Action0/Bridges

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Introduction

Defining properties of bridges

Properties

Number Version Size Description
00 (d) B Failback Type, a default TTD Bridge ID
01 (d) - -reserved-
08* (a) B Year of availability, counted from 1920 (set to 1920 for first bridge if newstartyear<1930)
09 (a) B Minimum length, not counting ramps
0A (a) B Maximum length, not counting ramps
0B (a) B Cost factor
0C (a) W Max. speed
0D (a) V Sprite layout, see below
0E (a) B Various flags, bitcoded
0F (b) D Long format year of availability, counted from year 0
10 (c) W Purchase text
11 (c) W Description of a rail bridge
12 (c) W Description of a road bridge

* The meaning of prop. 08 has changed in alpha 34, it used to be what is now prop. 0D.

(a) Available since TTDPatch 2.0.1 alpha 34

(b) TTDPatch 2.5 r1702, OpenTTD r7191

(c) TTDPatch 2.5 r1824, OpenTTD r10269

Descriptions

Sprite layout (0D)

Property 0D sets the sprite layout for bridges. Each part of a bridge has eight sprites for each of the four types (rail, road, monorail, maglev), making 32 sprites in total. Each bridge has 7 parts, though not all of them have different graphics.

The data for property 0D is variable sized, with the format being

Size Field Description
B tableid First table to define sprites for
B numtables Number of tables to define sprites for
V spritedata spritedata, numtables*32 DWORDs with sprite numbers

The tableid is the number of the first table to change. There are seven tables for each bridge, with the first six (0-5) being various middle parts and the last one (6) being the end pieces.

In each of the six middle part tables, there are four entries each for the following:

  • Rail X, Rail Y, Road X, Road Y, Monorail X, Monorail Y, Maglev X, Maglev Y

Where X is a bridge in /-direction and Y a bridge in \-direction.

The four entries are

  • Back & Floor, Front, Pillars, 0

Front and Pillars can be 0, meaning no sprite to draw. The fourth entry is always ignored.

In the end part table, there are again four entries each, but now for Rail flat, Rail ramp, Road flat, Road ramp, Monorail flat, Monorail ramp and Maglev flat, Maglev ramp.

The four entries in this case are

  • northern end X, northern end Y, southern end X, southern end Y

The sprite numbers can be any of TTD's sprite numbers.

To summarize, there are 7 tables for each of the 11 bridges. Each table contains 4*8 entries, making it 128 (80h) bytes large. The first six tables, number 0 to 5, are middle pieces, the last table, number 6, is the end pieces.

Colour Translations

In order to recolour a bridge, you can add one of the values from the table below to the sprite number of the sprite you wish to recolour. The colour translations from the table will use the default colour translation tables from the base sets. These translation tables will translate the 'brownish red' as used in the default bridges to the colour you specify.

Added value Little Endian Colour
031B8000h 00 80 1B 03 Blue
031C8000h 00 80 1C 03 Brown
031D8000h 00 80 1D 03 Pure white
031E8000h 00 80 1E 03 Red
031F8000h 00 80 1F 03 Green
03208000h 00 80 20 03 Blueish white (concrete)
03218000h 00 80 21 03 Yellow (golden steel)
03238000h 00 80 23 03 Grey


4366 translates to 0E 11 in little endian value and as such to 0E 11 00 00 in a dword. In order to convert to grey you'll have to add 00 80 23 03 to the dword value. This yields 0E 91 23 03. Use the latter in your bridge table to colour one of the monorail bridgeheads grey.


Bridge Layouts

There are five possible bridge layouts in TTD. The numbers in the table below reflect the bridge table numbers in the NFO code.

Layout Description
__ Bridge without middle part
_0_ Bridge of length 3
_0(23)1_ Bridge of even length
_0(23)4(23)1_ Bridge of (uneven) lengths 5, 9, 13, 17 etc.
_0(23)253(23)1_ Bridge of (uneven) lengths 7, 11, 15, 19 etc.

_ is used as a symbol to indicate bridgeheads (as defined in table 6).

Part 0 is always at the farthest end from the viewer.

Parts (23) are repeated n times as necessary, where n is any number equal or greater than 0.

Flags (0E)

The following flags can be set here:

Bit Value Meaning
0 1 Do not draw the far pillars for higher bridges

Long format year of availability (0F)

Set the year of availability of the bridge in years since 0. The date range is from 0 to 5000000. This property must be set after property 08 to take effect. In TTDPatch, bridge introduction dates outside the range 1920..2175 will be limited to this range.

Purchase text (10)

Set the text appearing in the purchase window, describing what this bridge is made of, or what kind of bridge it is.

Description of a rail(11) or road(12) bridge

Set the text used as a description by the query tool. When the bridge is used for carrying a rail, it will use property 11, and will use property 12 when it will be for road.

  • Note that, as for property 10, the textID can be either a TTD ID or a TextID in the DCxx range.

Bridge IDs

ID (dec) ID (hex) Description
0 00 Wooden Bridge
1 01 Concrete Bridge
2 02 Girder, Steel Bridge
3 03 Suspension, Concrete Bridge
4 04 Suspension, Steel (Bronze) Bridge
5 05 Suspension, Steel (Golden) Bridge
6 06 Cantilever, Steel (Bronze) Bridge
7 07 Cantilever, Steel (Brown) Bridge
8 08 Cantilever, Steel (Red) Bridg
9 09 Girder, Steel Bridge
10 0A Tubular, Steel (Bronze) Bridge
11 0B (OpenTTD Only) Tubular, Steel (Golden) Bridge
12 0C (OpenTTD Only) Tubular, Silicon Bridge

Example

Below is an example code which rebuilds the bronze steel suspension bridge (ID 04). The code fragment by itself has no use (no visual difference in game), but might be useful in order to understand the bridge code. Sprite numbers refer to the numbers in the base grf. The code might also be useful to re-enstate the default bridge if you only want to replace only one certain tracktype.

The complete recode of all default bridges including colour translations is available at TT-Forums: http://www.tt-forums.net/viewtopic.php?p=715362#p715362 

//SUSPENSION, STEEL (BRONZE) bridge (04)

-1 * 0 00 06 01 01 04 0D 00 02 //action 00 bridges, 01 property, 01 ID, ID, prop 0D, tableID 00, 07 tables

//table 00

A9 09 00 00     9F 09 00 00     B1 09 00 00     00 00 00 00 //rail X: Back&Floor;, Front, Pillars, 0
A5 09 00 00     97 09 00 00     AD 09 00 00     00 00 00 00 //rail Y: Back&Floor;, Front, Pillars, 0
9D 09 00 00     9F 09 00 00     B1 09 00 00     00 00 00 00 //Road X: Back&Floor;, Front, Pillars, 0
95 09 00 00     97 09 00 00     AD 09 00 00     00 00 00 00 //Road Y: Back&Floor;, Front, Pillars, 0
F2 10 00 00     9F 09 00 00     B1 09 00 00     00 00 00 00 //Mono X: Back&Floor;, Front, Pillars, 0
EE 10 00 00     97 09 00 00     AD 09 00 00     00 00 00 00 //Mono Y: Back&Floor;, Front, Pillars, 0
1A 11 00 00     9F 09 00 00     B1 09 00 00     00 00 00 00 //Mlev X: Back&Floor;, Front, Pillars, 0
16 11 00 00     97 09 00 00     AD 09 00 00     00 00 00 00 //Mlev Y: Back&Floor;, Front, Pillars, 0
//table 01
AA 09 00 00     A0 09 00 00     B2 09 00 00     00 00 00 00 //rail X: Back&Floor;, Front, Pillars, 0
A6 09 00 00     98 09 00 00     AE 09 00 00     00 00 00 00 //rail Y: Back&Floor;, Front, Pillars, 0
9E 09 00 00     A0 09 00 00     B2 09 00 00     00 00 00 00 //Road X: Back&Floor;, Front, Pillars, 0
96 09 00 00     98 09 00 00     AE 09 00 00     00 00 00 00 //Road Y: Back&Floor;, Front, Pillars, 0
F3 10 00 00     A0 09 00 00     B2 09 00 00     00 00 00 00 //Mono X: Back&Floor;, Front, Pillars, 0
EF 10 00 00     98 09 00 00     AE 09 00 00     00 00 00 00 //Mono Y: Back&Floor;, Front, Pillars, 0
1B 11 00 00     A0 09 00 00     B2 09 00 00     00 00 00 00 //Mlev X: Back&Floor;, Front, Pillars, 0
17 11 00 00     98 09 00 00     AE 09 00 00     00 00 00 00 //Mlev Y: Back&Floor;, Front, Pillars, 0
//table 02
AC 09 00 00     A4 09 00 00     B4 09 00 00     00 00 00 00 //rail X: Back&Floor;, Front, Pillars, 0
A8 09 00 00     9C 09 00 00     B0 09 00 00     00 00 00 00 //rail Y: Back&Floor;, Front, Pillars, 0
A2 09 00 00     A4 09 00 00     B4 09 00 00     00 00 00 00 //Road X: Back&Floor;, Front, Pillars, 0
9A 09 00 00     9C 09 00 00     B0 09 00 00     00 00 00 00 //Road Y: Back&Floor;, Front, Pillars, 0
F5 10 00 00     A4 09 00 00     B4 09 00 00     00 00 00 00 //Mono X: Back&Floor;, Front, Pillars, 0
F1 10 00 00     9C 09 00 00     B0 09 00 00     00 00 00 00 //Mono Y: Back&Floor;, Front, Pillars, 0
1D 11 00 00     A4 09 00 00     B4 09 00 00     00 00 00 00 //Mlev X: Back&Floor;, Front, Pillars, 0
19 11 00 00     9C 09 00 00     B0 09 00 00     00 00 00 00 //Mlev Y: Back&Floor;, Front, Pillars, 0
//table 03
AB 09 00 00     A3 09 00 00     B3 09 00 00     00 00 00 00 //rail X: Back&Floor;, Front, Pillars, 0
A7 09 00 00     9B 09 00 00     AF 09 00 00     00 00 00 00 //rail Y: Back&Floor;, Front, Pillars, 0
A1 09 00 00     A3 09 00 00     B3 09 00 00     00 00 00 00 //Road X: Back&Floor;, Front, Pillars, 0
99 09 00 00     9B 09 00 00     AF 09 00 00     00 00 00 00 //Road Y: Back&Floor;, Front, Pillars, 0
F4 10 00 00     A3 09 00 00     B3 09 00 00     00 00 00 00 //Mono X: Back&Floor;, Front, Pillars, 0
F0 10 00 00     9B 09 00 00     AF 09 00 00     00 00 00 00 //Mono Y: Back&Floor;, Front, Pillars, 0
1C 11 00 00     A3 09 00 00     B3 09 00 00     00 00 00 00 //Mlev X: Back&Floor;, Front, Pillars, 0
18 11 00 00     9B 09 00 00     AF 09 00 00     00 00 00 00 //Mlev Y: Back&Floor;, Front, Pillars, 0
//table 04
B6 09 00 00     BA 09 00 00     BC 09 00 00     00 00 00 00 //rail X: Back&Floor;, Front, Pillars, 0
B5 09 00 00     B9 09 00 00     BB 09 00 00     00 00 00 00 //rail Y: Back&Floor;, Front, Pillars, 0
B8 09 00 00     BA 09 00 00     BC 09 00 00     00 00 00 00 //Road X: Back&Floor;, Front, Pillars, 0
B7 09 00 00     B9 09 00 00     BB 09 00 00     00 00 00 00 //Road Y: Back&Floor;, Front, Pillars, 0
F7 10 00 00     BA 09 00 00     BC 09 00 00     00 00 00 00 //Mono X: Back&Floor;, Front, Pillars, 0
F6 10 00 00     B9 09 00 00     BB 09 00 00     00 00 00 00 //Mono Y: Back&Floor;, Front, Pillars, 0
1F 11 00 00     BA 09 00 00     BC 09 00 00     00 00 00 00 //Mlev X: Back&Floor;, Front, Pillars, 0
1E 11 00 00     B9 09 00 00     BB 09 00 00     00 00 00 00 //Mlev Y: Back&Floor;, Front, Pillars, 0
//table 05
BD 09 00 00     C1 09 00 00     00 00 00 00     00 00 00 00 //rail X: Back&Floor;, Front, Pillars, 0
BE 09 00 00     C2 09 00 00     00 00 00 00     00 00 00 00 //rail Y: Back&Floor;, Front, Pillars, 0
BF 09 00 00     C1 09 00 00     00 00 00 00     00 00 00 00 //Road X: Back&Floor;, Front, Pillars, 0
C0 09 00 00     C2 09 00 00     00 00 00 00     00 00 00 00 //Road Y: Back&Floor;, Front, Pillars, 0
F8 10 00 00     C1 09 00 00     00 00 00 00     00 00 00 00 //Mono X: Back&Floor;, Front, Pillars, 0
F9 10 00 00     C2 09 00 00     00 00 00 00     00 00 00 00 //Mono Y: Back&Floor;, Front, Pillars, 0
20 11 00 00     C1 09 00 00     00 00 00 00     00 00 00 00 //Mlev X: Back&Floor;, Front, Pillars, 0
21 11 00 00     C2 09 00 00     00 00 00 00     00 00 00 00 //Mlev Y: Back&Floor;, Front, Pillars, 0
//table 06
86 09 00 00     88 09 00 00     85 09 00 00     87 09 00 00 //rail flat: northern end X, northern end Y, southern end X, southern end Y
8A 09 00 00     8C 09 00 00     89 09 00 00     8B 09 00 00 //rail ramp: northern end X, northern end Y, southern end X, southern end Y
8E 09 00 00     90 09 00 00     8D 09 00 00     8F 09 00 00 //road flat: northern end X, northern end Y, southern end X, southern end Y
92 09 00 00     94 09 00 00     91 09 00 00     93 09 00 00 //road ramp: northern end X, northern end Y, southern end X, southern end Y
E7 10 00 00     E9 10 00 00     E6 10 00 00     E8 10 00 00 //mono flat: northern end X, northern end Y, southern end X, southern end Y
EB 10 00 00     ED 10 00 00     EA 10 00 00     EC 10 00 00 //mono ramp: northern end X, northern end Y, southern end X, southern end Y
0F 11 00 00     11 11 00 00     0E 11 00 00     10 11 00 00 //mlev flat: northern end X, northern end Y, southern end X, southern end Y
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