From 2cc03476b35d02bd71a14aa40986f75a6fb9a019 Mon Sep 17 00:00:00 2001
From: itsRevela <rexmarek@gmail.com>
Date: Wed, 1 Apr 2026 02:21:23 -0500
Subject: [PATCH] fix: skin preview animations too fast with VSync off

The walking and attack animations in the Change Skin menu were
frame-rate-dependent, advancing per render call with no delta time
scaling. With uncapped FPS they ran proportionally too fast.

Add time-based scaling relative to a 60fps baseline. The scale is
computed once per frame (cached for 0.5ms) so multiple skin previews
rendered in the same frame all animate at the correct speed.
---
 .../Common/UI/UIControl_PlayerSkinPreview.cpp | 62 +++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/Minecraft.Client/Common/UI/UIControl_PlayerSkinPreview.cpp b/Minecraft.Client/Common/UI/UIControl_PlayerSkinPreview.cpp
index b8c439b1..bed4012a 100644
--- a/Minecraft.Client/Common/UI/UIControl_PlayerSkinPreview.cpp
+++ b/Minecraft.Client/Common/UI/UIControl_PlayerSkinPreview.cpp
@@ -13,6 +13,56 @@
 //#define SKIN_PREVIEW_BOB_ANIM
 #define SKIN_PREVIEW_WALKING_ANIM
 
+#ifdef _WINDOWS64
+// Frame-rate-independent animation scaling.
+// The skin preview animations were designed for ~60fps (VSync on).
+// With uncapped FPS, each frame's contribution must be scaled down.
+// The scale is computed once per frame (keyed by frame counter) so
+// that multiple skin previews rendered in the same frame all use the
+// same value instead of measuring near-zero deltas between each other.
+static float s_skinAnimCachedScale = 1.0f;
+static double s_skinAnimLastTime = 0.0;
+static double s_skinAnimFreqInv = 0.0;
+
+static float GetSkinAnimDeltaScale()
+{
+	// Use the main loop's frame counter to detect a new frame.
+	// GetTickCount changes every ~16ms, but we need per-frame detection.
+	// Use a simple time threshold: if <0.1ms since last call, same frame.
+	if (s_skinAnimFreqInv == 0.0)
+	{
+		LARGE_INTEGER freq;
+		QueryPerformanceFrequency(&freq);
+		s_skinAnimFreqInv = 1.0 / (double)freq.QuadPart;
+	}
+	LARGE_INTEGER now;
+	QueryPerformanceCounter(&now);
+	double currentTime = (double)now.QuadPart * s_skinAnimFreqInv;
+
+	// If less than 0.5ms since last call, assume same frame -- reuse cached scale
+	double elapsed = currentTime - s_skinAnimLastTime;
+	if (s_skinAnimLastTime != 0.0 && elapsed < 0.0005)
+	{
+		return s_skinAnimCachedScale;
+	}
+
+	if (s_skinAnimLastTime == 0.0)
+	{
+		s_skinAnimLastTime = currentTime;
+		s_skinAnimCachedScale = 1.0f;
+		return 1.0f;
+	}
+
+	s_skinAnimLastTime = currentTime;
+
+	const double kBaselineFrameTime = 1.0 / 60.0;
+	float scale = static_cast<float>(elapsed / kBaselineFrameTime);
+	if (scale > 3.0f) scale = 3.0f;
+	s_skinAnimCachedScale = scale;
+	return scale;
+}
+#endif
+
 UIControl_PlayerSkinPreview::UIControl_PlayerSkinPreview()
 {
 	UIControl::setControlType(UIControl::ePlayerSkinPreview);
@@ -287,7 +337,11 @@ void UIControl_PlayerSkinPreview::render(EntityRenderer *renderer, double x, dou
 			break;
 		case e_SkinPreviewAnimation_Attacking:
 			model->holdingRightHand = true;
+#ifdef _WINDOWS64
+			m_swingTime += GetSkinAnimDeltaScale();
+#else
 			m_swingTime++;
+#endif
 			if (m_swingTime >= (Player::SWING_DURATION * 3) )
 			{
 				m_swingTime = 0;
@@ -340,8 +394,16 @@ void UIControl_PlayerSkinPreview::render(EntityRenderer *renderer, double x, dou
 
 #ifdef SKIN_PREVIEW_WALKING_ANIM
 	m_walkAnimSpeedO = m_walkAnimSpeed;
+#ifdef _WINDOWS64
+	{
+		float animScale = GetSkinAnimDeltaScale();
+		m_walkAnimSpeed += (0.1f - m_walkAnimSpeed) * 0.4f * animScale;
+		m_walkAnimPos += m_walkAnimSpeed * animScale;
+	}
+#else
 	m_walkAnimSpeed += (0.1f - m_walkAnimSpeed) * 0.4f;
 	m_walkAnimPos += m_walkAnimSpeed;
+#endif
 	float ws = m_walkAnimSpeedO + (m_walkAnimSpeed - m_walkAnimSpeedO) * a;
 	float wp = m_walkAnimPos - m_walkAnimSpeed * (1 - a);
 #else