Call the engine API and project script

In the plugin you can declare a special script file (scene script), the script and the script in the project (assets directory script) has the same environment, that is in this script can call the engine API and other projects Script to achieve:

• Traverse the nodes in the scene to get or change the data
• Call the other scripts in the project to complete the job

Register the scene script

First in the package.json addscene-script field, the value of the field is a script file path, relative to the expansion package directory:

    "Name": "foobar",
    "Scene-script": "scene-walker.js"

The path will point to packages / foobar / scene-walker.js, then let's see how to write the scene script.

Write the scene script

Scene-walker.js needs to be defined in such a way:

Module.exports = {
    'Get-canvas-children': function (event) {
        Var canvas = cc.find ('Canvas');
        Editor.log ('children length:' + canvas.children.length);

        If (event.reply) {
            Event.reply (canvas.children.length);
        }
    }
};

You can see that the scene script consists of one or more IPC message listening methods. After receiving the corresponding IPC message, we can use the methods and properties that are declared in the engine and the user component script in the function body.

Send a message from the extension package to the scene script

Next, in the main process and the rendering process of the extension package program, you can use the following interface to send a message to the scene-walker.js(assuming the extension package name isfoobar`):

Editor.Scene.callSceneScript ('foobar', 'get-canvas-children', function (err, length) {
    Console.log (`get-canvas-children callback: length - $ {length}`);
});

So that you can get in the expansion package to the scene of the Canvas root node how many child nodes, of course, can also be used to scene nodes for more inquiries and operations.

When calling a message, callSceneScript accepts the same parameter input as the other IPC message sending interface, or you can specify more pass and timeout times. For more information, see [IPC Workflow] (ipc-workflow.md).

Reference modules and plugin scripts in scene scripts

In addition to getting a specific node in the scene script via cc.find and manipulating the node and mounted components, we can also refer to the non-component modules in the project, or access the plug-in scripts through global variables.

Reference module

//MyModule.js
Module.exports = {
    Init: function () {
        // do initialization work
    }
}

//scene-walker.js
Module.exports = {
    'Init-module': function (event) {
        Var myModule = cc.require ('MyModule');
        MyModule.init ();
    }
};

Note that to use the same module reference mechanism as the project script, you must use cc.require in the scene script.

Reference plugin script

Directly use window.globalVar to access the global variables and methods declared in the plugin script.