Add Input::scrollV() to query vertical mouse wheel scroll events

binding-mri/input-binding.cpp

@@ -115,6 +115,13 @@ RB_METHOD(inputMouseY)
 	return rb_fix_new(shState->input().mouseY());
 }
 
+RB_METHOD(inputScrollV)
+{
+	RB_UNUSED_PARAM;
+
+	return rb_fix_new(shState->input().scrollV());
+}
+
 
 struct
 {
@@ -168,6 +175,7 @@ inputBindingInit()
 
 	_rb_define_module_function(module, "mouse_x", inputMouseX);
 	_rb_define_module_function(module, "mouse_y", inputMouseY);
+	_rb_define_module_function(module, "scroll_v", inputScrollV);
 
 	if (rgssVer >= 3)
 	{

src/eventthread.cpp

@@ -73,6 +73,7 @@ uint8_t EventThread::keyStates[];
 EventThread::JoyState EventThread::joyState;
 EventThread::MouseState EventThread::mouseState;
 EventThread::TouchState EventThread::touchState;
+SDL_atomic_t EventThread::verticalScrollDistance;
 
 /* User event codes */
 enum
@@ -380,6 +381,11 @@ void EventThread::process(RGSSThreadData &rtData)
 			updateCursorState(cursorInWindow, gameScreen);
 			break;
 
+		case SDL_MOUSEWHEEL :
+			/* Only consider vertical scrolling for now */
+			SDL_AtomicAdd(&verticalScrollDistance, event.wheel.y);
+			break;
+
 		case SDL_FINGERDOWN :
 			i = event.tfinger.fingerId;
 			touchState.fingers[i].down = true;

src/eventthread.h

@@ -31,6 +31,7 @@
 #include <SDL_joystick.h>
 #include <SDL_mouse.h>
 #include <SDL_mutex.h>
+#include <SDL_atomic.h>
 
 #include <string>
 
@@ -76,6 +77,7 @@ public:
 	static JoyState joyState;
 	static MouseState mouseState;
 	static TouchState touchState;
+	static SDL_atomic_t verticalScrollDistance;
 
 	static bool allocUserEvents();
 

src/input.cpp

@@ -28,6 +28,7 @@
 
 #include <SDL_scancode.h>
 #include <SDL_mouse.h>
+#include <SDL_atomic.h>
 
 #include <vector>
 #include <string.h>
@@ -287,6 +288,9 @@ struct InputPrivate
 	Input::ButtonCode repeating;
 	unsigned int repeatCount;
 
+	/* Cumulative vertical scroll distance since last update call */
+	int vScrollDistance;
+
 	struct
 	{
 		int active;
@@ -322,6 +326,8 @@ struct InputPrivate
 		dir4Data.previous = Input::None;
 
 		dir8Data.active = 0;
+
+		vScrollDistance = 0;
 	}
 
 	inline ButtonState &getStateCheck(int code)
@@ -640,6 +646,9 @@ void Input::update()
 	}
 
 	p->repeating = None;
+
+	/* Fetch new cumulative scroll distance and reset counter */
+	p->vScrollDistance = SDL_AtomicSet(&EventThread::verticalScrollDistance, 0);
 }
 
 bool Input::isPressed(int button)
@@ -681,6 +690,11 @@ int Input::mouseY()
 	return (EventThread::mouseState.y - rtData.screenOffset.y) * rtData.sizeResoRatio.y;
 }
 
+int Input::scrollV()
+{
+	return p->vScrollDistance;
+}
+
 Input::~Input()
 {
 	delete p;

src/input.h

@@ -58,6 +58,7 @@ public:
 	/* Non-standard extensions */
 	int mouseX();
 	int mouseY();
+	int scrollV();
 
 private:
 	Input(const RGSSThreadData &rtData);