GamepadHapticActuator.playEffect() with a magnitude < 0.1 has no effect

cdumez · cdumez · commit 2872417b1ad8 · 2023-01-13T07:38:53.000-08:00
https://bugs.webkit.org/show_bug.cgi?id=250522 Reviewed by Youenn Fablet. GamepadHapticActuator.playEffect() with a magnitude < 0.1 has no effect in Safari but triggers vibration in Chrome. This is causing the gamepad to vibrate a lot less with Safari than Chrome when playing games such as Forza on XBox Cloud. I noticed that passing a value < 0.1 as intensity to GameController doesn't result in any vibration of the gamepad. To address this we now scale the magnitude value to be in the [0.1; 1] range before passing it as intensity to the GameController framework. The exception is the value 0 which is still treated as 0 (no vibration). This makes the experience on XBox Cloud a lot more comparable between Safari and Chrome. * Source/WebCore/platform/gamepad/cocoa/GameControllerHapticEffect.mm: (WebCore::magnitudeToIntensity): (WebCore::GameControllerHapticEffect::create): Canonical link: https://commits.webkit.org/258874@main
diff --git a/Source/WebCore/platform/gamepad/cocoa/GameControllerHapticEffect.mm b/Source/WebCore/platform/gamepad/cocoa/GameControllerHapticEffect.mm
@@ -36,9 +36,22 @@
 
 namespace WebCore {
 
+static double magnitudeToIntensity(double magnitude)
+{
+    if (magnitude <= 0)
+        return 0;
+
+    // Magnitude is a value in the [0; 1] range. Intensity has the same range but with
+    // GameController, intensities below 0.1 don't register. To address this, we scale
+    // the magnitude to be in the [0.1; 1] range.
+    constexpr double newRange = 0.9;
+    constexpr double newMinimum = 0.1;
+    return (std::min(magnitude, 1.0) * newRange) + newMinimum;
+}
+
 std::unique_ptr<GameControllerHapticEffect> GameControllerHapticEffect::create(GameControllerHapticEngines& engines, const GamepadEffectParameters& parameters, CompletionHandler<void(bool)>&& completionHandler)
 {
-    auto createPlayer = [&](CHHapticEngine *engine, double intensity) -> RetainPtr<id> {
+    auto createPlayer = [&](CHHapticEngine *engine, double magnitude) -> RetainPtr<id> {
         NSDictionary* hapticDict = @{
             CHHapticPatternKeyPattern: @[
                 @{ CHHapticPatternKeyEvent: @{
@@ -47,7 +60,7 @@
                     CHHapticPatternKeyEventDuration: [NSNumber numberWithDouble:std::clamp<double>(parameters.duration / 1000., 0, GamepadEffectParameters::maximumDuration.seconds())],
                     CHHapticPatternKeyEventParameters: @[ @{
                         CHHapticPatternKeyParameterID: CHHapticEventParameterIDHapticIntensity,
-                        CHHapticPatternKeyParameterValue: [NSNumber numberWithDouble:std::clamp<double>(intensity, 0, 1)],
+                        CHHapticPatternKeyParameterValue: [NSNumber numberWithDouble:magnitudeToIntensity(magnitude)],
                     } ]
                 }, },
             ],
