Howto:Add sound effects to aircraft: Difference between revisions

; <code>&lt;expression&gt;</code>

: Defines an expression, and will replace all other tags in this volume/pitch tag.

; <code>&lt;property&gt;</code>

: Defines which property supplies the value for the calculation.

: Either a <property> or an <internal> should be defined.  If none is defined, the property reverts to its default.  For volume this is 0, meaning the sound will not be audible at all.

: The value is treated as a floating point number.

; <code>&lt;internal&gt;</code>

: Defines which internal variable should be used for the calculation.

: The value is treated as a floating point number.

: The following internals are available at this time:

:; dt_play

:: The number of seconds since the sound started playing.

:; dt_stop

:: The number of seconds after the sound has stopped.

; <code>&lt;delay-sec&gt;</code>

: Delay after which the sound starts playing.

: This is useful to let a property start two sounds at the same time, where the second is delayed until the first stopped playing.

; <code>&lt;type&gt;</code>

: Defines the function that should be used upon the property before it is used for calculating the net result:

:; lin

:: Linear handling of the property value. This is the default.

:; ln

:: Anything below 1 will return zero.

:; log

:: convert the property value to a true logarithmic value before scaling it. (log base 10)

:: Anything below 1 will return zero.

:; inv

:: Inverse linear handling (1/x).

:; abs

:; sqrt

:: Calculate the square root of the absolute value before scaling it.

; <code>&lt;factor&gt;</code>

: Defines the multiplication factor for the property value.

: A special condition is when scale is defined as a negative value. In this case the result of |<scale>| * <property) will be subtracted from &lt;default&gt;

; <code>&lt;offset&gt;</code>

: The initial value for this sound.

: This value is also used as an offset value for calculating the end result.

; <code>&lt;random&gt;</code>

: Add a bit of randomness to the offset. Only used for pitch.

; <code>&lt;min&gt;</code>

: Minimum allowed value.

: This is useful if sounds start to sound funny. Anything lower will be truncated to this value.

; <code>&lt;max&gt;</code>

: Maximum allowed value.

: This is useful if sounds gets to loud. Anything higher will be truncated to this value.

: Keep in mind that min & max are applied first, then offset.  So for example if min = 0, max = 0.5 and offset = 1.0, then the resulting values will range 1 to 1.5.