Difference between revisions of "LlCloud"
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|func=llCloud|sort=Cloud | |func=llCloud|sort=Cloud | ||
|return_type=float|p1_type=vector|p1_name=offset | |return_type=float|p1_type=vector|p1_name=offset | ||
|func_footnote | |func_footnote=Returned values are in the range [0.0, 2.0]. Values above 1.0 indicate rain.{{PBR}} | ||
|return_text=that is the cloud density at the | The Z component of '''offset''' is ignored. | ||
|spec | |return_text=that is the cloud density at the [[llGetPos|prim position]] + '''offset''' | ||
|caveats | |spec= | ||
SL features a [http://web.archive.org/web/20040703050532/http://secondlife.com/about/technology.php#14 cellular automata-based] {{LSLGC|Weather|weather}} system. There are 16x16 square cloud "cells" per [[region]]. | |||
|caveats= | |||
* There are currently no SecondLife clients that render rain. | |||
* The client attempts to render clouds from the cloud algorithm results sent from the server, which is why different clients can see different cloud formations and de-synchronizes cloud view from the server over time. The cloud density data is sent from the server to the client when the region is loaded by the client. This can happen when the region comes into view, during teleport or during login. | |||
|examples= | |examples= | ||
<lsl> | <lsl>default | ||
default | |||
{ | { | ||
touch_start(integer num) | touch_start(integer num) | ||
| Line 14: | Line 17: | ||
llSay(0,"Cloud density:" + (string)llCloud(ZERO_VECTOR)); | llSay(0,"Cloud density:" + (string)llCloud(ZERO_VECTOR)); | ||
} | } | ||
} | }</lsl> | ||
</lsl> | |||
|helpers | |helpers | ||
|also_functions= | |also_functions= | ||
{{LSL DefineRow||[[llWind]]}} | {{LSL DefineRow||[[llWind]]}} | ||
{{LSL DefineRow||[[llGetSunDirection]]}} | {{LSL DefineRow||[[llGetSunDirection]]}} | ||
|notes= | |notes= | ||
Clouds and [[llWind|wind]] are interrelated. | |||
=== Client === | |||
Clouds are always rendered between about 180-200m absolute height. | |||
=== Algorithm === | |||
The cloud seed/growth/dissipation algorithm uses a solenoidal vector field, which is a vector field with zero-divergence: {{noWrap|∇ · v {{=}} 0}} | The cloud seed/growth/dissipation algorithm uses a solenoidal vector field, which is a vector field with zero-divergence: {{noWrap|∇ · v {{=}} 0}} | ||
Revision as of 20:43, 3 February 2010
| LSL Portal | Functions | Events | Types | Operators | Constants | Flow Control | Script Library | Categorized Library | Tutorials |
Summary
Function: float llCloud( vector offset );| 43 | Function ID |
| 0.0 | Forced Delay |
| 10.0 | Energy |
Returns a float that is the cloud density at the prim position + offset
| • vector | offset |
Returned values are in the range [0.0, 2.0]. Values above 1.0 indicate rain. The Z component of offset is ignored.
Specification
SL features a cellular automata-based weather system. There are 16x16 square cloud "cells" per region.
Caveats
- There are currently no SecondLife clients that render rain.
- The client attempts to render clouds from the cloud algorithm results sent from the server, which is why different clients can see different cloud formations and de-synchronizes cloud view from the server over time. The cloud density data is sent from the server to the client when the region is loaded by the client. This can happen when the region comes into view, during teleport or during login.
Examples
<lsl>default {
touch_start(integer num)
{
llSay(0,"Cloud density:" + (string)llCloud(ZERO_VECTOR));
}
}</lsl>
Notes
Clouds and wind are interrelated.
Client
Clouds are always rendered between about 180-200m absolute height.
Algorithm
The cloud seed/growth/dissipation algorithm uses a solenoidal vector field, which is a vector field with zero-divergence: ∇ · v = 0
This condition is satisfied whenever v has a vector potential A, because if v = ∇ ⨯ A then ∇ · v = ∇ · (∇ ⨯ A) = 0
See Also
Functions
| • | llWind | |||
| • | llGetSunDirection |