Table of Contents

Decoration Object Related

In addition to train rendering, the use of JavaScript scripting with Decoration Object (Also known as Eye Candy) are also supported.

Adding script to Decoration Object

You can add a model that uses JavaScript to control rendering by writing something like this in your decor_obj.json file (Where decor_obj.json is the json file that contains the NTE decoration object):

decor_obj.json
{
  "nte_lcd": {
      "name": "NTE LCD Test",
      "translation": [ 0, 0, 0 ],
      "rotation": [ 0, 0, 0 ],
      "scale": [ 1, 1, 1 ],
      "scriptFiles": ["mtrsteamloco:eyecandies/js/nte_lcd_test/main.js"],
      "mirror": [ false, false, false ]
  }
}

In general, the parameters are the same as those required for regular decoration object json for NTE, except for the scriptFiles parameter.

If the model parameter is not specified, the JavaScript-driven elements will be overlaid on top of the existing model. Otherwise, the appearance will be controlled solely by JavaScript.

Parameter Description
scriptFiles An array containing the locations of .js scripts. Multiple scripts can be specified.
scriptTexts Optional parameter. An array containing the JavaScript text to be executed before script_files. Can be used when the same script is used for different block, but you need to set variables that are different for each block.

Note that JavaScript train uses script_files (Snake Case) in the MTR Custom Resource json, while NTE Decoration Object uses scriptFiles (Camel Case) in the respective Decoration Object json file.

Global Environment

All blocks of the same type use the same working environment (global variables and etc).

Code written in top-level space outside of functions will run when the resource pack is loaded, and can be used to load resources such as models and textures.

It is recommended to store resources (such as models, fonts and textures) which are the same for each block in the global variables to avoid excessive memory usage caused by loading the same copy of the content for each block.

Called Functions

Your script should include the following functions that the NTE will call as needed:

function create(ctx, state, blockEntity) { ... }
function render(ctx, state, blockEntity) { ... }
function dispose(ctx, state, blockEntity) { ... }
Functions Description
create It is called when the block is in sight by the client and can be used to perform some initialization operations, for example, to create dynamic textures.
render It is called approximately once per frame. It is used for basic display logic. In practice however, the code is executed in a separate thread so as not to slow down FPS. If it takes too long to execute the code, it can be called once every few frames instead of every frame.
dispose Called when the block goes out of sight. Can be used for things like releasing the dynamic textures to free up memory.

The NTE calls these functions with three parameters, each of which is described below.

Parameter Description
First (ctx) Used to pass Decoration Object rendering actions to the NTE. Type — EyeCandyScriptContext.
Second (state) A JavaScript object associated with a Decoration Object (Block). The initial value is {}, and its content can be set arbitrarily to store what should be different for each block.
Third (blockEntity) This returns the block entity of the placed decoration block.

The following lists all the rendering control operations that can be performed and all the information that can be obtained about blockEntity.

EyeCandyScriptContext

The following functions are called to control rendering. The functions for rendering models should be called each time render is called.

Same with train, a set of functions exists to aid development and debugging.

Functions And Objects Description
blockEntity.prefabId: string The id of the assigned decoration object, null if the decoration object does not have any decoration object assigned
blockEntity.translateX: float The value in meters on how much the Decoration Object is translated on the X-axis, this is configured via the GUI on NTE.
blockEntity.translateY: float The value in meters on how much the Decoration Object is translated on the Y-axis, this is configured via the GUI on NTE.
blockEntity.translateZ: float The value in meters on how much the Decoration Object is translated on the Z-axis, this is configured via the GUI on NTE.
blockEntity.rotateX: float The value in radians on how much the Decoration Object is rotated on the X-axis, this is configured via the GUI on NTE.
blockEntity.rotateY: float The value in radians on how much the Decoration Object is rotated on the Y-axis, this is configured via the GUI on NTE.
blockEntity.rotateZ: float The value in radians on how much the Decoration Object is rotated on the Z-axis, this is configured via the GUI on NTE.
blockEntity.fullLight: boolean Whether the Decoration Object is marked as “Full Light”, this is configured via the GUI on NTE.