ControllerEmu: Round input floats instead of casting to prevent almos…

…t-neutral values from being rounded down.

Source/Core/Core/HW/GCPadEmu.cpp

@@ -68,7 +68,7 @@ GCPad::GCPad(const unsigned int index) : m_index(index)
   groups.emplace_back(m_main_stick = new ControllerEmu::OctagonAnalogStick(
                           "Main Stick", _trans("Control Stick"), main_gate_radius));
 
-  constexpr auto c_gate_radius = ControlState(C_STICK_GATE_RADIUS) / GCPadStatus::MAIN_STICK_RADIUS;
+  constexpr auto c_gate_radius = ControlState(C_STICK_GATE_RADIUS) / GCPadStatus::C_STICK_RADIUS;
   groups.emplace_back(m_c_stick = new ControllerEmu::OctagonAnalogStick(
                           "C-Stick", _trans("C Stick"), c_gate_radius));
 
@@ -160,23 +160,19 @@ GCPadStatus GCPad::GetInput() const
   m_dpad->GetState(&pad.button, dpad_bitmasks);
 
   // sticks
-  const ControllerEmu::AnalogStick::StateData main_stick_state = m_main_stick->GetState();
-  pad.stickX = static_cast<u8>(GCPadStatus::MAIN_STICK_CENTER_X +
-                               (main_stick_state.x * GCPadStatus::MAIN_STICK_RADIUS));
-  pad.stickY = static_cast<u8>(GCPadStatus::MAIN_STICK_CENTER_Y +
-                               (main_stick_state.y * GCPadStatus::MAIN_STICK_RADIUS));
-
-  const ControllerEmu::AnalogStick::StateData c_stick_state = m_c_stick->GetState();
-  pad.substickX = static_cast<u8>(GCPadStatus::C_STICK_CENTER_X +
-                                  (c_stick_state.x * GCPadStatus::C_STICK_RADIUS));
-  pad.substickY = static_cast<u8>(GCPadStatus::C_STICK_CENTER_Y +
-                                  (c_stick_state.y * GCPadStatus::C_STICK_RADIUS));
+  const auto main_stick_state = m_main_stick->GetState();
+  pad.stickX = MapFloat<u8>(main_stick_state.x, GCPadStatus::MAIN_STICK_CENTER_X);
+  pad.stickY = MapFloat<u8>(main_stick_state.y, GCPadStatus::MAIN_STICK_CENTER_Y);
+
+  const auto c_stick_state = m_c_stick->GetState();
+  pad.substickX = MapFloat<u8>(c_stick_state.x, GCPadStatus::C_STICK_CENTER_X);
+  pad.substickY = MapFloat<u8>(c_stick_state.y, GCPadStatus::C_STICK_CENTER_Y);
 
   // triggers
   std::array<ControlState, 2> triggers;
   m_triggers->GetState(&pad.button, trigger_bitmasks, triggers.data());
-  pad.triggerLeft = static_cast<u8>(triggers[0] * 0xFF);
-  pad.triggerRight = static_cast<u8>(triggers[1] * 0xFF);
+  pad.triggerLeft = MapFloat<u8>(triggers[0], 0);
+  pad.triggerRight = MapFloat<u8>(triggers[1], 0);
 
   return pad;
 }

Source/Core/InputCommon/ControllerEmu/ControllerEmu.h

@@ -4,9 +4,11 @@
 
 #pragma once
 
+#include <cmath>
 #include <memory>
 #include <mutex>
 #include <string>
+#include <type_traits>
 #include <vector>
 
 #include "Common/Common.h"
@@ -50,6 +52,29 @@ class EmulatedController
 
   std::vector<std::unique_ptr<ControlGroup>> groups;
 
+  // Maps a float from -1.0..+1.0 to an integer of the provided values.
+  template <typename T, typename F>
+  static T MapFloat(F input_value, T zero_value, T neg_1_value = std::numeric_limits<T>::min(),
+                    T pos_1_value = std::numeric_limits<T>::max())
+  {
+    static_assert(std::is_integral<T>(), "T is only sane for int types.");
+    static_assert(std::is_floating_point<F>(), "F is only sane for float types.");
+
+    static_assert(std::numeric_limits<long>::min() <= std::numeric_limits<T>::min() &&
+                      std::numeric_limits<long>::max() >= std::numeric_limits<T>::max(),
+                  "long is not a superset of T. use of std::lround is not sane.");
+
+    // Here we round when converting from float to int.
+    // After applying our deadzone, resizing, and reshaping math
+    // we sometimes have a near-zero value which is slightly negative. (e.g. -0.0001)
+    // Casting would round down but rounding will yield our "zero_value".
+
+    if (input_value > 0)
+      return T(std::lround((pos_1_value - zero_value) * input_value + zero_value));
+    else
+      return T(std::lround((zero_value - neg_1_value) * input_value + zero_value));
+  }
+
 private:
   ciface::Core::DeviceQualifier m_default_device;
   bool m_default_device_is_connected{false};