From e26830bf71ca5968fc9d9d473966ea4b75120b56 Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Thu, 3 Nov 2016 11:11:46 +0100
Subject: logic/tracker, dinput, tracker/joystick: fix rounding errors

Issue: #487
Reported-by: @H-Bear-22
Closes #487

Also use a power of two for joy_axis_size. Floats are base 2.

axis_max in tracker/joystick had a fencepost error.
---
 dinput/win32-joystick.hpp                    | 2 +-
 logic/tracker.cpp                            | 6 +++++-
 tracker-joystick/ftnoir_tracker_joystick.cpp | 8 +++++---
 tracker-joystick/ftnoir_tracker_joystick.h   | 2 +-
 4 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/dinput/win32-joystick.hpp b/dinput/win32-joystick.hpp
index 4b48d4a1..6454c51c 100644
--- a/dinput/win32-joystick.hpp
+++ b/dinput/win32-joystick.hpp
@@ -55,7 +55,7 @@ struct OPENTRACK_DINPUT_EXPORT win32_joy_ctx
 
     using joys_t = std::unordered_map<QString, std::shared_ptr<joy>>;
 
-    static constexpr int joy_axis_size = 65535;
+    static constexpr int joy_axis_size = 65536;
 
     struct joy_info
     {
diff --git a/logic/tracker.cpp b/logic/tracker.cpp
index dc148eba..fd6ecfe7 100644
--- a/logic/tracker.cpp
+++ b/logic/tracker.cpp
@@ -141,9 +141,13 @@ void Tracker::logic()
     {
         using std::fmod;
         using std::copysign;
+        using std::fabs;
 
         const double x = value(i);
-        value(i) = fmod(x + copysign(180, x), 360) - copysign(180, x);
+        if (fabs(x) - 1e-2 > 180)
+            value(i) = fmod(x - copysign(180, -x), 360) + copysign(180, x);
+        else
+            value(i) = clamp(x, -180, 180);
     }
 
     logger.write_pose(raw); // raw
diff --git a/tracker-joystick/ftnoir_tracker_joystick.cpp b/tracker-joystick/ftnoir_tracker_joystick.cpp
index 263a5cb0..fff060d6 100644
--- a/tracker-joystick/ftnoir_tracker_joystick.cpp
+++ b/tracker-joystick/ftnoir_tracker_joystick.cpp
@@ -5,6 +5,7 @@
  * copyright notice and this permission notice appear in all copies.
  */
 #include "ftnoir_tracker_joystick.h"
+#include "compat/util.hpp"
 #include "api/plugin-api.hpp"
 #include <QMutexLocker>
 
@@ -48,11 +49,11 @@ void FTNoIR_Tracker::data(double *data)
         180,
         180
     };
-    
+
     const QString guid = s.guid;
     int axes[8];
     const bool ret = joy_ctx.poll_axis(guid, axes);
-    
+
     if (ret)
     {
         for (int i = 0; i < 6; i++)
@@ -61,7 +62,8 @@ void FTNoIR_Tracker::data(double *data)
             if (k < 0 || k >= 8)
                 data[i] = 0;
             else
-                data[i] = axes[k] * limits[i] / AXIS_MAX;
+                data[i] = clamp(axes[k] * limits[i] / AXIS_MAX,
+                                -limits[i], limits[i]);
         }
     }
 }
diff --git a/tracker-joystick/ftnoir_tracker_joystick.h b/tracker-joystick/ftnoir_tracker_joystick.h
index 0af1444e..a7e8fddd 100644
--- a/tracker-joystick/ftnoir_tracker_joystick.h
+++ b/tracker-joystick/ftnoir_tracker_joystick.h
@@ -45,7 +45,7 @@ public:
     void data(double *data);
     settings s;
     QString guid;
-    static constexpr int AXIS_MAX = win32_joy_ctx::joy_axis_size - 1;
+    static constexpr int AXIS_MAX = win32_joy_ctx::joy_axis_size;
     win32_joy_ctx joy_ctx;
 };
 
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