Add a null graphics system (enable with --gpu=null)

Still uses vulkan to drive xenia UI, may look into decoupling later.

premake5.lua

@@ -183,6 +183,7 @@ solution("xenia")
   include("src/xenia/cpu/backend/x64")
   include("src/xenia/debug/ui")
   include("src/xenia/gpu")
+  include("src/xenia/gpu/null")
   include("src/xenia/gpu/gl4")
   include("src/xenia/gpu/vulkan")
   include("src/xenia/hid")

src/xenia/app/xenia_main.cc

@@ -27,6 +27,7 @@
 
 // Available graphics systems:
 #include "xenia/gpu/gl4/gl4_graphics_system.h"
+#include "xenia/gpu/null/null_graphics_system.h"
 #include "xenia/gpu/vulkan/vulkan_graphics_system.h"
 
 // Available input drivers:
@@ -37,7 +38,7 @@
 #endif  // XE_PLATFORM_WIN32
 
 DEFINE_string(apu, "any", "Audio system. Use: [any, nop, xaudio2]");
-DEFINE_string(gpu, "any", "Graphics system. Use: [any, gl4, vulkan]");
+DEFINE_string(gpu, "any", "Graphics system. Use: [any, gl4, vulkan, null]");
 DEFINE_string(hid, "any", "Input system. Use: [any, nop, winkey, xinput]");
 
 DEFINE_string(target, "", "Specifies the target .xex or .iso to execute.");
@@ -75,6 +76,9 @@ std::unique_ptr<gpu::GraphicsSystem> CreateGraphicsSystem() {
   } else if (FLAGS_gpu.compare("vulkan") == 0) {
     return std::unique_ptr<gpu::GraphicsSystem>(
         new xe::gpu::vulkan::VulkanGraphicsSystem());
+  } else if (FLAGS_gpu.compare("null") == 0) {
+    return std::unique_ptr<gpu::GraphicsSystem>(
+        new xe::gpu::null::NullGraphicsSystem());
   } else {
     // Create best available.
     std::unique_ptr<gpu::GraphicsSystem> best;

src/xenia/gpu/null/null_command_processor.cc

@@ -0,0 +1,50 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2016 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#include "xenia/gpu/null/null_command_processor.h"
+
+namespace xe {
+namespace gpu {
+namespace null {
+
+NullCommandProcessor::NullCommandProcessor(NullGraphicsSystem* graphics_system,
+                                           kernel::KernelState* kernel_state)
+    : CommandProcessor(graphics_system, kernel_state) {}
+NullCommandProcessor::~NullCommandProcessor() = default;
+
+bool NullCommandProcessor::SetupContext() {
+  return CommandProcessor::SetupContext();
+}
+
+void NullCommandProcessor::ShutdownContext() {
+  return CommandProcessor::ShutdownContext();
+}
+
+void NullCommandProcessor::PerformSwap(uint32_t frontbuffer_ptr,
+                                       uint32_t frontbuffer_width,
+                                       uint32_t frontbuffer_height) {}
+
+Shader* NullCommandProcessor::LoadShader(ShaderType shader_type,
+                                         uint32_t guest_address,
+                                         const uint32_t* host_address,
+                                         uint32_t dword_count) {
+  return nullptr;
+}
+
+bool NullCommandProcessor::IssueDraw(PrimitiveType prim_type,
+                                     uint32_t index_count,
+                                     IndexBufferInfo* index_buffer_info) {
+  return true;
+}
+
+bool NullCommandProcessor::IssueCopy() { return true; }
+
+}  // namespace null
+}  // namespace gpu
+}  // namespace xe

src/xenia/gpu/null/null_command_processor.h

@@ -0,0 +1,48 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2016 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#ifndef XENIA_GPU_NULL_NULL_COMMAND_PROCESSOR_H_
+#define XENIA_GPU_NULL_NULL_COMMAND_PROCESSOR_H_
+
+#include "xenia/gpu/command_processor.h"
+#include "xenia/gpu/null/null_graphics_system.h"
+#include "xenia/gpu/xenos.h"
+#include "xenia/kernel/kernel_state.h"
+
+namespace xe {
+namespace gpu {
+namespace null {
+
+class NullCommandProcessor : public CommandProcessor {
+ public:
+  NullCommandProcessor(NullGraphicsSystem* graphics_system,
+                       kernel::KernelState* kernel_state);
+  ~NullCommandProcessor();
+
+ private:
+  bool SetupContext() override;
+  void ShutdownContext() override;
+
+  void PerformSwap(uint32_t frontbuffer_ptr, uint32_t frontbuffer_width,
+                   uint32_t frontbuffer_height) override;
+
+  Shader* LoadShader(ShaderType shader_type, uint32_t guest_address,
+                     const uint32_t* host_address,
+                     uint32_t dword_count) override;
+
+  bool IssueDraw(PrimitiveType prim_type, uint32_t index_count,
+                 IndexBufferInfo* index_buffer_info) override;
+  bool IssueCopy() override;
+};
+
+}  // namespace null
+}  // namespace gpu
+}  // namespace xe
+
+#endif  // XENIA_GPU_NULL_NULL_COMMAND_PROCESSOR_H_

src/xenia/gpu/null/null_graphics_system.cc

@@ -0,0 +1,53 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2016 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#include "xenia/gpu/null/null_graphics_system.h"
+
+#include "xenia/gpu/null//null_command_processor.h"
+#include "xenia/ui/vulkan/vulkan_provider.h"
+#include "xenia/xbox.h"
+
+namespace xe {
+namespace gpu {
+namespace null {
+
+NullGraphicsSystem::NullGraphicsSystem() {}
+
+NullGraphicsSystem::~NullGraphicsSystem() {}
+
+X_STATUS NullGraphicsSystem::Setup(cpu::Processor* processor,
+                                   kernel::KernelState* kernel_state,
+                                   ui::Window* target_window) {
+  // This is a null graphics system, but we still setup vulkan because UI needs
+  // it through us :|
+  provider_ = xe::ui::vulkan::VulkanProvider::Create(target_window);
+
+  return GraphicsSystem::Setup(processor, kernel_state, target_window);
+}
+
+void NullGraphicsSystem::Shutdown() { GraphicsSystem::Shutdown(); }
+
+std::unique_ptr<CommandProcessor> NullGraphicsSystem::CreateCommandProcessor() {
+  return std::unique_ptr<CommandProcessor>(
+      new NullCommandProcessor(this, kernel_state_));
+}
+
+void NullGraphicsSystem::Swap(xe::ui::UIEvent* e) {
+  if (!command_processor_) {
+    return;
+  }
+
+  auto& swap_state = command_processor_->swap_state();
+  std::lock_guard<std::mutex> lock(swap_state.mutex);
+  swap_state.pending = false;
+}
+
+}  // namespace null
+}  // namespace gpu
+}  // namespace xe

src/xenia/gpu/null/null_graphics_system.h

@@ -0,0 +1,41 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2016 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#ifndef XENIA_GPU_NULL_NULL_GRAPHICS_SYSTEM_H_
+#define XENIA_GPU_NULL_NULL_GRAPHICS_SYSTEM_H_
+
+#include <memory>
+
+#include "xenia/gpu/graphics_system.h"
+#include "xenia/gpu/command_processor.h"
+
+namespace xe {
+namespace gpu {
+namespace null {
+
+class NullGraphicsSystem : public GraphicsSystem {
+ public:
+  NullGraphicsSystem();
+  ~NullGraphicsSystem() override;
+
+  X_STATUS Setup(cpu::Processor* processor, kernel::KernelState* kernel_state,
+                 ui::Window* target_window) override;
+  void Shutdown() override;
+
+ private:
+  std::unique_ptr<CommandProcessor> CreateCommandProcessor() override;
+
+  void Swap(xe::ui::UIEvent* e) override;
+};
+
+}  // namespace null
+}  // namespace gpu
+}  // namespace xe
+
+#endif  // XENIA_GPU_NULL_NULL_GRAPHICS_SYSTEM_H_

src/xenia/gpu/null/premake5.lua

@@ -0,0 +1,21 @@
+project_root = "../../../.."
+include(project_root.."/tools/build")
+
+group("src")
+project("xenia-gpu-null")
+  uuid("42FCA0B3-4C20-4532-95E9-07D297013BE4")
+  kind("StaticLib")
+  language("C++")
+  links({
+    "xenia-base",
+    "xenia-gpu",
+    "xenia-ui",
+    "xenia-ui-vulkan",
+    "xxhash",
+  })
+  defines({
+  })
+  includedirs({
+    project_root.."/third_party/gflags/src",
+  })
+  local_platform_files()