OpenGL/GLU : Is there a built-in function for drawing circles?

Question

我知道有用于绘制矩形的内置函数(例如 glRecti())，并且认为圆也是一个非常基本的用法。

有没有这种画圆的内置函数？或者我应该总是自己实现它？

Answer 1

gluDisk() can be used to do so :

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.

Official manpage .