【OpenGL函数glRotatef的问题.glRotatef(30.0f,0.0f,1.0f,0.0f)第一个参数是指什么?表示模型物体绕Y轴逆时针旋转30?还是理解为坐标系顺时针旋转30..?glPushMatrix();glRotatef(ballR,0.0f,1.0f,0.0f);glTranslatef(-0】

　　OpenGL函数glRotatef的问题.

　　glRotatef(30.0f,0.0f,1.0f,0.0f)第一个参数是指什么?表示模型物体绕Y轴逆时针旋转30?还是理解为坐标系顺时针旋转30..?

　　glPushMatrix();

　　glRotatef(ballR,0.0f,1.0f,0.0f);

　　glTranslatef(-0.8,0.0f,0.0f);

　　glColor3ub(255,0,0);

　　glutSolidSphere(0.1f,15,15);

　　glPopMatrix();

　　如何解释球的旋转方向?