Add 2D sheet animation for nodes

doc/lua_api.txt

@@ -3702,7 +3702,26 @@ Definition tables
     * `image` (name)
 
 ### Tile animation definition
-* `{type="vertical_frames", aspect_w=16, aspect_h=16, length=3.0}`
+
+	{
+		type = "vertical_frames",
+		aspect_w = 16,
+		-- ^ specify width of a frame in pixels
+		aspect_h = 16,
+		-- ^ specify height of a frame in pixels
+		length = 3.0,
+		-- ^ specify full loop length
+	}
+
+	{
+		type = "sheet_2d",
+		frames_w = 5,
+		-- ^ specify width in number of frames
+		frames_h = 3,
+		-- ^ specify height in number of frames
+		frame_length = 0.5,
+		-- ^ specify length of a single frame
+	}
 
 ### Node definition (`register_node`)
 

games/minimal/mods/default/init.lua

@@ -1044,8 +1044,11 @@ minetest.register_node("default:lava_source", {
 	inventory_image = minetest.inventorycube("default_lava.png"),
 	drawtype = "liquid",
 	--tiles ={"default_lava.png"},
-	tiles ={
-		{name="default_lava_source_animated.png", animation={type="vertical_frames", aspect_w=16, aspect_h=16, length=3.0}}
+	tiles = {
+		{
+			name = "default_lava_source_animated.png",
+			animation = {type="sheet_2d", frames_w=3, frames_h=2, frame_length=0.5}
+		}
 	},
 	special_tiles = {
 		-- New-style lava source material (mostly unused)