Difference between revisions of "LlGetAlpha"
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(Add Blinn-Phong terminology to page following PBR release.) |
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{{LSL_Function/face|face|return= | {{LSL_Function | ||
|inject-2={{LSL_Function/face|face|return=1.0|get=returns the sum of alpha of all the faces on the prim, range {{Interval|gte=0|lte=[[llGetNumberOfSides|sides]]|lteh=sides|center=return}}{{Interval/Footnote}}.}} | |||
{{LSL_Function/alpha|alpha}} | |||
|func_id=50|func_sleep=0.0|func_energy=10.0 | |func_id=50|func_sleep=0.0|func_energy=10.0 | ||
|func=llGetAlpha|return_type=float | |func=llGetAlpha|return_type=float | ||
|p1_type=integer|p1_name=face | |p1_type=integer|p1_name=face | ||
|func_footnote= | |func_footnote= | ||
Otherwise the return is in the range | Otherwise the return is in the range {{Interval|gte=0|lte=1|center=return}}, with 0.0 being fully transparent and 1.0 being fully solid. | ||
|func_desc | |func_desc | ||
|return_text=that is the alpha of | |return_text=that is the [[PBR_Materials#Nomenclature_changes|Blinn-Phong]] alpha of {{LSLP|face}}. | ||
|spec | |spec | ||
|caveats | |caveats | ||
|constants | |constants | ||
|examples= | |examples= | ||
< | <source lang="lsl2">//Tells the owner the alpha on all sides | ||
default | default | ||
{ | { | ||
| Line 24: | Line 26: | ||
} | } | ||
} | } | ||
}</ | }</source> | ||
|helpers= | |helpers= | ||
< | <source lang="lsl2">float AveragePrimAlpha() | ||
{//Since this is so simple you may just want to inline it instead of including the function. | {//Since this is so simple you may just want to inline it instead of including the function. | ||
return (llGetAlpha(ALL_SIDES) / llGetNumberOfSides()); | return (llGetAlpha(ALL_SIDES) / llGetNumberOfSides()); | ||
}</ | }</source> | ||
<source lang="lsl2">//if face 0 is "transparent" then make the prim "visible" | |||
if (llGetAlpha(0)) ; | |||
else llSetAlpha(1.0, ALL_SIDES);</source> | |||
|also_functions= | |also_functions= | ||
{{LSL DefineRow||[[llSetAlpha]]|Sets the prim's alpha}} | {{LSL DefineRow||[[llSetAlpha]]|Sets the prim's alpha}} | ||
| Line 42: | Line 47: | ||
|notes | |notes | ||
|permission | |permission | ||
| | |deepnotes= | ||
====Rounding==== | |||
Alpha is stored in a single 8-bit byte, meaning there are 256 values that are possible. Consequently the values returned by this function are all multiples of 1/255. When the alpha value is initially stored the float value is rounded to the nearest multiple, turning 0.5 into 128/255 for example. | |||
|cat1 | |cat1 | ||
|cat2 | |cat2 | ||
Latest revision as of 12:26, 1 December 2023
| LSL Portal | Functions | Events | Types | Operators | Constants | Flow Control | Script Library | Categorized Library | Tutorials |
Summary
Function: float llGetAlpha( integer face );| 0.0 | Forced Delay |
| 10.0 | Energy |
Returns a float that is the Blinn-Phong alpha of face.
| • integer | face | – | face number or ALL_SIDES |
If face is ALL_SIDES then the function returns the sum of alpha of all the faces on the prim, range [0, sides][1]. Otherwise the return is in the range [0, 1], with 0.0 being fully transparent and 1.0 being fully solid.
Caveats
- If face indicates a face that does not exist the return is 1.0
Examples
//Tells the owner the alpha on all sides
default
{
state_entry()
{
integer i = 0;
integer max = llGetNumberOfSides();
while(i < max)
{
llSay(0,"Face "+(string)i+" alpha is " + (string)llGetAlpha(i));
++i;
}
}
}
Useful Snippets
float AveragePrimAlpha()
{//Since this is so simple you may just want to inline it instead of including the function.
return (llGetAlpha(ALL_SIDES) / llGetNumberOfSides());
}
//if face 0 is "transparent" then make the prim "visible"
if (llGetAlpha(0)) ;
else llSetAlpha(1.0, ALL_SIDES);
See Also
Functions
| • | llSetAlpha | – | Sets the prim's alpha | |
| • | llGetColor | – | Gets the prim's color | |
| • | llSetColor | – | Sets the prim's color | |
| • | llSetLinkColor | – | Sets link's color | |
| • | llSetLinkAlpha | – | Sets link's alpha | |
| • | llGetNumberOfSides | – | Gets the number of faces on the prim |
Articles
| • | Translucent Color |
Deep Notes
Rounding
Alpha is stored in a single 8-bit byte, meaning there are 256 values that are possible. Consequently the values returned by this function are all multiples of 1/255. When the alpha value is initially stored the float value is rounded to the nearest multiple, turning 0.5 into 128/255 for example.
Footnotes
- ^ The ranges in this article are written in Interval Notation.
Signature |
|---|
function float llGetAlpha( integer face ); |