   Lesson 44
  Hi,Lesson 44 is the lens flare tutorial.  Apparently, it has occlusion testing.  If the situation is right, it can be done vastly more efficiently.  In Python:model = glGetDoublev(GL_MODELVIEW_MATRIX)proj = glGetDoublev(GL_PROJECTION_MATRIX)view = glGetIntegerv(GL_VIEWPORT)winx,winy,winz = gluProject(lightpos[0],lightpos[1],lightpos[2],model,proj,view)winz = glReadPixels(winx,winy,1,1,GL_DEPTH_COMPONENT,GL_FLOAT)pos = gluUnProject(winx,winy,winz,model,proj,view)#if pos and lightpos are basically the same and 0<winx<view[2] and#0<winy<view[3], then the light is visible; draw the flare.I used this technique to produce:The planet can occlude the sun's flare.  It does so perfectly.Hope this helps,Geometrian   