Introduction

In this chapter, we will look at the recipes for handling 3D viewing tasks and object picking in OpenGL v3.3 and above. All of the real-time simulations, games, and other graphics applications require a virtual camera or a virtual viewer from the point of view of which the 3D scene is rendered. The virtual camera is itself placed in the 3D world and has a specific direction called the camera look direction. Internally, the virtual camera is itself a collection of translations and rotations, which is stored inside the viewing matrix.

Moreover, projection settings for the virtual camera control how big or small the objects appear on screen. This is the kind of functionality which is controlled through the real world camera lens. These are controlled through the projection matrix. In addition to specifying the viewing and projection matrices, the virtual camera may also help with reducing the amount of geometry pushed to the GPU. This is through a process called view frustum culling. Rather than rendering all of the objects in the scene, only those that are visible to the virtual camera are rendered, thus improving the runtime performance of the application.