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Overview

The Data Packer (grpgpack) is a command-line tool that converts game asset manifests into optimized binary formats used by the GRPG engine. It supports packing textures, tiles, objects, NPCs, and items.

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Installation

Build the data packer from source: 
cd ~/workspace/source/data-packer
go build -o grpgpack

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Commands

The data packer provides five subcommands for packing different asset types:

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tex - Pack Textures

Packs texture assets from a manifest file into a .grpgtex binary file. Usage: 
grpgpack tex -m <manifest> [-o <output>]
Flags:
  • -m, --manifest (required): Path to the texture manifest file
  • -o, --output (optional): Output file path (default: textures.grpgtex)
Example: 
grpgpack tex -m textures_manifest.gcfg -o textures.grpgtex
Manifest Format: 
[Texture] {
    name = "grass_tex"
    id = 1
    path = "assets/grass_texture.png"
}

[Texture] {
    name = "still_water"
    id = 2
    path = "assets/stone_texture.png"
}

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tile - Pack Tiles

Packs tile definitions from a manifest file into a .grpgtile binary file. Tiles reference textures from a .grpgtex file. Usage: 
grpgpack tile -m <manifest> -t <textures> [-o <output>]
Flags:
  • -m, --manifest (required): Path to the tile manifest file
  • -t, --textures (required): Path to the .grpgtex file
  • -o, --output (optional): Output file path (default: tiles.grpgtile)
Example: 
grpgpack tile -m tiles_manifest.gcfg -t textures.grpgtex -o tiles.grpgtile
Manifest Format: 
[Tile] {
    name = "grass"
    id = 1
    tex_name = "grass_tex"
}

[Tile] {
    name = "water"
    id = 2
    tex_name = "still_water"
}

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obj - Pack Objects

Packs object definitions from a manifest file into a .grpgobj binary file. Objects can have multiple textures, flags, and interaction properties. Usage: 
grpgpack obj -m <manifest> -t <textures> [-o <output>]
Flags:
  • -m, --manifest (required): Path to the object manifest file
  • -t, --textures (required): Path to the .grpgtex file
  • -o, --output (optional): Output file path (default: objs.grpgobj)
Example: 
grpgpack obj -m objects_manifest.gcfg -t textures.grpgtex -o objs.grpgobj
Manifest Format: 
[Obj] {
    name = "water_s"
    id = 1
    flags = []
    textures = ["still_water"]
    interact_text = ""
}

[Obj] {
    name = "i_water"
    id = 2
    flags = ["STATE", "INTERACT"]
    textures = ["still_water", "grass_tex"]
    interact_text = "Interact"
}
Available Flags:
  • STATE: Object has multiple states
  • INTERACT: Object can be interacted with

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npc - Pack NPCs

Packs NPC definitions from a manifest file into a .grpgnpc binary file. Usage: 
grpgpack npc -m <manifest> -t <textures> [-o <output>]
Flags:
  • -m, --manifest (required): Path to the NPC manifest file
  • -t, --textures (required): Path to the .grpgtex file
  • -o, --output (optional): Output file path (default: items.grpgitem)
Example: 
grpgpack npc -m npcs_manifest.gcfg -t textures.grpgtex -o npcs.grpgnpc
Manifest Format: 
[Npc] {
    name = "corey"
    id = 1
    texture = "still_water"
}

[Npc] {
    name = "grian"
    id = 2
    texture = "grass_tex"
}

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item - Pack Items

Packs item definitions from a manifest file into a .grpgitem binary file. Usage: 
grpgpack item -m <manifest> -t <textures> [-o <output>]
Flags:
  • -m, --manifest (required): Path to the item manifest file
  • -t, --textures (required): Path to the .grpgtex file
  • -o, --output (optional): Output file path (default: items.grpgitem)
Example: 
grpgpack item -m items_manifest.gcfg -t textures.grpgtex -o items.grpgitem
Manifest Format: 
[Item] {
    name = "berries"
    id = 1
    texture = "grass_tex"
}

[Item] {
    name = "potion"
    id = 2
    texture = "potion_tex"
}

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Workflow

1

Create Texture Manifest

Define all textures in a .gcfg manifest file with unique IDs and paths to PNG files.
2

Pack Textures

Run grpgpack tex to generate the .grpgtex binary file.
3

Create Asset Manifests

Define tiles, objects, NPCs, or items in separate manifest files, referencing texture names from the texture manifest.
4

Pack Assets

Run the appropriate grpgpack command (tile/obj/npc/item) with the asset manifest and the .grpgtex file.

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Common Errors

No manifest file provided: You must specify a manifest file with the -m flag.
No textures file provided: Commands other than tex require a .grpgtex file specified with the -t flag.

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Source Code

The data packer source code is located at: 
~/workspace/source/data-packer/
Key files:
  • main.go:20 - CLI command definitions
  • textures/cmd.go:18 - Texture packing implementation
  • tiles/cmd.go:13 - Tile packing implementation
  • objs/cmd.go:13 - Object packing implementation
  • npcs/cmd.go:13 - NPC packing implementation
  • items/cmd.go:13 - Item packing implementation

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