我试图用gluOrtho2D与glutBitmapCharacter,以便我可以在屏幕上呈现文本以及我的3D对象。但是,当我使用glOrtho2D时,我的3D对象消失了;我认为这是因为我没有将投影设置回OpenGL/GLUT默认值,但我不确定那是什么。使用OpenGL,我怎样才能在默认投影中正确使用gluOrtho2D?
无论如何,这是我使用呈现文本的功能:
void GlutApplication::RenderString(Point2f point, void* font, string s)
{
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
gluOrtho2D(0.0, WindowWidth, 0.0, WindowHeight);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
glDisable(GL_TEXTURE);
glDisable(GL_TEXTURE_2D);
glRasterPos2f(point.X, point.Y);
for (string::iterator i = s.begin(); i != s.end(); ++i)
{
glutBitmapCharacter(font, *i);
}
glEnable(GL_TEXTURE);
glEnable(GL_TEXTURE_2D);
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
glMatrixMode(GL_PROJECTION);
glPopMatrix();
}
而且,渲染功能类似于此:
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glLoadIdentity();
// Do some translation here.
// Draw some 3D objects.
glPopMatrix();
// For some reason, this stops the above from being rendered,
// where the camera is facing (I assume they are still being rendered).
Point2f statusPoint(10, 10);
RenderString(statusPoint, GLUT_BITMAP_9_BY_15, "Loading...");