计算机图形学中有关VUP矢量的探讨

Discussion on the vector VUP in computer graphics

为正确阐述图形学教材中世界坐标系下确定视坐标系时所采用的VUP矢量的作用及其确切含义,提出初始VUP矢量的概念,并将初始VUP矢量绕n矢量旋转与模拟相机横摇角(roll)的概念联系起来,由此得出任意VUP矢量的计算方法.利用该方法对OpenGL中的gluLookAt函数进行了再封装.在航海模拟器上的实验表明,使用该方法进行场景绘制的结果是准确的.

The concept of the initial vector VUP is proposed to correctly illustrate the real function and exact meaning of the vector VUP which is usually adopted to establish viewing coordinate system in world coordinate system in the existing graphics textbooks. The relationship between the roll of the analog camera and the initial vector VUP which rotates around the vector n is set up, thereby the general calculation method of the arbitrary vector VUP is deduced. The gluLookAt function in OpenGL is rewrapped by using the proposed method. Tests on the navigation simulator show that the proposed method in rendering is correct.