Refactor GPU resource management and rendering pipeline

- Introduced `Handle<T>` and `Identifier<T>` for lightweight, strongly-typed resource identifiers.
- Replaced `BitSet` with `UnsafeBitSet` for improved performance and memory safety.
- Refactored `Mesh` and `Material` into `MeshClass` and `MaterialClass` for better GPU resource handling.
- Added `D3D12ResourceDatabase` to centralize GPU resource tracking and lifecycle management.
- Updated `D3D12ShaderCompiler` to load shaders from disk and dynamically populate constant buffers and textures.
- Enhanced `ICommandBuffer` with new upload operations for buffers and textures.
- Refactored `Vertex` struct for simplified memory layout and better performance.
- Updated `MeshBuilder` and rendering logic to align with new resource and shader structures.
- Added `BindlessDescriptor` support to `TextureHandle` and `BufferHandle`.
- Removed unused classes and performed general cleanup.
- Updated unit tests and demos to reflect the new architecture.

Ghost.Graphics/RHI/ICommandBuffer.cs

@@ -1,4 +1,7 @@
+using Ghost.Graphics.D3D12;
 using Ghost.Graphics.Data;
+using Misaki.HighPerformance.LowLevel.Utilities;
+using System.Drawing;
 
 namespace Ghost.Graphics.RHI;
 
@@ -7,6 +10,11 @@ namespace Ghost.Graphics.RHI;
 /// </summary>
 public interface ICommandBuffer : IDisposable
 {
+    public CommandBufferType Type
+    {
+        get;
+    }
+
     /// <summary>
     /// Begins recording commands into this command buffer
     /// </summary>
@@ -22,7 +30,7 @@ public interface ICommandBuffer : IDisposable
     /// </summary>
     /// <param name="renderTarget">Render target to render into</param>
     /// <param name="clearColor">Color to clear the render target with</param>
-    public void BeginRenderPass(IRenderTarget renderTarget, Color16 clearColor);
+    public void BeginRenderPass(IRenderTarget renderTarget, Color128 clearColor);
 
     /// <summary>
     /// Ends the current render pass
@@ -66,7 +74,7 @@ public interface ICommandBuffer : IDisposable
     /// </summary>
     /// <param name="mesh">The mesh to be drawn. Must not be null.</param>
     /// <param name="material">The material to use for rendering the mesh. Must not be null.</param>
-    public void DrawMesh(Mesh mesh, Material material);
+    public void DrawMesh(MeshClass mesh, MaterialClass material);
 
     /// <summary>
     /// Dispatches compute threads
@@ -75,6 +83,26 @@ public interface ICommandBuffer : IDisposable
     /// <param name="threadGroupCountY">Thread groups in Y dimension</param>
     /// <param name="threadGroupCountZ">Thread groups in Z dimension</param>
     public void Dispatch(uint threadGroupCountX, uint threadGroupCountY = 1, uint threadGroupCountZ = 1);
+
+    /// <summary>
+    /// Uploads the specified data to the buffer represented by the given handle.
+    /// </summary>
+    /// <typeparam name="T">The unmanaged value type of the elements to upload to the buffer.</typeparam>
+    /// <param name="buffer">A handle to the buffer that will receive the uploaded data.</param>
+    /// <param name="data">A read-only span containing the data to upload to the buffer. The span must contain elements of type
+    /// <typeparamref name="T"/>.</param>
+    public void Upload<T>(BufferHandle buffer, ReadOnlySpan<T> data)
+        where T : unmanaged;
+
+    /// <summary>
+    /// Uploads texture data to the specified texture resource starting at the given subresource index.
+    /// </summary>
+    /// <param name="texture">The texture resource to which the subresource data will be uploaded. Must be a valid, initialized texture handle.</param>
+    /// <param name="firstSubresource">The index of the first subresource in the texture to receive data. Must be less than the total number of subresources in the texture.</param>
+    /// <param name="subresources">A reference to the structure containing the subresource data to upload. The data must match the format and layout expected by the texture.</param>
+    /// <param name="numSubresources">The number of subresources to upload, starting from <paramref name="firstSubresource"/>.
+    /// Must be greater than zero and not exceed the remaining subresources in the texture.</param>
+    public void Upload(TextureHandle texture, uint firstSubresource, ref SubResourceData subresources, uint numSubresources);
 }
 
 /// <summary>
@@ -82,21 +110,21 @@ public interface ICommandBuffer : IDisposable
 /// </summary>
 public struct ViewportDesc
 {
-    public float X;
-    public float Y;
-    public float Width;
-    public float Height;
-    public float MinDepth;
-    public float MaxDepth;
+    public float x;
+    public float y;
+    public float width;
+    public float height;
+    public float minDepth;
+    public float maxDepth;
 
     public ViewportDesc(float width, float height)
     {
-        X = 0;
-        Y = 0;
-        Width = width;
-        Height = height;
-        MinDepth = 0.0f;
-        MaxDepth = 1.0f;
+        x = 0;
+        y = 0;
+        this.width = width;
+        this.height = height;
+        minDepth = 0.0f;
+        maxDepth = 1.0f;
     }
 }
 
@@ -122,17 +150,28 @@ public struct RectDesc
 /// <summary>
 /// Resource states
 /// </summary>
+[Flags]
 public enum ResourceState
 {
     Common = 0,
-    VertexAndConstantBuffer = 0x1,
-    IndexBuffer = 0x2,
-    RenderTarget = 0x4,
-    UnorderedAccess = 0x8,
-    DepthWrite = 0x10,
-    DepthRead = 0x20,
-    PixelShaderResource = 0x80,
-    CopyDest = 0x400,
-    CopySource = 0x800,
+    VertexAndConstantBuffer = 1 << 0,
+    IndexBuffer = 1 << 1,
+    RenderTarget = 1 << 2,
+    UnorderedAccess = 1 << 3,
+    DepthWrite = 1 << 4,
+    DepthRead = 1 << 5,
+    PixelShaderResource = 1 << 6,
+    CopyDest = 1 << 7,
+    CopySource = 1 << 8,
+    GenericRead = 1 << 9,
+    IndirectArgument = 1 << 10,
     Present = 0,
 }
+
+
+public struct SubResourceData
+{
+    public unsafe void* pData;
+    public nint rowPitch;
+    public nint slicePitch;
+}