/**************************************************************************\ * * This file is part of the Coin 3D visualization library. * Copyright (C) 1998-2007 by Systems in Motion. All rights reserved. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * ("GPL") version 2 as published by the Free Software Foundation. * See the file LICENSE.GPL at the root directory of this source * distribution for additional information about the GNU GPL. * * For using Coin with software that can not be combined with the GNU * GPL, and for taking advantage of the additional benefits of our * support services, please contact Systems in Motion about acquiring * a Coin Professional Edition License. * * See http://www.coin3d.org/ for more information. * * Systems in Motion, Postboks 1283, Pirsenteret, 7462 Trondheim, NORWAY. * http://www.sim.no/ sales@sim.no coin-support@coin3d.org * \**************************************************************************/ #ifdef HAVE_CONFIG_H #include #endif // HAVE_CONFIG_H #ifdef HAVE_VRML97 /*! \class SoVRMLSpotLight SoVRMLSpotLight.h Inventor/VRMLnodes/SoVRMLSpotLight.h \brief The SoVRMLSpotLight class defines a spot light source. \ingroup VRMLnodes \WEB3DCOPYRIGHT \verbatim SpotLight { exposedField SFFloat ambientIntensity 0 # [0,1] exposedField SFVec3f attenuation 1 0 0 # [0,inf) exposedField SFFloat beamWidth 1.570796 # (0,pi/2] exposedField SFColor color 1 1 1 # [0,1] exposedField SFFloat cutOffAngle 0.785398 # (0,pi/2] exposedField SFVec3f direction 0 0 -1 # (-inf, inf) exposedField SFFloat intensity 1 # [0,1] exposedField SFVec3f location 0 0 0 # (-inf, inf) exposedField SFBool on TRUE exposedField SFFloat radius 100 # [0, inf) } \endverbatim The SpotLight node defines a light source that emits light from a specific point along a specific direction vector and constrained within a solid angle. Spotlights may illuminate geometry nodes that respond to light sources and intersect the solid angle defined by the SpotLight. Spotlight nodes are specified in the local coordinate system and are affected by ancestors' transformations. A detailed description of ambientIntensity, color, intensity, and VRML's lighting equations is provided in 4.6.6, Light sources (). More information on lighting concepts can be found in 4.14, Lighting model (), including a detailed description of the VRML lighting equations. The \e location field specifies a translation offset of the centre point of the light source from the light's local coordinate system origin. This point is the apex of the solid angle which bounds light emission from the given light source. The \e direction field specifies the direction vector of the light's central axis defined in the local coordinate system. The \e on field specifies whether the light source emits light. If on is TRUE, the light source is emitting light and may illuminate geometry in the scene. If on is FALSE, the light source does not emit light and does not illuminate any geometry. The \e radius field specifies the radial extent of the solid angle and the maximum distance from location that may be illuminated by the light source. The light source does not emit light outside this radius. The radius shall be greater than or equal to zero. Both \e radius and \e location are affected by ancestors' transformations (scales affect radius and transformations affect location). The \e cutOffAngle field specifies the outer bound of the solid angle. The light source does not emit light outside of this solid angle. The \e beamWidth field specifies an inner solid angle in which the light source emits light at uniform full intensity. The light source's emission intensity drops off from the inner solid angle (beamWidth) to the outer solid angle (cutOffAngle) as described in the following equations: \verbatim angle = the angle between the Spotlight's direction vector and the vector from the Spotlight location to the point to be illuminated if (angle >= cutOffAngle): multiplier = 0 else if (angle <= beamWidth): multiplier = 1 else: multiplier = (angle - cutOffAngle) / (beamWidth - cutOffAngle) intensity(angle) = SpotLight.intensity × multiplier \endverbatim If the beamWidth is greater than the cutOffAngle, beamWidth is defined to be equal to the cutOffAngle and the light source emits full intensity within the entire solid angle defined by cutOffAngle. Both beamWidth and cutOffAngle shall be greater than 0.0 and less than or equal to pi/2. Figure 6.16 depicts the beamWidth, cutOffAngle, direction, location, and radius fields of the SpotLight node.
Figure 6.16 -- SpotLight node
SpotLight illumination falls off with distance as specified by three attenuation coefficients. The attenuation factor is \verbatim 1/max(attenuation[0] + attenuation[1]×r + attenuation[2]×r^2 , 1), \endverbatim where r is the distance from the light to the surface being illuminated. The default is no attenuation. An attenuation value of (0, 0, 0) is identical to (1, 0, 0). Attenuation values shall be greater than or equal to zero. A detailed description of VRML's lighting equations is contained in 4.14, Lighting model (). */ /*! \var SoSFVec3f SoVRMLSpotLight::location The light position. Default value is (0, 0, 0). */ /*! \var SoSFVec3f SoVRMLSpotLight::direction The light direction. Default value is (0, 0, 1). */ /*! \var SoSFFloat SoVRMLSpotLight::beamWidth The spot beam width. Default value is PI/2. */ /*! \var SoSFFloat SoVRMLSpotLight::cutOffAngle The spot light cut off angle. Default value is PI/4. */ /*! \var SoSFFloat SoVRMLSpotLight::radius The light radius. Light is not emitted past it. Default value is 100. */ /*! \var SoSFVec3f SoVRMLSpotLight::attenuation The attenuiation vector. Default value is (1, 0, 0). */ #include #include #include #include #include #include #include #include #include #if COIN_DEBUG #include #endif // COIN_DEBUG #include SO_NODE_SOURCE(SoVRMLSpotLight); // Doc in parent void SoVRMLSpotLight::initClass(void) { SO_NODE_INTERNAL_INIT_CLASS(SoVRMLSpotLight, SO_VRML97_NODE_TYPE); } /*! Constructor. */ SoVRMLSpotLight::SoVRMLSpotLight(void) { SO_VRMLNODE_INTERNAL_CONSTRUCTOR(SoVRMLSpotLight); SO_VRMLNODE_ADD_EXPOSED_FIELD(location, (0.0f, 0.0f, 0.0f)); SO_VRMLNODE_ADD_EXPOSED_FIELD(direction,(0.0f, 0.0f, -1.0f)); SO_VRMLNODE_ADD_EXPOSED_FIELD(beamWidth, (float(M_PI)/2.0f)); SO_VRMLNODE_ADD_EXPOSED_FIELD(cutOffAngle, (float(M_PI)/4.0f)); SO_VRMLNODE_ADD_EXPOSED_FIELD(radius, (100.0f)); SO_VRMLNODE_ADD_EXPOSED_FIELD(attenuation, (1.0f, 0.0f, 0.0f)); } /*! Destructor. */ SoVRMLSpotLight::~SoVRMLSpotLight() { } // Doc in parent void SoVRMLSpotLight::GLRender(SoGLRenderAction * action) { if (!this->on.getValue()) return; SoState * state = action->getState(); int idx = SoGLLightIdElement::increment(state); if (idx < 0) { #if COIN_DEBUG SoDebugError::post("SoSpotLight::GLRender()", "Max # lights exceeded :(\n"); #endif // COIN_DEBUG return; } GLenum light = (GLenum) (idx + GL_LIGHT0); SbVec3f att = this->attenuation.getValue(); glLightf(light, GL_QUADRATIC_ATTENUATION, att[0]); glLightf(light, GL_LINEAR_ATTENUATION, att[1]); glLightf(light, GL_CONSTANT_ATTENUATION, att[2]); SbColor4f lightcolor(0.0f, 0.0f, 0.0f, 1.0f); lightcolor.setRGB(this->color.getValue()); lightcolor *= this->ambientIntensity.getValue(); 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()); SbVec3f loc = this->location.getValue(); // point (or spot) light when w = 1.0 SbVec4f posvec(loc[0], loc[1], loc[2], 1.0f); glLightfv(light, GL_POSITION, posvec.getValue()); glLightfv(light, GL_SPOT_DIRECTION, this->direction.getValue().getValue()); float cutoff = SbClamp(this->cutOffAngle.getValue(), 0.0f, float(M_PI)*0.5f) * 180.0f / float(M_PI); glLightf(light, GL_SPOT_EXPONENT, 0.0f); glLightf(light, GL_SPOT_CUTOFF, cutoff); // FIXME: consider radius and beamWidth } #endif // HAVE_VRML97