From d4997c6fb9e94f189075239e1ab58669f1c9af3b Mon Sep 17 00:00:00 2001
From: Connor McLaughlin <stenzek@gmail.com>
Date: Fri, 5 Feb 2021 00:39:42 +1000
Subject: [PATCH] Android: Manually scale axis values instead of using motion
 range

---
 .../src/cpp/android_controller_interface.cpp  | 10 +-------
 .../duckstation/EmulationSurfaceView.java     | 23 +++++++++++++++----
 2 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/android/app/src/cpp/android_controller_interface.cpp b/android/app/src/cpp/android_controller_interface.cpp
index e9d5241c9..6b97d0cbc 100644
--- a/android/app/src/cpp/android_controller_interface.cpp
+++ b/android/app/src/cpp/android_controller_interface.cpp
@@ -112,15 +112,7 @@ bool AndroidControllerInterface::HandleAxisEvent(u32 index, u32 axis, float valu
   const AxisCallback& cb = m_controllers[index].axis_mapping[static_cast<u32>(axis)][AxisSide::Full];
   if (cb)
   {
-    // Extend triggers from a 0 - 1 range to a -1 - 1 range for consistency with other inputs
-    if (axis == 4 && axis == 5)
-    {
-      cb((value * 2.0f) - 1.0f);
-    }
-    else
-    {
-      cb(value);
-    }
+    cb(value);
     return true;
   }
 
diff --git a/android/app/src/main/java/com/github/stenzek/duckstation/EmulationSurfaceView.java b/android/app/src/main/java/com/github/stenzek/duckstation/EmulationSurfaceView.java
index 0cdcb41c8..261ad4dac 100644
--- a/android/app/src/main/java/com/github/stenzek/duckstation/EmulationSurfaceView.java
+++ b/android/app/src/main/java/com/github/stenzek/duckstation/EmulationSurfaceView.java
@@ -208,6 +208,10 @@ public class EmulationSurfaceView extends SurfaceView {
         return !isExternalKeyCode(keyCode);
     }
 
+    private float clamp(float value, float min, float max) {
+        return (value < min) ? min : ((value > max) ? max : value);
+    }
+
     @Override
     public boolean onGenericMotionEvent(MotionEvent event) {
         final int source = event.getSource();
@@ -222,12 +226,21 @@ public class EmulationSurfaceView extends SurfaceView {
             final float axisValue = event.getAxisValue(mapping.deviceAxisOrButton);
             float emuValue;
 
-            if (mapping.deviceMotionRange != null) {
-                final float transformedValue = (axisValue - mapping.deviceMotionRange.getMin()) / mapping.deviceMotionRange.getRange();
-                emuValue = (transformedValue * 2.0f) - 1.0f;
-            } else {
-                emuValue = axisValue;
+            switch (mapping.deviceAxisOrButton) {
+                case MotionEvent.AXIS_BRAKE:
+                case MotionEvent.AXIS_GAS:
+                case MotionEvent.AXIS_LTRIGGER:
+                case MotionEvent.AXIS_RTRIGGER:
+                    // Scale 0..1 -> -1..1.
+                    emuValue = (clamp(axisValue, 0.0f, 1.0f) * 2.0f) - 1.0f;
+                    break;
+
+                default:
+                    // Everything else should already by -1..1 as per Android documentation.
+                    emuValue = clamp(axisValue, -1.0f, 1.0f);
+                    break;
             }
+
             Log.d("EmulationSurfaceView", String.format("axis %d value %f emuvalue %f", mapping.deviceAxisOrButton, axisValue, emuValue));
 
             if (mapping.axisMapping >= 0) {