# llGetAlpha

 LSL Portal
Function: float llGetAlpha( integer face );
 0 Forced Delay 10 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);
```

### 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

## 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

1. ^ The ranges in this article are written in Interval Notation.

#### Signature

```function float llGetAlpha( integer face );
```