ControllerInterface: Input detection improvements.

Source/Core/InputCommon/ControlReference/ControlReference.cpp

@@ -2,18 +2,24 @@
 // Licensed under GPLv2+
 // Refer to the license.txt file included.
 
+#include "InputCommon/ControlReference/ControlReference.h"
+
+#include <vector>
+
 #include "Common/Thread.h"
 // For InputGateOn()
 // This is a bad layering violation, but it's the cleanest
 // place I could find to put it.
 #include "Core/ConfigManager.h"
 #include "Core/Host.h"
 
-#include "InputCommon/ControlReference/ControlReference.h"
-
 using namespace ciface::ExpressionParser;
 
+namespace
+{
+// Compared to an input's current state (ideally 1.0) minus abs(initial_state) (ideally 0.0).
 constexpr ControlState INPUT_DETECT_THRESHOLD = 0.55;
+}  // namespace
 
 bool ControlReference::InputGateOn()
 {
@@ -110,56 +116,53 @@ ControlState OutputReference::State(const ControlState state)
   return 0.0;
 }
 
-//
-// InputReference :: Detect
-//
-// Wait for input on all binded devices
-// supports not detecting inputs that were held down at the time of Detect start,
-// which is useful for those crazy flightsticks that have certain buttons that are always held down
-// or some crazy axes or something
-// upon input, return pointer to detected Control
-// else return nullptr
-//
+// Wait for input on a particular device.
+// Inputs are considered if they are first seen in a neutral state.
+// This is useful for crazy flightsticks that have certain buttons that are always held down
+// and also properly handles detection when using "FullAnalogSurface" inputs.
+// Upon input, return a pointer to the detected Control, else return nullptr.
 ciface::Core::Device::Control* InputReference::Detect(const unsigned int ms,
                                                       ciface::Core::Device* const device)
 {
-  unsigned int time = 0;
-  std::vector<bool> states(device->Inputs().size());
+  struct InputState
+  {
+    ciface::Core::Device::Input& input;
+    ControlState initial_state;
+  };
 
-  if (device->Inputs().empty())
-    return nullptr;
+  std::vector<InputState> input_states;
+  for (auto* input : device->Inputs())
+  {
+    // Don't detect things like absolute cursor position.
+    if (!input->IsDetectable())
+      continue;
+
+    // Undesirable axes will have negative values here when trying to map a "FullAnalogSurface".
+    input_states.push_back({*input, input->GetState()});
+  }
 
-  // get starting state of all inputs,
-  // so we can ignore those that were activated at time of Detect start
-  std::vector<ciface::Core::Device::Input*>::const_iterator i = device->Inputs().begin(),
-                                                            e = device->Inputs().end();
-  for (std::vector<bool>::iterator state = states.begin(); i != e; ++i)
-    *state++ = ((*i)->GetState() > (1 - INPUT_DETECT_THRESHOLD));
+  if (input_states.empty())
+    return nullptr;
 
+  unsigned int time = 0;
   while (time < ms)
   {
+    Common::SleepCurrentThread(10);
+    time += 10;
+
     device->UpdateInput();
-    i = device->Inputs().begin();
-    for (std::vector<bool>::iterator state = states.begin(); i != e; ++i, ++state)
+    for (auto& input_state : input_states)
     {
-      // detected an input
-      if ((*i)->IsDetectable() && (*i)->GetState() > INPUT_DETECT_THRESHOLD)
-      {
-        // input was released at some point during Detect call
-        // return the detected input
-        if (false == *state)
-          return *i;
-      }
-      else if ((*i)->GetState() < (1 - INPUT_DETECT_THRESHOLD))
-      {
-        *state = false;
-      }
+      // We want an input that was initially 0.0 and currently 1.0.
+      const auto detection_score =
+          (input_state.input.GetState() - std::abs(input_state.initial_state));
+
+      if (detection_score > INPUT_DETECT_THRESHOLD)
+        return &input_state.input;
     }
-    Common::SleepCurrentThread(10);
-    time += 10;
   }
 
-  // no input was detected
+  // No input was detected. :'(
   return nullptr;
 }
 

Source/Core/InputCommon/ControlReference/ExpressionParser.cpp

@@ -217,7 +217,19 @@ class ControlExpression : public Expression
   std::shared_ptr<Device> m_device;
 
   explicit ControlExpression(ControlQualifier qualifier_) : qualifier(qualifier_) {}
-  ControlState GetValue() const override { return control ? control->ToInput()->GetState() : 0.0; }
+  ControlState GetValue() const override
+  {
+    if (!control)
+      return 0.0;
+
+    // Note: Inputs may return negative values in situations where opposing directions are
+    // activated. We clamp off the negative values here.
+
+    // FYI: Clamping values greater than 1.0 is purposely not done to support unbounded values in
+    // the future. (e.g. raw accelerometer/gyro data)
+
+    return std::max(0.0, control->ToInput()->GetState());
+  }
   void SetValue(ControlState value) override
   {
     if (control)

Source/Core/InputCommon/ControllerInterface/DInput/DInputJoystick.cpp

@@ -259,7 +259,7 @@ std::string Joystick::Hat::GetName() const
 
 ControlState Joystick::Axis::GetState() const
 {
-  return std::max(0.0, ControlState(m_axis - m_base) / m_range);
+  return ControlState(m_axis - m_base) / m_range;
 }
 
 ControlState Joystick::Button::GetState() const

Source/Core/InputCommon/ControllerInterface/Device.cpp

@@ -4,6 +4,7 @@
 
 #include "InputCommon/ControllerInterface/Device.h"
 
+#include <cmath>
 #include <memory>
 #include <sstream>
 #include <string>
@@ -68,6 +69,11 @@ Device::Output* Device::FindOutput(const std::string& name) const
   return nullptr;
 }
 
+ControlState Device::FullAnalogSurface::GetState() const
+{
+  return (1 + std::max(0.0, m_high.GetState()) - std::max(0.0, m_low.GetState())) / 2;
+}
+
 //
 // DeviceQualifier :: ToString
 //
@@ -214,5 +220,5 @@ bool DeviceContainer::HasConnectedDevice(const DeviceQualifier& qualifier) const
   const auto device = FindDevice(qualifier);
   return device != nullptr && device->IsValid();
 }
-}
-}
+}  // namespace Core
+}  // namespace ciface

Source/Core/InputCommon/ControllerInterface/Device.h

@@ -55,9 +55,22 @@ class Device
   class Input : public Control
   {
   public:
-    // things like absolute axes/ absolute mouse position will override this
+    // Things like absolute axes/ absolute mouse position should override this to prevent
+    // undesirable behavior in our mapping logic.
     virtual bool IsDetectable() { return true; }
+
+    // Implementations should return a value from 0.0 to 1.0 across their normal range.
+    // One input should be provided for each "direction". (e.g. 2 for each axis)
+    // If possible, negative values may be returned in situations where an opposing input is
+    // activated. (e.g. When an underlying axis, X, is currently negative, "Axis X-", will return a
+    // positive value and "Axis X+" may return a negative value.)
+    // Doing so is solely to allow our input detection logic to better detect false positives.
+    // This is necessary when making use of "FullAnalogSurface" as multiple inputs will be seen
+    // increasing from 0.0 to 1.0 as a user tries to map just one. The negative values provide a
+    // view of the underlying axis. (Negative values are clamped off before they reach
+    // expression-parser or controller-emu)
     virtual ControlState GetState() const = 0;
+
     Input* ToInput() override { return this; }
   };
 
@@ -96,11 +109,7 @@ class Device
   {
   public:
     FullAnalogSurface(Input* low, Input* high) : m_low(*low), m_high(*high) {}
-    ControlState GetState() const override
-    {
-      return (1 + m_high.GetState() - m_low.GetState()) / 2;
-    }
-
+    ControlState GetState() const override;
     std::string GetName() const override { return m_low.GetName() + *m_high.GetName().rbegin(); }
 
   private:

Source/Core/InputCommon/ControllerInterface/XInput/XInput.cpp

@@ -228,13 +228,13 @@ ControlState Device::Trigger::GetState() const
 
 ControlState Device::Axis::GetState() const
 {
-  return std::max(0.0, ControlState(m_axis) / m_range);
+  return ControlState(m_axis) / m_range;
 }
 
 void Device::Motor::SetState(ControlState state)
 {
   m_motor = (WORD)(state * m_range);
   m_parent->UpdateMotors();
 }
-}
-}
+}  // namespace XInput
+}  // namespace ciface

Source/Core/InputCommon/ControllerInterface/evdev/evdev.cpp

@@ -343,7 +343,7 @@ ControlState evdevDevice::Axis::GetState() const
   int value = 0;
   libevdev_fetch_event_value(m_dev, EV_ABS, m_code, &value);
 
-  return std::max(0.0, ControlState(value - m_base) / m_range);
+  return ControlState(value - m_base) / m_range;
 }
 
 evdevDevice::Effect::Effect(int fd) : m_fd(fd)