Gamepad: cleanup mappings and add support for Samsung and PS3 gamepads

The way we map axes does not look quite correct to me. We rely on the ordering
in which InputDevice enumerates the motion ranges. There are several problems
with that. First, I don't find any evidence in the documentation that there is
a defined ordering. This means that InputDevice.getMotionRanges() does not
guarantee to enumerate the axes in the same order on different devices or
in different api versions. Second, this leads to using magic constants.
Third, ideally one should be able to add the code for a new device or at least
check if it is correct by looking at the Android specific documentation of the
device. But those documentations refer to api constants like
MotionEvent.AXIS_FOO instead of the index of the motion range.
This CL cleans it up by storing the axes values associatively indexed by api
constants, just like we do for buttons. Finally, it adds the device specific
code for the Samsung and the PS3 gamepads.

TEST=http://www.html5rocks.com/en/tutorials/doodles/gamepad/gamepad-tester/tester.html
BUG=330094

Review URL: https://codereview.chromium.org/307413004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@275378 0039d316-1c4b-4281-b951-d872f2087c98

content/public/android/java/src/org/chromium/content/browser/input/GamepadDevice.java

@@ -11,6 +11,7 @@ import android.view.KeyEvent;
 import android.view.MotionEvent;
 
 import java.util.Arrays;
+import java.util.List;
 
 /**
  * Manages information related to each connected gamepad device.
@@ -29,16 +30,16 @@ class GamepadDevice {
     // All axis values must be linearly normalized to the range [-1.0 .. 1.0].
     // As appropriate, -1.0 should correspond to "up" or "left", and 1.0
     // should correspond to "down" or "right".
-    private float[] mAxisValues;
+    private final float[] mAxisValues = new float[CanonicalAxisIndex.NUM_CANONICAL_AXES];
 
-    private float[] mButtonsValues;
+    private final float[] mButtonsValues = new float[CanonicalButtonIndex.NUM_CANONICAL_BUTTONS];;
 
     // When the user agent recognizes the attached inputDevice, it is recommended
     // that it be remapped to a canonical ordering when possible. Devices that are
     // not recognized should still be exposed in their raw form. Therefore we must
     // pass the raw Button and raw Axis values.
-    private float[] mRawButtons;
-    private float[] mRawAxes;
+    private final float[] mRawButtons = new float[256];
+    private final float[] mRawAxes = new float[256];
 
     // An identification string for the gamepad.
     private String mDeviceName;
@@ -51,25 +52,15 @@ class GamepadDevice {
         mDeviceId = inputDevice.getId();
         mDeviceName = inputDevice.getName();
         mTimestamp = SystemClock.uptimeMillis();
-        mButtonsValues = new float[CanonicalButtonIndex.NUM_CANONICAL_BUTTONS];
-        mAxisValues = new float[CanonicalAxisIndex.NUM_CANONICAL_AXES];
-        mRawButtons = new float[256];
-        // Get the total number of axes supported by gamepad.
-        int totalAxes = 0;
-        for (MotionRange range : inputDevice.getMotionRanges()) {
-            if ((range.getSource() & InputDevice.SOURCE_CLASS_JOYSTICK) != 0) {
-                totalAxes++;
-            }
-        }
         // Get axis ids and initialize axes values.
-        mAxes = new int[totalAxes];
-        mRawAxes = new float[totalAxes];
+        final List<MotionRange> ranges = inputDevice.getMotionRanges();
+        mAxes = new int[ranges.size()];
         int i = 0;
-        for (MotionRange range : inputDevice.getMotionRanges()) {
+        for (MotionRange range : ranges) {
             if ((range.getSource() & InputDevice.SOURCE_CLASS_JOYSTICK) != 0) {
-                mAxes[i] = range.getAxis();
-                mRawAxes[i] = 0.0f;
-                i++;
+                int axis = range.getAxis();
+                assert axis < 256;
+                mAxes[i++] = axis;
             }
         }
     }
@@ -157,10 +148,10 @@ class GamepadDevice {
         if (!GamepadList.isGamepadEvent(event)) return false;
         // Update axes values.
         for (int i = 0; i < mAxes.length; i++) {
-            mRawAxes[i] = event.getAxisValue(mAxes[i]);
+            int axis = mAxes[i];
+            mRawAxes[axis] = event.getAxisValue(axis);
         }
         mTimestamp = event.getEventTime();
         return true;
     }
-
 }