Hp-Phigs Graphics Performance - HP b2600 Administration Manual

hp-PHIGS Graphics Performance

Performance Optimized For:
•
Light Sources:
Best: up to 8 directional light
o
sources, plus ambient
Good: a mixture of up to 8
o
directional and positional light
sources, plus ambient
•
Directional eyepoint, set via:
pescape_u230/pgse_u3 (C),
o
pue230/pus003 (FORTRAN)
•
Back face culling off, or back face culling
on with supplied geometric normals
•
View clipping on, set via:
pset_view_rep (C), psvwr
o
(FORTRAN)
•
True colour mapping in a direct colour
environment
•
Isotropic modeling matrix (angle-
preserving)
Page 109
Optimized vs. Normal 3D Performance
Rendering Conditions
Graphics Administration Guide for HP-UX 10.20
Factors Affecting Performance:
• A total of more than 8 directional and
positional light sources cause a noticeable
performance degradation
• Picking (including direct pick and logical
device picking)
• Any of the following ways of heavily
interleaving changes:
o Frequent attribute changes (e.g.,
frequent changes of line colour)
relative to the number of primitives
being drawn
o Frequent changes of the type of
primitive (e.g., switching between
Fill Areas and Polylines at a high
frequency)
o Frequent changes of vertex format
(i.e., the data being supplied with
each vertex)
o Frequent changes of modal state,
such as:
HLHSR mode or ID
Colour mapping method
Light sources enabled
Depth cueing state
o Frequent switching between two or
more active workstations
o Frequent mixing of Xlib and hp-
PHIGS calls
• Redundant or unnecessary setup (e.g.
setting attributes that are not relevant to the
primitives being drawn)
• Model clipping on
• HLHSR in software via PowerShade (on
unaccelerated graphics devices)