Fix mouse position backward compatibility with new SDL2 versions.

Clamp the mouse coordinates to the window's dimensions.

src/modules/event/sdl/Event.cpp

@@ -51,6 +51,13 @@ static void windowToDPICoords(double *x, double *y)
  window->windowToDPICoords(x, y);
 }
 
+static void clampToWindow(double *x, double *y)
+{
+ auto window = Module::getInstance<window::Window>(Module::M_WINDOW);
+ if (window)
+ window->clampPositionInWindow(x, y);
+}
+
 #ifndef LOVE_MACOSX
 static void normalizedToDPICoords(double *x, double *y)
 {
@@ -253,8 +260,16 @@ Message *Event::convert(const SDL_Event &e)
  double y = (double) e.motion.y;
  double xrel = (double) e.motion.xrel;
  double yrel = (double) e.motion.yrel;
+
+ // SDL reports mouse coordinates outside the window bounds when click-and-
+ // dragging. For compatibility we clamp instead since user code may not be
+ // able to handle out-of-bounds coordinates. SDL has a hint to turn off
+ // auto capture, but it doesn't report the mouse's position at the edge of
+ // the window if the mouse moves fast enough when it's off.
+ clampToWindow(&x, &y);
  windowToDPICoords(&x, &y);
  windowToDPICoords(&xrel, &yrel);
+
  vargs.emplace_back(x);
  vargs.emplace_back(y);
  vargs.emplace_back(xrel);
@@ -280,7 +295,10 @@ Message *Event::convert(const SDL_Event &e)
 
  double px = (double) e.button.x;
  double py = (double) e.button.y;
+
+ clampToWindow(&px, &py);
  windowToDPICoords(&px, &py);
+
  vargs.emplace_back(px);
  vargs.emplace_back(py);
  vargs.emplace_back((double) button);

src/modules/mouse/sdl/Mouse.cpp

@@ -49,6 +49,13 @@ static void DPIToWindowCoords(double *x, double *y)
  window->DPIToWindowCoords(x, y);
 }
 
+static void clampToWindow(double *x, double *y)
+{
+ auto window = Module::getInstance<window::Window>(Module::M_WINDOW);
+ if (window)
+ window->clampPositionInWindow(x, y);
+}
+
 const char *Mouse::getName() const
 {
  return "love.mouse.sdl";
@@ -119,24 +126,16 @@ bool Mouse::isCursorSupported() const
 
 double Mouse::getX() const
 {
- int x;
- SDL_GetMouseState(&x, nullptr);
-
- double dx = (double) x;
- windowToDPICoords(&dx, nullptr);
-
- return dx;
+ double x, y;
+ getPosition(x, y);
+ return x;
 }
 
 double Mouse::getY() const
 {
- int y;
- SDL_GetMouseState(nullptr, &y);
-
- double dy = (double) y;
- windowToDPICoords(nullptr, &dy);
-
- return dy;
+ double x, y;
+ getPosition(x, y);
+ return y;
 }
 
 void Mouse::getPosition(double &x, double &y) const
@@ -146,6 +145,14 @@ void Mouse::getPosition(double &x, double &y) const
 
  x = (double) mx;
  y = (double) my;
+
+ // SDL reports mouse coordinates outside the window bounds when click-and-
+ // dragging. For compatibility we clamp instead since user code may not be
+ // able to handle out-of-bounds coordinates. SDL has a hint to turn off
+ // auto capture, but it doesn't report the mouse's position at the edge of
+ // the window if the mouse moves fast enough when it's off.
+ clampToWindow(&x, &y);
+
  windowToDPICoords(&x, &y);
 }
 

src/modules/window/Window.h

@@ -193,6 +193,8 @@ class Window : public Module
  virtual int getPixelWidth() const = 0;
  virtual int getPixelHeight() const = 0;
 
+ virtual void clampPositionInWindow(double *wx, double *wy) const = 0;
+
  // Note: window-space coordinates are not necessarily the same as
  // density-independent units (which toPixels and fromPixels use.)
  virtual void windowToPixelCoords(double *x, double *y) const = 0;

src/modules/window/sdl/Window.cpp

@@ -1124,6 +1124,13 @@ int Window::getPixelHeight() const
  return pixelHeight;
 }
 
+void Window::clampPositionInWindow(double *wx, double *wy) const
+{
+ if (wx != nullptr)
+ *wx = std::min(std::max(0.0, *wx), (double) getWidth() - 1);
+ if (wy != nullptr)
+ *wy = std::min(std::max(0.0, *wy), (double) getHeight() - 1);
+}
 
 void Window::windowToPixelCoords(double *x, double *y) const
 {

src/modules/window/sdl/Window.h

@@ -104,6 +104,8 @@ class Window final : public love::window::Window
  int getPixelWidth() const override;
  int getPixelHeight() const override;
 
+ void clampPositionInWindow(double *wx, double *wy) const override;
+
  void windowToPixelCoords(double *x, double *y) const override;
  void pixelToWindowCoords(double *x, double *y) const override;