Adding support for horizontal scrolling (touch pad and touch screen)

Also, adding support for devices which report fractional scrolling
amounts. E.g. a mouse with a continuous mouse wheel, or a Mac touch
pad. This is currently only supported in lwjgl3. It can probably be
added to android and maybe to gwt.

InputProcessor scrolled method now receives scroll amount for X and
Y. Changed type to float to support devices which report fractional
scroll amounts. Updated InputEvent in scene2d accordingly: added
scrollAmountX, scrollAmountY attributes and corresponding setters and
getters.

Input event queue can receive float scrolling values. Since the queue
stores the events with integers. Scrolling values are stored in fixed
precision format, with 8 bits for the fraction.

Updated backends accordingly: lwjgl, lwjgl3, android and gwt.

CHANGES

@@ -22,6 +22,7 @@
 - API Change: Removed arm abi from SharedLibraryLoader
 - API Addition: Added a Lwjgl3ApplicationConfiguration#foregroundFPS option.
 - API Change: Utility classes are now final and have a private constructor to prevent instantiation.
+- API Change: InputProcessor scrolled method now receives scroll amount for X and Y. Changed type to float to support devices which report fractional scroll amounts. Updated InputEvent in scene2d accordingly: added scrollAmountX, scrollAmountY attributes and corresponding setters and getters.
 
 [1.9.11]
 - Update to MobiVM 2.3.8

backends/gdx-backend-android/src/com/badlogic/gdx/backends/android/AndroidMouseHandler.java

@@ -35,7 +35,8 @@ public boolean onGenericMotion (MotionEvent event, DefaultAndroidInput input) {
 		final int action = event.getAction() & MotionEvent.ACTION_MASK;
 
 		int x = 0, y = 0;
-		int scrollAmount = 0;
+		int scrollAmountX = 0;
+		int scrollAmountY = 0;
 
 		long timeStamp = System.nanoTime();
 		synchronized (input) {
@@ -44,15 +45,16 @@ public boolean onGenericMotion (MotionEvent event, DefaultAndroidInput input) {
 				x = (int)event.getX();
 				y = (int)event.getY();
 				if ((x != deltaX) || (y != deltaY)) { // Avoid garbage events
-					postTouchEvent(input, TouchEvent.TOUCH_MOVED, x, y, 0, timeStamp);
+					postTouchEvent(input, TouchEvent.TOUCH_MOVED, x, y, 0, 0, timeStamp);
 					deltaX = x;
 					deltaY = y;
 				}
 				break;
 
 			case MotionEvent.ACTION_SCROLL:
-				scrollAmount = (int)-Math.signum(event.getAxisValue(MotionEvent.AXIS_VSCROLL));
-				postTouchEvent(input, TouchEvent.TOUCH_SCROLLED, 0, 0, scrollAmount, timeStamp);
+				scrollAmountY = (int)-Math.signum(event.getAxisValue(MotionEvent.AXIS_VSCROLL));
+				scrollAmountX = (int)-Math.signum(event.getAxisValue(MotionEvent.AXIS_HSCROLL));
+				postTouchEvent(input, TouchEvent.TOUCH_SCROLLED, 0, 0, scrollAmountX, scrollAmountY, timeStamp);
 
 			}
 		}
@@ -75,13 +77,14 @@ else if (action == MotionEvent.ACTION_SCROLL)
 		Gdx.app.log("AndroidMouseHandler", "action " + actionStr);
 	}
 
-	private void postTouchEvent (DefaultAndroidInput input, int type, int x, int y, int scrollAmount, long timeStamp) {
+	private void postTouchEvent (DefaultAndroidInput input, int type, int x, int y, int scrollAmountX, int scrollAmountY, long timeStamp) {
 		TouchEvent event = input.usedTouchEvents.obtain();
 		event.timeStamp = timeStamp;
 		event.x = x;
 		event.y = y;
 		event.type = type;
-		event.scrollAmount = scrollAmount;
+		event.scrollAmountX = scrollAmountX;
+		event.scrollAmountY = scrollAmountY;
 		input.touchEvents.add(event);
 	}
 

backends/gdx-backend-android/src/com/badlogic/gdx/backends/android/DefaultAndroidInput.java

@@ -77,7 +77,8 @@ static class TouchEvent {
 		int type;
 		int x;
 		int y;
-		int scrollAmount;
+		int scrollAmountX;
+		int scrollAmountY;
 		int button;
 		int pointer;
 	}
@@ -419,7 +420,7 @@ public void processEvents () {
 						processor.mouseMoved(e.x, e.y);
 						break;
 					case TouchEvent.TOUCH_SCROLLED:
-						processor.scrolled(e.scrollAmount);
+					    processor.scrolled(e.scrollAmountX,e.scrollAmountY);
 					}
 					usedTouchEvents.free(e);
 				}

backends/gdx-backend-lwjgl/src/com/badlogic/gdx/backends/lwjgl/DefaultLwjglInput.java

@@ -367,7 +367,7 @@ public void processEvents () {
 						processor.mouseMoved(e.x, e.y);
 						break;
 					case TouchEvent.TOUCH_SCROLLED:
-						processor.scrolled(e.scrollAmount);
+						processor.scrolled(0, e.scrollAmount);
 					}
 					usedTouchEvents.free(e);
 				}

backends/gdx-backend-lwjgl/src/com/badlogic/gdx/backends/lwjgl/LwjglAWTInput.java

@@ -383,7 +383,7 @@ void processEvents () {
 						processor.mouseMoved(e.x, e.y);
 						break;
 					case TouchEvent.TOUCH_SCROLLED:
-						processor.scrolled(e.scrollAmount);
+						processor.scrolled(0, e.scrollAmount);
 						break;
 					}
 					usedTouchEvents.free(e);

backends/gdx-backend-lwjgl3/src/com/badlogic/gdx/backends/lwjgl3/DefaultLwjgl3Input.java

@@ -87,31 +87,10 @@ public void invoke(long window, int codepoint) {
 	};
 
 	private GLFWScrollCallback scrollCallback = new GLFWScrollCallback() {
-		private long pauseTime = 250000000L; //250ms
-		private float scrollYRemainder;
-		private long lastScrollEventTime;
 		@Override
 		public void invoke(long window, double scrollX, double scrollY) {
 			DefaultLwjgl3Input.this.window.getGraphics().requestRendering();
-			if (scrollYRemainder > 0 && scrollY < 0 || scrollYRemainder < 0 && scrollY > 0 ||
-				TimeUtils.nanoTime() - lastScrollEventTime > pauseTime ) { 
-				// fire a scroll event immediately:
-				//  - if the scroll direction changes; 
-				//  - if the user did not move the wheel for more than 250ms
-				scrollYRemainder = 0;
-				int scrollAmount = (int)-Math.signum(scrollY);
-				eventQueue.scrolled(scrollAmount);
-				lastScrollEventTime = TimeUtils.nanoTime();
-			}
-			else {
-				scrollYRemainder += scrollY;
-				while (Math.abs(scrollYRemainder) >= 1) {
-					int scrollAmount = (int)-Math.signum(scrollY);
-					eventQueue.scrolled(scrollAmount);
-					lastScrollEventTime = TimeUtils.nanoTime();
-					scrollYRemainder += scrollAmount;
-				}
-			}
+			eventQueue.scrolled(-(float)scrollX, -(float)scrollY);
 		}
 	};
 

backends/gdx-backends-gwt/src/com/badlogic/gdx/backends/gwt/DefaultGwtInput.java

@@ -679,7 +679,7 @@ private void handleEvent (NativeEvent e) {
 		}
 		if (e.getType().equals(getMouseWheelEvent())) {
 			if (processor != null) {
-				processor.scrolled((int)getMouseWheelVelocity(e));
+				processor.scrolled(0, (int)getMouseWheelVelocity(e));
 			}
 			this.currentEventTimeStamp = TimeUtils.nanoTime();
 			e.preventDefault();

extensions/gdx-tools/src/com/badlogic/gdx/tools/particleeditor/ParticleEditor.java

@@ -350,11 +350,11 @@ public OrthoCamController (OrthographicCamera camera) {
 			}
 
 			@Override
-			public boolean scrolled (int amount) {
-				worldCamera.zoom += amount * 0.01f;
+			public boolean scrolled (float amountX, float amountY) {
+				worldCamera.zoom += amountY * 0.01f;
 				worldCamera.zoom = MathUtils.clamp(worldCamera.zoom, 0.01f, 5000);
 				worldCamera.update();
-				return super.scrolled(amount);
+				return super.scrolled(amountX,amountY);
 			}
 
 			@Override
@@ -599,7 +599,7 @@ public boolean mouseMoved (int x, int y) {
 		}
 
 		@Override
-		public boolean scrolled (int amount) {
+		public boolean scrolled (float amountX, float amountY) {
 			return false;
 		}
 

gdx/src/com/badlogic/gdx/InputAdapter.java

@@ -50,7 +50,7 @@ public boolean mouseMoved (int screenX, int screenY) {
 	}
 
 	@Override
-	public boolean scrolled (int amount) {
+	public boolean scrolled (float amountX, float amountY) {
 		return false;
 	}
 }

gdx/src/com/badlogic/gdx/InputEventQueue.java

@@ -92,7 +92,7 @@ public void drain () {
 				localProcessor.mouseMoved(q[i++], q[i++]);
 				break;
 			case SCROLLED:
-				localProcessor.scrolled(q[i++]);
+				localProcessor.scrolled(q[i++] / 256f, q[i++] / 256f);
 				break;
 			default:
 				throw new RuntimeException();
@@ -133,7 +133,7 @@ private synchronized int next (int nextType, int i) {
 				i += 2;
 				break;
 			case SCROLLED:
-				i++;
+				i += 2;
 				break;
 			default:
 				throw new RuntimeException();
@@ -218,10 +218,11 @@ public synchronized boolean mouseMoved (int screenX, int screenY) {
 		return false;
 	}
 
-	public synchronized boolean scrolled (int amount) {
+	public synchronized boolean scrolled(float amountX, float amountY) {
 		queue.add(SCROLLED);
 		queueTime();
-		queue.add(amount);
+		queue.add((int)(amountX * 256));
+		queue.add((int)(amountY * 256));
 		return false;
 	}
 

gdx/src/com/badlogic/gdx/InputMultiplexer.java

@@ -150,11 +150,11 @@ public boolean mouseMoved (int screenX, int screenY) {
 		return false;
 	}
 
-	public boolean scrolled (int amount) {
+	public boolean scrolled (float amountX,float amountY) {
 		Object[] items = processors.begin();
 		try {
 			for (int i = 0, n = processors.size; i < n; i++)
-				if (((InputProcessor)items[i]).scrolled(amount)) return true;
+				if (((InputProcessor)items[i]).scrolled(amountX, amountY)) return true;
 		} finally {
 			processors.end();
 		}

gdx/src/com/badlogic/gdx/InputProcessor.java

@@ -67,7 +67,8 @@ public interface InputProcessor {
 	public boolean mouseMoved (int screenX, int screenY);
 
 	/** Called when the mouse wheel was scrolled. Will not be called on iOS.
-	 * @param amount the scroll amount, -1 or 1 depending on the direction the wheel was scrolled.
+	 * @param amountX the horizontal scroll amount, negative or positive depending on the direction the wheel was scrolled.
+	 * @param amountY the vertical scroll amount, negative or positive depending on the direction the wheel was scrolled.
 	 * @return whether the input was processed. */
-	public boolean scrolled (int amount);
+	public boolean scrolled (float amountX, float amountY);
 }

gdx/src/com/badlogic/gdx/graphics/g3d/utils/CameraInputController.java

@@ -203,8 +203,8 @@ public boolean touchDragged (int screenX, int screenY, int pointer) {
 	}
 
 	@Override
-	public boolean scrolled (int amount) {
-		return zoom(amount * scrollFactor * translateUnits);
+	public boolean scrolled (float amountX, float amountY) {
+		return zoom(amountY * scrollFactor * translateUnits);
 	}
 
 	public boolean zoom (float amount) {

gdx/src/com/badlogic/gdx/input/RemoteSender.java

@@ -198,7 +198,7 @@ public boolean mouseMoved (int x, int y) {
 	}
 
 	@Override
-	public boolean scrolled (int amount) {
+	public boolean scrolled (float amountX, float amountY) {
 		return false;
 	}
 

gdx/src/com/badlogic/gdx/scenes/scene2d/InputEvent.java

@@ -24,8 +24,8 @@
  * @see InputListener */
 public class InputEvent extends Event {
 	private Type type;
-	private float stageX, stageY;
-	private int pointer, button, keyCode, scrollAmount;
+	private float stageX, stageY, scrollAmountX, scrollAmountY;
+	private int pointer, button, keyCode;
 	private char character;
 	private @Null Actor relatedActor;
 	private boolean touchFocus = true;
@@ -103,13 +103,21 @@ public void setCharacter (char character) {
 		this.character = character;
 	}
 
-	/** The amount the mouse was scrolled. Valid for: scrolled. */
-	public int getScrollAmount () {
-		return scrollAmount;
+	/** The amount the mouse was scrolled horizontally. Valid for: scrolled. */
+	public float getScrollAmountX () {
+		return scrollAmountX;
+	}
+	/** The amount the mouse was scrolled vertically. Valid for: scrolled. */
+	public float getScrollAmountY () {
+		return scrollAmountY;
+	}
+
+	public void setScrollAmountX (float scrollAmount) {
+		this.scrollAmountX = scrollAmount;
 	}
 
-	public void setScrollAmount (int scrollAmount) {
-		this.scrollAmount = scrollAmount;
+	public void setScrollAmountY (float scrollAmount) {
+		this.scrollAmountY = scrollAmount;
 	}
 
 	/** The actor related to the event. Valid for: enter and exit. For enter, this is the actor being exited, or null. For exit,

gdx/src/com/badlogic/gdx/scenes/scene2d/InputListener.java

@@ -74,7 +74,7 @@ public boolean handle (Event e) {
 		case mouseMoved:
 			return mouseMoved(event, tmpCoords.x, tmpCoords.y);
 		case scrolled:
-			return scrolled(event, tmpCoords.x, tmpCoords.y, event.getScrollAmount());
+			return scrolled(event, tmpCoords.x, tmpCoords.y, event.getScrollAmountX(), event.getScrollAmountY());
 		case enter:
 			enter(event, tmpCoords.x, tmpCoords.y, event.getPointer(), event.getRelatedActor());
 			return false;
@@ -128,7 +128,7 @@ public void exit (InputEvent event, float x, float y, int pointer, @Null Actor t
 	}
 
 	/** Called when the mouse wheel has been scrolled. When true is returned, the event is {@link Event#handle() handled}. */
-	public boolean scrolled (InputEvent event, float x, float y, int amount) {
+	public boolean scrolled (InputEvent event, float x, float y, float amountX, float amountY) {
 		return false;
 	}
 

gdx/src/com/badlogic/gdx/scenes/scene2d/Stage.java

@@ -386,15 +386,16 @@ public boolean mouseMoved (int screenX, int screenY) {
 
 	/** Applies a mouse scroll event to the stage and returns true if an actor in the scene {@link Event#handle() handled} the
 	 * event. This event only occurs on the desktop. */
-	public boolean scrolled (int amount) {
+	public boolean scrolled (float amountX, float amountY) {
 		Actor target = scrollFocus == null ? root : scrollFocus;
 
 		screenToStageCoordinates(tempCoords.set(mouseScreenX, mouseScreenY));
 
 		InputEvent event = Pools.obtain(InputEvent.class);
 		event.setStage(this);
 		event.setType(InputEvent.Type.scrolled);
-		event.setScrollAmount(amount);
+		event.setScrollAmountX(amountX);
+		event.setScrollAmountY(amountY);
 		event.setStageX(tempCoords.x);
 		event.setStageY(tempCoords.y);
 		target.fire(event);

gdx/src/com/badlogic/gdx/scenes/scene2d/ui/ScrollPane.java

@@ -214,13 +214,12 @@ public boolean handle (Event event) {
 		addListener(flickScrollListener);
 
 		addListener(new InputListener() {
-			public boolean scrolled (InputEvent event, float x, float y, int amount) {
+			public boolean scrolled (InputEvent event, float x, float y, float scrollAmountX, float scrollAmountY) {
 				setScrollbarsVisible(true);
-				if (scrollY)
-					setScrollY(amountY + getMouseWheelY() * amount);
-				else if (scrollX) //
-					setScrollX(amountX + getMouseWheelX() * amount);
-				else
+				if (scrollY || scrollX) {
+					setScrollY(amountY + getMouseWheelY() * scrollAmountY);
+					setScrollX(amountX + getMouseWheelX() * scrollAmountX);
+				} else
 					return false;
 				return true;
 			}