based on a field of view of the camera, as well as the closest and furthest distances the camera is able to see from its current position. When all this data is put together, a perspective matrix can be computed, which is later used for rendering geometry. The frustum for this type of camera is symmetric, so when divided in half vertically or horizontally, the frustum is the same size. Objects are then drawn onto the near plane based on this projection matrix. The entire scene is drawn, with potentially many objects. When finished, the final frame will show everything in focus, unless effort is taken to create visual effects to make the scene appear similar to what the world would look like from a human eye (such as blurring, lighting changes, etc).