RecolorSprites

Recolor Sprites

Changing how other sprites are drawn

Recolor sprites are pseudosprites used to recolor other sprites, most often to apply company colors. A recolour sprite is simply a re-mapping of TTDs original colour table.

Syntax

A recolor sprite has the following format:

<Sprite-number> * 257 00 <recolor-table>

Element	Size	Description
<Sprite-number>	dec	A sequential sprite number
257	dec	The total number of bytes used in this action, always 257
00	B	literal 00
<recolor-table>	256*B	See below

Description

00

At first glance, it is easy to confuse a recolor sprite with an action 0, most often for trains. Attempting to read the recolor sprite as an action 0 will usually reveal that there are far too many bytes. Another clue is that recolor sprites are always 257 bytes long.

The correct method to distinguish recolor sprites and action 0s is to note that recolor sprites can only appear in an Action5 or ActionA block, and action 0s can only appear outside such a block.

recolor-table

A 256-byte recolor table. A byte at the offset equal to the index of the source color specifies the color to be drawn.

Note that the offsets and bytes are different depending on whether the GRF is being loaded in TTD DOS or TTD Win. If you create a grf that contains recolor sprites, you may find it necessary to maintain two separate versions, or use an Action7 that checks variable 83 to guard the introducing action 5/A and the recolor sprite(s).

Usage

Recolor sprites are applied in one of two ways.

Non-transparently

Each pixel in the sprite is looked up in the recolor table, and then the color specified at that offset is drawn on the screen. If the resultant color is 00 ("transparent blue"), then if the sprite's compression bit 3 is not set, nothing is drawn; otherwise (i.e. if the sprite is in chunked data format) the actual color 00 (which is black) is drawn.

Transparently

For each sprite pixel that is not transparent, the current (on-screen) color of the pixel at the location where the sprite pixel would be drawn is looked up in the recolor table, and then redrawn in the new color. If the recolor lookup returns 00 ("transparent blue"), the resultant color is actually black. Other than is-transparent-blue/not-transparent-blue, the actual colors of the pixels in a sprite that is drawn transparently are meaningless.

Default recolour sprites

TTD already defines a number of recolour sprites for various uses, e.g. for the semi-transparency of glass or the re-colouring of the tubular bridges, company colours or some houses.

Sprite number (dec)	Sprite number (hex)	Description
771	0x303	A pulsating red tile is drawn if you try to build a wrong tunnel or raise/lower land where it is not possible
772	0x304	Makes a square red. is used when removing rails or other stuff
773	0x305	This draws a blueish square (catchment areas for example) translations for the company colour (blue-ish colours are replaced)
775	0x307	company colour to dark blue
776	0x308	company colour to pale green
777	0x309	company colour to pink
778	0x30A	company colour to yellow
779	0x30B	company colour to red
780	0x30C	company colour to light blue
781	0x30D	company colour to green
782	0x30E	company colour to dark green
783	0x30F	company colour to blue
784	0x310	company colour to cream
785	0x311	company colour to mauve
786	0x312	company colour to purple
787	0x313	company colour to orange
788	0x314	company colour to brown
789	0x315	company colour to grey
790	0x316	company colour to white (darker parts are blue-ish) translations for "brownish red" colour used by some town buildings and bridges
791	0x317	bare land, for rail and road (crossings)
795	0x31B	structure to blue
796	0x31C	structure to brownish (e.g. cantilever bridges)
797	0x31D	structure to white
798	0x31E	structure to red (e.g. bridges)
799	0x31F	structure to green (e.g. bridges)
800	0x320	structure to concrete (e.g. suspension bridge)
801	0x321	structure to yellow (e.g. suspension bridge + tubular) special colour translations
802	0x322	glass effect
803	0x323	maps to grey (e.g. tubular bridge or newspaper)
804	0x324	crashed vehicle (grey-ish)
1438	0x59E	church red
1439	0x59F	church cream

For the company colour translation a translation to dark blue (0x307) is the identity translation which replaces every colour with itself. You can use it in cases where a remapping is needed, but you don't want to recolor anything.

Dual company colours

You can also use the dual-company-colour recolour sprites. However, they are no default TTD sprites and thus they do not have fixed sprite numbers. You can determine the spritenumber of the first 2CC recolour sprite via Patch Variable 11. You then need Action 6 to put the needed recolourings into actions where needed.

Starting from the spritenumber from patch variable 11 there are 256 recolour sprites. Their order follows the default company recolourings above. The second company colour changes every 16 sprites, so every combination of first and second colour is available:

Offset from first sprite (dec)	Offset from first sprite (hex)	First colour (colours 0xC6 to 0xCD)	Second colour (colours 0x50 to 0x57)
0	0x00	dark blue	dark blue
1	0x01	pale green	dark blue
:	:	:	:
15	0x0F	white	dark blue
16	0x10	dark blue	pale green
:	:	:	:
31	0x1F	white	pale green
32	0x20	dark blue	pink
:	:	:	:
255	0xFF	white	white

You'll notice in hex that the low nibble of the offset represents the first company colour from 0 (dark blue) to F (white), and the high nibble represents the second company colour.