Added osgSim library which encapulsulates light points.

Added osglightpoint demo.

src/osgSim/Sector.cpp

@@ -0,0 +1,178 @@
+//C++ header - Open Scene Graph Simulation - Copyright (C) 1998-2002 Robert Osfield
+// Distributed under the terms of the GNU General Public License (GPL)
+// as published by the Free Software Foundation.
+//
+// All software using osgSim must be GPL'd or excempted via the 
+// purchase of the Open Scene Graph Professional License (OSGPL)
+// for further information contact robert@openscenegraph.com.
+
+#include <osgSim/Sector>
+
+using namespace osgSim;
+
+
+//
+// Elevation Range 
+//
+
+void AzimRange::setAzimuthRange(float minAzimuth,float maxAzimuth,float fadeAngle)
+{
+    // clamp the azimuth range.
+    const float twoPI = 2.0f*(float)osg::PI;
+    while(minAzimuth>maxAzimuth) minAzimuth -= twoPI;
+
+    // compute the centerline
+    float centerAzim = (minAzimuth+maxAzimuth)*0.5f;
+    _cosAzim = cos(centerAzim);
+    _sinAzim = sin(centerAzim);
+
+    // compute the half angle range of the sector.
+    float angle = (maxAzimuth-minAzimuth)*0.5f;
+    _cosAngle = cos(angle);
+
+    // clamp the fade angle to valid values.
+    fadeAngle = osg::clampAbove(fadeAngle,0.0f);
+    if (angle+fadeAngle>osg::PI) _cosFadeAngle = -1.0f;
+    else _cosFadeAngle = cos(angle+fadeAngle);
+
+}
+
+
+//
+// Elevation Range 
+//
+void ElevationRange::setElevationRange(float minElevation,float maxElevation,float fadeAngle)
+{
+    if (minElevation>maxElevation)
+    {
+        // need to swap angle pair.
+        float tmp = minElevation;
+        minElevation = maxElevation;
+        maxElevation = tmp;
+    }
+
+    minElevation = osg::clampTo(minElevation,(float)-osg::PI_2,(float)osg::PI_2);
+    maxElevation = osg::clampTo(maxElevation,(float)-osg::PI_2,(float)osg::PI_2);
+    fadeAngle = osg::clampTo(fadeAngle,0.0f,(float)osg::PI_2);
+
+    _cosMinElevation = cos(osg::PI_2-minElevation);
+    _cosMaxElevation = cos(osg::PI_2-maxElevation);
+
+    float minFadeAngle = osg::PI_2-minElevation+fadeAngle;
+    if (minFadeAngle>=osg::PI) _cosMinFadeElevation = -1.0f;
+    else _cosMinFadeElevation = cos(minFadeAngle);
+
+    float maxFadeAngle = osg::PI_2-maxElevation-fadeAngle;
+    if (maxFadeAngle<=0.0f) _cosMaxFadeElevation = 1.0f;
+    else _cosMaxFadeElevation = cos(maxFadeAngle);
+
+}
+
+float ElevationRange::getMinElevation() const
+{
+    return osg::PI_2-acos(_cosMinElevation);
+}
+
+float ElevationRange::getMaxElevation() const
+{
+    return osg::PI_2-acos(_cosMaxElevation);
+}
+
+//
+// ElevationSector
+//
+AzimSector::AzimSector(float minAzimuth,float maxAzimuth,float fadeAngle):
+    Sector(),
+    AzimRange()
+{
+    setAzimuthRange(minAzimuth,maxAzimuth,fadeAngle);
+}
+
+float AzimSector::operator() (const osg::Vec3& eyeLocal) const
+{
+    return azimSector(eyeLocal);
+}
+
+//
+// ElevationSector
+//
+ElevationSector::ElevationSector(float minElevation,float maxElevation,float fadeAngle):
+    Sector(),
+    ElevationRange()
+{
+    setElevationRange(minElevation,maxElevation,fadeAngle);
+}
+
+float ElevationSector::operator() (const osg::Vec3& eyeLocal) const
+{
+    return elevationSector(eyeLocal);
+}
+
+//
+// AzimElevationSector
+//
+AzimElevationSector::AzimElevationSector(float minAzimuth,float maxAzimuth,float minElevation,float maxElevation,float fadeAngle):
+    Sector(),
+    AzimRange(),
+    ElevationRange()
+{
+    setAzimuthRange(minAzimuth,maxAzimuth,fadeAngle);
+    setElevationRange(minElevation,maxElevation,fadeAngle);
+}
+
+
+float AzimElevationSector::operator() (const osg::Vec3& eyeLocal) const
+{
+    float azimIntensity = azimSector(eyeLocal);
+    if (azimIntensity==0.0) return 0.0; // out of sector.
+    float elevIntensity = elevationSector(eyeLocal);
+    if (elevIntensity==0.0) return 0.0; // out of sector.
+    if (azimIntensity<=elevIntensity) return azimIntensity;
+    return elevIntensity;
+}
+
+//
+// ConeSector
+//
+ConeSector::ConeSector(const osg::Vec3& axis,float angle,float fadeangle):
+            Sector()
+{
+    setAxis(axis);
+    setAngle(angle,fadeangle);
+}
+
+void ConeSector::setAxis(const osg::Vec3& axis)
+{
+    _axis = axis;
+    _axis.normalize();
+}
+
+const osg::Vec3& ConeSector::getAxis() const
+{
+    return _axis;
+}
+
+void ConeSector::setAngle(float angle,float fadeangle)
+{
+    _cosAngle = cos(angle);
+    _cosAngleFade = cos(angle+fadeangle);
+}
+
+float ConeSector::getAngle() const
+{
+    return acos(_cosAngle);
+}
+
+float ConeSector::getFadeAngle() const
+{
+    return acos(_cosAngleFade)-acos(_cosAngle);
+}
+
+float ConeSector::operator() (const osg::Vec3& eyeLocal) const
+{
+    float dotproduct = eyeLocal*_axis;
+    float length = eyeLocal.length();
+    if (dotproduct>_cosAngle*length) return 1.0f; // fully in sector
+    if (dotproduct<_cosAngleFade*length) return 0.0f; // out of sector
+    return (dotproduct-_cosAngleFade*length)/((_cosAngle-_cosAngleFade)*length);
+}