gluPartialDisk
[New
- Windows 95, OEM Service Release 2]
The gluPartialDisk function draws an arc of a
disk.
void gluPartialDisk(
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GLUquadricObj * qobj, |
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GLdouble innerRadius, |
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GLdouble outerRadius, |
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GLint slices,
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GLint loops, |
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GLdouble startAngle,
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GLdouble sweepAngle |
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); |
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Parameters
qobj
A quadric
object (created with gluNewQuadric).
innerRadius
The inner
radius of the partial disk (can be zero).
outerRadius
The outer
radius of the partial disk.
slices
The number of
subdivisions around the z-axis.
loops
The number of
concentric rings about the origin into which the partial disk is subdivided.
startAngle
The starting
angle, in degrees, of the disk portion.
sweepAngle
The sweep
angle, in degrees, of the disk portion.
Remarks
The gluPartialDisk function renders a partial
disk on the z = 0 plane. A partial disk is similar to a full disk,
except that only the subset of the disk from startAngle through startAngle
+ sweepAngle is included (where 0 degrees is along the positive y-axis,
90 degrees is along the positive x-axis, 180 degrees is along the negative
y-axis, and 270 degrees is along the negative x-axis).
The partial disk has a radius of outerRadius
and contains a concentric circular hole with a radius of innerRadius. If
innerRadius is zero, then no hole is generated. The partial disk is
subdivided around the z-axis into slices (like pizza slices), and also about
the z-axis into rings (as specified by slices and loops,
respectively).
With respect to orientation, the positive z-side of
the partial disk is considered to be outside (see gluQuadricOrientation). This means that if the
orientation is set to GLU_OUTSIDE, then any normals generated point along the
positive z-axis.
If you have turned on texturing (with gluQuadricTexture),
gluPartialDisk generates texture coordinates linearly such that where r
= outerRadius, the value at (r, 0, 0) is (1, 0.5); at (0, r,
0) it is (0.5, 1); at (r, 0, 0) it is (0, 0.5); and at (0, r, 0)
it is (0.5, 0).
See Also