glRotate

Name

glRotatef , glRotatex - multiply the current matrix by a rotation matrix

C Specification

void glRotatef(GLfloat angle, GLfloat x, GLfloat y, GLfloat z)
void glRotatex(GLfixed angle, GLfixed x, GLfixed y, GLfixed z)

Parameters

angle: Specifies the angle of rotation, in degrees.
x, y, z: Specify the x, y, and z coordinates of a vector, respectively.

Description

glRotate produces a rotation of angle degrees around the vector (x, y, z) . The current matrix (see glMatrixMode) is multiplied by a rotation matrix with the product replacing the current matrix, as if glMultMatrix were called with the following matrix as its argument:

(

x² (1 - c) + c	xy (1 - c) - zs	xz (1 - c) + ys	0
xy (1 - c) + zs	y² (1 - c) + c	yz (1 - c) - xs	0
xz (1 - c) - ys	yz (1 - c) + xs	z² (1 - c) + c	0
0	0	0	1

)

Where c = cos (angle) , s = sin (angle) , and || (x, y, z) || = 1, (if not, the GL will normalize this vector).

If the matrix mode is either GL_MODELVIEW or GL_PROJECTION, all objects drawn after glRotate is called are rotated. Use glPushMatrix and glPopMatrix to save and restore the unrotated coordinate system.

Notes

This rotation follows the right-hand rule, so if the vector (x, y, z) points toward the user, the rotation will be counterclockwise.

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