Support `vibrate(intensity, mode)` for iOS

[ParticleG]

On iOS 10.0+, iPadOS 10.0+ and Mac Catalyst 13.1+, it is possible for iPhones and iPads to generate different type of viberations, Not just a fixed 400ms one. Just Mapping seconds to UIFeedbackGenerator's subclasses like this:

if (@available(iOS 10.0, *)) {
	// iOS 10.0 and above
	UIImpactFeedbackGenerator *impact = nil;
	if (seconds >= 0.5 && seconds < 1.5) {
		impact = [[UIImpactFeedbackGenerator alloc] initWithStyle:UIImpactFeedbackStyleLight];
	} else if (seconds >= 1.5 && seconds < 2.5) {
		impact = [[UIImpactFeedbackGenerator alloc] initWithStyle:UIImpactFeedbackStyleMedium];
	} else if (seconds >= 2.5) {
		impact = [[UIImpactFeedbackGenerator alloc] initWithStyle:UIImpactFeedbackStyleHeavy];
	} else {
		return;
	}
	[impact impactOccurred];
	return;
}

[ParticleG]

And iOS13+ seems have even more options, I'll test them later

[ParticleG]

Add the second param to vibrate method with default value default, while on iOS default means the old fixed 500ms vibration, so it won't affect existing codes:

// src/modules/system/wrap_System.cpp
int w_vibrate(lua_State *L)
{
	double seconds = luaL_optnumber(L, 1, 0.5);
	const char *mode = luaL_optstring(L, 2, "default");
	instance()->vibrate(seconds, mode);
	return 0;
}

And ignore mode param on Android(For now):

// src/modules/system/System.cpp
void System::vibrate(double seconds, const std::string &mode) const
{
#ifdef LOVE_ANDROID
	love::android::vibrate(seconds);
	LOVE_UNUSED(mode);
#elif defined(LOVE_IOS)
	love::ios::vibrate(seconds, mode);
#else
	LOVE_UNUSED(seconds);
	LOVE_UNUSED(mode);
#endif
}

Then process them on iOS:

void vibrate(const double intensity, const std::string &mode)
{
	@autoreleasepool
	{
		if (mode != "default" && @available(iOS 10.0, *)) {
			// iOS 10.0 and above
			UIImpactFeedbackGenerator *impact = nil;
			if (mode == "light") {
				impact = [[UIImpactFeedbackGenerator alloc] initWithStyle:UIImpactFeedbackStyleLight];
			} else if (mode == "medium") {
				impact = [[UIImpactFeedbackGenerator alloc] initWithStyle:UIImpactFeedbackStyleMedium];
			} else if (mode == "heavy") {
				impact = [[UIImpactFeedbackGenerator alloc] initWithStyle:UIImpactFeedbackStyleHeavy];
			}
			if (@available(iOS 13.0, *)) {
				// iOS 13.0 and above
				if (mode == "soft") {
					impact = [[UIImpactFeedbackGenerator alloc] initWithStyle:UIImpactFeedbackStyleSoft];
				} else if (mode == "rigid") {
					impact = [[UIImpactFeedbackGenerator alloc] initWithStyle:UIImpactFeedbackStyleRigid];
				}
				if(impact != nil){
					[impact impactOccurredWithIntensity:(intensity < 0 ? 0 : (intensity > 1 ? 1 : intensity))];
					return;
				}
			}
			if(impact != nil){
				[impact impactOccurred];
				return;
			}
		}
		AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);
	}
}

[slime73]

Per my comment in the pull request (https://github.com/love2d/love/pull/1905#issuecomment-1445454068), I don't really feel good about having platform-specific function parameters. I wonder if some of Android's haptic feedback APIs are similar enough to the ones you've investigated for iOS that the two backends can both implement a mode parameter.

[ParticleG]

Android actually has similar "light", "medium" and "heavy" haptic feedbacks. Like EFFECT_TICK, EFFECT_CLICK and EFFECT_HEAVY_CLICK on Android 10+ , while android has much more customization options.

[ParticleG]

Another solution is continue using simgle seconds parameter, since Android can automatically switch between haptic vibration and normal long vibration depends on how long the vibration is (On my OnePlus 7 Pro with A 13, shorter than 0.3s are haptic vibrations), maybe we could manually set a custom curve to tell iOS when to switch from haptic vibration to long vibration.