Viewport: Add zero arg constructor (RGSS3) and bind in MRI

src/viewport.cpp

@@ -26,6 +26,7 @@
 #include "util.h"
 #include "quad.h"
 #include "glstate.h"
+#include "graphics.h"
 
 #include <SDL_rect.h>
 
@@ -112,6 +113,18 @@ Viewport::Viewport(Rect *rect)
 	initViewport(rect->x, rect->y, rect->width, rect->height);
 }
 
+#ifdef RGSS3
+
+Viewport::Viewport()
+    : SceneElement(*shState->screen()),
+      sceneLink(this)
+{
+	const Graphics &graphics = shState->graphics();
+	initViewport(0, 0, graphics.width(), graphics.height());
+}
+
+#endif
+
 void Viewport::initViewport(int x, int y, int width, int height)
 {
 	p = new ViewportPrivate(x, y, width, height, this);

src/viewport.h

@@ -34,6 +34,11 @@ class Viewport : public Scene, public SceneElement, public Flashable, public Dis
 public:
 	Viewport(int x, int y, int width, int height);
 	Viewport(Rect *rect);
+
+#ifdef RGSS3
+	Viewport();
+#endif
+
 	~Viewport();
 
 	DECL_ATTR( Rect,  Rect*  )