From 7e41c98cd3b5f0d4ac0a79610f9e47a6f5ec6168 Mon Sep 17 00:00:00 2001
From: falsycat <me@falsy.cat>
Date: Sun, 13 Oct 2019 00:00:00 +0000
Subject: [PATCH] [update] Implemented a background transition for selecting
 songs.

---
 .bin/songs/list.json |  2 +-
 src/sj/SelectScene.d | 33 ++++++++++++++++++++++++---------
 src/sj/Song.d        | 24 +++++++++++++++++++-----
 3 files changed, 44 insertions(+), 15 deletions(-)

diff --git a/.bin/songs/list.json b/.bin/songs/list.json
index 22be6a8..851c9ad 100644
--- a/.bin/songs/list.json
+++ b/.bin/songs/list.json
@@ -9,7 +9,7 @@
       "play-offset": 1000,
       "play-loop": 2000,
       "bg-inner-color": [0.8, 0.8, 0.8, 1],
-      "bg-outer-color": [0.8, 0.8, 0.8, 1]
+      "bg-outer-color": [0.1, 0.1, 0.1, 1]
     }
   }
 ]
diff --git a/src/sj/SelectScene.d b/src/sj/SelectScene.d
index 0471ebd..caed85e 100644
--- a/src/sj/SelectScene.d
+++ b/src/sj/SelectScene.d
@@ -120,14 +120,14 @@ private class FirstSetupState : AbstractSceneState {
  public:
   this(SelectScene owner) {
     super(owner);
-    stage_appear_state_ = new StageAppearState(owner);
+    stage_appear_state_ = new SongAppearState(owner);
   }
 
   enum AnimeFrames  = 30;
-  enum BgInnerColor = vec4(0.8, 0.6, 0.6, 1);
+  enum BgInnerColor = vec4(0.4, 0.2, 0.2, 1);
   enum BgOuterColor = vec4(-0.4, -0.4, -0.4, 1);
 
-  enum CubeRotationSpeed = vec3(0, PI/10, 0);
+  enum CubeRotationSpeed = vec3(0, PI/5, 0);
   enum CubeInterval   = 0.06;
 
   void Initialize() {
@@ -154,7 +154,7 @@ private class FirstSetupState : AbstractSceneState {
   }
 
  private:
-  StageAppearState stage_appear_state_;
+  SongAppearState stage_appear_state_;
 
   Animation anime_;
 
@@ -163,7 +163,7 @@ private class FirstSetupState : AbstractSceneState {
 
   Easing!float cube_interval_ease_;
 }
-private class StageAppearState : AbstractSceneState {
+private class SongAppearState : AbstractSceneState {
  public:
   this(SelectScene owner) {
     super(owner);
@@ -177,7 +177,16 @@ private class StageAppearState : AbstractSceneState {
 
     anime_ = Animation(AnimeFrames);
 
-    cube_interval_ease_ = Easing!float(owner.lobby_.cube_interval, 0.005);
+    auto lobby = owner.lobby_;
+
+    cube_rota_speed_ease_ = Easing!vec3(
+        FirstSetupState.CubeRotationSpeed, CubeRotationSpeed);
+    cube_interval_ease_ = Easing!float(lobby.cube_interval, 0.005);
+
+    with (owner.songs_[song_index_].preview) {
+      bg_inner_ease_ = Easing!vec4(lobby.background.inner_color, bg_inner_color);
+      bg_outer_ease_ = Easing!vec4(lobby.background.outer_color, bg_outer_color);
+    }
 
     sfSound_setBuffer(owner.sound_, owner.soundres_.spotlight);
     sfSound_play(owner.sound_);
@@ -185,9 +194,11 @@ private class StageAppearState : AbstractSceneState {
   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);
+    owner.lobby_.cube_matrix.rotation += cube_rota_speed_ease_.Calculate(ratio);
+    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);
     return CreateResult(this);
   }
 
@@ -196,5 +207,9 @@ private class StageAppearState : AbstractSceneState {
 
   Animation anime_;
 
+  Easing!vec3  cube_rota_speed_ease_;
   Easing!float cube_interval_ease_;
+
+  Easing!vec4 bg_inner_ease_;
+  Easing!vec4 bg_outer_ease_;
 }
diff --git a/src/sj/Song.d b/src/sj/Song.d
index bdbd8f7..1701147 100644
--- a/src/sj/Song.d
+++ b/src/sj/Song.d
@@ -6,8 +6,7 @@ import std.array,
        std.exception,
        std.json,
        std.path,
-       std.string,
-       std.typecons;
+       std.string;
 
 import derelict.sfml2.audio,
        derelict.sfml2.system;
@@ -26,9 +25,9 @@ class Song {
     size_t play_offset;
 
     ///
-    Nullable!vec4 bg_inner_color;
+    vec4 bg_inner_color = vec4(0, 0, 0, 0);
     ///
-    Nullable!vec4 bg_outer_color;
+    vec4 bg_outer_color = vec4(0, 0, 0, 0);
   }
 
   ///
@@ -51,7 +50,13 @@ class Song {
     music_       = sfMusic_createFromFile(music_path.toStringz).enforce;
     script_path_ = buildPath(basepath, json["script"].str);
 
-    // TODO: update preview config
+    with (preview_) {
+      const preview_json = json["preview"];
+
+      play_offset    = preview_json["play-offset"].integer;
+      bg_inner_color = GetVectorFromJson!4(preview_json["bg-inner-color"]);
+      bg_outer_color = GetVectorFromJson!4(preview_json["bg-outer-color"]);
+    }
   }
   ~this() {
     sfMusic_destroy(music_);
@@ -83,6 +88,15 @@ class Song {
   static float GetNumericAsFloatFromJson(in JSONValue json) {
     return json.type == JSONType.float_? json.floating: json.integer;
   }
+  static Vector!(float, dim) GetVectorFromJson(size_t dim)(in JSONValue json) {
+    (json.array.length == dim).enforce;
+
+    Vector!(float, dim) v;
+    static foreach (i; 0..dim) {
+      v.vector[i] = GetNumericAsFloatFromJson(json.array[i]);
+    }
+    return v;
+  }
 
   string name_;