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32
33 /*!
34 \class SoLight SoLight.h Inventor/nodes/SoLight.h
35 \brief The SoLight class is the base class for light emitting nodes.
36
37 \ingroup nodes
38
39 This node type is abstract and does not in itself provide any light
40 sources to the scene, you need to use one of its subclasses.
41
42 There are a few important things to know about light sources in
43 Coin. First of all, the more light sources you have in your scene,
44 the slower the rendering will be. The impact on rendering speed is
45 highly dependent on the graphics hardware and/or rendering subsystem
46 software implementation (i.e. how optimized an OpenGL you or your
47 users are running), but it could be severe.
48
49 Another issue which is important to know is that OpenGL rendering
50 engines usually have a fixed maximum number of available light
51 sources which can be present in the state at the same time. If you
52 reach the maximum number, further light sources will simply be
53 ignored. The maximum number of light sources for OpenGL rendering
54 can be found by using:
55
56 \code
57 #include <Inventor/elements/SoGLLightIdElement.h>
58 #include <Inventor/nodes/SoSubNodeP.h>
59 // ...[snip]...
60 int nrlights = SoGLLightIdElement::getMaxGLSources();
61 \endcode
62
63 If you are clever with how you use light sources, you can get away
64 with using a lot more lights in a scene graph than the max available
65 from the rendering system. This is because light sources are stacked
66 on the traversal state, just like other appearance data. So if you
67 put light sources under SoSeparator nodes, they will be popped off
68 and "forgotten" for the remaining geometry of the scene graph after
69 the subgraph below an SoSeparator has been traversed.
70 */
71
72 #include <Inventor/nodes/SoLight.h>
73
74 #include <Inventor/actions/SoCallbackAction.h>
75 #include <Inventor/actions/SoGLRenderAction.h>
76 #include <Inventor/elements/SoGLLightIdElement.h>
77 #include <Inventor/elements/SoLightAttenuationElement.h>
78 #include <Inventor/elements/SoLightElement.h>
79 #include <Inventor/elements/SoModelMatrixElement.h>
80 #include <Inventor/elements/SoViewingMatrixElement.h>
81
82 #include "nodes/SoSubNodeP.h"
83
84 /*!
85 \var SoSFBool SoLight::on
86
87 Whether light source should be on or off. The on-flag defaults to \c
88 TRUE.
89 */
90 /*!
91 \var SoSFFloat SoLight::intensity
92
93 Intensity of light source. This decides how much the light source
94 should affect the colors etc of the scene geometry. Valid range is
95 0.0 (none) to 1.0 (maximum). Default value is 1.0.
96 */
97 /*!
98 \var SoSFColor SoLight::color
99
100 Color of light source. Default is an all-white light source.
101 */
102
103
104 SO_NODE_ABSTRACT_SOURCE(SoLight);
105
106 /*!
107 Constructor.
108 */
SoLight(void)109 SoLight::SoLight(void)
110 {
111 SO_NODE_INTERNAL_CONSTRUCTOR(SoLight);
112
113 SO_NODE_ADD_FIELD(on, (TRUE));
114 SO_NODE_ADD_FIELD(intensity, (1.0f));
115 SO_NODE_ADD_FIELD(color, (SbColor(1.0f, 1.0f, 1.0f)));
116 }
117
118 /*!
119 Destructor.
120 */
~SoLight()121 SoLight::~SoLight()
122 {
123 }
124
125 // Doc from superclass.
126 void
initClass(void)127 SoLight::initClass(void)
128 {
129 SO_NODE_INTERNAL_INIT_ABSTRACT_CLASS(SoLight, SO_FROM_INVENTOR_1);
130
131 SO_ENABLE(SoGLRenderAction, SoLightAttenuationElement);
132 SO_ENABLE(SoGLRenderAction, SoGLLightIdElement);
133 SO_ENABLE(SoGLRenderAction, SoLightElement);
134
135 SO_ENABLE(SoCallbackAction, SoLightAttenuationElement);
136 SO_ENABLE(SoCallbackAction, SoLightElement);
137 }
138
139 // Doc from superclass.
140 void
callback(SoCallbackAction * action)141 SoLight::callback(SoCallbackAction * action)
142 {
143 SoState * state = action->getState();
144 SoLightElement::add(state, this, (SoModelMatrixElement::get(state) *
145 SoViewingMatrixElement::get(state)));
146 }
147