In-Game Hologram Controls

Relevant source files

The following files were used as context for generating this wiki page:

• src/HoloPrint.js
• README.md
• src/translations/en_US.json
• src/packTemplate/render_controllers/holoprint.hologram.render_controllers.json
• src/packTemplate/models/entity/holoprint.hologram.geo.json
• src/index.js

In-game hologram controls allow users to interact with and manipulate 3D build projections directly within Minecraft Bedrock Edition. These controls are implemented through a combination of item-based detection, Molang scripts, and entity render controllers. By holding specific items or interacting with an armor stand, players can modify the hologram's visibility, position, rotation, and active layers.

Sources: README.md:35-37, src/HoloPrint.js:63-65

Control Architecture and Logic

The control system operates by detecting the item currently held by the player or the armor stand. When a match is found based on pre-defined ItemCriteria, the resource pack updates internal Molang variables (prefixed with v.hologram.*). These variables then drive the transformations in the entity's geometry and visibility states in the render controller.

Interaction Flow

The flow of control from item detection to visual update. Sources: src/HoloPrint.js:380-410, src/packTemplate/render_controllers/holoprint.hologram.render_controllers.json:4-15

Molang Variable Mapping

Controls primarily manipulate variables that influence the hologram_alignment_wrapper and hologram_offset_wrapper bones within the entity's geometry.

Action	Primary Molang Variable	Triggering Mechanism
Visibility	v.hologram.rendering	Holding/Interacting with Toggle Item
Translation	v.hologram.offset	Update based on movement control
Rotation	v.hologram.rotation	Incremental change on interaction
Active Layer	v.hologram.layer	Sneak/Stand state with layer item

Sources: src/HoloPrint.js:283-305, src/packTemplate/models/entity/holoprint.hologram.geo.json:11-16

Default Item Mappings

HoloPrint defines a set of default items used to trigger specific hologram behaviors. These can be customized during the pack generation process via the web interface.

Control Action	Default Item	Description
Toggle Rendering	Brick	Switches the hologram visibility on/off.
Change Transparency	Amethyst Shard	Increases opacity when standing, decreases when sneaking.
Change Layer	Leather	Increases layer index; sneaking decreases it.
Move Hologram	Stick	Adjusts the XYZ position of the projection.
Rotate Hologram	Copper Ingot	Rotates the structure around the Y-axis.
Block Validation	Iron Ingot	Toggles visual feedback for correct/incorrect blocks.
Change Layer Mode	Flint	Toggles between "Single Layer" and "All Layers Below".
Save Backup	Paper	Saves the current hologram configuration state.
Disable Controls	Bone	Prevents further player manipulation of the hologram.

Sources: src/HoloPrint.js:46-59, README.md:39-52, src/translations/en_US.json:34-45

Render Controller Integration

The rendering of holograms is managed by controller.render.holoprint.hologram. It utilizes arrays of textures and geometries to switch between different structures and opacity levels dynamically.

The sequence of events when a player manipulates the hologram position. Sources: src/packTemplate/render_controllers/holoprint.hologram.render_controllers.json:4-28, src/packTemplate/models/entity/holoprint.hologram.geo.json:30-35

Component Visibility

The render controller switches visibility based on the following logic:

1. Main Hologram: Rendered when v.hologram.rendering is true.
2. Wrong Block Overlay: Visible when v.hologram.show_wrong_block_overlay is triggered during validation.
3. Valid Structure Overlay: Shown when v.hologram.validating is active and v.wrong_blocks is zero.

Sources: src/packTemplate/render_controllers/holoprint.hologram.render_controllers.json:34-60, src/HoloPrint.js:321-330

Implementation Details

Item Criteria Definition

Controls are defined using the ItemCriteria structure, which supports both specific item names and tags (e.g., minecraft:planks).

export function createItemCriteria(names, tags = []) {
    if(!Array.isArray(names)) { names = [names]; }
    if(!Array.isArray(tags)) { tags = [tags]; }
    return { names, tags };
}

Sources: src/HoloPrint.js:655-663

Armor Stand Initialization

When an armor stand is used to host a hologram, it runs an initialization script to set default values, including the initial structure index and activation state.

entityDescription["scripts"]["initialize"].push(functionToMolang(entityScripts.armorStandInitialization, {
    structureSize: structureSizes[0],
    initialOffset: config.INITIAL_OFFSET,
    defaultTextureIndex,
    singleLayerMode: HOLOGRAM_LAYER_MODES.SINGLE,
    structureCount: structureFiles.length
}));

Sources: src/HoloPrint.js:293-300

User Interface Configuration

The configuration for these controls is exposed to the user through the generatePackForm. Users can override default item criteria before the resource pack is generated. The ItemCriteriaInput component handles the selection of names and tags, which are then passed to the makePack function.

Sources: src/index.js:220-235, src/index.js:468-485

Conclusion

The in-game hologram control system provides a robust mechanism for manipulating structures within Minecraft Bedrock Edition. By leveraging native resource pack features like render controllers and Molang-driven animations, it enables a feature set comparable to Java Edition mods like Litematica without requiring external behavior packs or experimental features.