Starbase Graphics Performance
Optimized vs. Normal 3D Performance
Performance Optimized For: Factors Affecting Performance:
Rendering Conditions
• Best: up to 8 directional light sources, plus
ambient
• Good: a mixture of up to 8 directional and
positional light sources, plus ambient
• Directional eyepoint set with view_point
• Back face culling off, or back face culling
on with supplied geometric normals
• View clipping on
• Isotropic modeling matrix (angle-
preserving)
• shade_mode set to CMAP_FULL
• A total of more than 8 directional and
positional light sources cause a noticeable
performance degradation
• Picking
• Any of the following ways of heavily
interleaving changes:
o Frequent attribute changes (e.g.,
frequent changes of line color)
relative to the number of primitives
being drawn
o Frequent changes of the type of
primitive (e.g., switching between
polygons with 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:
Double-buffering
Z-buffering
Shade mode
Light sources enabled
Depth cueing state
Texture mapping state
o Frequent switching between two or
more file descriptors
o Frequent mixing of Xlib and
Starbase calls
• Redundant or unnecessary setup (e.g.
setting attributes that are not relevant to the
primitives being drawn)
• Deformation on
• Model clipping on
• HLHSR in software via PowerShade (on
unaccelerated graphics devices)
Graphics Administration Guide for HP-UX 10.20
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