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Operators and Keywords

Function List:

C++ API

: camlight
: camlight right
: camlight left
: camlight headlight
: camlight (az, el)
: camlight (…, style)
: camlight (hl, …)
: h = camlight (…)

Add a light object to a figure using a simple interface.

When called with no arguments, a light object is added to the current plot and is placed slightly above and to the right of the camera’s current position: this is equivalent to camlight right. The commands camlight left and camlight headlight behave similarly with the placement being either left of the camera position or centered on the camera position.

For more control, the light position can be specified by an azimuthal rotation az and an elevation angle el, both in degrees, relative to the current properties of the camera.

The optional string style specifies whether the light is a local point source ("local", the default) or placed at infinite distance ("infinite").

If the first argument hl is a handle to a light object, then act on this light object rather than creating a new object.

The optional return value h is a graphics handle to the light object. This can be used to move or further change properties of the light object.

Examples:

Add a light object to a plot 

sphere (36);
camlight

Position the light source exactly 

camlight (45, 30);

Here the light is first pitched upwards from the camera position by 30 degrees. It is then yawed by 45 degrees to the right. Both rotations are centered around the camera target.

Return a handle to further manipulate the light object 

clf
sphere (36);
hl = camlight ("left");
set (hl, "color", "r");

See also: light.

Demonstration 1

The following code

 ## Adding lights to a scene
 sphere (64);
 camlight

 ## Add a second light
 camlight left

 title ({"camlight()", "lights are left and right"});

Produces the following figure

Figure 1

Demonstration 2

The following code

 sphere (48);
 title ({"camlight()", "light in fixed position ignores camera change"});
 axis equal;
 shading flat;
 view (30, 30);

 camlight

 for a = 30:2:390
   view (a, 30);
   drawnow ();
   pause (0.01);
 endfor

Produces the following figure

Figure 1

Demonstration 3

The following code

 sphere (48);
 title ({"camlight()", "update light position with camera change"});
 axis equal;  shading flat
 view (30, 30);

 hl = camlight ();          # keep a handle to the light

 for a = 30:2:390
   view (a, 30);
   camlight (hl, "right");  # update light position
   drawnow ();
   pause (0.01);
 endfor

Produces the following figure

Figure 1

Package: octave