From 91abcd32dcab9ef5de5cd4ba03f3e47fd6e314e9 Mon Sep 17 00:00:00 2001
From: Sanjay Govind <sanjay.govind9@gmail.com>
Date: Sun, 22 Dec 2024 23:55:13 +1300
Subject: [PATCH] WiimoteEmu: Fix Drum Extension Velocity

---
 .../Core/HW/WiimoteEmu/Extension/Drums.cpp    | 17 ++++++++-------
 .../Core/Core/HW/WiimoteEmu/Extension/Drums.h | 21 +++++++++++--------
 2 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/Source/Core/Core/HW/WiimoteEmu/Extension/Drums.cpp b/Source/Core/Core/HW/WiimoteEmu/Extension/Drums.cpp
index 24ceda4029..fd0214fe51 100644
--- a/Source/Core/Core/HW/WiimoteEmu/Extension/Drums.cpp
+++ b/Source/Core/Core/HW/WiimoteEmu/Extension/Drums.cpp
@@ -101,7 +101,7 @@ void Drums::BuildDesiredExtensionState(DesiredExtensionState* target_state)
   state.drum_pads = 0;
   m_pads->GetState(&state.drum_pads, drum_pad_bitmasks.data(), m_input_override_function);
 
-  state.softness = u8(7 - std::lround(m_hit_strength_setting.GetValue() * 7 / 100));
+  state.softness = u8(0x7F - std::lround(m_hit_strength_setting.GetValue() * 0x7F / 100));
 }
 
 void Drums::Update(const DesiredExtensionState& target_state)
@@ -118,23 +118,21 @@ void Drums::Update(const DesiredExtensionState& target_state)
     desired_state.stick_y = STICK_CENTER;
     desired_state.buttons = 0;
     desired_state.drum_pads = 0;
-    desired_state.softness = 7;
+    desired_state.softness = 0x7F;
   }
 
   DataFormat drum_data = {};
+  u8 velocity = 0x7F;
 
   // The meaning of these bits are unknown but they are usually set.
   drum_data.unk1 = 0b11;
   drum_data.unk2 = 0b11;
-  drum_data.unk3 = 0b1;
-  drum_data.unk4 = 0b1;
   drum_data.unk5 = 0b11;
 
   // Send no velocity data by default.
   drum_data.velocity_id = u8(VelocityID::None);
   drum_data.no_velocity_data_1 = 1;
   drum_data.no_velocity_data_2 = 1;
-  drum_data.softness = 7;
 
   drum_data.stick_x = desired_state.stick_x;
   drum_data.stick_y = desired_state.stick_y;
@@ -164,7 +162,7 @@ void Drums::Update(const DesiredExtensionState& target_state)
       drum_data.no_velocity_data_1 = 0;
       drum_data.no_velocity_data_2 = 0;
 
-      drum_data.softness = desired_state.softness;
+      velocity = desired_state.softness;
 
       // A drum-pad hit causes the relevent bit to be triggered for the next 10 frames.
       constexpr u8 HIT_FRAME_COUNT = 10;
@@ -174,6 +172,11 @@ void Drums::Update(const DesiredExtensionState& target_state)
       break;
     }
   }
+  drum_data.velocity0 = velocity;
+  drum_data.velocity1 = velocity >> 1;
+  drum_data.velocity2 = velocity >> 2;
+  drum_data.velocity3 = velocity >> 3;
+  drum_data.velocity64 = velocity >> 4;
 
   // Figure out which drum-pad bits to send.
   // Note: Relevent bits are not set until after velocity data has been sent.
@@ -190,7 +193,7 @@ void Drums::Update(const DesiredExtensionState& target_state)
   }
 
   // Flip button and drum-pad bits. (0 == pressed)
-  drum_data.buttons ^= 0xff;
+  drum_data.buttons ^= 0x7e;
   drum_data.drum_pads ^= 0xff;
 
   // Copy data to proper region in the "register".
diff --git a/Source/Core/Core/HW/WiimoteEmu/Extension/Drums.h b/Source/Core/Core/HW/WiimoteEmu/Extension/Drums.h
index ba65e48877..99288f958b 100644
--- a/Source/Core/Core/HW/WiimoteEmu/Extension/Drums.h
+++ b/Source/Core/Core/HW/WiimoteEmu/Extension/Drums.h
@@ -5,6 +5,7 @@
 
 #include <array>
 
+#include "Common/BitField.h"
 #include "Core/HW/WiimoteEmu/Extension/Extension.h"
 #include "InputCommon/ControllerEmu/Setting/NumericSetting.h"
 
@@ -47,24 +48,28 @@ public:
     // Seemingly random.
     u8 unk2 : 2;
 
-    // Always 1 with no velocity data and seemingly random otherwise.
-    u8 unk3 : 1;
+    u8 velocity3 : 1;
+
     // For which "pad" the velocity data is for.
     u8 velocity_id : 7;
 
-    // Always 1 with no velocity data and seemingly random otherwise.
-    u8 unk4 : 1;
+    u8 velocity2 : 1;
     // 1 with no velocity data and 0 when velocity data is present.
     u8 no_velocity_data_1 : 1;
     // These two bits seem to always be set. (0b11)
     u8 unk5 : 2;
     // 1 with no velocity data and 0 when velocity data is present.
     u8 no_velocity_data_2 : 1;
-    // How "soft" a drum pad has been hit as a range from 0:very-hard to 7:very-soft.
-    u8 softness : 3;
+
+    u8 velocity64 : 3;
 
     // Button bits.
-    u8 buttons;
+    union
+    {
+      u8 buttons;  // buttons
+      BitField<0, 1, u8> velocity0;
+      BitField<7, 1, u8> velocity1;
+    };
 
     // Drum-pad bits.
     u8 drum_pads;
@@ -94,8 +99,6 @@ public:
 
   void DoState(PointerWrap& p) override;
 
-  // FYI: The low/high bits of the button byte are "random" when velocity data is present.
-  // static constexpr u8 HAVE_VELOCITY_DATA = 0b10000001;
   static constexpr u8 BUTTON_PLUS = 0x04;
   static constexpr u8 BUTTON_MINUS = 0x10;