#VRML V2.0 utf8
##<load file=web3d-navigate>

########
## Proto

## Nsphere:generates n-sided sphere
## author: peter gerstmann, based on example in The Annotated VRML 97 Reference
##         pgerstma@cgrg.ohio-state.edu
##         http://www.cgrg.ohio-state.edu


PROTO nsphere [
   field SFInt32 latitudeLines 50
   field SFInt32 longitudeLines 50
   field SFFloat creaseAngle 3.14
]
{
   DEF IFS IndexedFaceSet {
      coord DEF C Coordinate { }
      texCoord DEF TC TextureCoordinate { }
      creaseAngle IS creaseAngle
   }
   DEF S Script {
      field SFInt32 numLat IS latitudeLines
      field SFInt32 numLong IS longitudeLines
      eventOut MFVec3f c_changed
      eventOut MFVec2f tc_changed
      eventOut MFInt32 ci_changed
      url [
         "javascript:
         function initialize() {
            var r, angle, x, y, z;
            var i, j, polyIndex;
            // Compute coordinates, texture coordinates:
            for (i = 0; i < numLat; i++) {
               y = 2 * ( i / (numLat-1) ) - 1;
               r = Math.sqrt( 1 - y*y );
               for (j = 0; j < numLong; j++) {
                  angle = 2 * Math.PI * j / numLong;
                  x = -Math.sin(angle)*r;
                  z = -Math.cos(angle)*r;
                  c_changed[i*numLong+j] = new SFVec3f(x,y,z);
                  tc_changed[i*numLong+j] = new SFVec2f( j/numLong, i/(numLat-1) );
               }
            }
            // And compute indices:
            for (i = 0; i < numLat-1; i++) {
               for (j = 0; j < numLong; j++) {
                  polyIndex = 5*(i*numLong+j);
                  ci_changed[polyIndex+0] = i*numLong+j;
                  ci_changed[polyIndex+1] = i*numLong+(j+1)%numLong;
                  ci_changed[polyIndex+2] = (i+1)*numLong+(j+1)%numLong;
                  ci_changed[polyIndex+3] = (i+1)*numLong+j;
                  ci_changed[polyIndex+4] = -1;  // End-of-polygon
               }
            }
         }"
      ]
   }
   ROUTE S.c_changed TO C.set_point
   ROUTE S.tc_changed TO TC.set_point
   ROUTE S.ci_changed TO IFS.set_coordIndex
}