Finish splitting functionality of the Vulkan and D3D12 backends into …

…RenderingDeviceDriver.

core/config/project_settings.cpp

@@ -1470,6 +1470,8 @@ ProjectSettings::ProjectSettings() {
 	GLOBAL_DEF_BASIC("gui/common/snap_controls_to_pixels", true);
 	GLOBAL_DEF_BASIC("gui/fonts/dynamic_fonts/use_oversampling", true);
 
+	GLOBAL_DEF_RST(PropertyInfo(Variant::INT, "rendering/rendering_device/vsync/frame_queue_size", PROPERTY_HINT_RANGE, "2,3,1"), 2);
+	GLOBAL_DEF_RST(PropertyInfo(Variant::INT, "rendering/rendering_device/vsync/swapchain_image_count", PROPERTY_HINT_RANGE, "2,4,1"), 3);
 	GLOBAL_DEF(PropertyInfo(Variant::INT, "rendering/rendering_device/staging_buffer/block_size_kb", PROPERTY_HINT_RANGE, "4,2048,1,or_greater"), 256);
 	GLOBAL_DEF(PropertyInfo(Variant::INT, "rendering/rendering_device/staging_buffer/max_size_mb", PROPERTY_HINT_RANGE, "1,1024,1,or_greater"), 128);
 	GLOBAL_DEF(PropertyInfo(Variant::INT, "rendering/rendering_device/staging_buffer/texture_upload_region_size_px", PROPERTY_HINT_RANGE, "1,256,1,or_greater"), 64);

doc/classes/ProjectSettings.xml

@@ -2698,6 +2698,20 @@
 		</member>
 		<member name="rendering/rendering_device/staging_buffer/texture_upload_region_size_px" type="int" setter="" getter="" default="64">
 		</member>
+		<member name="rendering/rendering_device/vsync/frame_queue_size" type="int" setter="" getter="" default="2">
+			The number of frames to track on the CPU side before stalling to wait for the GPU.
+			Try the [url=https://darksylinc.github.io/vsync_simulator/]V-Sync Simulator[/url], an interactive interface that simulates presentation to better understand how it is affected by different variables under various conditions.
+			[b]Note:[/b] This property is only read when the project starts. There is currently no way to change this value at run-time.
+		</member>
+		<member name="rendering/rendering_device/vsync/swapchain_image_count" type="int" setter="" getter="" default="3">
+			The number of images the swapchain will consist of (back buffers + front buffer).
+			[code]2[/code] corresponds to double-buffering and [code]3[/code] to triple-buffering.
+			Double-buffering may give you the lowest lag/latency but if V-Sync is on and the system can't render at 60 fps, the framerate will go down in multiples of it (e.g. 30 fps, 15, 7.5, etc.). Triple buffering gives you higher framerate (specially if the system can't reach a constant 60 fps) at the cost of up to 1 frame of latency, with [constant DisplayServer.VSYNC_ENABLED] (FIFO).
+			Use double-buffering with [constant DisplayServer.VSYNC_ENABLED]. Triple-buffering is a must if you plan on using [constant DisplayServer.VSYNC_MAILBOX] mode.
+			Try the [url=https://darksylinc.github.io/vsync_simulator/]V-Sync Simulator[/url], an interactive interface that simulates presentation to better understand how it is affected by different variables under various conditions.
+			[b]Note:[/b] This property is only read when the project starts. There is currently no way to change this value at run-time.
+			[b]Note:[/b] Some platforms may restrict the actual value.
+		</member>
 		<member name="rendering/rendering_device/vulkan/max_descriptors_per_pool" type="int" setter="" getter="" default="64">
 		</member>
 		<member name="rendering/scaling_3d/fsr_sharpness" type="float" setter="" getter="" default="0.2">

doc/classes/RenderingDevice.xml

@@ -590,8 +590,9 @@
 		</method>
 		<method name="screen_get_framebuffer_format" qualifiers="const">
 			<return type="int" />
+			<param index="0" name="screen" type="int" default="0" />
 			<description>
-				Returns the screen's framebuffer format.
+				Returns the framebuffer format of the given screen.
 				[b]Note:[/b] Only the main [RenderingDevice] returned by [method RenderingServer.get_rendering_device] has a format. If called on a local [RenderingDevice], this method prints an error and returns [constant INVALID_ID].
 			</description>
 		</method>