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/*!
\class SoDirectionalLight SoDirectionalLight.h Inventor/nodes/SoDirectionalLight.h
\brief The SoDirectionalLight class is a node type for specifying directional light sources.
\ingroup nodes
A directional light source provides a model of light sources which
are at infinite distance from the geometry it illuminates, thereby
having no set position and consisting of an infinite volume of
parallel rays.
This is of course a simplified model of far-away light sources, as
"infinite distance" is impossible.
The sun shining on objects on earth is a good example of something
which can be modeled rather well for the most common purposes with a
directional light source.
See also documentation of parent class for important information
regarding light sources in general.
FILE FORMAT/DEFAULTS:
\code
DirectionalLight {
on TRUE
intensity 1
color 1 1 1
direction 0 0 -1
}
\endcode
A common thing to do with an SoDirectionalLight is to connect it to
a camera, so it works in the style of a head light to that camera.
This can easily be accomplished by linking an SoRotation::rotation
field, influencing the light, to the SoCamera::orientation
field. Here is a complete example iv-file demonstrating the
technique:
\verbatim
#Inventor V2.1 ascii
DEF mycam PerspectiveCamera { }
TransformSeparator {
SoRotation { rotation = USE mycam.orientation }
DirectionalLight { direction 0 0 -1 }
}
Cube { }
\endverbatim
(The SoTransformSeparator is included to keep the effect of the
SoRotation node within a scope where it will only influence the
light, and not the geometry following the light in the scene graph.)
*/
// *************************************************************************
#include
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif // HAVE_CONFIG_H
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include "nodes/SoSubNodeP.h"
// *************************************************************************
/*!
\var SoSFVec3f SoDirectionalLight::direction
The direction of the light source. Defaults to pointing along the
negative z-axis.
*/
// *************************************************************************
SO_NODE_SOURCE(SoDirectionalLight);
// *************************************************************************
/*!
Constructor.
*/
SoDirectionalLight::SoDirectionalLight(void)
{
SO_NODE_INTERNAL_CONSTRUCTOR(SoDirectionalLight);
SO_NODE_ADD_FIELD(direction, (0.0f, 0.0f, -1.0f));
}
/*!
Destructor.
*/
SoDirectionalLight::~SoDirectionalLight()
{
}
// Doc from superclass.
void
SoDirectionalLight::initClass(void)
{
SO_NODE_INTERNAL_INIT_CLASS(SoDirectionalLight, SO_FROM_INVENTOR_1|SoNode::VRML1);
}
// *************************************************************************
// Doc from superclass.
void
SoDirectionalLight::GLRender(SoGLRenderAction * action)
{
if (!this->on.getValue()) return;
SoState * state = action->getState();
int idx = SoGLLightIdElement::increment(state);
if (idx < 0) {
#if COIN_DEBUG
SoDebugError::postWarning("SoDirectionalLight::GLRender",
"Max # of OpenGL lights exceeded :(");
#endif // COIN_DEBUG
return;
}
SoLightElement::add(state, this, SoModelMatrixElement::get(state) *
SoViewingMatrixElement::get(state));
GLenum light = (GLenum) (idx + GL_LIGHT0);
SbColor4f lightcolor(0.0f, 0.0f, 0.0f, 1.0f);
// disable ambient contribution from this light source
glLightfv(light, GL_AMBIENT, lightcolor.getValue());
lightcolor.setRGB(this->color.getValue());
lightcolor *= this->intensity.getValue();
glLightfv(light, GL_DIFFUSE, lightcolor.getValue());
glLightfv(light, GL_SPECULAR, lightcolor.getValue());
// GL directional light is specified towards light source
SbVec3f dir = - this->direction.getValue();
if (dir.normalize() == 0.0f) {
#if COIN_DEBUG
SoDebugError::postWarning("SoDirectionalLight::GLRender",
"Direction is a null vector.");
#endif // COIN_DEBUG
}
// directional when w = 0.0
SbVec4f dirvec(dir[0], dir[1], dir[2], 0.0f);
glLightfv(light, GL_POSITION, dirvec.getValue());
glLightf(light, GL_SPOT_EXPONENT, 0.0);
glLightf(light, GL_SPOT_CUTOFF, 180.0);
glLightf(light, GL_CONSTANT_ATTENUATION, 1);
glLightf(light, GL_LINEAR_ATTENUATION, 0);
glLightf(light, GL_QUADRATIC_ATTENUATION, 0);
}
// *************************************************************************