GLU Quadrics Objects

GLUquadricObj * pointTool;

// create the rendering tool
pointTool=gluNewQuadric();
gluQuadricDrawStyle(pointTool,GLU_POINT);

// delete the rendering tool
gluDeleteQuadric(pointTool);

The default drawing style is to fill in shapes using polygon and triangle strip primitives, GLU_FILL

`GLU_FILL`	Fill in using polygon and triangle strip primitives.
`GLU_LINE`	Render wireframe objects using line primitives.
`GLU_SILHOUETTE`	Render using line primitives, render only outside edges.
`GLU_POINT`	Render using point primitives.

We can generate lighting normals for quadrics.

void gluQuadricNormals(GLUquadricObj * obj, GLenum mode)

mode
`GLU_NONE`	No lighting normals.
`GLU_FLAT`	Lighting normals generated for each polygon - faceted appearance.
`GLU_SMOOTH`	Lighting normals generated for each vertex - smooth appearance.

We can control the direction of lighting normals eg. may be inside or outside a sphere.

gluQuadricOrientation(fillTool,GLU_OUTSIDE);
gluQuadricOrientation(fillTool,GLU_INSIDE);

Cylinder

void gluCylinder(GLUquadricObj * obj,
                 GLdouble baseRadius, GLdouble topRadius,
                 GLdouble height,
                 GLint slices, GLint stacks)

The cylinder is projected height units along the positive z-axis.
slices: subdivisions around the cylinder (sides) - 20 = fairly smooth curve, otherwise faceted appearance
stacks: subdivisions along cylinder - set high for spotlights or lots of specular light (20), otherwise set to 2 for top and bottom

Make cones by specifying a top or bottom radius of 0.0.

Ends of cylinder not filled in. Fill them in with disks if you wish.

void gluDisk(GLUquadricObj *obj,
             GLdouble innerRadius, GLdouble outerRadius,
             GLint slices, GLint loops)

innerRadius and outerRadius control the size of the hole and disk.
Set innerRadius to 0.0 to render a solid circle.
slices: number of sides to disk (eg. 3 for equilateral triangle, 6 for a washer 20 for a circle).
loops: number of concentric rings rendered eg. 1 for circles 2 for washers. Using larger values for loops improves specular lighting and the effect of spotlights.

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

startAngle: clockwise angle in degrees from the top of the disk
sweepAngle: number of degrees of arc to draw eg. 90^o is a quarter disk

void gluSphere(GLUquadricObj *obj,
               GLdouble radius,
               GLint slices,GLint stacks)

slices: longitude stacks: latitude

Fran Soddell email:F.Soddell@bendigo.latrobe.edu.au

last updated 17 September 2002