Revision as of 06:52, 12 May 2022

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LSL

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Code Snippets

sRGB EOTF

Note that when converting a colour from regular LSL space (sRGB) to linear space for use in a light, it's likely quicker and cleaner to use the internal function llsRGB2Linear. This is mostly a function that can be used for fun to manipulate the gamma space of colours.

LSL Portal

Function: vector srgb_eotf( vector color, float gamma );

Converts a gamma-encoded color value to linear space. Useful when dealing with lights (as these expect a non-gamma-encoded color).
Returns a vector

• vector	color
• float	gamma

Specification

vector srgb_eotf(vector color, float gamma) //To convert from regular LSL colour to light colour, gamma value should be 2.4
{ //Conversion from gamma-encoded sRGB space to linear space. Credit: Jenna Huntsman, Christopher J. Howard
    vector low = color / 12.92;
    vector high = <llPow((color.x + 0.055)/1.055,gamma), llPow((color.y + 0.055)/1.055, gamma), llPow((color.z + 0.055)/1.055, gamma)>;
    return mix(low, high, step(<0.04045,0.04045,0.04045>, color));
}

float max(float x, float y)
{ //Return the higher of 2 given values.
    if( y > x ) return y;
    return x;
}

vector mix(vector x, vector y, vector t)
{
    vector ret;
    ret.x = x.x*(1-t.x) + y.x*t.x;
    ret.y = x.y*(1-t.y) + y.y*t.y;
    ret.z = x.z*(1-t.z) + y.z*t.z;  
    return ret;
}

vector step(vector edge, vector x)
{
    vector ret = <1,1,1>;
    if(x.x < edge.x) ret.x = 0;
    if(x.y < edge.y) ret.x = 0;
    if(x.z < edge.z) ret.x = 0;
    return ret;
}

Examples

vector LampCol = <1,0.74510,0.47451>; //3200 kelvin
llSetLinkPrimitiveParamsFast(LINK_THIS,[PRIM_POINT_LIGHT,1,srgb_eotf(LampCol,2.4),1,20,0,PRIM_GLOW,ALL_SIDES,1,PRIM_COLOR,ALL_SIDES,LampCol,1,PRIM_FULLBRIGHT,ALL_SIDES,1]);
//Set light source colour and prim colour to same colour; despite taking different input values.

Random Notes

I be a placeholder. At least for now.

Editor note: All sections below this box are considered drafts, and may move, change name, or be deleted at any time.

Photo Checklist Page Update

This is some text. I need to do something here.

Lens Settings

The table below contains settings for simulating various real-life lenses within Second Life. These settings will change the camera's Field of View (FoV), as well as Depth of field (DoF) settings. You may want to play around with some of these settings (for example, the Aperture value) to manipulate the depth-of-field effect.

Tip: The default Second Life camera is roughly equivalent to a full frame digital (36x24mm sensor) camera using 31mm lens.

For reference, the following table describes the debug settings changed, their units, and what the setting does. Default values are not provided as these settings may vary between viewers.

Debug Setting Glossary
Debug Setting	Units	Description
CameraAngle	Radians	Camera Field-of-View angle, horizontal. Equivalent to Angle of View - width degrees to equate a real lens. This changes the visible FoV.
CameraDoFResScale	Linear	Amount to scale down resolution of DoF effect. Manipulating this value may change performance.
CameraFieldOfView	Degrees	Field-of-View angle used for the DoF effect. Note that this value is the height FoV, NOT width.
CameraFNumber	F Stop	F Stop (or Aperture) value to be simulated by DoF effect. This is the value you should change to adjust the intensity of the DoF effect.
CameraFocalLength	mm	Focal length of the lens to be simulated by the DoF effect.
CameraMaxCoF	mm*1000	Lens Circle of Confusion value to be simulated by the DoF effect.
CameraFocusTransitionTime	Seconds	Time the camera will take to transition between 2 focal planes.

Editor note: The below settings assume that the screen is in the 16:9 aspect ratio - These values vary depending on aspect ratio, so if you have a screen of a different ratio, you may need to recalculate these values.

Note: To manipulate the intensity of the Depth-of-Field effect, change the aperture (F number) value. Common values are: 1.4, 2, 2.8, 4, 8, 12, 16, 20, 24

8 mm (Fisheye)
Debug Setting	Value
CameraAngle	2.306
CameraFieldOfView	103.4
CameraFocalLength	8
CameraMaxCoF	29.0

16 mm
Debug Setting	Value
CameraAngle	1.688
CameraFieldOfView	64.65
CameraFocalLength	16
CameraMaxCoF	29.0

24 mm
Debug Setting	Value
CameraAngle	1.287
CameraFieldOfView	45.75
CameraFocalLength	24
CameraMaxCoF	29.0

31 mm (SL Default)
Debug Setting	Value
CameraAngle	1.047
CameraFieldOfView	35.98
CameraFocalLength	31
CameraMaxCoF	29.0

50 mm
Debug Setting	Value
CameraAngle	0.691
CameraFieldOfView	22.9
CameraFocalLength	50
CameraMaxCoF	29.0

75 mm
Debug Setting	Value
CameraAngle	0.471
CameraFieldOfView	15.38
CameraFocalLength	75
CameraMaxCoF	29.0

100 mm
Debug Setting	Value
CameraAngle	0.350
CameraFieldOfView	11.56
CameraFocalLength	100
CameraMaxCoF	29.0

Did you know that you can leave DoF enabled for daily use? Try the settings given above for 31 mm, with an F-Stop (F number) value of 16.0.

How to calculate lens settings

If you don't have a 16:9 aspect ratio monitor, you will want to recalculate the lens settings.

To recalculate the lens settings:

Visit this website: [1]
Enter the desired focal length of the lens.
- The desired focal length is also one of the settings we need. (Debug setting: CameraFocalLength)
Scroll down, and select Option 1.
- Advanced users: You may also want to change the sensor size if you are trying to match footage shot with a specific camera (e.g. a phone camera). See the following website to get some additional values: Sensor chart
Under Option 1, select the desired Aspect Ratio crop.
Click Recalculate.
Visit this website in a new tab or window: [2]
Enter the value from the first website called "Angle of View - Diagonal Degrees" in the "deg" field of the second website.
- The value given in the "rad" field is the new value for your FoV (Debug setting: CameraAngle).
Back on the first website, find the value for "Angle of View - Height Degrees".
- The value in this field is the new value for the DoF FoV (Debug setting: CameraFieldOfView)

Lighting

Tip: The Second Life Knowledge Base has a great article explaining the core basics around Second Life's lighting system, albeit a little outdated. See here

Lighting in Second Life is just as important as your framing for your scene - it governs everything that you see; as it does in real life.

Second Life has 4 types of light:

Ambient light - this is the light which is applied across the entire scene, and does not cast shadows.
Sun / Moon light - this is the light that is emitted from the sun or moon, when present. This does cast shadows.
Point lights - this is the default type of light that Second Life uses. It acts similarly to a lightbulb, wherein light is cast out in all directions.
Projector lights - these lights will emit light in a specific beam pattern, for example, a car headlamp or a flashlight.

General tips

The white point (<255,255,255>) of color in Second Life is actually a "cool white" (equivalent to 6504 kelvin), following a specification called CIE Illuminant D65.
When lighting a dark or night scene, instead of using dim 'white' lights, you should instead use lights with a blue cast (Approx. ~9000 (TODO: Double check this value) kelvin). This is simulating a phenomenon in the human eye, wherein perceived color gains a blue shift before losing color vision altogether. This is known as the Purkinje effect.

Environment preset

In Second Life, lighting starts with the choice of your Environment preset, introduced as part of EEP. By default, the viewer uses whichever preset the landowner has decided to use on their parcel.

Your selection of Environment Preset governs 2 types of light that are present in Second Life - Ambient and Sun / Moon light.

Ambient light can be changed via the Environment Editor > Atmosphere & Lighting > Ambient Color. Note that Ambient light is also attenuated by the Cloud coverage (Environment Editor > Clouds > Cloud Coverage) value - the higher the coverage, the more ambient light there is.
Sun / Moon light can be changed via the Environment Editor > Sun & Moon > Color.

Tip: While many people play with 'flat' environment presets (e.g. CalWL), these often make for poor photography lighting. Avoid using these where possible, instead, try making use of specific photography presets for your shoots.

Warning: When selecting presets, endeavour to use EEP-specific (i.e. not converted from the prior WindLight system) presets, as older presets would have undergone a conversion into the new EEP Settings asset, which is not a perfect conversion.

In-world lighting

Another thing to consider is placing lights in-world. Any object in-world can be made into either a point or projector light (via the Build floater > Features > Light).

In a studio setting, it's recommended to use projector lamps wherever possible to keep tight control of the lighting in your scene. It also matches real-life photography lamps, most of which are actually different forms of projector lamps.

The below example makes use of basic 3 point lighting on a plain background.

Lit with point lights only
Lit with projector lights only

Photo Settings

General

Viewer: Alchemy Project AgileAkita (6.5.5.1529)
Pose: loel - spring serenade 05
Environment Preset: Studio Saberhagen - Studio Dark (P)
Lens: 75mm
Advanced Lighting Model: Enabled
Depth-of-Field: Enabled, Aperture 2.0

Viewer-Specific

Tonemapper: Uncharted, Exposure 2.4
LUT: LUT Test33 v44.cube

Hovever, a mixture of Point and Projector lamps is generally the best way to light most scenes.

Lit with ambient light only.
Lit with point lights only.
Lit with projector lights only.
Lit with a mix of point and projector lights.