[update] Implemented animations for scene transition.

src/sj/SelectScene.d

@@ -1,13 +1,20 @@
 /// License: MIT
 module sj.SelectScene;
 
+import std.math,
+       std.variant;
+
 import derelict.sfml2.audio;
 
+import gl4d;
+
 import sj.KeyInput,
        sj.LobbyWorld,
        sj.ProgramSet,
        sj.SceneInterface,
        sj.TitleScene,
+       sj.util.Animation,
+       sj.util.Easing,
        sj.util.audio;
 
 ///
@@ -20,6 +27,9 @@ class SelectScene : SceneInterface {
 
     sound_ = sfSound_create();
     soundres_.Load();
+
+    first_state_ = new FirstSetupState(this);
+    status_      = first_state_;
   }
   ~this() {
     sfSound_destroy(sound_);
@@ -33,13 +43,19 @@ class SelectScene : SceneInterface {
 
   ///
   void Initialize() {
+    first_state_.Initialize();
+    status_ = first_state_;
   }
   override SceneInterface Update(KeyInput input) {
-    if (input.up) {
-      title_scene_.Initialize();
-      return title_scene_;
-    }
-    return this;
+    SceneInterface     next_scene = this;
+    AbstractSceneState next_state;
+
+    status_.Update(input).visit!(
+        (SceneInterface     scene) { next_scene = scene; },
+        (AbstractSceneState state) { next_state = state; }
+      );
+    status_ = next_state;
+    return next_scene;
   }
   override void Draw() {
     lobby_.Draw();
@@ -67,4 +83,111 @@ class SelectScene : SceneInterface {
   sfSound* sound_;
 
   SoundResources soundres_;
+
+  FirstSetupState first_state_;
+
+  AbstractSceneState status_;
+}
+
+private abstract class AbstractSceneState {
+ public:
+  alias UpdateResult = Algebraic!(AbstractSceneState, SceneInterface);
+
+  this(SelectScene owner) {
+    owner_ = owner;
+  }
+
+  abstract UpdateResult Update(KeyInput input);
+
+  @property SelectScene owner() {
+    return owner_;
+  }
+
+ protected:
+  static UpdateResult CreateResult(SceneInterface s) {
+    return UpdateResult(s);
+  }
+  static UpdateResult CreateResult(AbstractSceneState s) {
+    return UpdateResult(s);
+  }
+ private:
+  SelectScene owner_;
+}
+
+private class FirstSetupState : AbstractSceneState {
+ public:
+  this(SelectScene owner) {
+    super(owner);
+    stage_appear_state_ = new StageAppearState(owner);
+  }
+
+  enum AnimeFrames  = 30;
+  enum BgInnerColor = vec4(0.8, 0.6, 0.6, 1);
+  enum BgOuterColor = vec4(-0.4, -0.4, -0.4, 1);
+
+  enum CubeRotationSpeed = vec3(0, PI/10, 0);
+  enum CubeInterval   = 0.06;
+
+  void Initialize() {
+    anime_ = Animation(AnimeFrames);
+    bg_inner_ease_ = Easing!vec4(owner.lobby_.background.inner_color, BgInnerColor);
+    bg_outer_ease_ = Easing!vec4(owner.lobby_.background.outer_color, BgOuterColor);
+
+    cube_interval_ease_ = Easing!float(owner.lobby_.cube_interval, CubeInterval);
+  }
+  override UpdateResult Update(KeyInput input) {
+    const ratio = anime_.Update();
+
+    owner.lobby_.cube_matrix.rotation += CubeRotationSpeed * (ratio+0.2);
+    owner.lobby_.cube_interval = cube_interval_ease_.Calculate(ratio);
+
+    owner.lobby_.background.inner_color = bg_inner_ease_.Calculate(ratio);
+    owner.lobby_.background.outer_color = bg_outer_ease_.Calculate(ratio);
+
+    if (anime_.isFinished) {
+      stage_appear_state_.Initialize();
+      return CreateResult(stage_appear_state_);
+    }
+    return CreateResult(this);
+  }
+
+ private:
+  StageAppearState stage_appear_state_;
+
+  Animation anime_;
+
+  Easing!vec4 bg_inner_ease_;
+  Easing!vec4 bg_outer_ease_;
+
+  Easing!float cube_interval_ease_;
+}
+private class StageAppearState : AbstractSceneState {
+ public:
+  this(SelectScene owner) {
+    super(owner);
+  }
+
+  enum AnimeFrames       = 30;
+  enum CubeRotationSpeed = vec3(0, PI/500, 0);
+
+  void Initialize() {  // TODO: pass a stage data
+    anime_ = Animation(AnimeFrames);
+    cube_interval_ease_ = Easing!float(owner.lobby_.cube_interval, 0.005);
+
+    sfSound_setBuffer(owner.sound_, owner.soundres_.spotlight);
+    sfSound_play(owner.sound_);
+  }
+  override UpdateResult Update(KeyInput input) {
+    const ratio = anime_.Update();
+
+    owner.lobby_.cube_matrix.rotation += CubeRotationSpeed +
+      (FirstSetupState.CubeRotationSpeed - CubeRotationSpeed) * (1-ratio);
+    owner.lobby_.cube_interval = cube_interval_ease_.Calculate(ratio);
+    return CreateResult(this);
+  }
+
+ private:
+  Animation anime_;
+
+  Easing!float cube_interval_ease_;
 }

src/sj/TitleScene.d

@@ -1,7 +1,8 @@
 /// License: MIT
 module sj.TitleScene;
 
-import std.math;
+import std.conv,
+       std.math;
 
 import gl4d;
 
@@ -10,7 +11,9 @@ import sj.KeyInput,
        sj.ProgramSet,
        sj.SelectScene,
        sj.SceneInterface,
-       sj.TitleTextProgram;
+       sj.TitleTextProgram,
+       sj.util.Animation,
+       sj.util.Easing;
 
 ///
 class TitleScene : SceneInterface {
@@ -23,10 +26,35 @@ class TitleScene : SceneInterface {
     return m;
   }();
 
+  ///
+  enum AnimationFrame = 30;
+  ///
+  enum BgInnerColor = vec4(0.9, 0.9, 0.9, 1);
+  ///
+  enum BgOuterColor = vec4(-0.1, -0.1, -0.1, 1);
+  ///
+  enum CubeInterval = 0.005;
+
   ///
   this(LobbyWorld lobby, ProgramSet program) {
     lobby_ = lobby;
     title_ = program.Get!TitleTextProgram;
+
+    lobby_.view.pos    = vec3(0, -0.15, -1);
+    lobby_.view.target = vec3(0, -0.15, 0);
+    lobby_.view.up     = vec3(0, 1, 0);
+
+    lobby_.background.inner_color = BgInnerColor;
+    lobby_.background.outer_color = BgOuterColor;
+
+    lobby_.light_pos                    = vec3(0, 9, -1);
+    lobby_.cube_material.diffuse_color  = vec3(0.1, 0.1, 0.1);
+    lobby_.cube_material.light_color    = vec3(1, 0.8, 0.8);
+    lobby_.cube_material.light_power    = vec3(100, 100, 100);
+    lobby_.cube_material.ambient_color  = vec3(0.2, 0.2, 0.2);
+    lobby_.cube_material.specular_color = vec3(0.5, 0.2, 0.2);
+
+    lobby_.cube_interval = CubeInterval;
   }
 
   ///
@@ -36,25 +64,23 @@ class TitleScene : SceneInterface {
 
   ///
   void Initialize() {
-    lobby_.view.pos    = vec3(0, -0.15, -1);
-    lobby_.view.target = vec3(0, -0.15, 0);
-    lobby_.view.up     = vec3(0, 1, 0);
+    anime_ = Animation(AnimationFrame);
 
-    lobby_.background.inner_color = vec4(0.9, 0.9, 0.9, 1);
-    lobby_.background.outer_color = vec4(-0.1, -0.1, -0.1, 1);
+    bg_inner_ease_ = Easing!vec4(lobby_.background.inner_color, BgInnerColor);
+    bg_outer_ease_ = Easing!vec4(lobby_.background.outer_color, BgOuterColor);
 
-    lobby_.light_pos                    = vec3(0, 9, -1);
-    lobby_.cube_material.diffuse_color  = vec3(0.1, 0.1, 0.1);
-    lobby_.cube_material.light_color    = vec3(1, 0.8, 0.8);
-    lobby_.cube_material.light_power    = vec3(100, 100, 100);
-    lobby_.cube_material.ambient_color  = vec3(0.2, 0.2, 0.2);
-    lobby_.cube_material.specular_color = vec3(0.5, 0.2, 0.2);
-
-    frame_ = 0;
+    cube_interval_ease_ = Easing!float(lobby_.cube_interval, CubeInterval);
   }
   override SceneInterface Update(KeyInput input) {
+    const ratio = anime_.Update();
+
     lobby_.cube_matrix.rotation += vec3(PI/600, PI/600, PI/600);
 
+    lobby_.background.inner_color = bg_inner_ease_.Calculate(ratio);
+    lobby_.background.outer_color = bg_outer_ease_.Calculate(ratio);
+
+    lobby_.cube_interval = cube_interval_ease_.Calculate(ratio);
+
     if (input.down) {
       select_scene_.Initialize();
       return select_scene_;
@@ -63,7 +89,8 @@ class TitleScene : SceneInterface {
   }
   override void Draw() {
     lobby_.Draw();
-    title_.Draw(lobby_.Projection, lobby_.view.Create(), TitleMatrix, frame_++);
+    title_.Draw(lobby_.Projection, lobby_.view.Create(), TitleMatrix,
+        (anime_.frame%int.max).to!int);
   }
 
  private:
@@ -73,5 +100,9 @@ class TitleScene : SceneInterface {
 
   TitleTextProgram title_;
 
-  int frame_;
+  Animation anime_;
+
+  Easing!vec4 bg_inner_ease_;
+  Easing!vec4 bg_outer_ease_;
+  Easing!float cube_interval_ease_;
 }

src/sj/util/Animation.d

@@ -0,0 +1,30 @@
+/// License: MIT
+module sj.util.Animation;
+
+import std.algorithm;
+
+///
+struct Animation {
+ public:
+  ///
+  this(size_t frame_count) {
+    frame_count_ = frame_count;
+  }
+  ///
+  float Update() {
+    return (frame_++ * 1f / frame_count_).clamp(0f, 1f);
+  }
+  ///
+  @property bool isFinished() const {
+    return frame_ >= frame_count_;
+  }
+  ///
+  @property size_t frame() const {
+    return frame_;
+  }
+
+ private:
+  size_t frame_count_;
+
+  size_t frame_;
+}

src/sj/util/Easing.d

@@ -0,0 +1,37 @@
+/// License: MIT
+module sj.util.Easing;
+
+///
+enum EasingType {
+  Linear,
+  LinearMountain,
+}
+
+///
+struct Easing(T) {
+ public:
+  ///
+  this(T st, T ed, EasingType type = EasingType.Linear) {
+    st_   = st;
+    ed_   = ed;
+    type_ = type;
+  }
+
+  ///
+  T Calculate(float t) {
+    final switch (type_) with (EasingType) {
+      case LinearMountain:
+        t = t*2;
+        t = t > 1? 2-t: t;
+        goto case;
+      case Linear:
+        return (ed_ - st_) * t + st_;
+    }
+  }
+
+ private:
+  T st_;
+  T ed_;
+
+  EasingType type_;
+}