Visibility and Hidden Surface Removal

Depth sort algorithm
• Determine a visibility (depth) ordering of objects
which will ensure a correct picture if objects are
rendered in that order – object-space algorithm
• If no objects overlap in depth z, it is only
necessary to sort them by decreasing z (furthest to
closest) and render them – back-to-front rendering
with painters algorithm
• Otherwise, it may be necessary to modify objects,
e.g., by intersecting and splitting polygons, to get
depth order
© Machiraju/Zhang/Möller