WiimoteCommon: Tweak battery level math.

5 files changed, 21 insertions, 11 deletions

diff --git a/Source/Core/Core/HW/WiimoteCommon/WiimoteConstants.h b/Source/Core/Core/HW/WiimoteCommon/WiimoteConstants.h
index 2203eb3df2..99cf0e04e7 100644
--- a/Source/Core/Core/HW/WiimoteCommon/WiimoteConstants.h
+++ b/Source/Core/Core/HW/WiimoteCommon/WiimoteConstants.h
@@ -10,10 +10,6 @@ namespace WiimoteCommon
 {
 constexpr u8 MAX_PAYLOAD = 23;
 
-// Based on testing, old WiiLi.org docs, and WiiUse library:
-// Max battery level seems to be 0xc8 (decimal 200)
-constexpr u8 MAX_BATTERY_LEVEL = 0xc8;
-
 enum class InputReportID : u8
 {
   Status = 0x20,
diff --git a/Source/Core/Core/HW/WiimoteCommon/WiimoteReport.h b/Source/Core/Core/HW/WiimoteCommon/WiimoteReport.h
index 35c81518bb..39f4c5705a 100644
--- a/Source/Core/Core/HW/WiimoteCommon/WiimoteReport.h
+++ b/Source/Core/Core/HW/WiimoteCommon/WiimoteReport.h
@@ -207,6 +207,22 @@ struct InputReportStatus
   u8 leds : 4;
   u8 padding2[2];
   u8 battery;
+
+  constexpr float GetEstimatedCharge() const
+  {
+    return battery * BATTERY_LEVEL_M / BATTERY_MAX + BATTERY_LEVEL_B;
+  }
+  void SetEstimatedCharge(float charge)
+  {
+    battery = u8(std::lround((charge - BATTERY_LEVEL_B) / BATTERY_LEVEL_M * BATTERY_MAX));
+  }
+
+private:
+  static constexpr auto BATTERY_MAX = std::numeric_limits<decltype(battery)>::max();
+
+  // Linear fit of battery level mid-point for charge bars in home menu.
+  static constexpr float BATTERY_LEVEL_M = 2.46f;
+  static constexpr float BATTERY_LEVEL_B = -0.013f;
 };
 static_assert(sizeof(InputReportStatus) == 6, "Wrong size");
 
diff --git a/Source/Core/Core/HW/WiimoteEmu/EmuSubroutines.cpp b/Source/Core/Core/HW/WiimoteEmu/EmuSubroutines.cpp
index 8d98a93d59..5100ae74fc 100644
--- a/Source/Core/Core/HW/WiimoteEmu/EmuSubroutines.cpp
+++ b/Source/Core/Core/HW/WiimoteEmu/EmuSubroutines.cpp
@@ -235,13 +235,12 @@ void Wiimote::HandleRequestStatus(const OutputReportRequestStatus&)
 
   // Update status struct
   m_status.extension = m_extension_port.IsDeviceConnected();
-
-  m_status.battery = u8(std::lround(m_battery_setting.GetValue() / 100 * MAX_BATTERY_LEVEL));
+  m_status.SetEstimatedCharge(m_battery_setting.GetValue() / ciface::BATTERY_INPUT_MAX_VALUE);
 
   if (Core::WantsDeterminism())
   {
     // One less thing to break determinism:
-    m_status.battery = MAX_BATTERY_LEVEL;
+    m_status.SetEstimatedCharge(1.f);
   }
 
   // Less than 0x20 triggers the low-battery flag:
diff --git a/Source/Core/InputCommon/ControllerInterface/Wiimote/Wiimote.cpp b/Source/Core/InputCommon/ControllerInterface/Wiimote/Wiimote.cpp
index 059138e52a..3ff61621d8 100644
--- a/Source/Core/InputCommon/ControllerInterface/Wiimote/Wiimote.cpp
+++ b/Source/Core/InputCommon/ControllerInterface/Wiimote/Wiimote.cpp
@@ -288,8 +288,7 @@ Device::Device(std::unique_ptr<WiimoteReal::Wiimote> wiimote) : m_wiimote(std::m
   AddInput(new AnalogInput<float>(&m_classic_state.triggers[1], classic_prefix + "R-Analog", 1.f));
 
   // Specialty inputs:
-  AddInput(new UndetectableAnalogInput<u8>(
-      &m_battery, "Battery", WiimoteCommon::MAX_BATTERY_LEVEL / ciface::BATTERY_INPUT_MAX_VALUE));
+  AddInput(new UndetectableAnalogInput<float>(&m_battery, "Battery", 1.f));
   AddInput(new UndetectableAnalogInput<WiimoteEmu::ExtensionNumber>(
       &m_extension_number_input, "Attached Extension", WiimoteEmu::ExtensionNumber(1)));
   AddInput(new UndetectableAnalogInput<bool>(&m_mplus_attached_input, "Attached MotionPlus", 1));
@@ -1550,7 +1549,7 @@ void Device::ProcessStatusReport(const InputReportStatus& status)
   // Update status periodically to keep battery level value up to date.
   m_status_outdated_time = Clock::now() + std::chrono::seconds(10);
 
-  m_battery = status.battery;
+  m_battery = status.GetEstimatedCharge() * BATTERY_INPUT_MAX_VALUE;
   m_leds = status.leds;
 
   if (!status.ir)
diff --git a/Source/Core/InputCommon/ControllerInterface/Wiimote/Wiimote.h b/Source/Core/InputCommon/ControllerInterface/Wiimote/Wiimote.h
index 75296c65b1..87165faff4 100644
--- a/Source/Core/InputCommon/ControllerInterface/Wiimote/Wiimote.h
+++ b/Source/Core/InputCommon/ControllerInterface/Wiimote/Wiimote.h
@@ -233,7 +233,7 @@ private:
 
   // Status report is requested every so often to update the battery level.
   Clock::time_point m_status_outdated_time = Clock::now();
-  u8 m_battery = 0;
+  float m_battery = 0;
   u8 m_leds = 0;
 
   bool m_speaker_configured = false;