Visibility and Hidden Surface Removal

Scanline: scan example 3
• At scanline y = g: AET has AB, DE, BC, FE
– Render background color and then ABC as
before
Computed
incrementally
as in z-buffer
– At DE: invert in-out flag of DEF; check depth
information of “in” polygons (ABC and DEF in a
list of “in” polygons)
– Render DEF
– At BC: still render DEF
if no penetration
– At FE: go background
– Next scanline © Machiraju/Zhang/Möller
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