Manage custom shaders in Engine

src/demo/demo.cc

@@ -50,6 +50,10 @@ Demo::~Demo() {
 bool Demo::Initialize() {
   saved_data_.Load(kSaveFileName);
 
+  Engine::Get().LoadCustomShader("sky_without_nebula",
+                                 "sky_without_nebula.glsl");
+  Engine::Get().LoadCustomShader("sky", "sky.glsl");
+
   if (!font_.Load("PixelCaps!.ttf"))
     return false;
 
@@ -162,11 +166,6 @@ void Demo::Update(float delta_time) {
     UpdateGameState(delta_time);
 }
 
-void Demo::ContextLost() {
-  sky_.ContextLost();
-  enemy_.ContextLost();
-}
-
 void Demo::LostFocus() {}
 
 void Demo::GainedFocus(bool from_interstitial_ad) {

src/demo/demo.h

@@ -27,7 +27,7 @@ class Demo final : public eng::Game {
 
   void Update(float delta_time) final;
 
-  void ContextLost() final;
+  void ContextLost() final {}
 
   void LostFocus() final;
 

src/demo/enemy.cc

@@ -13,8 +13,6 @@
 #include "engine/font.h"
 #include "engine/image.h"
 #include "engine/renderer/geometry.h"
-#include "engine/renderer/shader.h"
-#include "engine/shader_source.h"
 #include "engine/sound.h"
 
 #include "demo/demo.h"
@@ -76,8 +74,7 @@ float SnapSpawnPosX(int col) {
 
 }  // namespace
 
-Enemy::Enemy()
-    : chromatic_aberration_(Engine::Get().CreateRenderResource<Shader>()) {}
+Enemy::Enemy() = default;
 
 Enemy::~Enemy() = default;
 
@@ -205,10 +202,6 @@ void Enemy::Pause(bool pause) {
   boss_animator_.PauseOrResumeAll(pause);
 }
 
-void Enemy::ContextLost() {
-  CreateShaders();
-}
-
 bool Enemy::HasTarget(DamageType damage_type) {
   DCHECK(damage_type > kDamageType_Invalid && damage_type < kDamageType_Any);
 
@@ -423,7 +416,7 @@ void Enemy::StopAllEnemyUnits(bool chromatic_aberration_effect) {
       continue;
 
     if (chromatic_aberration_effect) {
-      e.sprite.SetCustomShader(chromatic_aberration_.get());
+      e.sprite.SetCustomShader("chromatic_aberration");
       e.chromatic_aberration_active_ = true;
     }
 
@@ -1193,9 +1186,6 @@ std::unique_ptr<Image> Enemy::GetScoreImage(EnemyType enemy_type) {
 }
 
 bool Enemy::CreateRenderResources() {
-  if (!CreateShaders())
-    return false;
-
   Engine::Get().SetImageSource("skull_tex", "enemy_anims_01_frames_ok.png",
                                true);
   Engine::Get().SetImageSource("bug_tex", "enemy_anims_02_frames_ok.png", true);
@@ -1213,16 +1203,9 @@ bool Enemy::CreateRenderResources() {
         "score_tex"s + std::to_string(i),
         std::bind(&Enemy::GetScoreImage, this, (EnemyType)i), true);
 
-  return true;
-}
+  Engine::Get().LoadCustomShader("chromatic_aberration",
+                                 "chromatic_aberration.glsl");
 
-bool Enemy::CreateShaders() {
-  auto source = std::make_unique<ShaderSource>();
-  if (!source->Load("chromatic_aberration.glsl"))
-    return false;
-  chromatic_aberration_->Create(std::move(source),
-                                Engine::Get().GetQuad()->vertex_description(),
-                                Engine::Get().GetQuad()->primitive(), false);
   return true;
 }
 

src/demo/enemy.h

@@ -15,7 +15,6 @@
 
 namespace eng {
 class Image;
-class Shader;
 class Sound;
 }  // namespace eng
 
@@ -30,8 +29,6 @@ class Enemy {
 
   void Pause(bool pause);
 
-  void ContextLost();
-
   bool HasTarget(DamageType damage_type);
   base::Vector2f GetTargetPos(DamageType damage_type);
 
@@ -106,7 +103,6 @@ class Enemy {
     eng::SoundPlayer hit;
   };
 
-  std::unique_ptr<eng::Shader> chromatic_aberration_;
   float chromatic_aberration_offset_ = 0;
 
   eng::ImageQuad boss_;
@@ -169,7 +165,6 @@ class Enemy {
   std::unique_ptr<eng::Image> GetScoreImage(EnemyType enemy_type);
 
   bool CreateRenderResources();
-  bool CreateShaders();
 
   void TranslateEnemyUnit(EnemyUnit& e, const base::Vector2f& delta);
 };

src/demo/sky_quad.cc

@@ -6,14 +6,12 @@
 #include "engine/engine.h"
 #include "engine/renderer/geometry.h"
 #include "engine/renderer/shader.h"
-#include "engine/shader_source.h"
 
 using namespace base;
 using namespace eng;
 
 SkyQuad::SkyQuad()
-    : shader_(Engine::Get().CreateRenderResource<Shader>()),
-      sky_offset_{
+    : sky_offset_{
           0, Lerp(0.0f, 10.0f, Engine::Get().GetRandomGenerator().Rand())} {
   last_sky_offset_ = sky_offset_;
 }
@@ -22,10 +20,9 @@ SkyQuad::~SkyQuad() = default;
 
 bool SkyQuad::Create(bool without_nebula) {
   without_nebula_ = without_nebula;
-  if (!CreateShaders())
-    return false;
-
   scale_ = Engine::Get().GetScreenSize();
+  shader_ = Engine::Get().GetCustomShader(
+      without_nebula ? "sky_without_nebula" : "sky");
 
   color_animator_.Attach(this);
 
@@ -54,10 +51,6 @@ void SkyQuad::Draw(float frame_frac) {
   Engine::Get().GetQuad()->Draw();
 }
 
-void SkyQuad::ContextLost() {
-  CreateShaders();
-}
-
 void SkyQuad::SwitchColor(const Vector4f& color) {
   color_animator_.Pause(Animator::kBlending);
   color_animator_.SetTime(Animator::kBlending, 0);
@@ -66,17 +59,6 @@ void SkyQuad::SwitchColor(const Vector4f& color) {
   color_animator_.Play(Animator::kBlending, false);
 }
 
-bool SkyQuad::CreateShaders() {
-  Engine& engine = Engine::Get();
-
-  auto source = std::make_unique<ShaderSource>();
-  if (!source->Load(without_nebula_ ? "sky_without_nebula.glsl" : "sky.glsl"))
-    return false;
-  shader_->Create(std::move(source), engine.GetQuad()->vertex_description(),
-                  Engine::Get().GetQuad()->primitive(), false);
-  return true;
-}
-
 void SkyQuad::SetSpeed(float speed) {
   speed_ = speed;
 }

src/demo/sky_quad.h

@@ -36,8 +36,6 @@ class SkyQuad : public eng::Animatable {
   // Drawable interface.
   void Draw(float frame_frac) final;
 
-  void ContextLost();
-
   void SwitchColor(const base::Vector4f& color);
 
   void SetSpeed(float speed);
@@ -45,7 +43,7 @@ class SkyQuad : public eng::Animatable {
   const base::Vector4f& nebula_color() { return nebula_color_; }
 
  private:
-  std::unique_ptr<eng::Shader> shader_;
+  eng::Shader* shader_;
 
   base::Vector2f sky_offset_ = {0, 0};
   base::Vector2f last_sky_offset_ = {0, 0};
@@ -57,8 +55,6 @@ class SkyQuad : public eng::Animatable {
   float speed_ = 0;
 
   bool without_nebula_ = false;
-
-  bool CreateShaders();
 };
 
 #endif  // DEMO_SKY_QUAD_H

src/engine/engine.cc

@@ -109,6 +109,7 @@ void Engine::Shutdown() {
   game_.reset();
   stats_->Destory();
   textures_.clear();
+  shaders_.clear();
 }
 
 void Engine::Update(float delta_time) {
@@ -277,6 +278,42 @@ void Engine::ReleaseTexture(const std::string& asset_name) {
     it->second.texture->Destroy();
 }
 
+void Engine::LoadCustomShader(const std::string& asset_name,
+                              const std::string& file_name) {
+  if (shaders_.contains(asset_name)) {
+    DLOG << "Shader already exists: " << asset_name;
+    return;
+  }
+
+  auto& s = shaders_[asset_name] = {CreateRenderResource<Shader>(), file_name};
+
+  auto source = std::make_unique<ShaderSource>();
+  if (!source->Load(file_name))
+    return;
+  s.shader->Create(std::move(source), quad_->vertex_description(),
+                   quad_->primitive(), false);
+}
+
+Shader* Engine::GetCustomShader(const std::string& asset_name) {
+  auto it = shaders_.find(asset_name);
+  if (it == shaders_.end()) {
+    DLOG << "Shader not found: " << asset_name;
+    return nullptr;
+  }
+
+  return it->second.shader.get();
+}
+
+void Engine::RemoveCustomShader(const std::string& asset_name) {
+  auto it = shaders_.find(asset_name);
+  if (it == shaders_.end()) {
+    DLOG << "Shader not found: " << asset_name;
+    return;
+  }
+
+  shaders_.erase(it);
+}
+
 void Engine::AddInputEvent(std::unique_ptr<InputEvent> event) {
   if (replaying_)
     return;
@@ -452,6 +489,13 @@ void Engine::ContextLost() {
     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();
 }
 

src/engine/engine.h

@@ -79,6 +79,11 @@ class Engine {
   Texture* AcquireTexture(const std::string& asset_name);
   void ReleaseTexture(const std::string& asset_name);
 
+  void LoadCustomShader(const std::string& asset_name,
+                        const std::string& file_name);
+  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();
 
@@ -158,6 +163,12 @@ class Engine {
     size_t use_count = 0;
   };
 
+  // Class holding information about shader resources managed by engine.
+  struct ShaderResource {
+    std::unique_ptr<Shader> shader;
+    std::string file_name;
+  };
+
   static Engine* singleton;
 
   Platform* platform_ = nullptr;
@@ -184,8 +195,9 @@ class Engine {
 
   std::list<Animator*> animators_;
 
-  // Textures mapped by asset name.
+  // Managed render resources mapped by asset name.
   std::unordered_map<std::string, TextureResource> textures_;
+  std::unordered_map<std::string, ShaderResource> shaders_;
 
   std::unique_ptr<ImageQuad> stats_;
 

src/engine/image_quad.cc

@@ -49,8 +49,8 @@ void ImageQuad::AutoScale() {
   SetSize(size);
 }
 
-void ImageQuad::SetCustomShader(Shader* shader) {
-  custom_shader_ = shader;
+void ImageQuad::SetCustomShader(const std::string& asset_name) {
+  custom_shader_ = Engine::Get().GetCustomShader(asset_name);
   custom_uniforms_.clear();
 }
 

src/engine/image_quad.h

@@ -28,7 +28,7 @@ class ImageQuad final : public Animatable {
 
   void AutoScale();
 
-  void SetCustomShader(Shader* shader);
+  void SetCustomShader(const std::string& asset_name);
 
   template <typename T>
   void SetCustomUniform(const std::string& name, T value) {