diff --git a/build/android/app/CMakeLists.txt b/build/android/app/CMakeLists.txt
index 129ee62..e10cd65 100644
--- a/build/android/app/CMakeLists.txt
+++ b/build/android/app/CMakeLists.txt
@@ -74,7 +74,6 @@ add_library(kaliber SHARED
     ../../../src/engine/platform/asset_file_android.cc
     ../../../src/engine/platform/asset_file.cc
     ../../../src/engine/platform/platform_android.cc
-    ../../../src/engine/platform/platform.cc
     ../../../src/engine/renderer/geometry.cc
     ../../../src/engine/renderer/opengl/render_command.cc
     ../../../src/engine/renderer/opengl/renderer_opengl_android.cc
diff --git a/build/linux/Makefile b/build/linux/Makefile
index 022be5a..8da112c 100644
--- a/build/linux/Makefile
+++ b/build/linux/Makefile
@@ -106,7 +106,6 @@ ENGINE_SRC := \
   $(SRC_ROOT)/engine/persistent_data.cc \
   $(SRC_ROOT)/engine/platform/asset_file_linux.cc \
   $(SRC_ROOT)/engine/platform/asset_file.cc \
-  $(SRC_ROOT)/engine/platform/platform.cc \
   $(SRC_ROOT)/engine/platform/platform_linux.cc \
   $(SRC_ROOT)/engine/renderer/geometry.cc \
   $(SRC_ROOT)/engine/renderer/opengl/render_command.cc \
diff --git a/src/demo/credits.cc b/src/demo/credits.cc
index 898903a..fe721ee 100644
--- a/src/demo/credits.cc
+++ b/src/demo/credits.cc
@@ -95,7 +95,7 @@ void Credits::Show() {
 void Credits::Hide() {
   text_animator_.SetEndCallback(Animator::kBlending, [&]() -> void {
     for (int i = 0; i < kNumLines; ++i)
-      text_[i].Destory();
+      text_[i].Destroy();
     text_animator_.SetEndCallback(Animator::kBlending, nullptr);
     text_animator_.SetVisible(false);
   });
diff --git a/src/engine/engine.cc b/src/engine/engine.cc
index 7a6de43..f14cf21 100644
--- a/src/engine/engine.cc
+++ b/src/engine/engine.cc
@@ -1,6 +1,7 @@
 #include "engine/engine.h"
 
 #include "base/log.h"
+#include "base/task_runner.h"
 #include "engine/animator.h"
 #include "engine/audio/audio_mixer.h"
 #include "engine/drawable.h"
@@ -13,36 +14,52 @@
 #include "engine/mesh.h"
 #include "engine/platform/platform.h"
 #include "engine/renderer/geometry.h"
+#include "engine/renderer/opengl/renderer_opengl.h"
 #include "engine/renderer/renderer.h"
 #include "engine/renderer/shader.h"
 #include "engine/renderer/texture.h"
+#include "engine/renderer/vulkan/renderer_vulkan.h"
 #include "engine/shader_source.h"
 #include "third_party/texture_compressor/texture_compressor.h"
 
+#define USE_VULKAN_RENDERER 1
+
 using namespace base;
 
 namespace eng {
 
+extern void KaliberMain(Platform* platform) {
+  TaskRunner::CreateThreadLocalTaskRunner();
+  Engine(platform).Run();
+}
+
 Engine* Engine::singleton = nullptr;
 
-Engine::Engine(Platform* platform, Renderer* renderer)
+Engine::Engine(Platform* platform)
     : platform_(platform),
-      renderer_(renderer),
-      audio_mixer_{std::make_unique<AudioMixer>()} {
+      audio_mixer_{std::make_unique<AudioMixer>()},
+      quad_{std::make_unique<Geometry>(nullptr)},
+      pass_through_shader_{std::make_unique<Shader>(nullptr)},
+      solid_shader_{std::make_unique<Shader>(nullptr)} {
   DCHECK(!singleton);
   singleton = this;
 
-  renderer_->SetContextLostCB(std::bind(&Engine::ContextLost, this));
-
-  quad_ = CreateRenderResource<Geometry>();
-  pass_through_shader_ = CreateRenderResource<Shader>();
-  solid_shader_ = CreateRenderResource<Shader>();
+  platform_->SetObserver(this);
 
   stats_ = std::make_unique<ImageQuad>();
 }
 
 Engine::~Engine() {
+  LOG << "Shutting down engine.";
+
+  game_.reset();
   stats_.reset();
+  textures_.clear();
+  shaders_.clear();
+  quad_.reset();
+  pass_through_shader_.reset();
+  solid_shader_.reset();
+  renderer_.reset();
   singleton = nullptr;
 }
 
@@ -50,7 +67,43 @@ Engine& Engine::Get() {
   return *singleton;
 }
 
-bool Engine::Initialize() {
+void Engine::Run() {
+  Initialize();
+
+  timer_.Reset();
+  float accumulator = 0.0;
+  float frame_frac = 0.0f;
+
+  for (;;) {
+    Draw(frame_frac);
+
+    // Accumulate time.
+    timer_.Update();
+    accumulator += timer_.GetSecondsPassed();
+
+    // Subdivide the frame time using fixed time steps.
+    while (accumulator >= time_step_) {
+      TaskRunner::GetThreadLocalTaskRunner()->SingleConsumerRun();
+
+      platform_->Update();
+      Update(time_step_);
+
+      if (platform_->should_exit()) {
+        return;
+      }
+      accumulator -= time_step_;
+    };
+
+    // Calculate frame fraction from remainder of the frame time.
+    frame_frac = accumulator / time_step_;
+  }
+}
+
+void Engine::Initialize() {
+  thread_pool_.Initialize();
+
+  CreateRenderer(true);
+
   // Normalize viewport.
   if (GetScreenWidth() > GetScreenHeight()) {
     float aspect_ratio = (float)GetScreenWidth() / (float)GetScreenHeight();
@@ -66,37 +119,16 @@ bool Engine::Initialize() {
 
   LOG << "image scale factor: " << GetImageScaleFactor();
 
-  CreateTextureCompressors();
-
   system_font_ = std::make_unique<Font>();
   system_font_->Load("engine/RobotoMono-Regular.ttf");
 
-  if (!CreateRenderResources())
-    return false;
-
   SetImageSource("stats_tex", std::bind(&Engine::PrintStats, this));
   stats_->SetZOrder(std::numeric_limits<int>::max());
 
   game_ = GameFactoryBase::CreateGame("");
-  if (!game_) {
-    LOG << "No game found to run.";
-    return false;
-  }
+  CHECK(game_) << "No game found to run.";
 
-  if (!game_->Initialize()) {
-    LOG << "Failed to initialize the game.";
-    return false;
-  }
-
-  return true;
-}
-
-void Engine::Shutdown() {
-  LOG << "Shutting down engine.";
-  game_.reset();
-  stats_->Destory();
-  textures_.clear();
-  shaders_.clear();
+  CHECK(game_->Initialize()) << "Failed to initialize the game.";
 }
 
 void Engine::Update(float delta_time) {
@@ -137,20 +169,6 @@ void Engine::Draw(float frame_frac) {
   renderer_->Present();
 }
 
-void Engine::LostFocus() {
-  audio_mixer_->Suspend();
-
-  if (game_)
-    game_->LostFocus();
-}
-
-void Engine::GainedFocus(bool from_interstitial_ad) {
-  audio_mixer_->Resume();
-
-  if (game_)
-    game_->GainedFocus(from_interstitial_ad);
-}
-
 void Engine::AddDrawable(Drawable* drawable) {
   DCHECK(std::find(drawables_.begin(), drawables_.end(), drawable) ==
          drawables_.end());
@@ -179,25 +197,30 @@ void Engine::RemoveAnimator(Animator* animator) {
   }
 }
 
-void Engine::SwitchRenderer(bool vulkan) {
-  Renderer* new_renderer = platform_->SwitchRenderer(vulkan);
-  if (new_renderer == renderer_)
+void Engine::CreateRenderer(bool vulkan) {
+  if ((dynamic_cast<RendererVulkan*>(renderer_.get()) && vulkan) ||
+      (dynamic_cast<RendererOpenGL*>(renderer_.get()) && !vulkan))
     return;
 
-  renderer_ = new_renderer;
+  if (vulkan)
+    renderer_ = std::make_unique<RendererVulkan>();
+  else
+    renderer_ = std::make_unique<RendererOpenGL>();
   renderer_->SetContextLostCB(std::bind(&Engine::ContextLost, this));
+
+  bool result = InitializeRenderer();
+  LOG_IF(!result) << "Failed to initialize " << renderer_->GetDebugName()
+                  << " renderer.";
+  if (!result && vulkan) {
+    LOG << "Fallback to OpenGL renderer.";
+    renderer_ = std::make_unique<RendererOpenGL>();
+    renderer_->SetContextLostCB(std::bind(&Engine::ContextLost, this));
+    result = InitializeRenderer();
+  }
+  CHECK(result) << "Failed to initialize " << renderer_->GetDebugName()
+                << " renderer.";
+
   CreateTextureCompressors();
-
-  for (auto& t : textures_)
-    t.second.texture->SetRenderer(renderer_);
-
-  for (auto& s : shaders_)
-    s.second.shader->SetRenderer(renderer_);
-
-  quad_->SetRenderer(renderer_);
-  pass_through_shader_->SetRenderer(renderer_);
-  solid_shader_->SetRenderer(renderer_);
-
   ContextLost();
 }
 
@@ -323,40 +346,6 @@ void Engine::RemoveCustomShader(const std::string& asset_name) {
   shaders_.erase(it);
 }
 
-void Engine::AddInputEvent(std::unique_ptr<InputEvent> event) {
-  if (replaying_)
-    return;
-
-  switch (event->GetType()) {
-    case InputEvent::kDragEnd:
-      if (((GetScreenSize() / 2) * 0.9f - event->GetVector()).Length() <=
-          0.25f) {
-        SetSatsVisible(!stats_->IsVisible());
-        // TODO: Enqueue DragCancel so we can consume this event.
-      }
-      break;
-    case InputEvent::kKeyPress:
-      if (event->GetKeyPress() == 's') {
-        SetSatsVisible(!stats_->IsVisible());
-        // Consume event.
-        return;
-      }
-      break;
-    case InputEvent::kDrag:
-      if (stats_->IsVisible()) {
-        if ((stats_->GetPosition() - event->GetVector()).Length() <=
-            stats_->GetSize().y)
-          stats_->SetPosition(event->GetVector());
-        // TODO: Enqueue DragCancel so we can consume this event.
-      }
-      break;
-    default:
-      break;
-  }
-
-  input_queue_.push_back(std::move(event));
-}
-
 std::unique_ptr<InputEvent> Engine::GetNextInputEvent() {
   std::unique_ptr<InputEvent> event;
 
@@ -490,6 +479,81 @@ bool Engine::IsMobile() const {
   return platform_->mobile_device();
 }
 
+void Engine::OnWindowCreated() {
+  InitializeRenderer();
+}
+
+void Engine::OnWindowDestroyed() {
+  renderer_->Shutdown();
+}
+
+void Engine::OnWindowResized(int width, int height) {
+  if (width != renderer_->screen_width() ||
+      height != renderer_->screen_height()) {
+    renderer_->Shutdown();
+    InitializeRenderer();
+  }
+}
+
+void Engine::LostFocus() {
+  audio_mixer_->Suspend();
+
+  if (game_)
+    game_->LostFocus();
+}
+
+void Engine::GainedFocus(bool from_interstitial_ad) {
+  timer_.Reset();
+  audio_mixer_->Resume();
+
+  if (game_)
+    game_->GainedFocus(from_interstitial_ad);
+}
+
+void Engine::AddInputEvent(std::unique_ptr<InputEvent> event) {
+  if (replaying_)
+    return;
+
+  event->SetVector(ToPosition(event->GetVector()) * Vector2f(1, -1));
+
+  switch (event->GetType()) {
+    case InputEvent::kDragEnd:
+      if (((GetScreenSize() / 2) * 0.9f - event->GetVector()).Length() <=
+          0.25f) {
+        SetSatsVisible(!stats_->IsVisible());
+        // TODO: Enqueue DragCancel so we can consume this event.
+      }
+      break;
+    case InputEvent::kKeyPress:
+      if (event->GetKeyPress() == 's') {
+        SetSatsVisible(!stats_->IsVisible());
+        // Consume event.
+        return;
+      }
+      break;
+    case InputEvent::kDrag:
+      if (stats_->IsVisible()) {
+        if ((stats_->GetPosition() - event->GetVector()).Length() <=
+            stats_->GetSize().y)
+          stats_->SetPosition(event->GetVector());
+        // TODO: Enqueue DragCancel so we can consume this event.
+      }
+      break;
+    default:
+      break;
+  }
+
+  input_queue_.push_back(std::move(event));
+}
+
+bool Engine::InitializeRenderer() {
+#if defined(__ANDROID__)
+  return renderer_->Initialize(platform_->GetWindow());
+#elif defined(__linux__)
+  return renderer_->Initialize(platform_->GetDisplay(), platform_->GetWindow());
+#endif
+}
+
 void Engine::CreateTextureCompressors() {
   tex_comp_alpha_.reset();
   tex_comp_opaque_.reset();
@@ -513,24 +577,10 @@ void Engine::CreateTextureCompressors() {
 }
 
 void Engine::ContextLost() {
-  CreateRenderResources();
+  quad_->SetRenderer(renderer_.get());
+  pass_through_shader_->SetRenderer(renderer_.get());
+  solid_shader_->SetRenderer(renderer_.get());
 
-  for (auto& t : textures_) {
-    t.second.texture->Destroy();
-    RefreshImage(t.first);
-  }
-
-  for (auto& s : shaders_) {
-    auto source = std::make_unique<ShaderSource>();
-    if (source->Load(s.second.file_name))
-      s.second.shader->Create(std::move(source), quad_->vertex_description(),
-                              quad_->primitive(), false);
-  }
-
-  game_->ContextLost();
-}
-
-bool Engine::CreateRenderResources() {
   // This creates a normalized unit sized quad.
   static const char vertex_description[] = "p2f;t2f";
   static const float vertices[] = {
@@ -545,23 +595,37 @@ bool Engine::CreateRenderResources() {
 
   // Create the shader we can reuse for texture rendering.
   auto source = std::make_unique<ShaderSource>();
-  if (!source->Load("engine/pass_through.glsl")) {
+  if (source->Load("engine/pass_through.glsl")) {
+    pass_through_shader_->Create(std::move(source), quad_->vertex_description(),
+                                 quad_->primitive(), false);
+  } else {
     LOG << "Could not create pass through shader.";
-    return false;
   }
-  pass_through_shader_->Create(std::move(source), quad_->vertex_description(),
-                               quad_->primitive(), false);
 
   // Create the shader we can reuse for solid rendering.
   source = std::make_unique<ShaderSource>();
-  if (!source->Load("engine/solid.glsl")) {
+  if (source->Load("engine/solid.glsl")) {
+    solid_shader_->Create(std::move(source), quad_->vertex_description(),
+                          quad_->primitive(), false);
+  } else {
     LOG << "Could not create solid shader.";
-    return false;
   }
-  solid_shader_->Create(std::move(source), quad_->vertex_description(),
-                        quad_->primitive(), false);
 
-  return true;
+  for (auto& t : textures_) {
+    t.second.texture->SetRenderer(renderer_.get());
+    RefreshImage(t.first);
+  }
+
+  for (auto& s : shaders_) {
+    s.second.shader->SetRenderer(renderer_.get());
+    auto source = std::make_unique<ShaderSource>();
+    if (source->Load(s.second.file_name))
+      s.second.shader->Create(std::move(source), quad_->vertex_description(),
+                              quad_->primitive(), false);
+  }
+
+  if (game_)
+    game_->ContextLost();
 }
 
 void Engine::SetSatsVisible(bool visible) {
@@ -569,7 +633,7 @@ void Engine::SetSatsVisible(bool visible) {
   if (visible)
     stats_->Create("stats_tex");
   else
-    stats_->Destory();
+    stats_->Destroy();
 }
 
 std::unique_ptr<Image> Engine::PrintStats() {
diff --git a/src/engine/engine.h b/src/engine/engine.h
index 5bf42a1..3f9ec7b 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -8,8 +8,11 @@
 #include <unordered_map>
 
 #include "base/random.h"
+#include "base/thread_pool.h"
+#include "base/timer.h"
 #include "base/vecmath.h"
 #include "engine/persistent_data.h"
+#include "engine/platform/platform_observer.h"
 
 class TextureCompressor;
 
@@ -29,24 +32,16 @@ class Shader;
 class Texture;
 class Platform;
 
-class Engine {
+class Engine : public PlatformObserver {
  public:
   using CreateImageCB = std::function<std::unique_ptr<Image>()>;
 
-  Engine(Platform* platform, Renderer* renderer);
+  Engine(Platform* platform);
   ~Engine();
 
   static Engine& Get();
 
-  bool Initialize();
-
-  void Shutdown();
-
-  void Update(float delta_time);
-  void Draw(float frame_frac);
-
-  void LostFocus();
-  void GainedFocus(bool from_interstitial_ad);
+  void Run();
 
   void AddDrawable(Drawable* drawable);
   void RemoveDrawable(Drawable* drawable);
@@ -54,7 +49,7 @@ class Engine {
   void AddAnimator(Animator* animator);
   void RemoveAnimator(Animator* animator);
 
-  void SwitchRenderer(bool vulkan);
+  void CreateRenderer(bool vulkan);
 
   void Exit();
 
@@ -66,7 +61,7 @@ class Engine {
 
   template <typename T>
   std::unique_ptr<T> CreateRenderResource() {
-    return std::unique_ptr<T>(static_cast<T*>(new T(renderer_)));
+    return std::unique_ptr<T>(static_cast<T*>(new T(renderer_.get())));
   }
 
   void SetImageSource(const std::string& asset_name,
@@ -86,7 +81,6 @@ class Engine {
   Shader* GetCustomShader(const std::string& asset_name);
   void RemoveCustomShader(const std::string& asset_name);
 
-  void AddInputEvent(std::unique_ptr<InputEvent> event);
   std::unique_ptr<InputEvent> GetNextInputEvent();
 
   void StartRecording(const Json::Value& payload);
@@ -174,10 +168,9 @@ class Engine {
   static Engine* singleton;
 
   Platform* platform_ = nullptr;
-  Renderer* renderer_ = nullptr;
 
+  std::unique_ptr<Renderer> renderer_;
   std::unique_ptr<AudioMixer> audio_mixer_;
-
   std::unique_ptr<Game> game_;
 
   std::unique_ptr<Geometry> quad_;
@@ -221,14 +214,29 @@ class Engine {
   bool replaying_ = false;
   unsigned int replay_index_ = 0;
 
+  base::ThreadPool thread_pool_;
+  base::Timer timer_;
   base::Randomf random_;
 
+  void Initialize();
+
+  void Update(float delta_time);
+  void Draw(float frame_frac);
+
+  // PlatformObserver implementation
+  void OnWindowCreated() final;
+  void OnWindowDestroyed() final;
+  void OnWindowResized(int width, int height) final;
+  void LostFocus() final;
+  void GainedFocus(bool from_interstitial_ad) final;
+  void AddInputEvent(std::unique_ptr<InputEvent> event) final;
+
+  bool InitializeRenderer();
+
   void CreateTextureCompressors();
 
   void ContextLost();
 
-  bool CreateRenderResources();
-
   void SetSatsVisible(bool visible);
   std::unique_ptr<Image> PrintStats();
 
diff --git a/src/engine/image_quad.cc b/src/engine/image_quad.cc
index ab2e11a..dee7504 100644
--- a/src/engine/image_quad.cc
+++ b/src/engine/image_quad.cc
@@ -13,7 +13,7 @@ namespace eng {
 ImageQuad::ImageQuad() = default;
 
 ImageQuad::~ImageQuad() {
-  Destory();
+  Destroy();
 }
 
 void ImageQuad::Create(const std::string& asset_name,
@@ -32,7 +32,8 @@ void ImageQuad::Create(const std::string& asset_name,
   asset_name_ = asset_name;
 }
 
-void ImageQuad::Destory() {
+// TODO: typo
+void ImageQuad::Destroy() {
   if (texture_) {
     Engine::Get().ReleaseTexture(asset_name_);
     texture_ = nullptr;
diff --git a/src/engine/image_quad.h b/src/engine/image_quad.h
index d483774..c7e7629 100644
--- a/src/engine/image_quad.h
+++ b/src/engine/image_quad.h
@@ -24,7 +24,7 @@ class ImageQuad final : public Animatable {
               int frame_width = 0,
               int frame_height = 0);
 
-  void Destory();
+  void Destroy();
 
   void AutoScale();
 
diff --git a/src/engine/input_event.h b/src/engine/input_event.h
index e99fa33..e37d808 100644
--- a/src/engine/input_event.h
+++ b/src/engine/input_event.h
@@ -27,6 +27,8 @@ class InputEvent {
   InputEvent(Type type, char key) : type_(type), key_(key) {}
   ~InputEvent() = default;
 
+  void SetVector(base::Vector2f vec) { vec_ = vec; }
+
   Type GetType() const { return type_; }
 
   size_t GetPointerId() const { return pointer_id_; }
diff --git a/src/engine/platform/platform.cc b/src/engine/platform/platform.cc
deleted file mode 100644
index c65d6ea..0000000
--- a/src/engine/platform/platform.cc
+++ /dev/null
@@ -1,98 +0,0 @@
-#include "engine/platform/platform.h"
-
-#include "base/log.h"
-#include "base/task_runner.h"
-#include "engine/engine.h"
-#include "engine/renderer/opengl/renderer_opengl.h"
-#include "engine/renderer/vulkan/renderer_vulkan.h"
-
-#define USE_VULKAN_RENDERER 1
-
-using namespace base;
-
-namespace eng {
-
-Platform::Platform() = default;
-
-Platform::~Platform() = default;
-
-Renderer* Platform::SwitchRenderer(bool vulkan) {
-  DCHECK(renderer_);
-
-  if ((dynamic_cast<RendererVulkan*>(renderer_.get()) && vulkan) ||
-      (dynamic_cast<RendererOpenGL*>(renderer_.get()) && !vulkan))
-    return renderer_.get();
-
-  if (vulkan)
-    renderer_ = std::make_unique<RendererVulkan>();
-  else
-    renderer_ = std::make_unique<RendererOpenGL>();
-
-  bool result = InitializeRenderer();
-  CHECK(result) << "Failed to initialize " << renderer_->GetDebugName()
-                << " renderer.";
-  LOG << "Switched to " << renderer_->GetDebugName() << " renderer.";
-  return renderer_.get();
-}
-
-void Platform::InitializeCommon() {
-  LOG << "Initializing platform.";
-
-  thread_pool_.Initialize();
-  TaskRunner::CreateThreadLocalTaskRunner();
-
-#if (USE_VULKAN_RENDERER == 1)
-  renderer_ = std::make_unique<RendererVulkan>();
-#else
-  renderer_ = std::make_unique<RendererOpenGL>();
-#endif
-}
-
-void Platform::ShutdownCommon() {
-  LOG << "Shutting down platform.";
-
-  renderer_->Shutdown();
-}
-
-void Platform::RunMainLoop() {
-  engine_ =
-      std::make_unique<Engine>(this, renderer_.get());
-  bool res = engine_->Initialize();
-  CHECK(res) << "Failed to initialize the engine.";
-
-  // Use fixed time steps.
-  float time_step = engine_->time_step();
-
-  timer_.Reset();
-  float accumulator = 0.0;
-  float frame_frac = 0.0f;
-
-  for (;;) {
-    engine_->Draw(frame_frac);
-
-    // Accumulate time.
-    timer_.Update();
-    accumulator += timer_.GetSecondsPassed();
-
-    // Subdivide the frame time.
-    while (accumulator >= time_step) {
-      TaskRunner::GetThreadLocalTaskRunner()->SingleConsumerRun();
-
-      Update();
-      engine_->Update(time_step);
-
-      if (should_exit_) {
-        thread_pool_.Shutdown();
-        engine_->Shutdown();
-        engine_.reset();
-        return;
-      }
-      accumulator -= time_step;
-    };
-
-    // Calculate frame fraction from remainder of the frame time.
-    frame_frac = accumulator / time_step;
-  }
-}
-
-}  // namespace eng
diff --git a/src/engine/platform/platform.h b/src/engine/platform/platform.h
index 977a868..37e1805 100644
--- a/src/engine/platform/platform.h
+++ b/src/engine/platform/platform.h
@@ -1,12 +1,8 @@
 #ifndef ENGINE_PLATFORM_PLATFORM_H
 #define ENGINE_PLATFORM_PLATFORM_H
 
-#include <memory>
 #include <string>
 
-#include "base/thread_pool.h"
-#include "base/timer.h"
-
 #if defined(__ANDROID__)
 
 #include "../../base/vecmath.h"
@@ -24,27 +20,22 @@ struct ANativeWindow;
 
 namespace eng {
 
-class Renderer;
-class Engine;
+class PlatformObserver;
 
 class Platform {
  public:
-  Platform();
-  ~Platform();
-
 #if defined(__ANDROID__)
-  void Initialize(android_app* app);
+  Platform(android_app* app);
 #elif defined(__linux__)
-  void Initialize();
+  Platform();
 #endif
-
-  void Shutdown();
+  ~Platform();
 
   void Update();
 
   void Exit();
 
-  Renderer* SwitchRenderer(bool vulkan);
+  void SetObserver(PlatformObserver* observer) { observer_ = observer; }
 
   void Vibrate(int duration);
 
@@ -54,8 +45,6 @@ class Platform {
 
   void SetKeepScreenOn(bool keep_screen_on);
 
-  void RunMainLoop();
-
   int GetDeviceDpi() const { return device_dpi_; }
 
   const std::string& GetRootPath() const { return root_path_; }
@@ -66,9 +55,16 @@ class Platform {
 
   bool mobile_device() const { return mobile_device_; }
 
- protected:
-  base::Timer timer_;
+  bool should_exit() const { return should_exit_; }
 
+#if defined(__ANDROID__)
+  ANativeWindow* GetWindow();
+#elif defined(__linux__)
+  Display* GetDisplay();
+  Window GetWindow();
+#endif
+
+ private:
   bool mobile_device_ = false;
   int device_dpi_ = 100;
   std::string root_path_;
@@ -78,10 +74,7 @@ class Platform {
   bool has_focus_ = false;
   bool should_exit_ = false;
 
-  std::unique_ptr<Renderer> renderer_;
-  std::unique_ptr<Engine> engine_;
-
-  base::ThreadPool thread_pool_;
+  PlatformObserver* observer_ = nullptr;
 
 #if defined(__ANDROID__)
 
@@ -116,13 +109,10 @@ class Platform {
   bool CreateWindow(int width, int height);
   void DestroyWindow();
 
+  XVisualInfo* GetXVisualInfo(Display* display);
+
 #endif
 
-  void InitializeCommon();
-  void ShutdownCommon();
-
-  bool InitializeRenderer();
-
   Platform(const Platform&) = delete;
   Platform& operator=(const Platform&) = delete;
 };
diff --git a/src/engine/platform/platform_android.cc b/src/engine/platform/platform_android.cc
index 1bf6c13..8adf003 100644
--- a/src/engine/platform/platform_android.cc
+++ b/src/engine/platform/platform_android.cc
@@ -1,15 +1,15 @@
 #include "engine/platform/platform.h"
 
+#include <memory>
+
 #include <android_native_app_glue.h>
 #include <dlfcn.h>
 #include <jni.h>
 #include <unistd.h>
 
 #include "base/log.h"
-#include "base/task_runner.h"
-#include "engine/engine.h"
 #include "engine/input_event.h"
-#include "engine/renderer/renderer.h"
+#include "engine/platform/platform_observer.h"
 
 using namespace base;
 
@@ -201,10 +201,12 @@ int32_t GetDensityDpi(android_app* app) {
 
 namespace eng {
 
+void KaliberMain(Platform* platform);
+
 int32_t Platform::HandleInput(android_app* app, AInputEvent* event) {
   Platform* platform = reinterpret_cast<Platform*>(app->userData);
 
-  if (!platform->engine_)
+  if (!platform->observer_)
     return 0;
 
   if (AInputEvent_getType(event) == AINPUT_EVENT_TYPE_KEY &&
@@ -212,7 +214,7 @@ int32_t Platform::HandleInput(android_app* app, AInputEvent* event) {
     if (AKeyEvent_getAction(event) == AKEY_EVENT_ACTION_UP) {
       auto input_event =
           std::make_unique<InputEvent>(InputEvent::kNavigateBack);
-      platform->engine_->AddInputEvent(std::move(input_event));
+      platform->observer_->AddInputEvent(std::move(input_event));
     }
     return 1;
   } else if (AInputEvent_getType(event) == AINPUT_EVENT_TYPE_MOTION) {
@@ -227,7 +229,6 @@ int32_t Platform::HandleInput(android_app* app, AInputEvent* event) {
       int32_t id = AMotionEvent_getPointerId(event, i);
       if (id < 2) {
         pos[id] = {AMotionEvent_getX(event, i), AMotionEvent_getY(event, i)};
-        pos[id] = platform->engine_->ToPosition(pos[id]);
       }
     }
 
@@ -239,34 +240,30 @@ int32_t Platform::HandleInput(android_app* app, AInputEvent* event) {
     switch (flags) {
       case AMOTION_EVENT_ACTION_DOWN:
       case AMOTION_EVENT_ACTION_POINTER_DOWN:
-        // DLOG << "AMOTION_EVENT_ACTION_DOWN - pointer_id: " << pointer_id;
         platform->pointer_pos_[pointer_id] = pos[pointer_id];
         platform->pointer_down_[pointer_id] = true;
-        input_event =
-            std::make_unique<InputEvent>(InputEvent::kDragStart, pointer_id,
-                                         pos[pointer_id] * Vector2f(1, -1));
+        input_event = std::make_unique<InputEvent>(InputEvent::kDragStart,
+                                                   pointer_id, pos[pointer_id]);
         break;
 
       case AMOTION_EVENT_ACTION_UP:
       case AMOTION_EVENT_ACTION_POINTER_UP:
-        // DLOG << "AMOTION_EVENT_ACTION_UP -   pointer_id: " << pointer_id;
         platform->pointer_pos_[pointer_id] = pos[pointer_id];
         platform->pointer_down_[pointer_id] = false;
-        input_event =
-            std::make_unique<InputEvent>(InputEvent::kDragEnd, pointer_id,
-                                         pos[pointer_id] * Vector2f(1, -1));
+        input_event = std::make_unique<InputEvent>(InputEvent::kDragEnd,
+                                                   pointer_id, pos[pointer_id]);
         break;
 
       case AMOTION_EVENT_ACTION_MOVE:
         if (platform->pointer_down_[0] && pos[0] != platform->pointer_pos_[0]) {
           platform->pointer_pos_[0] = pos[0];
-          input_event = std::make_unique<InputEvent>(InputEvent::kDrag, 0,
-                                                     pos[0] * Vector2f(1, -1));
+          input_event =
+              std::make_unique<InputEvent>(InputEvent::kDrag, 0, pos[0]);
         }
         if (platform->pointer_down_[1] && pos[1] != platform->pointer_pos_[1]) {
           platform->pointer_pos_[1] = pos[1];
-          input_event = std::make_unique<InputEvent>(InputEvent::kDrag, 1,
-                                                     pos[1] * Vector2f(1, -1));
+          input_event =
+              std::make_unique<InputEvent>(InputEvent::kDrag, 1, pos[1]);
         }
         break;
 
@@ -276,7 +273,7 @@ int32_t Platform::HandleInput(android_app* app, AInputEvent* event) {
     }
 
     if (input_event) {
-      platform->engine_->AddInputEvent(std::move(input_event));
+      platform->observer_->AddInputEvent(std::move(input_event));
       return 1;
     }
   }
@@ -295,30 +292,23 @@ void Platform::HandleCmd(android_app* app, int32_t cmd) {
       DLOG << "APP_CMD_INIT_WINDOW";
       if (app->window != NULL) {
         platform->SetFrameRate(60);
-        bool res = platform->InitializeRenderer();
-        CHECK(res) << "Failed to initialize "
-                   << platform->renderer_->GetDebugName() << " renderer.";
+        if (platform->observer_)
+          platform->observer_->OnWindowCreated();
       }
       break;
 
     case APP_CMD_TERM_WINDOW:
       DLOG << "APP_CMD_TERM_WINDOW";
-      platform->renderer_->Shutdown();
+      if (platform->observer_)
+        platform->observer_->OnWindowDestroyed();
       break;
 
     case APP_CMD_CONFIG_CHANGED:
       DLOG << "APP_CMD_CONFIG_CHANGED";
-      if (platform->app_->window != NULL) {
-        int width = platform->renderer_->screen_width();
-        int height = platform->renderer_->screen_height();
-        if (width != ANativeWindow_getWidth(app->window) ||
-            height != ANativeWindow_getHeight(app->window)) {
-          platform->renderer_->Shutdown();
-          bool res = platform->InitializeRenderer();
-          CHECK(res) << "Failed to initialize "
-                     << platform->renderer_->GetDebugName() << " renderer.";
-        }
-      }
+      if (platform->app_->window != NULL && platform->observer_)
+        platform->observer_->OnWindowResized(
+            ANativeWindow_getWidth(app->window),
+            ANativeWindow_getHeight(app->window));
       break;
 
     case APP_CMD_STOP:
@@ -327,18 +317,18 @@ void Platform::HandleCmd(android_app* app, int32_t cmd) {
 
     case APP_CMD_GAINED_FOCUS:
       DLOG << "APP_CMD_GAINED_FOCUS";
-      platform->timer_.Reset();
+      // platform->timer_.Reset();
       platform->has_focus_ = true;
-      if (platform->engine_)
-        platform->engine_->GainedFocus(g_showing_interstitial_ad);
+      if (platform->observer_)
+        platform->observer_->GainedFocus(g_showing_interstitial_ad);
       g_showing_interstitial_ad = false;
       break;
 
     case APP_CMD_LOST_FOCUS:
       DLOG << "APP_CMD_LOST_FOCUS";
       platform->has_focus_ = false;
-      if (platform->engine_)
-        platform->engine_->LostFocus();
+      if (platform->observer_)
+        platform->observer_->LostFocus();
       break;
 
     case APP_CMD_LOW_MEMORY:
@@ -347,11 +337,8 @@ void Platform::HandleCmd(android_app* app, int32_t cmd) {
   }
 }
 
-void Platform::Initialize(android_app* app) {
-  Platform::InitializeCommon();
-
+Platform::Platform(android_app* app) {
   app_ = app;
-
   mobile_device_ = true;
 
   root_path_ = ::GetApkPath(app->activity);
@@ -385,8 +372,8 @@ void Platform::Initialize(android_app* app) {
   Update();
 }
 
-void Platform::Shutdown() {
-  Platform::ShutdownCommon();
+Platform::~Platform() {
+  LOG << "Shutting down platform.";
 }
 
 void Platform::Update() {
@@ -439,16 +426,14 @@ void Platform::SetFrameRate(float frame_rate) {
   }
 }
 
-bool Platform::InitializeRenderer() {
-  return renderer_->Initialize(app_->window);
+ANativeWindow* Platform::GetWindow() {
+  return app_->window;
 }
 
 }  // namespace eng
 
 void android_main(android_app* app) {
-  eng::Platform platform;
-  platform.Initialize(app);
-  platform.RunMainLoop();
-  platform.Shutdown();
+  eng::Platform platform(app);
+  eng::KaliberMain(&platform);
   _exit(0);
 }
diff --git a/src/engine/platform/platform_linux.cc b/src/engine/platform/platform_linux.cc
index 4d0982d..30b83d8 100644
--- a/src/engine/platform/platform_linux.cc
+++ b/src/engine/platform/platform_linux.cc
@@ -1,19 +1,19 @@
 #include "engine/platform/platform.h"
 
+#include <memory>
+
 #include "base/log.h"
-#include "base/task_runner.h"
 #include "base/vecmath.h"
-#include "engine/engine.h"
 #include "engine/input_event.h"
-#include "engine/renderer/renderer.h"
+#include "engine/platform/platform_observer.h"
 
 using namespace base;
 
 namespace eng {
 
-void Platform::Initialize() {
-  Platform::InitializeCommon();
+void KaliberMain(Platform* platform);
 
+Platform::Platform() {
   root_path_ = "../../";
   LOG << "Root path: " << root_path_.c_str();
 
@@ -26,10 +26,6 @@ void Platform::Initialize() {
   bool res = CreateWindow(800, 1205);
   CHECK(res) << "Failed to create window.";
 
-  res = InitializeRenderer();
-  CHECK(res) << "Failed to initialize " << renderer_->GetDebugName()
-             << " renderer.";
-
   XSelectInput(display_, window_,
                KeyPressMask | Button1MotionMask | ButtonPressMask |
                    ButtonReleaseMask | FocusChangeMask);
@@ -37,9 +33,8 @@ void Platform::Initialize() {
   XSetWMProtocols(display_, window_, &WM_DELETE_WINDOW, 1);
 }
 
-void Platform::Shutdown() {
-  Platform::ShutdownCommon();
-
+Platform::~Platform() {
+  LOG << "Shutting down platform.";
   DestroyWindow();
 }
 
@@ -52,47 +47,41 @@ void Platform::Update() {
         KeySym key = XLookupKeysym(&e.xkey, 0);
         auto input_event =
             std::make_unique<InputEvent>(InputEvent::kKeyPress, (char)key);
-        engine_->AddInputEvent(std::move(input_event));
+        observer_->AddInputEvent(std::move(input_event));
         // TODO: e.xkey.state & (ShiftMask | ControlMask | Mod1Mask | Mod4Mask))
         break;
       }
       case MotionNotify: {
         Vector2f v(e.xmotion.x, e.xmotion.y);
-        v = engine_->ToPosition(v);
-        // DLOG << "drag: " << v;
-        auto input_event = std::make_unique<InputEvent>(InputEvent::kDrag, 0,
-                                                        v * Vector2f(1, -1));
-        engine_->AddInputEvent(std::move(input_event));
+        auto input_event =
+            std::make_unique<InputEvent>(InputEvent::kDrag, 0, v);
+        observer_->AddInputEvent(std::move(input_event));
         break;
       }
       case ButtonPress: {
         if (e.xbutton.button == 1) {
           Vector2f v(e.xbutton.x, e.xbutton.y);
-          v = engine_->ToPosition(v);
-          // DLOG << "drag-start: " << v;
-          auto input_event = std::make_unique<InputEvent>(
-              InputEvent::kDragStart, 0, v * Vector2f(1, -1));
-          engine_->AddInputEvent(std::move(input_event));
+          auto input_event =
+              std::make_unique<InputEvent>(InputEvent::kDragStart, 0, v);
+          observer_->AddInputEvent(std::move(input_event));
         }
         break;
       }
       case ButtonRelease: {
         if (e.xbutton.button == 1) {
           Vector2f v(e.xbutton.x, e.xbutton.y);
-          v = engine_->ToPosition(v);
-          // DLOG << "drag-end!";
-          auto input_event = std::make_unique<InputEvent>(
-              InputEvent::kDragEnd, 0, v * Vector2f(1, -1));
-          engine_->AddInputEvent(std::move(input_event));
+          auto input_event =
+              std::make_unique<InputEvent>(InputEvent::kDragEnd, 0, v);
+          observer_->AddInputEvent(std::move(input_event));
         }
         break;
       }
       case FocusOut: {
-        engine_->LostFocus();
+        observer_->LostFocus();
         break;
       }
       case FocusIn: {
-        engine_->GainedFocus(false);
+        observer_->GainedFocus(false);
         break;
       }
       case ClientMessage: {
@@ -127,7 +116,7 @@ bool Platform::CreateWindow(int width, int height) {
 
   Window root_window = DefaultRootWindow(display_);
 
-  XVisualInfo* visual_info = renderer_->GetXVisualInfo(display_);
+  XVisualInfo* visual_info = GetXVisualInfo(display_);
   if (!visual_info) {
     LOG << "No appropriate visual found.";
     return false;
@@ -151,22 +140,35 @@ bool Platform::CreateWindow(int width, int height) {
 void Platform::DestroyWindow() {
   if (display_) {
     XDestroyWindow(display_, window_);
+#if 0  // TODO: Figure out why XCloseDisplay is crashing
     XCloseDisplay(display_);
+#endif
     display_ = nullptr;
     window_ = 0;
   }
 }
 
-bool Platform::InitializeRenderer() {
-  return renderer_->Initialize(display_, window_);
+Display* Platform::GetDisplay() {
+  return display_;
+}
+
+Window Platform::GetWindow() {
+  return window_;
+}
+
+XVisualInfo* Platform::GetXVisualInfo(Display* display) {
+  long visual_mask = VisualScreenMask;
+  int num_visuals;
+  XVisualInfo visual_info_template = {};
+  visual_info_template.screen = DefaultScreen(display);
+  return XGetVisualInfo(display, visual_mask, &visual_info_template,
+                        &num_visuals);
 }
 
 }  // namespace eng
 
 int main(int argc, char** argv) {
   eng::Platform platform;
-  platform.Initialize();
-  platform.RunMainLoop();
-  platform.Shutdown();
+  eng::KaliberMain(&platform);
   return 0;
 }
diff --git a/src/engine/platform/platform_observer.h b/src/engine/platform/platform_observer.h
new file mode 100644
index 0000000..d6c11a8
--- /dev/null
+++ b/src/engine/platform/platform_observer.h
@@ -0,0 +1,23 @@
+#ifndef ENGINE_PLATFORM_PLATFORM_OBSERVER_H
+#define ENGINE_PLATFORM_PLATFORM_OBSERVER_H
+
+namespace eng {
+
+class InputEvent;
+
+class PlatformObserver {
+ public:
+  PlatformObserver() = default;
+  virtual ~PlatformObserver() = default;
+
+  virtual void OnWindowCreated() = 0;
+  virtual void OnWindowDestroyed() = 0;
+  virtual void OnWindowResized(int width, int height) = 0;
+  virtual void LostFocus() = 0;
+  virtual void GainedFocus(bool from_interstitial_ad) = 0;
+  virtual void AddInputEvent(std::unique_ptr<InputEvent> event) = 0;
+};
+
+}  // namespace eng
+
+#endif  // ENGINE_PLATFORM_PLATFORM_OBSERVER_H
diff --git a/src/engine/renderer/opengl/renderer_opengl.h b/src/engine/renderer/opengl/renderer_opengl.h
index 75f983a..aa7c9f4 100644
--- a/src/engine/renderer/opengl/renderer_opengl.h
+++ b/src/engine/renderer/opengl/renderer_opengl.h
@@ -89,10 +89,6 @@ class RendererOpenGL final : public Renderer {
 
   const char* GetDebugName() final { return "OpenGL"; }
 
-#if defined(__linux__) && !defined(__ANDROID__)
-  XVisualInfo* GetXVisualInfo(Display* display) final;
-#endif
-
  private:
   struct GeometryOpenGL {
     struct Element {
diff --git a/src/engine/renderer/opengl/renderer_opengl_linux.cc b/src/engine/renderer/opengl/renderer_opengl_linux.cc
index 5bb452a..267a5bf 100644
--- a/src/engine/renderer/opengl/renderer_opengl_linux.cc
+++ b/src/engine/renderer/opengl/renderer_opengl_linux.cc
@@ -21,9 +21,11 @@ bool RendererOpenGL::Initialize(Display* display, Window window) {
 void RendererOpenGL::OnDestroy() {}
 
 bool RendererOpenGL::InitInternal() {
-  // Create the OpenGL context.
+  GLint glx_attributes[] = {GLX_RGBA, GLX_DEPTH_SIZE, 24, GLX_DOUBLEBUFFER,
+                            None};
+  XVisualInfo* visual_info = glXChooseVisual(display_, 0, glx_attributes);
   glx_context_ =
-      glXCreateContext(display_, GetXVisualInfo(display_), NULL, GL_TRUE);
+      glXCreateContext(display_, visual_info, NULL, GL_TRUE);
   if (!glx_context_) {
     LOG << "Couldn't create the glx context.";
     return false;
@@ -59,11 +61,4 @@ void RendererOpenGL::HandleCmdPresent(RenderCommand* cmd) {
   }
 }
 
-XVisualInfo* RendererOpenGL::GetXVisualInfo(Display* display) {
-  // Look for the right visual to set up the OpenGL context.
-  GLint glx_attributes[] = {GLX_RGBA, GLX_DEPTH_SIZE, 24, GLX_DOUBLEBUFFER,
-                            None};
-  return glXChooseVisual(display, 0, glx_attributes);
-}
-
 }  // namespace eng
diff --git a/src/engine/renderer/renderer.h b/src/engine/renderer/renderer.h
index e6bed68..2ce496b 100644
--- a/src/engine/renderer/renderer.h
+++ b/src/engine/renderer/renderer.h
@@ -94,10 +94,6 @@ class Renderer {
 
   virtual const char* GetDebugName() = 0;
 
-#if defined(__linux__) && !defined(__ANDROID__)
-  virtual XVisualInfo* GetXVisualInfo(Display* display) = 0;
-#endif
-
  protected:
   struct TextureCompression {
     unsigned etc1 : 1;
diff --git a/src/engine/renderer/vulkan/renderer_vulkan.h b/src/engine/renderer/vulkan/renderer_vulkan.h
index 38b9bee..5e54c98 100644
--- a/src/engine/renderer/vulkan/renderer_vulkan.h
+++ b/src/engine/renderer/vulkan/renderer_vulkan.h
@@ -74,10 +74,6 @@ class RendererVulkan final : public Renderer {
 
   const char* GetDebugName() final { return "Vulkan"; }
 
-#if defined(__linux__) && !defined(__ANDROID__)
-  XVisualInfo* GetXVisualInfo(Display* display) final;
-#endif
-
  private:
   // VkBuffer or VkImage with allocator.
   template <typename T>
diff --git a/src/engine/renderer/vulkan/renderer_vulkan_linux.cc b/src/engine/renderer/vulkan/renderer_vulkan_linux.cc
index 4cb66bd..35eea3d 100644
--- a/src/engine/renderer/vulkan/renderer_vulkan_linux.cc
+++ b/src/engine/renderer/vulkan/renderer_vulkan_linux.cc
@@ -24,13 +24,4 @@ bool RendererVulkan::Initialize(Display* display, Window window) {
   return InitializeInternal();
 }
 
-XVisualInfo* RendererVulkan::GetXVisualInfo(Display* display) {
-  long visual_mask = VisualScreenMask;
-  int num_visuals;
-  XVisualInfo visual_info_template = {};
-  visual_info_template.screen = DefaultScreen(display);
-  return XGetVisualInfo(display, visual_mask, &visual_info_template,
-                        &num_visuals);
-}
-
 }  // namespace eng