QT_opengl_gluPerspective没有定义的处理方法

例如:

gluPerspective( 45.0, (GLfloat)width/(GLfloat)height, 0.1,100.0 );

转换为:

GLfloat zNear = 0.1;

GLfloat zFar = 100.0;

GLfloat aspect = (GLfloat)width/(GLfloat)height;

GLfloat fH = tan(GLfloat(90.0/360.0*3.14159))*zNear;

GLfloat fW = fH * aspect;

glFrustum(-fW, fW, -fH, fH, zNear, zFar);