gluPartialDisk

  • Article

The gluPartialDisk function draws an arc of a disk.

void gluPartialDisk(
  GLUquadricObj *qobj,  GLdouble innerRadius,  GLdouble outerRadius,  GLint slices,  GLint loops,  GLdouble startAngle,  GLdouble sweepAngle);

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).

Requirements

**  Windows NT/2000:** Requires Windows NT 3.5 or later.
**  Windows 95/98:** Requires Windows 95 or later. Available as a redistributable for Windows 95.
**  Header:** Declared in Glu.h.
**  Library:** Use Glu32.lib.

See Also

gluCylinder, gluDisk, gluNewQuadric, gluQuadricOrientation, gluQuadricTexture, gluSphere