HP b2600 Reference Manual page 481

Visibility Tests can be used by a programmer to determine whether or not a primitive or
set of primitives are visible against the current contents of the depth buffer; "Visibile" in
this context means that at least one pixel passes the depth test. This differs from
previous Occlusion Culling extensions by allowing the programmer to provide memory
for many different Visibility Test results to be returned at the same time.
Notes
The contents of 'buffer' are undefined before a glGet of GL_VISIBILITY_TEST_hp is
called. See Description section above for more information on when the contents of
'buffer' become valid.
The programmer is responsible for allocating the memory for 'buffer'. If an incorrect
'size' is specified, memory corruption may occur.
Errors
•
•
•
Associated Gets
glGet with argument GL_VISIBILITY_TEST_hp
See Also
glNextVisibilityTesthp
glIsEnabled with argument
Chapter 20
GL_INVALID_VALUE is generated if 'size' is negative.
GL_INVALID_OPERATION is generated if glVisibilityBufferhp is called while
GL_VISIBILITY_TEST_hp is enabled (via glEnable()), or if
glEnable(GL_VISIBILITY_TEST_hp) is called before glVisibilityBufferhp is called
at least once.
GL_INVALID_OPERATION is generated if glVisibilityBufferhp is called between a
call to glBegin and the corresponding call to glEnd.
V
glVisibilityBufferhp
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