failed trying to procedurally generate a cube sphere

Nebulix/Nebulix.csproj

@@ -7,7 +7,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Silk.NET.Input" Version="2.17.1" />
+    <PackageReference Include="Silk.NET.Input" Version="2.20.0" />
   </ItemGroup>
 
 </Project>

src/ArrayExtensions.cs

@@ -0,0 +1,19 @@
+namespace Engine_silk.NET
+{
+	public static class ArrayExtensions
+	{
+		/// <summary>
+		/// Copies the given arrays to the start of this array. The order of <paramref name="arrays"/> is preserved
+		/// </summary>
+		/// <param name="arrays">The arrays copied into this array</param>
+		public static void CopyFrom(this Array array, params Array[] arrays)
+		{
+			int lastIndex = 0;
+			for (int i = 0; i < arrays.Length; i++)
+			{
+				arrays[i].CopyTo(array, lastIndex);
+				lastIndex += arrays[i].Length;
+			}
+		}
+	}
+}

src/Engine_silk.NET.csproj

@@ -2,16 +2,16 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Silk.NET.Input" Version="2.17.1" />
-    <PackageReference Include="Silk.NET.OpenGL" Version="2.17.1" />
-    <PackageReference Include="Silk.NET.Windowing" Version="2.17.1" />
+    <PackageReference Include="Silk.NET.Input" Version="2.20.0" />
+    <PackageReference Include="Silk.NET.OpenGL" Version="2.20.0" />
+    <PackageReference Include="Silk.NET.Windowing" Version="2.20.0" />
     <PackageReference Include="StbImageSharp" Version="2.27.13" />
   </ItemGroup>
 

src/Program.cs

@@ -140,7 +140,7 @@ public static class Program
 
 		_vbo = _gl.GenBuffer();
 		_gl.BindBuffer(BufferTargetARB.ArrayBuffer, _vbo);
-		_gl.BufferData(BufferTargetARB.ArrayBuffer, (nuint)(vertices.Length * sizeof(float)), verticesData, BufferUsageARB.StaticDraw);
+		_gl.BufferData(BufferTargetARB.ArrayBuffer, (nuint)(verticesData.Length * sizeof(float)), verticesData, BufferUsageARB.StaticDraw);
 
 		//_ebo = _gl.GenBuffer();
 		//_gl.BindBuffer(BufferTargetARB.ElementArrayBuffer, _ebo);
@@ -157,6 +157,9 @@ public static class Program
 		_gl.VertexAttribPointer(2, 2, VertexAttribPointerType.Float, false, 8 * sizeof(float), (void*)(6 * sizeof(float)));
 
 		_texture = new Texture2D(_gl, "images/container.png", ImageFormat.RGBA);
+
+		Sphere s = new(_gl, 1, 10);
+		s.GetVertices();
 	}
 
 	private static void OnUpdate(double deltaTime)

src/Sphere.cs

@@ -0,0 +1,122 @@
+using Silk.NET.Maths;
+using Silk.NET.OpenGL;
+
+namespace Engine_silk.NET
+{
+	// TODO: Think about just creating a cube with a certain resolution and then use this cube to generate the Sphere.
+	// also maybe make an ISphere and call this class "CubeSphere"?
+	public class Sphere(GL gl, float radius, uint resolution)
+	{
+		public void CreateSphere()
+		{
+			uint _vao, _vbo, _ebo;
+
+			_vao = gl.CreateVertexArray();
+			gl.BindVertexArray(_vao);
+
+			ReadOnlySpan<float> verticesData = GetVertices();
+
+			_vbo = gl.GenBuffer();
+			gl.BindBuffer(BufferTargetARB.ArrayBuffer, _vbo);
+			gl.BufferData(BufferTargetARB.ArrayBuffer, (nuint)(verticesData.Length * sizeof(float)), verticesData, BufferUsageARB.StaticDraw);
+
+		}
+
+		public void RenderSphere()
+		{
+
+		}
+
+		// TODO: make this private after testing
+		public ReadOnlySpan<float> GetVertices()
+		{
+			var front = GetSide(Vector3D<float>.UnitZ).Item1;
+			var back = GetSide(-Vector3D<float>.UnitZ).Item1;
+			var up = GetSide(Vector3D<float>.UnitY).Item1;
+			var down = GetSide(-Vector3D<float>.UnitY).Item1;
+			var left = GetSide(Vector3D<float>.UnitX).Item1;
+			var right = GetSide(-Vector3D<float>.UnitX).Item1;
+
+			var finalArray = new float[front.Length + back.Length + up.Length + down.Length + left.Length + right.Length];
+			finalArray.CopyFrom(front, back, up, down, left, right);
+
+			return new ReadOnlySpan<float>(finalArray);
+		}
+
+		/// <param name="normal">The unit vector in which the side should point. E.g. Vector.Up</param>
+		private (float[], float[]) GetSide(Vector3D<float> normal)
+		{
+			//float upperBound = radius, lowerBound = -radius;
+			float stepSize = 2f / resolution;
+
+			List<float> vertices = new((int)(3 * resolution * resolution * 2)); // resolution * resolution == number of rows/columns; 3 * ... == each vertex has 3 positions; 2 * ... == vertex also needs normal
+
+			Vector3D<float> position = normal;
+			for (int row = 0; row <= resolution; row++)
+			{
+				for (int col = 0; col <= resolution; col++)
+				{
+					if (normal.X != 0)
+					{
+						position.Y = row * stepSize - 1;
+						position.Z = col * stepSize - 1;
+					}
+					else if (normal.Y != 0)
+					{
+						position.X = row * stepSize - 1;
+						position.Z = col * stepSize - 1;
+					}
+					else if (normal.Z != 0)
+					{
+						position.X = row * stepSize - 1;
+						position.Y = col * stepSize - 1;
+					}
+                    vertices.AddRange([position.X, position.Y, position.Z, normal.X, normal.Y, normal.Z]);
+				}
+			}
+
+			List<uint> indices = new((int)(resolution * resolution * 6)); // ... * 6 == one quad has 6 indices and we have resolution * resolution quads
+            Console.WriteLine($"Indices size before Loop: {indices.Capacity}");
+
+			uint vi = 0; // vertexIndex
+            for (uint i = 0; i < vertices.Count; i += 6)
+            {
+				if ((vi + 1) % resolution == 0)
+				{
+					vi++;
+					continue;
+				}
+
+				indices.AddRange([vi, vi+1, vi+1+resolution, 
+								  vi, vi+1+resolution, vi+resolution]);
+				vi++;
+            }
+
+            Console.WriteLine($"Indices size after Loop: {indices.Count}");
+
+            return (vertices.ToArray(), []);
+		}
+
+		// top left origin, stepsizeX, stepsizeY (maybe index of first vertex?)
+		// https://youtu.be/QN39W020LqU?si=a66D1Lnic1vNaC6l&t=89
+		private Face Quad(uint resolution, uint row, uint column)
+		{
+			// TODO: change coordinates according to the direction the quad should be looking
+			// https://catlikecoding.com/unity/tutorials/procedural-meshes/cube-sphere/
+			float[] vertices = [
+				 1.0f,  1.0f, 0.0f,  // top right
+				 1.0f, -1.0f, 0.0f,  // bottom right
+				-1.0f, -1.0f, 0.0f,  // bottom left
+				-1.0f,  1.0f, 0.0f   // top left 
+			];
+			uint[] indices = [
+				0, 1, 3,   // first triangle
+				1, 2, 3    // second triangle
+			];
+
+			return new Face(vertices, indices);
+		}
+	}
+
+	internal record struct Face(float[] Vertices, uint[] Indices);
+}