gluPartialDisk

NAME

gluPartialDisk -- draw an arc of a disk

C SPECIFICATION

void gluPartialDisk(GLUquadricObj *qobj,

GLdouble innerRadius,

GLdouble outerRadius,

GLint slices,

GLint loops,

GLdouble startAngle,

GLdouble sweepAngle)

PARAMETERS

qobj

Specifies a quadrics object (created with gluNewQuadric).

innerRadius

Specifies the inner radius of the partial disk (can be zero).

outerRadius

Specifies the outer radius of the partial disk.

slices

Specfies the number of subdivisions around the z axis.

loops

Specifies the number of concentric rings about the origin into which the partial disk is subdivided.

startAngle

Specifies the starting angle, in degrees, of the disk portion.

sweepAngle

Specifies the sweep angle, in degrees, of the disk portion.

DESCRIPTION

gluPartialDisk 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 +y axis, 90 degrees along the +x axis, 180 along the -y axis, and 270 along the -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 +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 +z axis. Otherwise, they point along the -z axis.

If texturing is turned on (with gluQuadricTexture), texture coordinates are generated 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).