I have a code in which you can switch between perspective and orthographics projections. in perspective one can simply zoom on the model by translating along the screen Z axis; this clearly will not work in ortho and in ortho i use scaling. since i am using two different methods to perform zooming, when i then switch between the ortho and perspective projections the model is usually not visible.
how can i do the zooming consistently in the two projection modes ? should i use glFrustum and glOrtho directly; any example code would be very helpful.