The nfo/grf Technical Reference

Creating new graphics sets

Introduction

These pages contain info on how to make new graphics sets. The reference on the actions is up-to-date, whereas the tutorial is still under construction. Stay tuned.

The main advantage of nfo/grf is versatility and performance. Because of tight integration with the game's state engine, there's nearly no limit for the nfo/grf coder (many of nfo's features in existence since years haven't made it into set development as of today!) in conjunction with an excellent performance, because of it's heavily optimized byte code for processing and displaying sprites.

In TTDPatch, the resulting byte code is even compiled into CPU instructions directly, something which couldn't be accomplished by any script-related approach.

OTOH, the "drawback" of using plain nfo is that it's hard to write and even harder to read. There have been several approaches to remedy this by supplying additional programs for lexical checking and beautifying nfo-code (renum), graphics frontends for nfo-programming (GRFmaker), and high-level languages compiling into NFO (m4nfo and NML).

However, to get the most out of these approaches, a thorough knowledge of plain nfo is still important, both for the game developer and for the graphic's set author, something that this newly compilated and revised technical reference would like to provide.

A downloadable version of these pages, in the form of a zip file containing all individual pages as HTML files, is available here.

Table of contents

GRFTutorial - A tutorial on writing new graphics for TTDPatch
- Preliminaries - What you need to know and do when making new graphics
- DrawingSprites - How to draw new sprites
- PalettesAndCoordinates - How to work with palettes, and the 2D and 3D coordinates
- NFOFoundations - How to get started on .nfo editing
- TheFirstVehicle - Getting your first vehicle into the game
- SelectiveGrfLoading - Selectively loading GRF files
- VariableVehicleID - How to implement grfs with variable vehicle IDs
- StationDrawingTutorial - How to draw new stations for TTDPatch
- CallbacksTut - Tutorial on using callbacks
- GeneralNfoStrategy - General strategy for writing NFO files
- SampleNfoFile - A simple NFO file
- UsingGRFMaker - Information about how to use GRFMaker
- UnfinishedTutorials - List of tutorials that still need to be written
  - TestingChanges - How to test changes you make to your graphics files
  - SettingSpeedEtc - How to set speed and other properties of your vehicle
  - NamingYourVehicle - How to give your new vehicle a name
  - EnsuringCompatibility - How to make your file compatible with others
  - ShowingLoadingStates - How to show gradual loading effects
  - DifferentCargoTypes - How to have your wagon show different cargo types
  - WagonOverride - How to make train sets with matching wagons
  - LiveryChanges - How to have your vehicle's graphics change with time or other factors
  - RandomLivery - How to get random livery
  - PoweredWagons - How to make trains which have powered wagons
  - SpecialEffects - Various special effects you can use for new graphics
GRFActionsDetailed - Technical reference of the new .grf actions
- Action0 - Defining new graphics feature properties
  - Action0General - Action 0 properties common to all vehicle types
  - Action0Trains - Action 0 properties for trains
  - Action0RoadVehicles - Action 0 properties for road vehicles
  - Action0Ships - Action 0 properties for ships
  - Action0Planes - Action 0 properties for planes
  - Action0Stations - Action 0 properties for new stations
  - Action0Canals - Action 0 - Properties for canals / rivers
  - Action0Bridges - Defining properties of bridges
  - Action0Houses - Action 0 properties of houses
    - DefaultHouseProps - Default property values for TTD's houses
  - Action0GeneralVariables - Action 0 properties for general variables
  - Action0IndustryTiles - Action 0 properties for industry tiles
    - IndustryTileDefaultProps - Default property values for TTD's industry tiles
  - Action0Industries - Action 0 properties for industries
    - IndustryDefaultProps - Default properties values for TTD's industries
  - Action0Cargos - Action 0 properties for cargo types
    - CargoDefaultProps - Default property values for TTD's cargo types
  - Action0SoundEffects - Action 0 properties for new sound effects
  - Action0Objects - Action 0 properties for new objects
  - Action0Railtypes - Action 0 properties for rail types
  - Action0AirportTiles - Action 0 properties for airport tiles
  - Action0Airports - Action 0 properties for airports
- Action1 - Define a set of real sprites
- Action2 - Define graphics set IDs
  - Action2Vehicles - Defining set-IDs for vehicles
  - Action2Stations - Defining station set-IDs
  - Action2Canals - Defining an action2 for canals
  - Action2HousesIndustryTiles - Defining an action 2 for houses, industry tiles and object
  - Action2Industries - Defining the industry production callback
  - Action2Cargos - Defining set-IDs for cargos
  - Action2Objects - Action2 for Objects
  - Action2Railtypes - Action2 for Railtypes
  - VariationalAction2 - Variational Action 2
    - VarAction2Advanced - Advanced features of Variational Action 2
    - VarAction2Vehicles - Variational Action 2 Variables for Vehicles
    - VarAction2Stations - Variational Action 2 Variables for Stations
    - VarAction2Cities - Variational Action 2 Variables for Cities
    - VarAction2Canals - Variational Action 2 Variables for Canals
    - VarAction2Bridges - Variational Action 2 Variables for Bridges
    - VarAction2Houses - Variational Action 2 Variables for Houses
    - VarAction2IndustryTiles - Variational Action 2 Variables for Industry and Airport Tiles
    - VarAction2Industries - Variational Action 2 Variables for Industries
    - VarAction2Cargos - Variational Action 2 Variables for cargos
    - VarAction2NewSignals - Variational Action 2 Variables for New Signals
    - VarAction2Objects - Variational Action 2 Variables for Objects
    - VarAction2Railtypes - Variational Action 2 for Railtypes
  - RandomAction2 - Randomized Action 2
  - Callbacks - List of available callbacks
- Action3 - Associate vehicles with graphics set IDs
  - Action3LiveryOverride - Change wagon livery to match the engine
- Action4 - Define vehicle names or other texts
- Action5 - Define TTDPatch specific graphics sets
- Action6 - Modify the contents of the following sprite
- Action7 - Conditionally skip sprites or jump to label
  - TTDPatchFlags - TTDPatch Flags for Action 7/9 Variable 85
- Action8 - Define GRF ID, Name and Description
- Action9 - (see action 7 above)
- ActionA - Modify TTD's sprites
- ActionB - Generate error messages
- ActionC - Do nothing.
- ActionD - Assign parameters and calculate results
  - ReadingOtherGRFParameters - Reading another GRF file's parameters
  - ReadingPatchVariables
  - GRFResourceManagement - Preventing conflicts with limited resources
- ActionE - Deactivate other graphics files or force activation of current file
- ActionF - Define new town name styles
- Action10 - Define GOTO label for action 7/9
- Action11 - Define new sound data
- Action12 - Load font glyphs
- Action13 - Translate GRF-specific strings
- Action14 - Static GRF Information
- RealSprites - Sprites that actually get drawn on the screen
- RecolorSprites - Changing how other sprites are drawn
AdditionalReferences - Various reference lists for GRF-related items
- CargoTypes - Cargo types in TTD
- IndustryTypes - Industry types in TTD
- BaseCosts - List of all base costs
- VehicleIDs - List of vehicle IDs
- TextIDs - TextIDs to use for Action 4
- SpriteErrors - Explanation of all possible sprite error messages
- StringCodes - Description of characters in TTD's character set
- GrfLoadingStages - Stages of loading a GRF file
- DebuggingGRFCode - Tools for debugging problems in GRF code