From 107158d1a96e5d886b5cefa767ca35b816a41857 Mon Sep 17 00:00:00 2001
From: MaybeMaru <97055307+MaybeMaru@users.noreply.github.com>
Date: Tue, 18 Jun 2024 00:54:57 +0200
Subject: [PATCH] add beat modifier

---
 README.md                                     |  1 +
 source/funkin/util/FunkMath.hx                |  8 ++--
 .../funkin/util/frontend/ModchartManager.hx   | 22 ++++++-----
 .../util/frontend/modifiers/BeatModifier.hx   | 37 +++++++++++++++++++
 4 files changed, 54 insertions(+), 14 deletions(-)
 create mode 100644 source/funkin/util/frontend/modifiers/BeatModifier.hx

diff --git a/README.md b/README.md
index 688b39be..8bdac36f 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,7 @@ Current version is beta 2.0, beta 3.0 soon to come!
 * [Midnight](https://github.com/what-is-a-git) - More accurate memory counter
 * [cyn](https://twitter.com/cyn0x8) - Demon Blur Shader
 * [Cracsthor](https://gamebanana.com/members/1844732) - PhantomMuff font
+* [4mbr0s32](https://github.com/4mbr0s3-2) - Modifiers from Schmovin
 
 ## How to make a mod
 
diff --git a/source/funkin/util/FunkMath.hx b/source/funkin/util/FunkMath.hx
index 845dde30..062a12b0 100644
--- a/source/funkin/util/FunkMath.hx
+++ b/source/funkin/util/FunkMath.hx
@@ -4,10 +4,10 @@ import flixel.math.FlxMatrix;
 
 class FunkMath
 {
-    public static inline var PI:Float = 3.14159265358979323846;
-	public static inline var DOUBLE_PI:Float = PI * 2;
-	public static inline var TO_RADS:Float = PI / 180;
-	public static inline var TO_DEGREES:Float = 180 / PI;
+    @:keep public static inline var PI:Float = 3.14159265358979323846;
+	@:keep public static inline var DOUBLE_PI:Float = PI * 2;
+	@:keep public static inline var TO_RADS:Float = PI / 180;
+	@:keep public static inline var TO_DEGREES:Float = 180 / PI;
 
 	public static inline function isZero(value:Float):Bool {
 		return Math.abs(value) < 0.0001;
diff --git a/source/funkin/util/frontend/ModchartManager.hx b/source/funkin/util/frontend/ModchartManager.hx
index fec3055e..86d05c3e 100644
--- a/source/funkin/util/frontend/ModchartManager.hx
+++ b/source/funkin/util/frontend/ModchartManager.hx
@@ -13,10 +13,20 @@ enum abstract Modifiers(String) from String to String {
     var BOOST = "BOOST";
     var DRUNK = "DRUNK";
     var TIPSY = "TIPSY";
+    var BEAT = "BEAT";
 }
 
 class ModchartManager extends EventHandler
 {
+    var modifiers:Map<String, Void->BasicModifier> = [
+        COS => () -> return new CosModifier(),
+        SIN => () -> return new SinModifier(),
+        BOOST => () -> return new BoostModifier(),
+        DRUNK => () -> return new DrunkModifier(),
+        TIPSY => () -> return new TipsyModifier(),
+        BEAT => () -> return new BeatModifier()
+    ];
+
     private var strumLines:Map<Int, StrumLineGroup> = [];
 
     var __postUpdate:Void->Void;
@@ -46,16 +56,6 @@ class ModchartManager extends EventHandler
         return new ModchartManager();
     }
 
-    // TODO: this crap
-
-    var modifiers:Map<String, Void->BasicModifier> = [
-        COS => () -> return new CosModifier(),
-        SIN => () -> return new SinModifier(),
-        BOOST => () -> return new BoostModifier(),
-        DRUNK => () -> return new DrunkModifier(),
-        TIPSY => () -> return new TipsyModifier()
-    ];
-
     function modifierFromName(name:String):BasicModifier {
         if (modifiers.exists(name)) {
             return modifiers.get(name)();
@@ -63,6 +63,8 @@ class ModchartManager extends EventHandler
         return null;
     }
 
+    // TODO: add a way for scripted modifiers to get the current mod data values
+
     public function makeModifier(name:String, defaultValues:Array<Dynamic>, callbacks:Dynamic) {
         name = name.toUpperCase().trim();
         modifiers.set(name, () -> {
diff --git a/source/funkin/util/frontend/modifiers/BeatModifier.hx b/source/funkin/util/frontend/modifiers/BeatModifier.hx
new file mode 100644
index 00000000..d2d868f9
--- /dev/null
+++ b/source/funkin/util/frontend/modifiers/BeatModifier.hx
@@ -0,0 +1,37 @@
+package funkin.util.frontend.modifiers;
+
+import funkin.util.frontend.ModchartManager.Modifiers;
+
+class BeatModifier extends BasicModifier
+{
+    public function new() {
+        super(BEAT, false);
+    }
+
+    function getAmplitude(currentBeat:Float)
+    {
+        var beat = currentBeat % 1;
+        var amp:Float = 0;
+        if (beat <= 0.3)
+            amp = FlxEase.quadIn((0.3 - beat) / 0.3) * 0.3;
+        else if (beat >= 0.7)
+            amp = -FlxEase.quadOut((beat - 0.7) / 0.3) * 0.3;
+        var neg = 1;
+        if (currentBeat % 2 >= 1)
+            neg = -1;
+        return amp / 0.3 * neg;
+    }
+
+    override function manageStrumUpdate(strum:NoteStrum, elapsed:Float, beat:Float) {
+        var size:Float = data[0];
+        if (FunkMath.isZero(size))
+            return;
+
+        strum.xModchart += scaleWidth(getAmplitude(Math.abs(beat))) * size;
+    }
+
+    // [size]
+    override function getDefaultValues() {
+        return [0.5];
+    }
+}
\ No newline at end of file