The [PCKPacker] is used to create packages in application runtime.
[codeblock]
var packer = PCKPacker.new()
packer.pck_start("test.pck", 0)
packer.add_file("res://text.txt", "text.txt")
packer.flush(false)
[/codeblock]
The above [PCKPacker] creates package [b]test.pck[/b], then adds a file named [b]text.txt[/b] in the root of the package.
Adds the [code]source_path[/code] file to the current PCK package at the [code]pck_path[/code] internal path (should start with [code]res://[/code]).