!
! makesphere
!
!        make a sphere object
!
        subroutine makesphere
#include "interface.h"

        integer SPHERE
        integer ii
        real i, r, z, a, RADIUS, PI
        parameter (PI = 3.1415926535, RADIUS = 10.0, SPHERE = 1)

        call makeobj(SPHERE)

!
! create the latitudinal rings
!
            do 10 ii = 0, 180, 20
                call pushmatrix
                    i=real(ii)
                    call rotate(i, 'y')
                    call circle(0.0, 0.0, RADIUS)
                call popmatrix
10          continue
                
!
! create the longitudinal rings
!
            call pushmatrix
                call rotate(90.0, 'x')
                do 20 ia = -90, 90, 20
                    a=ia
                    r = RADIUS * cos(a * PI / 180.0)
                    z = RADIUS * sin(a * PI / 180.0)
                    call pushmatrix
                        call translate(0.0, 0.0, -z)
                        call circle(0.0, 0.0, r)
                    call popmatrix      
20              continue
            call popmatrix

        call closeobj

        end

!
!@(#)  a demonstration of objects
!
        program fballs
#include "interface.h"

        integer SPHERE
        integer BLACK, RED, GREEN, YELLOW, BLUE, MAGENTA, CYAN, WHITE
        real RADIUS
        parameter (RADIUS = 10.0)
        parameter(SPHERE = 1)
        parameter(BLACK = 0)
        parameter(RED = 1)
        parameter(GREEN = 2)
        parameter(YELLOW = 3)
        parameter(BLUE = 4)
        parameter(MAGENTA = 5)
        parameter(CYAN = 6)
        parameter(WHITE = 7)
        character device*50

        print*,'Enter output device:'
        read(*,'(a)') device

        call vinit(device)

        call vsetflush(.false.)

!
! set up our viewing transformation
!
        call perspective(90.0, 1.0, 0.001, 500.0)
        call lookat(13.0, 13.0, 8.0, 0.0, 0.0, 0.0, 0.0)

        call color(BLACK)
        call clear

!
! Call a routine to make the sphere object
!
        call makesphere

!
! Now draw the sphere object scaled down. We use the pushmatrix
! and the popmatrix to preserve the transformation matrix so
! that only this sphere is drawn scaled. The callobj then enables
! us to draw the sphere we generated with makeobj in makesphere.
!
        call color(CYAN)

        call pushmatrix
            call scale(0.5, 0.5, 0.5)
            call callobj(SPHERE)
        call popmatrix

!
! now we draw the same sphere translated, with a different
! scale and color.
!
        call color(WHITE)

        call pushmatrix
            call translate(0.0, (-1.4) * RADIUS, 1.4 * RADIUS)
            call scale(0.3, 0.3, 0.3)
            call callobj(SPHERE)
        call popmatrix

!
! and maybe a few more times....
!

        call color(RED)

        call pushmatrix
            call translate(0.0, RADIUS, 0.7 * RADIUS)
            call scale(0.2, 0.2, 0.2)
            call callobj(SPHERE)
        call popmatrix

        call color(GREEN)

        call pushmatrix
            call translate(0.0, 1.5 * RADIUS, -RADIUS)
            call scale(0.15, 0.15, 0.15)
            call callobj(SPHERE)
        call popmatrix

        call color(YELLOW)

        call pushmatrix
            call translate(0.0, -RADIUS, -RADIUS)
            call scale(0.12, 0.12, 0.12)
            call callobj(SPHERE)
        call popmatrix

        call color(BLUE)

        call pushmatrix
            call translate(0.0, (-2.0)*RADIUS, -RADIUS)
            call scale(0.3, 0.3, 0.3)
            call callobj(SPHERE)
        call popmatrix

        idum=getkey()

        call vexit

        end