From 9992ba1a79a2302e7ce2499c1b157ad552bd395d Mon Sep 17 00:00:00 2001
From: Philip Rebohle <philip.rebohle@tu-dortmund.de>
Date: Thu, 30 Aug 2018 15:14:26 +0200
Subject: [PATCH] [d3d11] Add more general counter buffer allocator

We're going to need it for more than just UAV counters soon.
---
 src/d3d11/d3d11_counter_buffer.cpp | 52 ++++++++++++++++++++++++
 src/d3d11/d3d11_counter_buffer.h   | 63 ++++++++++++++++++++++++++++++
 src/d3d11/meson.build              |  1 +
 3 files changed, 116 insertions(+)
 create mode 100644 src/d3d11/d3d11_counter_buffer.cpp
 create mode 100644 src/d3d11/d3d11_counter_buffer.h

diff --git a/src/d3d11/d3d11_counter_buffer.cpp b/src/d3d11/d3d11_counter_buffer.cpp
new file mode 100644
index 000000000..84a359c1a
--- /dev/null
+++ b/src/d3d11/d3d11_counter_buffer.cpp
@@ -0,0 +1,52 @@
+#include "d3d11_counter_buffer.h"
+#include "d3d11_device.h"
+
+namespace dxvk {
+
+  D3D11CounterBuffer::D3D11CounterBuffer(
+    const Rc<DxvkDevice>&       Device,
+    const DxvkBufferCreateInfo& BufferInfo,
+          VkDeviceSize          SliceLength)
+  : m_device      (Device),
+    m_bufferInfo  (BufferInfo),
+    m_sliceLength (SliceLength) {
+    
+  }
+  
+
+  D3D11CounterBuffer::~D3D11CounterBuffer() {
+
+  }
+
+
+  DxvkBufferSlice D3D11CounterBuffer::AllocSlice() {
+    std::lock_guard<std::mutex> lock(m_mutex);
+
+    if (m_freeSlices.size() == 0)
+      CreateBuffer();
+    
+    DxvkBufferSlice slice = m_freeSlices.back();
+    m_freeSlices.pop_back();
+    return slice;
+  }
+
+
+  void D3D11CounterBuffer::FreeSlice(const DxvkBufferSlice& Slice) {
+    std::lock_guard<std::mutex> lock(m_mutex);
+    m_freeSlices.push_back(Slice);
+  }
+
+
+  void D3D11CounterBuffer::CreateBuffer() {
+    Rc<DxvkBuffer> buffer = m_device->createBuffer(
+      m_bufferInfo, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
+    
+    VkDeviceSize sliceCount = m_bufferInfo.size / m_sliceLength;
+    
+    for (uint32_t i = 0; i < sliceCount; i++) {
+      m_freeSlices.push_back(DxvkBufferSlice(
+        buffer, m_sliceLength * i, m_sliceLength));
+    }
+  }
+
+}
\ No newline at end of file
diff --git a/src/d3d11/d3d11_counter_buffer.h b/src/d3d11/d3d11_counter_buffer.h
new file mode 100644
index 000000000..d22df1dfe
--- /dev/null
+++ b/src/d3d11/d3d11_counter_buffer.h
@@ -0,0 +1,63 @@
+#pragma once
+
+#include "d3d11_include.h"
+
+#include "../dxvk/dxvk_buffer.h"
+#include "../dxvk/dxvk_device.h"
+
+namespace dxvk {
+
+  class D3D11Device;
+
+  /**
+   * \brief D3D11 UAV counter slice allocator
+   * 
+   * Thread safe allocator for buffer slices of
+   * the same size, which are typically used to
+   * store counters (such as UAV counters).
+   */
+  class D3D11CounterBuffer : public RcObject {
+
+  public:
+
+    D3D11CounterBuffer(
+      const Rc<DxvkDevice>&       Device,
+      const DxvkBufferCreateInfo& BufferInfo,
+            VkDeviceSize          SliceLength);
+    
+    ~D3D11CounterBuffer();
+
+    /**
+     * \brief Allocates a counter slice
+     * 
+     * Picks a slice from the free list or
+     * creates a new buffer if necessary.
+     * \returns The counter slice
+     */
+    DxvkBufferSlice AllocSlice();
+
+    /**
+     * \brief Frees a counter slice
+     * 
+     * Adds the given slice back to the
+     * free list so that it can be reused.
+     * \param [in] Slice the slice to free
+     */
+    void FreeSlice(
+      const DxvkBufferSlice&      Slice);
+
+  private:
+
+    Rc<DxvkDevice>                m_device;
+
+    DxvkBufferCreateInfo          m_bufferInfo;
+    VkDeviceSize                  m_sliceLength;
+
+    std::mutex                    m_mutex;
+    std::vector<DxvkBufferSlice>  m_freeSlices;
+
+    void CreateBuffer();
+
+  };
+
+}
\ No newline at end of file
diff --git a/src/d3d11/meson.build b/src/d3d11/meson.build
index 4ce774444..f70815b00 100644
--- a/src/d3d11/meson.build
+++ b/src/d3d11/meson.build
@@ -23,6 +23,7 @@ d3d11_src = [
   'd3d11_context.cpp',
   'd3d11_context_def.cpp',
   'd3d11_context_imm.cpp',
+  'd3d11_counter_buffer.cpp',
   'd3d11_depth_stencil.cpp',
   'd3d11_device.cpp',
   'd3d11_enums.cpp',