03/18/2003
15-462 Graphics I
5
Blending Errors
•Operations are not commutative
•Operations are not idempotent
•Interaction with hidden-surface removal
–Polygon behind opaque one should be culled
–Translucent in front of others should be composited
–Solution: make z-buffer read-only for translucent polygons with  glDepthMask(GL_FALSE);