From 00036950d68896b50df6ca9d7079a646278f7119 Mon Sep 17 00:00:00 2001
From: Patedam <pgillen.pro@gmail.com>
Date: Sun, 2 Aug 2026 19:33:20 -0400
Subject: [PATCH] Converted d3d12 buffers to arena. Using linked list as i'm
 not sure how many buffers i will use total

---
 Juliet/src/Graphics/D3D12/D3D12Buffer.cpp | 29 +++++++++++++++++++----
 Juliet/src/Graphics/D3D12/D3D12Buffer.h   |  7 ++++--
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/Juliet/src/Graphics/D3D12/D3D12Buffer.cpp b/Juliet/src/Graphics/D3D12/D3D12Buffer.cpp
index bd0c077..a6a604a 100644
--- a/Juliet/src/Graphics/D3D12/D3D12Buffer.cpp
+++ b/Juliet/src/Graphics/D3D12/D3D12Buffer.cpp
@@ -1,17 +1,19 @@
-#include <Core/Memory/Allocator.h>
 #include <Graphics/D3D12/D3D12Buffer.h>
 
 #include <Core/Logging/LogManager.h>
 #include <Core/Logging/LogTypes.h>
+#include <Core/Memory/Allocator.h>
 #include <Graphics/D3D12/D3D12CommandList.h>
 #include <Graphics/D3D12/D3D12DescriptorHeap.h>
 #include <Graphics/D3D12/D3D12GraphicsDevice.h>
-#include <Graphics/D3D12/D3D12Utils.h>
 
 namespace Juliet::D3D12
 {
     namespace
     {
+        // Linked List of free buffers
+        D3D12Buffer* FreeBuffers = nullptr;
+
         enum class D3D12BufferType : uint8
         {
             Base,
@@ -53,18 +55,36 @@ namespace Juliet::D3D12
             {
                 Internal::ReleaseDescriptor(buffer->Descriptor);
             }
+            buffer->Descriptor = {};
 
             if (buffer->Handle)
             {
                 buffer->Handle->Release();
+                buffer->Handle = nullptr;
             }
-            Free(buffer);
+            buffer->CurrentState = D3D12_RESOURCE_STATE_COMMON;
+            buffer->Size         = 0;
+
+            buffer->Next = FreeBuffers;
+            FreeBuffers  = buffer;
         }
 
         D3D12Buffer* CreateBuffer(NonNullPtr<D3D12Driver> d3d12Driver, size_t size, size_t stride, BufferUsage usage,
                                   D3D12BufferType type, bool isDynamic)
         {
-            auto* buffer = static_cast<D3D12Buffer*>(Calloc(1, sizeof(D3D12Buffer)));
+            D3D12Buffer* buffer = nullptr;
+            if (FreeBuffers)
+            {
+                buffer      = FreeBuffers;
+                FreeBuffers = buffer->Next;
+                buffer->Next = nullptr;
+            }
+
+            if (!buffer)
+            {
+                buffer = ArenaPushStruct<D3D12Buffer>(d3d12Driver->DriverArena JULIET_DEBUG_PARAM("D3D12Buffer"));
+            }
+
             if (!buffer)
             {
                 return nullptr;
@@ -243,6 +263,7 @@ namespace Juliet::D3D12
     {
         auto  d3d12Buffer = reinterpret_cast<D3D12Buffer*>(buffer.Get());
         void* ptr         = nullptr;
+
         // 0-0 range means we don't intend to read anything.
         D3D12_RANGE readRange = { 0, 0 };
         if (FAILED(d3d12Buffer->Handle->Map(0, &readRange, &ptr)))
diff --git a/Juliet/src/Graphics/D3D12/D3D12Buffer.h b/Juliet/src/Graphics/D3D12/D3D12Buffer.h
index af99f0b..d179b2b 100644
--- a/Juliet/src/Graphics/D3D12/D3D12Buffer.h
+++ b/Juliet/src/Graphics/D3D12/D3D12Buffer.h
@@ -4,7 +4,6 @@
 #include <Graphics/D3D12/D3D12DescriptorHeap.h>
 #include <Graphics/GraphicsBuffer.h>
 
-
 namespace Juliet
 {
     struct CommandList;
@@ -14,10 +13,14 @@ namespace Juliet::D3D12
 {
     struct D3D12Buffer
     {
+        // Note: This three variables need to stay at the top and in this order
         Internal::D3D12Descriptor Descriptor;
         ID3D12Resource*           Handle;
         D3D12_RESOURCE_STATES     CurrentState;
-        size_t                    Size;
+
+        // Anything here can be any order
+        D3D12Buffer* Next;
+        size_t       Size;
     };
 
     extern GraphicsBuffer* CreateGraphicsBuffer(NonNullPtr<GPUDriver> driver, size_t size, size_t stride,