puts "========"
puts "0029300: Visualization, TKOpenGl - provide depth pre-pass option"
puts "========"

vclear
vclose ALL
vinit View1

# display objects
psphere s 1
box b 1 2 3
vaxo
vdisplay -dispMode 1 s b
vaspects b -setColor RED -setTransparency 0.5
vfit
vzbufftrihedron
vmoveto 150 250
vcaps -ffp 0
vrenderparams -shadingModel phong

vrenderparams -depthPrePass off
vdump $::imagedir/${::casename}_1.png

vrenderparams -depthPrePass on
vdump $::imagedir/${::casename}_2.png

if { [diffimage $::imagedir/${::casename}_1.png $::imagedir/${::casename}_2.png 0 0 0 $::imagedir/${::casename}_diff.png] != 0 } { puts "Error: images differ" }