Gamepad API for Android

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

Index: content/public/android/java/src/org/chromium/content/browser/input/GamepadDataMapper.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/input/GamepadDataMapper.java b/content/public/android/java/src/org/chromium/content/browser/input/GamepadDataMapper.java
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+++ b/content/public/android/java/src/org/chromium/content/browser/input/GamepadDataMapper.java
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+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.content.browser.input;
+
+import android.view.KeyEvent;
+import android.view.MotionEvent;
+
+import org.chromium.base.JNINamespace;
+import org.chromium.content.browser.input.gamepad_mapping.CanonicalAxisIndex;
+import org.chromium.content.browser.input.gamepad_mapping.CanonicalButtonIndex;
+
+import java.util.Arrays;
+
+/**
+ * Device specific input data converter for Gamepad API.
+ * Implemented per device by subclasses.
+ */
+@JNINamespace("content")
+abstract class GamepadDataMapper {
+    protected static final String PS3_SIXAXIS_DEVICE_NAME = "Sony PLAYSTATION(R)3 Controller";
+    protected static final String STANDARD_GAMEPAD_NAME = "(STANDARD_GAMEPAD)";
+    protected static final String STANDARD_MAPPING = "standard";
+
+    protected final WebGamepadData mData;
+
+    public abstract WebGamepadData map(float[] axes, boolean[] buttons);
+
+    // Factory method.
+    public static GamepadDataMapper createDataMapper(String deviceName) {
+        if (deviceName.equals(PS3_SIXAXIS_DEVICE_NAME))
+            return new PS3SixAxisGamepadDataMapper();
+
+        return new GenericGamepadDataMapper(deviceName);
+    }
+
+    protected GamepadDataMapper(String deviceName) {
+        mData = new WebGamepadData();
+        mData.id = deviceName + " " + STANDARD_GAMEPAD_NAME;
+        mData.mapping = STANDARD_MAPPING;
+        mData.axes = new float[CanonicalAxisIndex.NUM_CANONICAL_AXES];
+        mData.buttons = new float[CanonicalButtonIndex.NUM_CANONICAL_BUTTONS];
+    }
+
+    protected void clearAxesAndButtons() {
+        Arrays.fill(mData.axes, 0);
+        Arrays.fill(mData.buttons, 0);
+    }
+
+    // Most of the time we jut use 1 for pressed and 0 for not pressed.
+    // Note that however some devices can represent some buttons of the standard gamepad
+    // with analog values so we still want to store the button values as floats.
+    // For example the Samsung EI-GP20 maps dpad to AXIS_HAT_X and AXIS_HAT_Y.
+    protected float buttonValue(boolean pressed) { return pressed ? 1.0f : 0.0f; }
+
+    protected void mapCommonXYAxes(float[] axes) {
+        mData.axes[CanonicalAxisIndex.AXIS_LEFT_STICK_X] = axes[MotionEvent.AXIS_X];
+        mData.axes[CanonicalAxisIndex.AXIS_LEFT_STICK_Y] = axes[MotionEvent.AXIS_Y];
+    }
+
+    protected void mapCommonTriggerAxes(float[] axes) {
+        mData.buttons[CanonicalButtonIndex.BUTTON_LEFT_SHOULDER] = axes[MotionEvent.AXIS_LTRIGGER];
+        mData.buttons[CanonicalButtonIndex.BUTTON_RIGHT_SHOULDER] = axes[MotionEvent.AXIS_RTRIGGER];
+    }
+
+    protected void mapCommonTriggerButtons(boolean[] buttons) {
+        boolean l1 = buttons[KeyEvent.KEYCODE_BUTTON_L1];
+        boolean r1 = buttons[KeyEvent.KEYCODE_BUTTON_R1];
+        mData.buttons[CanonicalButtonIndex.BUTTON_LEFT_TRIGGER] = buttonValue(l1);
+        mData.buttons[CanonicalButtonIndex.BUTTON_RIGHT_TRIGGER] = buttonValue(r1);
+    }
+
+    protected void mapCommonThumbstickButtons(boolean[] buttons) {
+        boolean thumbL = buttons[KeyEvent.KEYCODE_BUTTON_THUMBL];
+        boolean thumbR = buttons[KeyEvent.KEYCODE_BUTTON_THUMBR];
+        mData.buttons[CanonicalButtonIndex.BUTTON_LEFT_THUMBSTICK] = buttonValue(thumbL);
+        mData.buttons[CanonicalButtonIndex.BUTTON_RIGHT_THUMBSTICK] = buttonValue(thumbR);
+    }
+
+    protected void mapCommonStartSelectButtons(boolean[] buttons) {
+        boolean select = buttons[KeyEvent.KEYCODE_BUTTON_SELECT];
+        boolean start = buttons[KeyEvent.KEYCODE_BUTTON_START];
+        mData.buttons[CanonicalButtonIndex.BUTTON_BACK_SELECT] = buttonValue(select);
+        mData.buttons[CanonicalButtonIndex.BUTTON_START] = buttonValue(start);
+    }
+
+    protected void mapCommonDpadButtons(boolean[] buttons) {
+        boolean dpadDown = buttons[KeyEvent.KEYCODE_DPAD_DOWN];
+        boolean dpadUp = buttons[KeyEvent.KEYCODE_DPAD_UP];
+        boolean dpadLeft = buttons[KeyEvent.KEYCODE_DPAD_LEFT];
+        boolean dpadRight = buttons[KeyEvent.KEYCODE_DPAD_RIGHT];
+        mData.buttons[CanonicalButtonIndex.BUTTON_DPAD_DOWN] = buttonValue(dpadDown);
+        mData.buttons[CanonicalButtonIndex.BUTTON_DPAD_UP] = buttonValue(dpadUp);
+        mData.buttons[CanonicalButtonIndex.BUTTON_DPAD_LEFT] = buttonValue(dpadLeft);
+        mData.buttons[CanonicalButtonIndex.BUTTON_DPAD_RIGHT] = buttonValue(dpadRight);
+    }
+
+    protected void mapCommonXYABButtons(boolean[] buttons) {
+        boolean bA = buttons[KeyEvent.KEYCODE_BUTTON_A];
+        boolean bB = buttons[KeyEvent.KEYCODE_BUTTON_B];
+        boolean bX = buttons[KeyEvent.KEYCODE_BUTTON_X];
+        boolean bY = buttons[KeyEvent.KEYCODE_BUTTON_Y];
+        mData.buttons[CanonicalButtonIndex.BUTTON_PRIMARY] = buttonValue(bA);
+        mData.buttons[CanonicalButtonIndex.BUTTON_SECONDARY] = buttonValue(bB);
+        mData.buttons[CanonicalButtonIndex.BUTTON_TERTIARY] = buttonValue(bX);
+        mData.buttons[CanonicalButtonIndex.BUTTON_QUATERNARY] = buttonValue(bY);
+    }
+}
+
+// This is a last resort if we find a device that we don't know about.
+// The Android API is general enough that this can be better than nothing
+// but we should not really rely on this.
+class GenericGamepadDataMapper extends GamepadDataMapper {
+    private final String mDeviceName;
+
+    GenericGamepadDataMapper(String deviceName) {
+        super(deviceName);
+        mDeviceName = deviceName;
+    }
+
+    // Find something for right stick x and y.
+    private void mapRightSticks(float[] axes) {
+        int position = CanonicalAxisIndex.AXIS_RIGHT_STICK_X;
+        // position + 1 is AXIS_RIGHT_STICK_Y.
+        assert mData.axes.length > position + 1;
+        float x = axes[MotionEvent.AXIS_RX];
+        float y = axes[MotionEvent.AXIS_RY];
+        if (x != 0 || y != 0) {
+            mData.axes[position++] = x;
+            mData.axes[position] = y;
+            return;
+        }
+        x = axes[MotionEvent.AXIS_Z];
+        y = axes[MotionEvent.AXIS_RZ];
+        if (x != 0 || y != 0) {
+            mData.axes[position++] = x;
+            mData.axes[position] = y;
+            return;
+        }
+        x = axes[MotionEvent.AXIS_HAT_X];
+        y = axes[MotionEvent.AXIS_HAT_Y];
+        if (x != 0 || y != 0) {
+            mData.axes[position++] = x;
+            mData.axes[position] = y;
+        }
+    }
+
+    public WebGamepadData map(float[] axes, boolean[] buttons) {
+        clearAxesAndButtons();
+
+        mapCommonXYAxes(axes);
+        mapRightSticks(axes);
+        mapCommonTriggerAxes(axes);
+        mapCommonXYABButtons(buttons);
+        mapCommonTriggerButtons(buttons);
+        mapCommonThumbstickButtons(buttons);
+        mapCommonStartSelectButtons(buttons);
+        mapCommonDpadButtons(buttons);
+
+        // TODO(b.kelemen): meta is missing.
+
+        return mData;
+    }
+}
+
+class PS3SixAxisGamepadDataMapper extends GamepadDataMapper {
+    PS3SixAxisGamepadDataMapper() {
+        super(PS3_SIXAXIS_DEVICE_NAME);
+    }
+
+    public WebGamepadData map(float[] axes, boolean[] buttons) {
+        clearAxesAndButtons();
+
+        mapCommonXYAxes(axes);
+
+        mData.axes[CanonicalAxisIndex.AXIS_RIGHT_STICK_X] = axes[MotionEvent.AXIS_Z];
+        mData.axes[CanonicalAxisIndex.AXIS_RIGHT_STICK_Y] = axes[MotionEvent.AXIS_RZ];
+
+        mapCommonTriggerAxes(axes);
+
+        boolean bA = buttons[KeyEvent.KEYCODE_BUTTON_A];
+        boolean bB = buttons[KeyEvent.KEYCODE_BUTTON_B];
+        boolean bX = buttons[KeyEvent.KEYCODE_BUTTON_X];
+        boolean bY = buttons[KeyEvent.KEYCODE_BUTTON_Y];
+        mData.buttons[CanonicalButtonIndex.BUTTON_PRIMARY] = buttonValue(bX);
+        mData.buttons[CanonicalButtonIndex.BUTTON_SECONDARY] = buttonValue(bY);
+        mData.buttons[CanonicalButtonIndex.BUTTON_TERTIARY] = buttonValue(bA);
+        mData.buttons[CanonicalButtonIndex.BUTTON_QUATERNARY] = buttonValue(bB);
+
+        mapCommonTriggerButtons(buttons);
+        mapCommonThumbstickButtons(buttons);
+        mapCommonStartSelectButtons(buttons);
+        mapCommonDpadButtons(buttons);
+
+        // TODO(b.kelemen): PS button is missing. Looks like it is swallowed by Android
+        // but probably there is a way to configure otherwise and in this case we should
+        // handle it.
+
+        return mData;
+    }
+}
+
+// TODO(b.kelemen): add more implementations. It would be nice to support at least those that are
+// supported on Linux.