puts "========"
puts "Transparency - check different blend operators"
puts "========"

# custom shapes
set aShape1 [locate_data_file occ/Top.brep]
set aShape2 [locate_data_file occ/Bottom.brep]

vinit View1
vsetdispmode 1
vsetgradientbg 180 180 180 255 255 255 2
restore $aShape1 s1
restore $aShape2 s2
vdisplay s1
vdisplay s2
vsettransparency s1 0.5
vsettransparency s2 0.5

# check blending artifacts
vviewparams -scale 4.519 -at 93.051 -88.513 17.789 -eye -156.923 -151.929 6.147 -up -0.246 0.969 0.002

vrenderparams -oit off
vdump $imagedir/${casename}_blend_artifacts_unordered.png

vrenderparams -oit 1.0
vdump $imagedir/${casename}_blend_artifacts_oit.png

# check depth occlusion
vsetcolor s1 red
vsetcolor s2 black

vviewparams -scale 5.807 -at -59.913 -276.799 -4.312 -eye -69.465 -20.350 23.739 -up 0.999 0.038 -0.009

vrenderparams -oit off
vdump $imagedir/${casename}_occlusion_unordered.png

vrenderparams -oit 0.0
vdump $imagedir/${casename}_occlusion_oit_nodepth.png

vrenderparams -oit 1.0
vdump $imagedir/${casename}_occlusion_oit.png