From fade4c28477b9810133eb695b5d8fb3257d0cbd9 Mon Sep 17 00:00:00 2001
From: Rasmus Anthin <scratty@gmail.com>
Date: Mon, 18 Nov 2024 08:13:58 +0100
Subject: [PATCH] Added header Animation.h

---
 Animation.h | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 Animation.h

diff --git a/Animation.h b/Animation.h
new file mode 100644
index 0000000..8e49269
--- /dev/null
+++ b/Animation.h
@@ -0,0 +1,55 @@
+//
+//  Animations.h
+//  Termin8or
+//
+//  Created by Rasmus Anthin on 2024-11-18.
+//
+
+#pragma once
+#include <Core/Math.h>
+#include <functional>
+
+
+namespace easings
+{
+  std::function<float(float)> ease_in_sine = [](float t)
+  {
+    return 1.f - std::cos((t * math::c_pi) * 0.5f);
+  };
+  
+  std::function<float(float)> ease_out_sine = [](float t)
+  {
+    return std::sin((t * math::c_pi) * 0.5f);
+  };
+}
+
+
+struct TransitionAnimation
+{
+  float ease_in_start_time_s = 0.f;
+  float ease_in_end_time_s = 0.f;
+  float ease_out_start_time_s = 0.f;
+  float ease_out_end_time_s = 0.f;
+  
+  float animate(float time_s, float value_start, float value_stationary, float value_end,
+                std::function<float(float)>& ease_in_func, std::function<float(float)>& ease_out_func) const
+  {
+    float t_ease_in = math::value_to_param(time_s, ease_in_start_time_s, ease_in_end_time_s);
+    if (math::in_range<float>(t_ease_in, {}, 0.f, Range::FreeOpen))
+      return value_start;
+    if (math::in_range<float>(t_ease_in, 0.f, 1.f, Range::ClosedOpen))
+      return math::lerp(ease_in_func(1.f - t_ease_in), value_stationary, value_start);
+    float t_ease_out = math::value_to_param(time_s, ease_out_start_time_s, ease_out_end_time_s);
+    if (math::in_range<float>(t_ease_out, 0.f, 1.f, Range::ClosedOpen))
+      return math::lerp(ease_out_func(1.f - t_ease_out), value_end, value_stationary);
+    if (math::in_range<float>(t_ease_out, 1.f, {}, Range::ClosedFree))
+      return value_end;
+    return value_stationary;
+  }
+  
+  bool done(float time_s) const
+  {
+    float t_ease_out = math::value_to_param(time_s, ease_out_start_time_s, ease_out_end_time_s);
+    return math::in_range<float>(t_ease_out, 1.f, {}, Range::ClosedFree);
+  }
+};