff --git a/Raylib-cs/types/Mesh.cs b/Raylib-cs/types/Mesh.cs
index 116542e..6f6980d 100644
--- a/Raylib-cs/types/Mesh.cs
+++ b/Raylib-cs/types/Mesh.cs
@@ -9,6 +9,15 @@ namespace Raylib_cs;
 [StructLayout(LayoutKind.Sequential)]
 public unsafe partial struct Mesh
 {
+    /// <summary>
+    ///  Creates a mesh ready for default vertex data allocation
+    /// </summary>
+    public Mesh(int vertexCount, int triangleCount)
+    {
+        VertexCount = vertexCount;
+        TriangleCount = triangleCount;
+    }
+
     /// <summary>
     ///  Number of vertices stored in arrays
     /// </summary>
@@ -24,37 +33,37 @@ public unsafe partial struct Mesh
     /// <summary>
     /// Vertex position (XYZ - 3 components per vertex) (shader-location = 0)
     /// </summary>
-    public float* Vertices;
+    public float* Vertices = default;
 
     /// <summary>
     /// Vertex texture coordinates (UV - 2 components per vertex) (shader-location = 1)
     /// </summary>
-    public float* TexCoords;
+    public float* TexCoords = default;
 
     /// <summary>
     /// Vertex second texture coordinates (useful for lightmaps) (shader-location = 5)
     /// </summary>
-    public float* TexCoords2;
+    public float* TexCoords2 = default;
 
     /// <summary>
     /// Vertex normals (XYZ - 3 components per vertex) (shader-location = 2)
     /// </summary>
-    public float* Normals;
+    public float* Normals = default;
 
     /// <summary>
     /// Vertex tangents (XYZW - 4 components per vertex) (shader-location = 4)
     /// </summary>
-    public float* Tangents;
+    public float* Tangents = default;
 
     /// <summary>
     /// Vertex colors (RGBA - 4 components per vertex) (shader-location = 3)
     /// </summary>
-    public byte* Colors;
+    public byte* Colors = default;
 
     /// <summary>
     /// Vertex indices (in case vertex data comes indexed)
     /// </summary>
-    public ushort* Indices;
+    public ushort* Indices = default;
 
     #endregion
 
@@ -63,22 +72,22 @@ public unsafe partial struct Mesh
     /// <summary>
     /// Animated vertex positions (after bones transformations)
     /// </summary>
-    public float* AnimVertices;
+    public float* AnimVertices = default;
 
     /// <summary>
     /// Animated normals (after bones transformations)
     /// </summary>
-    public float* AnimNormals;
+    public float* AnimNormals = default;
 
     /// <summary>
     /// Vertex bone ids, up to 4 bones influence by vertex (skinning)
     /// </summary>
-    public byte* BoneIds;
+    public byte* BoneIds = default;
 
     /// <summary>
     /// Vertex bone weight, up to 4 bones influence by vertex (skinning)
     /// </summary>
-    public float* BoneWeights;
+    public float* BoneWeights = default;
 
     #endregion
 
@@ -87,12 +96,12 @@ public unsafe partial struct Mesh
     /// <summary>
     /// OpenGL Vertex Array Object id
     /// </summary>
-    public uint VaoId;
+    public uint VaoId = default;
 
     /// <summary>
     /// OpenGL Vertex Buffer Objects id (default vertex data, uint[])
     /// </summary>
-    public uint* VboId;
+    public uint* VboId = default;
 
     #endregion
 }
diff --git a/Raylib-cs/types/MeshExtensions.cs b/Raylib-cs/types/MeshExtensions.cs
new file mode 100644
index 0000000..964ce6e
--- /dev/null
+++ b/Raylib-cs/types/MeshExtensions.cs
@@ -0,0 +1,90 @@
+using System;
+
+namespace Raylib_cs;
+
+internal static unsafe class MeshExtensions
+{
+    /// <summary>Allocate mesh vertices</summary>
+    public static void AllocVertices(ref this Mesh mesh)
+    {
+        mesh.Vertices = Raylib.New<float>(3 * mesh.VertexCount);
+    }
+
+    /// <summary>Allocate mesh texcoords</summary>
+    public static void AllocTexcoords(ref this Mesh mesh)
+    {
+        mesh.TexCoords = Raylib.New<float>(2 * mesh.VertexCount);
+    }
+
+    /// <summary>Allocate mesh texcoords2</summary>
+    public static void AllocTexcoords2(ref this Mesh mesh)
+    {
+        mesh.TexCoords2 = Raylib.New<float>(2 * mesh.VertexCount);
+    }
+
+    /// <summary>Allocate mesh normals</summary>
+    public static void AllocNormals(ref this Mesh mesh)
+    {
+        mesh.Normals = Raylib.New<float>(3 * mesh.VertexCount);
+    }
+
+    /// <summary>Allocate mesh tangents</summary>
+    public static void AllocTangents(ref this Mesh mesh)
+    {
+        mesh.Tangents = Raylib.New<float>(4 * mesh.VertexCount);
+    }
+
+    /// <summary>Allocate mesh colors</summary>
+    public static void AllocColors(ref this Mesh mesh)
+    {
+        mesh.Colors = Raylib.New<byte>(4 * mesh.VertexCount);
+    }
+
+    /// <summary>Allocate mesh indices</summary>
+    public static void AllocIndices(ref this Mesh mesh)
+    {
+        mesh.Indices = Raylib.New<ushort>(3 * mesh.TriangleCount);
+    }
+
+    /// <summary>Access mesh vertices</summary>
+    public static Span<T> VerticesAs<T>(this Mesh mesh) where T : unmanaged
+    {
+        return new(mesh.Vertices, 3 * mesh.VertexCount * sizeof(float) / sizeof(T));
+    }
+
+    /// <summary>Access mesh texcoords</summary>
+    public static Span<T> TexcoordsAs<T>(this Mesh mesh) where T : unmanaged
+    {
+        return new(mesh.TexCoords, 2 * mesh.VertexCount * sizeof(float) / sizeof(T));
+    }
+
+    /// <summary>Access mesh texcoords2</summary>
+    public static Span<T> Texcoords2As<T>(this Mesh mesh) where T : unmanaged
+    {
+        return new(mesh.TexCoords2, 2 * mesh.VertexCount * sizeof(float) / sizeof(T));
+    }
+
+    /// <summary>Access mesh normals</summary>
+    public static Span<T> NormalsAs<T>(this Mesh mesh) where T : unmanaged
+    {
+        return new(mesh.Normals, 3 * mesh.VertexCount * sizeof(float) / sizeof(T));
+    }
+
+    /// <summary>Access mesh tangents</summary>
+    public static Span<T> TangentsAs<T>(this Mesh mesh) where T : unmanaged
+    {
+        return new(mesh.Tangents, 4 * mesh.VertexCount * sizeof(float) / sizeof(T));
+    }
+
+    /// <summary>Access mesh colors</summary>
+    public static Span<T> ColorsAs<T>(this Mesh mesh) where T : unmanaged
+    {
+        return new(mesh.Colors, 4 * mesh.VertexCount * sizeof(byte) / sizeof(T));
+    }
+
+    /// <summary>Access mesh indices</summary>
+    public static Span<T> IndicesAs<T>(this Mesh mesh) where T : unmanaged
+    {
+        return new(mesh.Indices, 3 * mesh.TriangleCount * sizeof(ushort) / sizeof(T));
+    }
+}
diff --git a/Raylib-cs/types/Raylib.Utils.cs b/Raylib-cs/types/Raylib.Utils.cs
index 96b4cdc..98b9526 100644
--- a/Raylib-cs/types/Raylib.Utils.cs
+++ b/Raylib-cs/types/Raylib.Utils.cs
@@ -222,6 +222,12 @@ public static unsafe partial class Raylib
         }
     }
 
+    /// <summary>C++ style memory allocator</summary>
+    public static T* New<T>(int count) where T : unmanaged
+    {
+        return (T*)MemAlloc(count * sizeof(T));
+    }
+
     /// <summary>Load file data as byte array (read)</summary>
     public static byte* LoadFileData(string fileName, ref uint bytesRead)
     {