2D: Add batching to RendererCanvasRenderRD

Author: stuartcarnie

doc/classes/ProjectSettings.xml

@@ -2341,6 +2341,9 @@
 			[b]Note:[/b] This property is only read when the project starts. To change the physics FPS at runtime, set [member Engine.physics_ticks_per_second] instead.
 			[b]Note:[/b] Only [member physics/common/max_physics_steps_per_frame] physics ticks may be simulated per rendered frame at most. If more physics ticks have to be simulated per rendered frame to keep up with rendering, the project will appear to slow down (even if [code]delta[/code] is used consistently in physics calculations). Therefore, it is recommended to also increase [member physics/common/max_physics_steps_per_frame] if increasing [member physics/common/physics_ticks_per_second] significantly above its default value.
 		</member>
+		<member name="rendering/2d/batching/item_buffer_size" type="int" setter="" getter="" default="16384">
+			Maximum number of canvas item commands that can be batched into a single draw call.
+		</member>
 		<member name="rendering/2d/sdf/oversize" type="int" setter="" getter="" default="1">
 			Controls how much of the original viewport size should be covered by the 2D signed distance field. This SDF can be sampled in [CanvasItem] shaders and is used for [GPUParticles2D] collision. Higher values allow portions of occluders located outside the viewport to still be taken into account in the generated signed distance field, at the cost of performance. If you notice particles falling through [LightOccluder2D]s as the occluders leave the viewport, increase this setting.
 			The percentage specified is added on each axis and on both sides. For example, with the default setting of 120%, the signed distance field will cover 20% of the viewport's size outside the viewport on each side (top, right, bottom, left).