Time cycle

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The timecyc.dat data file contains the most important settings about the game's appearance. Basically it stores important information like colors and lighting for different hardcoded weather situations for each time of day. The settings themselves are constant and build a cycle around the whole day. So the exact name of the setting is time cycle.

In Vice City the timecyc.dat file additionally stores settings for different interior appearances. There are 23 of those extra settings in one extra section (internally called "EXTRACOLOURS"). Each game hour represents one constant setting.

File format

A comment in the timecyc.dat file is preceded by a series of slashes ("//"). The game's parser simply ignores comments so that the number of uncommented lines must be a multiple of 24 for GTA III and Vice City (representing one for each ingame hour) and a multiple of 8 for San Andreas (representing 00am, 05am, 06am, 07am, 00pm, 07pm, 08pm and 10pm in the order they appear). Each value of one entry gets interpolated with the previous and the next setting of the current ingame weather.

Data types

The file uses the following different data types directly or indirectly on an abstract level inside structures:

• INT8/UINT8 - signed/unsigned 8 bit integer (1 byte)
• INT32/UINT32 - signed/unsigned 32 bit integer (4 byte)
• FLOAT - single precision floating point number (4 byte)
• TColor - UINT8[3] representing the red, green and blue level (in the order they appear) of a color. (3 byte)

File hierarchy

As mentioned above each setting consists out of a constant number of entries separated by whitespaces. The following table lists the entries and their descriptions in the order they appear:

			Name	Data type	Description
X			Static ambience color	TColor	The color of ambient light on map objects (see IPL).
X			Dynamic ambience color	TColor	The color of ambient light on dynamically created objects like pedestrians and vehicles.
X		–	Static ambience blur color	TColor	Blurrig color value for static ambience color.
X		–	Dynamic ambience blur color	TColor	Blurrig color value for dynamic ambience color.
X			Direct light color	TColor	The color of direct light on dynamicly created objects like pedestriants and vehicles. Present in the timecyc.dat of GTA SA, but not loaded and unused by the game.
X			Sky top color	TColor	The color of the top of the skysphere.
X			Sky bottom color	TColor	The color of the bottom of the skysphere.
X			Sun core color	TColor	The color of the core sprite of the sun.
X			Sun corona color	TColor	The color of the corona sprite of the sun.
X			Sun core size	FLOAT	The size of the core sprite of the sun.
X			Sun corona size	FLOAT	The size of the corona sprite of the sun.
X			Sprite brightness	FLOAT	The the brightness of the above mentioned sprites.
X			Shadow intensity	INT32	The intensity of the shadows of objects like pedestriants, vehicles or poles.
X			Light shading value	INT32	Value used for the shading algorithm on pedestirants and vehicles [?].
X			Pole shading value	INT32	Shading value for map objects with flag 32768.
X			Far clipping offset	FLOAT	The distance of the far clipping plane from the camera.
X			Fog start offset	FLOAT	The range of the distance fog from the camera.
X			Light on ground	FLOAT	Amount of light on the ground of the sea [?].
X			Lower clouds color	TColor	Color of the lower clounds.
X		–	Upper clouds top color	TColor	Color of the top of the upper clouds.
X			Upper clouds bottom color	TColor	Color of the bottom of the upper clouds.
X		–	Blur color	TColor	The color of trails.
X			Water color	TColor	Color of the water vertices.
X			Water alpha level	UINT8	Alpha level for water vertices.
–		X	Color correction 1 alpha	UINT8	Alpha level for first color correction value.
–		X	Color correction 1	TColor	First color correction value.
–		X	Color correction 2 alpha	UINT8	Alpha level for second color correction value.
–		X	Color correction 2	TColor	Second color correction value.
–		X	Lower clouds alpha level	UINT8	Alpha level for lower clouds.
–		X	Highlight min intensity	UINT8	Intensity limit for PS2 radiosity effect.
–		X	Water fog alpha.	UINT8	Water fading to white, amount of white light on water. Usually 0.
–		X	Directional multiplier	FLOAT	Multiplier for the main directional light. Always 1.0, but missing in PC timecyc.dat

Timecyc.dat and Timecycp.dat

The PS2, PC and Xbox versions of San Andreas ship two timecycle files: timecyc.dat and timecycp.dat. The PS2 and Xbox version load timecycp.dat and ignore timecyc.dat while the PC loads timecyc.dat and ignore timecycp.dat. The mobile version only ships with and loads the PC timecyc.dat. Timecycp.dat is the same file in all games, timecyc.dat differs between versions: On the PS2 and Xbox the file is the same as timecycp.dat except for some different colors in one line. The PC timecyc.dat on the other hand differs more and is actually broken: RAINY_COUNTRYSIDE 8PM starts with '255' instead of '22 22 22' which causes the whole line to parsed incorrectly. Furthmore the last column (directionalMult) is missing in all lines and consequently interpreted as zero. This causes the main directional light (normally used on peds and vehicles) to be effectively turned off. It is unclear whether this is intentional but as a subsitute for the disabled dynamic directional light a hardcoded fixed light that doesn't change color is used for vehicle rendering. If the directional multplier is set to 1.0, vehicles will then become too bright and in addition the vehicle light will cause problems because it overrides D3D light 0 (this has been fixed in SilentPatch).

Another difference in the PC timecyc.dat are the postfx alpha values. It's the only file that uses the standard alpha range (255 = opaque), while all other files use the PS2 alpha range (128 = opaque). To convert from the PS2 to standard range, all games (except the PS2 game naturally) double those alpha values after reading them. This can be considered a bug in the PC and mobile games as the alpha values already are in standard range.

In conclusion, all games expect a PS2 timecyc(p).dat file, so it's not recommended to use the PC timecyc.dat file at all.

Weather types

GTA III

Type	Enum	Image
0	WEATHER_SUNNY
1	WEATHER_CLOUDY
2	WEATHER_RAINY
3	WEATHER_FOGGY

Vice City

Type	Enum	Image
0	WEATHER_SUNNY
1	WEATHER_CLOUDY
2	WEATHER_RAINY
3	WEATHER_FOGGY
4	WEATHER_EXTRA_SUNNY
5	WEATHER_HURRICANE
6	WEATHER_EXTRA_COLOURS

San Andreas	Liberty City Stories	Vice City Stories	GTA V
Ryosuke's website Multi Theft Auto wiki	Sunny Image Cloudy Image Rainy Image Foggy Image Extra Sunny Image Hurricane Image Extra Colors Image Snow Image	Sunny Image Cloudy Image Rainy Image Foggy Image Extra Sunny Image Hurricane Image Extra Colors Image Extra Sunny #2 Image	BLIZZARD CLEAR CLEARING CLOUDS EXTRASUNNY FOGGY NEUTRAL OVERCAST RAIN SMOG SNOW SNOWLIGHT THUNDER XMAS

This section is incomplete. You can help by fixing and expanding it.

Weather lists

Weather is actually not random in GTA 3D Trilogy. Every game hour, the games go through the list of weather types to determine the upcoming weather.

GTA III

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 01 02 02 01 00 00 00 01 03 03 01 00 00 01 01 
00 00 00 00 00 00 00 00 01 01 02 02 01 02 01 00 00 00 00 00 00 00 00 00 00 03 03 00 00 00 02 01

This array for v1.0 starts at 0x5FFBC8 in memory.

Vice City

No hurricane

04 04 04 04 04 04 04 04 00 00 00 04 04 04 00 00 00 04 04 04 04 00 00 04 04 04 04 04 04 04 04 04 
04 04 00 00 00 00 00 00 00 00 00 01 02 02 02 02 01 00 00 00 00 04 04 04 04 04 04 04 04 04 04 04

This array for v1.0 starts at 0x699EE4 in memory.

Hurricane

04 04 04 04 04 04 04 04 00 00 00 04 04 04 00 00 00 04 04 01 05 05 01 00 04 04 04 04 04 04 04 04 
04 04 00 00 00 00 00 00 00 00 00 00 01 05 05 05 01 00 00 00 00 04 04 04 04 04 04 04 04 04 04 04

This array for v1.0 starts at 0x699F64 in memory.

San Andreas

Map of SA weather regions

In San Andreas the map is divided into weather regions whose boundaries are hardcoded. These regions roughly cover major game cities and countryside locations. Each weather region has its own set of unique weathers listed below.

Countryside

13 13 13 13 13 13 13 13 14 15 09 09 15 14 13 14 14 13 13 13 13 14 14 13 13 13 13 13 13 13 13 13 
13 13 14 14 14 14 14 14 15 09 09 15 16 16 16 16 15 14 14 14 14 13 13 13 13 13 13 13 13 13 13 13

This array for v1.0 starts at 0x8D5EB0 in memory.

Los Santos

02 02 00 00 00 02 02 02 03 00 03 02 00 00 03 03 03 04 04 00 00 01 01 00 02 02 02 02 02 02 02 02 
02 02 03 03 03 03 03 03 02 02 03 03 00 00 16 00 04 01 01 01 01 00 00 02 02 02 02 02 02 02 02 02

This array for v1.0 starts at 0x8D5EF0 in memory.

San Fierro

05 05 05 05 05 07 07 09 09 07 05 05 05 05 05 07 07 07 08 08 07 07 05 05 05 05 06 06 05 07 09 09 
07 05 05 07 05 05 06 06 05 05 05 07 07 08 08 07 07 09 09 05 05 06 06 06 05 05 06 07 07 06 06 05

This array for v1.0 starts at 0x8D5F30 in memory.

Las Venturas

11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 10 10 10 10 10 11 11 11 11 11 11 11 11 
11 10 11 11 11 11 10 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 10 10 12 12 10 12 10 10

This array for v1.0 starts at 0x8D5F70 in memory.

Bone County

17 17 17 19 19 17 17 17 17 17 17 17 17 17 17 17 17 17 17 18 18 18 18 18 17 17 17 17 17 17 17 17 
17 17 17 17 17 19 19 19 17 17 17 17 17 17 17 17 17 17 18 18 18 17 17 17 17 17 17 17 19 19 19 17

This array for v1.0 starts at 0x8D5FB0 in memory.

Liberty City Stories

00 04 00 01 01 00 00 00 04 04 00 02 00 00 01 01 03 01 00 00 00 01 02 03 01 01 00 04 00 00 01 03
02 03 01 00 00 01 05 01 00 04 04 00 00 00 00 04 00 00 01 03 01 00 01 01 00 04 01 05 01 00 00 04

Mission script

01B5		forces the upcoming weather type
01B6		forces the weather type immediately
01B7		releases the forced weather type
0251		stores the weather state
0252		restores the weather state
04F9		sets the extra colors
04FA		clears the extra colors
057C		allows hurricane weather

Tools

• VC:Weather
• G-CYC
• In-game Timecyc Editor

External links

•  GTAForums: Modding timecyc.dat for Vice City