luaengine: video:size(), video:pixels(), screen:refresh_attoseconds() [vadosnaprimer] (#5334)

* luaengine: video:size(), video:pixels(), screen:refresh_attoseconds()

pixels() and size() correspond to internal game resolution covering all screens and internal pixel colors. the same values are used for bitmap dumping. similar things available for screen_device lua library take into account final UI resolution and colors, so they can't be used when accurate framebuffer is needed.

refresh_attoseconds() allows to calculate precise numerator and denominator for framerate

src/emu/video.cpp

@@ -1261,10 +1261,8 @@ void video_manager::create_snapshot_bitmap(screen_device *screen)
 	}
 
 	// get the minimum width/height and set it on the target
-	s32 width = m_snap_width;
-	s32 height = m_snap_height;
-	if (width == 0 || height == 0)
-		m_snap_target->compute_minimum_size(width, height);
+	s32 width, height;
+	compute_snapshot_size(width, height);
 	m_snap_target->set_bounds(width, height);
 
 	// if we don't have a bitmap, or if it's not the right size, allocate a new one
@@ -1282,6 +1280,40 @@ void video_manager::create_snapshot_bitmap(screen_device *screen)
 }
 
 
+//-------------------------------------------------
+//  compute_snapshot_size - computes width and
+//  height of the current snapshot target
+//  accounting for OPTION_SNAPSIZE
+//-------------------------------------------------
+
+void video_manager::compute_snapshot_size(s32 &width, s32 &height)
+{
+	width = m_snap_width;
+	height = m_snap_height;
+	if (width == 0 || height == 0)
+		m_snap_target->compute_minimum_size(width, height);
+}
+
+
+//-------------------------------------------------
+//  pixels - fills the specified buffer with the
+//  RGB values of each pixel in the snapshot target
+//-------------------------------------------------
+
+void video_manager::pixels(u32 *buffer)
+{
+	create_snapshot_bitmap(nullptr);
+	for (int y = 0; y < m_snap_bitmap.height(); y++)
+	{
+		const u32 *src = &m_snap_bitmap.pix(y, 0);
+		for (int x = 0; x < m_snap_bitmap.width(); x++)
+		{
+			*buffer++ = *src++;
+		}
+	}
+}
+
+
 //-------------------------------------------------
 //  open_next - open the next non-existing file of
 //  type filetype according to our numbering

src/emu/video.h

@@ -73,6 +73,8 @@ public:
 	void toggle_record_mng() { toggle_record_movie(MF_MNG); }
 	void toggle_record_avi() { toggle_record_movie(MF_AVI); }
 	osd_file::error open_next(emu_file &file, const char *extension, uint32_t index = 0);
+	void compute_snapshot_size(s32 &width, s32 &height);
+	void pixels(u32 *buffer);
 
 	// render a frame
 	void frame_update(bool from_debugger = false);

src/frontend/mame/luaengine.cpp

@@ -1819,7 +1819,9 @@ void lua_engine::initialize()
  * video:skip_this_frame() - is current frame going to be skipped
  * video:speed_factor() - get speed factor
  * video:speed_percent() - get percent from realtime
- * video:frame_update()
+ * video:frame_update() - render a frame
+ * video:size() - get width and height of snapshot bitmap in pixels
+ * video:pixels() - get binary bitmap of all screens as string
  *
  * video.frameskip - current frameskip
  * video.throttled - throttle state
@@ -1848,6 +1850,22 @@ void lua_engine::initialize()
 			"speed_factor", &video_manager::speed_factor,
 			"speed_percent", &video_manager::speed_percent,
 			"frame_update", &video_manager::frame_update,
+			"size", [](video_manager &vm) {
+					s32 width, height;
+					vm.compute_snapshot_size(width, height);
+					return std::tuple<s32, s32>(width, height);
+				},
+			"pixels", [](video_manager &vm, sol::this_state s) {
+					lua_State *L = s;
+					luaL_Buffer buff;
+					s32 width, height;
+					vm.compute_snapshot_size(width, height);
+					int size = width * height * 4;
+					u32 *ptr = (u32 *)luaL_buffinitsize(L, &buff, size);
+					vm.pixels(ptr);
+					luaL_pushresultsize(&buff, size);
+					return sol::make_reference(L, sol::stack_reference(L, -1));
+				},
 			"frameskip", sol::property(&video_manager::frameskip, &video_manager::set_frameskip),
 			"throttled", sol::property(&video_manager::throttled, &video_manager::set_throttled),
 			"throttle_rate", sol::property(&video_manager::throttle_rate, &video_manager::set_throttle_rate));
@@ -1920,7 +1938,7 @@ void lua_engine::initialize()
  * target:hidden() - is target hidden
  * target:is_ui_target() - is ui render target
  * target:index() - target index
- * target:view_name(index) - current target layout view name
+ * target:view_name([opt] index) - current target layout view name
  *
  * target.max_update_rate -
  * target.view - current target layout view
@@ -2005,8 +2023,9 @@ void lua_engine::initialize()
  * screen:height() - screen height
  * screen:width() - screen width
  * screen:orientation() - screen angle, flipx, flipy
- * screen:refresh() - screen refresh rate
- * screen:snapshot() - save snap shot
+ * screen:refresh() - screen refresh rate in Hz
+ * screen:refresh_attoseconds() - screen refresh rate in attoseconds
+ * screen:snapshot([opt] filename) - save snap shot
  * screen:type() - screen drawing type
  * screen:frame_number() - screen frame count
  * screen:name() - screen device full name
@@ -2095,6 +2114,7 @@ void lua_engine::initialize()
 					return std::tuple<int, bool, bool>(rotation_angle, flags & ORIENTATION_FLIP_X, flags & ORIENTATION_FLIP_Y);
 				},
 			"refresh", [](screen_device &sdev) { return ATTOSECONDS_TO_HZ(sdev.refresh_attoseconds()); },
+			"refresh_attoseconds", [](screen_device &sdev) { return sdev.refresh_attoseconds(); },
 			"snapshot", [this](screen_device &sdev, sol::object filename) -> sol::object {
 					emu_file file(machine().options().snapshot_directory(), OPEN_FLAG_WRITE | OPEN_FLAG_CREATE | OPEN_FLAG_CREATE_PATHS);
 					osd_file::error filerr;