NMLTutorial/Base graphics replacement

NML Tutorial

Installation

Graphics files

Language files

NML Syntax

Starting an NML file (grf block)

• Creating a road vehicle

Item blocks

• • Item definition

Spriteset & spritegroup blocks

• • Adding the graphics

Template blocks

• • Templating the graphics

Cargotable block

• • Cargo-dependent graphics

Callbacks and switch blocks

• Creating a tram

• • Make it articulated

• • Adding the graphics

• • Fix the purchase menu

• Creating a train

Railtypetable block

• • Single engine

• • Three part articulated

• • Four part refit

GRF Parameters

• • Real life recolour scheme

• Creating an object

Spritelayout blocks

• • Adding the graphics

Version checks

• • Objects on slopes

32 bit sprites

• Adding 32 bit sprites

Base graphics replacement

• 32 bit base graphics

Conclusion

Glossary

NML Documentation

A base graphics set provides the graphics you see when you have no NewGRFs loaded. If you don't want to add any new elements to the game, you can easily replace just these graphics via NewGRF.

There are to distinct types of base graphis: those originating from TTD and those that were added later to TTDPatch and OpenTTD. The first type is replaced by means of the replace block, the latter by means of the replacenew block. The way these blocks work are similar to the spriteset block.

Replace TTD sprites

And by this we mean the graphics that originally were in TTD. If you use OpenGFX, this will of course replace OpenGFX sprites and not TTD sprites. But in either case we mean replacements of the sprites in trg1(r).grf (TTD) or ogfx1_base.grf. It's useful to have a decode (grfcodec) of either of those grfs available to look up the sprite numbers. If you don't have that, you can find one here (choose to view the full resolution version below the thumbnail).

Once you have the sprites you want to replace and know their sprite numbers, you can start writing your replace. The general syntax is as follows:

replace [<identifier>] (<sprite-id> [, <image-file>]) {
	<list_of_realsprites>
}

The <identifier> is something you choose yourself. It's useful to prefix it with replace_ to avoid confusion with other identifiers in your code. It's optional if you only want to replace regular 8 bit sprites, but required if you also want to provide 32 bit sprites and/or sprites for different zoom levels. The <sprite-id> is the sprite number of the first sprite you want to replace. You can then place all consecutive replacement sprites in this block. As soon as there is a gap, you start a new replace block. The <image-file> is again optional. Like with a spriteset you can either provide a single filename for all sprites inside the block, or omit the filename here and specify the filename for each realsprite individually.

The <list_of_realsprites> is the same as for spriteset blocks.

Climates other than temperate

The previous method will provide replacement sprites for all climates at the same time. If you want to provide different sprites for each climate, you'll have to write different replace blocks for each climate. Each of these climate specific blocks are guarded by if-statements as introduced earlier. In the if-statement you will test the active climate, using the climate general variable. Depending on the climate, this variable is equal to one of the following: CLIMATE_TEMPERATE, CLIMATE_ARCTIC, CLIMATE_TROPICAL or CLIMATE_TOYLAND.

This will allow you to write something like the following:

if (climate == CLIMATE_ARCTIC) {
	replace replace_roads (1332 , "gfx/roads_arctic.png) {
		template_roads(0,0)
	}
}
else if (climate == CLIMATE_TROPICAL) {
	replace replace_roads (1332 , "gfx/roads_tropical.png) {
		template_roads(0,0)
	}
}
else if (climate == CLIMATE_TOYLAND) {
	replace replace_roads (1332 , "gfx/roads_toyland.png) {
		template_roads(0,0)
	}
}
else { //in all other cases the climate will be temperate, so we need not test this
	replace replace_roads (1332 , "gfx/roads_temperate.png) {
		template_roads(0,0)
	}
}

Replace OpenGFX sprites

« Road vehicle 32 bit sprites

NML Tutorial: Base graphics replacement

32 bit base graphics »