ReadingPatchVariables

From GRFSpecs

Introduction

Since TTDPatch 2.0.1 alpha 48, it has been possible to use action D to read various special Patch variables. These are usually switch values, but there are also a few other useful values.

Syntax

<Sprite-number> * <Length> 0D <target> <operation> <variable> FE FF FF 00 00

Element	Size	Description
0D	B	Defines action 0D
<target>	B	Target parameter
<operation>	B	As for ActionD, but only assignment is valid.
<variable>	B	Patch variable number to read. See below.
FE	B	Defines a special variable access
FF FF 00 00	D	Indicates that a patch variable is being read

variable

The following patch variables are defined:

variable	Switch	Version	Value
00	miscmods/-Yo	2.5	Bit switch
01	experimentalfeatures/-XF	2.5	Bit switch
02	morevehicles/-x	2.5	Vehicle array multiplier
03	mountains and curves/-mc	2.5	Two bytes with four sets of two bits
04	planecrashcontrol/-Xc	2.5	Bit switch
05	autorenew/-Xa	2.5	Signed value
06	multihead/-M	2.5	Speed increase, in percent
07	disasters/-XD	2.5	Bit switch
08	unifiedmaglev/-XM	2.5	Unified maglev mode
09	bridgespeedlimits/-XX	2.5	Speed fraction, in percent
0A	---	2.5	TTD Language, see the "new scheme" for action 4
0B	startyear/-XY	0.6 2.5	Year-1920
0C	morebuildoptions/-YB	2.5	Bit switch
0D	moresteam/-YM	2.5	value=LF (two hex digits), L=length, F=frequency
0E	freighttrains/-Yf	0.6 2.5	weight factor
0F	wagonspeedlimits/-YL	0.6 2.5	Speed increase for empty wagons
10	planespeed/-YP	0.6 2.5	speed factor
11	dual company colors	0.6 2.5	2CC colormap base sprite
12	miscmods2/-Zm	2.6	Bit switch
13	map size information	0.6 2.6	Format = -MABXYSS M the type of map bit 0 set: squared map. Clear : rectangular map bit 1 set: Y is the bigger edge(bit 0 is clear).Clear : X is the bigger edge. A minimum edge(log2) of the map B maximum edge(log2) of the map XY edges(log2) of each side of the map. SS combination of both X and Y, thus giving the size(log2) of the map All map sizes will be substracted by 6, as to keep the size 64 the smallest one, thus zero based
14	maximum height level	1.2	Maximal possible height level of a tile. Currently fixed at 15.

If experimentalfeatures, miscmods, or miscmods2 are off, the corresponding value will be zero. For all other switches, the value is unspecified if the switch is off, so action 7 variable 85 should be checked first.