RecolorSprites

From GRFSpecs
Jump to: navigation, search

Introduction

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
translations for selection highlights
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)
translation for infrastructure ground sprites
791 0x317 bare land, for rail and road (crossings)
translations for "brownish red" colour used by some town buildings and bridges
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)
other
802 0x322 glass effect
803 0x323 maps to greyscale (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

Supported by OpenTTD 0.60.6 Supported by TTDPatch 2.52.5 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.