0x45 — background_play_animation

Background animation command. It resolves optional character abstraction data and calls CBackGround::PlayAnimation.

proven— handler traced, and exercised by at least one shipped script.

At a glance

Opcode	`0x45` (69)
Handler	`CRadiScript::Command_45`
Signature	`CRadiScript::Command_45(int,SCR_DATA*,unsigned int,unsigned int)`
Translation unit	`r_script_run4.cpp`
Address	— debug build; click for all 3
Handler size	`0x1B0` (432 bytes)
Engine name	`background_play_animation`
Family	Background, map, landscape and camera
Command size	`4 + extra_words * 4` bytes

Handler behaviour

Background animation command. It resolves optional character abstraction data and calls CBackGround::PlayAnimation.

Encoding

The command header is one 32-bit word, as described in §3 Instruction encoding:

 31            24 23            16 15             8 7              0
+----------------+----------------+----------------+----------------+
|  flags         |  argument byte |  extra words   |  0x45          |
+----------------+----------------+----------------+----------------+

Bits 8–15 give the number of 32-bit operand words that follow. Bits 16–23 are handed to the handler as a bitfield; on character commands bit 0 normally says whether a character selector word is present. Bit 31 is the keep-going bit.

Operand fields

15 documented fields. input fields are read from the command's operand words; derived fields are computed from other fields rather than stored separately.

Field	Role	Meaning
`char_ref_stream`	input	Bit 5 of the argument byte: when the control word has bit 15 set, an explicit character-reference word follows in place of the third float.
`children_share_range`	derived	Children play the same frame range as the parent rather than their own.
`float0`	input	Float parameter 0 consumed by this command.
`float1`	input	Float parameter 1 consumed by this command.
`float2`	input	Float parameter 2 consumed by this command.
`frames_are_keys`	derived	Treat the frame numbers as key indices rather than frame counts.
`has_float0`	derived	Whether `float0` is present on this line.
`has_float1`	derived	Whether `float1` is present on this line.
`has_float2_or_char`	derived	Whether `float2 or char` is present on this line.
`include_children`	derived	Also play the animation on the object's child nodes.
`name`	input	Object or animation name this line acts on, as text. The engine reads it as a NUL-terminated string; `name_fill` covers the bytes after the terminator.
`name_source`	input	Selects where a name operand comes from, such as an inline four-word string.
`repeat`	input	How many extra times to loop: `0` plays once, `forever` loops until stopped.
`restart_if_playing`	derived	Restart from the beginning if this animation is already running.
`yield`	derived	Pause the script here for one game frame; the next command runs on the following update. Lines without it keep running immediately.

Engine calls

Engine functions this handler was observed calling:

CBackGround::PlayAnimation(const char*,unsigned int,float,float,float,unsigned int,unsigned int,unsigned short)
CRadiScript::GetAbstractionCharacterNumber(unsigned int&,unsigned int&,const SCR_DATA*)

Bit masks

Masks the handler applies to its argument byte or operand words:

0xFFFF 0x0003 0x0001 0x0002 0x0004 0x8000 0x0020 0x00FF