PRIM ALPHA MODE

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Description

Constant: integer PRIM_ALPHA_MODE = 38;

The integer constant PRIM_ALPHA_MODE has the value 38

Used to get or set the diffuse texture alpha rendering mode of a prim's face.

llSetPrimitiveParams

[ PRIM_ALPHA_MODE, integer face, integer alpha_mode, integer mask_cutoff ]
• integer face face number or ALL_SIDES
• integer alpha_mode which PRIM_ALPHA_MODE_ to use - valid options are PRIM_ALPHA_MODE_NONE, PRIM_ALPHA_MODE_BLEND, PRIM_ALPHA_MODE_MASK, and PRIM_ALPHA_MODE_EMISSIVE
• integer mask_cutoff when the alpha rendering mode is PRIM_ALPHA_MODE_MASK, sets the alpha value above which a pixel renders as fully opaque, in the range 0 to 255

Used with llSetPrimitiveParams & llSetLinkPrimitiveParams.

Caveats

  • If texture is missing from the prim's inventory and it is not a UUID or it is not a texture then an error is shouted on DEBUG_CHANNEL.
  • If texture is a UUID then there are no new asset permissions consequences for the object.
    • The resulting object develops no new usage restrictions that might have occurred if the asset had been placed in the prims inventory.
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Examples

<lsl>llSetPrimitiveParams([ PRIM_ALPHA_MODE, ALL_SIDES, PRIM_ALPHA_MODE_NONE, 0 ]); llSetPrimitiveParams([ PRIM_ALPHA_MODE, ALL_SIDES, PRIM_ALPHA_MODE_MASK, 130 ]);</lsl>

llGetPrimitiveParams

llGetPrimitiveParams([ PRIM_ALPHA_MODE, integer face ]);

Returns the list [ integer alpha_mode, integer mask_cutoff ]

• integer face face number or ALL_SIDES

• integer alpha_mode which PRIM_ALPHA_MODE_ to use - valid options are PRIM_ALPHA_MODE_NONE, PRIM_ALPHA_MODE_BLEND, PRIM_ALPHA_MODE_MASK, and PRIM_ALPHA_MODE_EMISSIVE
• integer mask_cutoff when the alpha rendering mode is PRIM_ALPHA_MODE_MASK, sets the alpha value above which a pixel renders as fully opaque, in the range 0 to 255

Caveats

  • If face is ALL_SIDES then the PRIM_ALPHA_MODE works on all sides.
  • If face indicates a face that does not exist the PRIM_ALPHA_MODE return is an empty list.
  • If face indicates a face that exists but does not contain a material, the PRIM_ALPHA_MODE return is [ PRIM_ALPHA_MODE_BLEND, 0 ]
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Target

In the case of llGetPrimitiveParams is either the prim the script resides in, or the prim specified by the immediately prior PRIM_LINK_TARGET call. However in the case of llGetLinkPrimitiveParams, it is either the value of the link parameter, or the prim specified by the immediately prior PRIM_LINK_TARGET call.

Related Articles

Functions

•  llSetPrimitiveParams
•  llSetLinkPrimitiveParams
•  llGetPrimitiveParams
•  llGetLinkNumber Returns the link number of the prim the script is in.

Notes

Link Numbers

Each prim that makes up an object has an address, a link number. To access a specific prim in the object, the prim's link number must be known. In addition to prims having link numbers, avatars seated upon the object do as well.

  • If an object consists of only one prim, and there are no avatars seated upon it, the (root) prim's link number is zero.
  • However, if the object is made up of multiple prims or there is an avatar seated upon the object, the root prim's link number is one.

When an avatar sits on an object, it is added to the end of the link set and will have the largest link number. In addition to this, while an avatar is seated upon an object, the object is unable to link or unlink prims without unseating all avatars first.

Counting Prims & Avatars

There are two functions of interest when trying to find the number of prims and avatars on an object.

integer GetPrimCount() { //always returns only the number of prims
    if(llGetAttached())//Is it attached?
        return llGetNumberOfPrims();//returns avatars and prims but attachments can't be sat on.
    return llGetObjectPrimCount(llGetKey());//returns only prims but won't work on attachments.
}
See llGetNumberOfPrims for more about counting prims and avatars.

Errata

If a script located in a child prim erroneously attempts to access link 0, it will get or set the property of the linkset's root prim. This bug (BUG-5049) is preserved for broken legacy scripts.

Deep Notes

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Footnotes

  1. ^ LINK_ROOT does not work on single prim objects. Unless there is an avatar sitting on the object.

Signature

integer PRIM_ALPHA_MODE = 38;