SDL: Implement touchscreen support

minetest · Dec 16, 2023 · a06c2d6 · a06c2d6
1 parent 9b52d6f
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diff --git a/source/Irrlicht/CIrrDeviceSDL.cpp b/source/Irrlicht/CIrrDeviceSDL.cpp
@@ -254,6 +254,11 @@ CIrrDeviceSDL::CIrrDeviceSDL(const SIrrlichtCreationParameters& param)
 		}
 	}
 
+	// Minetest has its own code to synthesize mouse events from touch events,
+	// so we prevent SDL from doing it.
+	SDL_SetHint(SDL_HINT_TOUCH_MOUSE_EVENTS, "0");
+	SDL_SetHint(SDL_HINT_MOUSE_TOUCH_EVENTS, "0");
+
 	// create keymap
 	createKeyMap();
 
@@ -740,6 +745,67 @@ bool CIrrDeviceSDL::run()
 
 			postEventFromUser(irrevent);
 			break;
+
+		case SDL_FINGERDOWN:
+			{
+				finger_ids.push_back(SDL_event.tfinger.fingerId);
+				size_t finger_idx = finger_ids.size() - 1;
+				size_t finger_count = finger_ids.size();
+
+				irrevent.EventType = irr::EET_TOUCH_INPUT_EVENT;
+				irrevent.TouchInput.Event = irr::ETIE_PRESSED_DOWN;
+				irrevent.TouchInput.ID = finger_idx;
+				irrevent.TouchInput.X = SDL_event.tfinger.x * Width;
+				irrevent.TouchInput.Y = SDL_event.tfinger.y * Height;
+				irrevent.TouchInput.touchedCount = finger_count;
+
+				postEventFromUser(irrevent);
+			}
+			break;
+
+		case SDL_FINGERMOTION:
+			{
+				auto iter = std::find(finger_ids.begin(), finger_ids.end(),
+						SDL_event.tfinger.fingerId);
+				size_t finger_idx = std::distance(finger_ids.begin(), iter);
+				size_t finger_count = finger_ids.size();
+				if (finger_idx == finger_count) {
+					// This shouldn't ever happen. Anyway, let's allocate a new ID.
+					finger_ids.push_back(SDL_event.tfinger.fingerId);
+				}
+
+				irrevent.EventType = irr::EET_TOUCH_INPUT_EVENT;
+				irrevent.TouchInput.Event = irr::ETIE_MOVED;
+				irrevent.TouchInput.ID = finger_idx;
+				irrevent.TouchInput.X = SDL_event.tfinger.x * Width;
+				irrevent.TouchInput.Y = SDL_event.tfinger.y * Height;
+				irrevent.TouchInput.touchedCount = finger_count;
+
+				postEventFromUser(irrevent);
+			}
+			break;
+
+		case SDL_FINGERUP:
+			{
+				auto iter = std::find(finger_ids.begin(), finger_ids.end(),
+						SDL_event.tfinger.fingerId);
+				size_t finger_idx = std::distance(finger_ids.begin(), iter);
+				// To match Android behavior, still count the pointer that was just released.
+				size_t finger_count = finger_ids.size();
+				if (finger_idx != finger_count) {
+					finger_ids.erase(finger_ids.begin() + finger_idx);
+				}
+
+				irrevent.EventType = irr::EET_TOUCH_INPUT_EVENT;
+				irrevent.TouchInput.Event = irr::ETIE_LEFT_UP;
+				irrevent.TouchInput.ID = finger_idx;
+				irrevent.TouchInput.X = SDL_event.tfinger.x * Width;
+				irrevent.TouchInput.Y = SDL_event.tfinger.y * Height;
+				irrevent.TouchInput.touchedCount = finger_count;
+
+				postEventFromUser(irrevent);
+			}
+			break;
 
 		default:
 			break;

diff --git a/source/Irrlicht/CIrrDeviceSDL.h b/source/Irrlicht/CIrrDeviceSDL.h
@@ -318,6 +318,11 @@ namespace irr
 
 		core::array<SKeyMap> KeyMap;
 		SDL_SysWMinfo Info;
+
+		// Minetest expects touch pointer IDs to be consecutive, as they are on
+		// Android. SDL doesn't guarantee this, so we emulate it.
+		// This is also used to implement the "touchedCount" field.
+		std::vector<SDL_FingerID> finger_ids;
 	};
 
 } // end namespace irr