Figure 7.20: Several examples of post-rendering image warp: (a) Before warping, a larger image is rasterized. The red box shows the part that is intended to be sent to the display based on the viewpoint that was used at the time of rasterization; (b) A negative yaw (turning the head to the right) causes the red box to shift to the right. The image appears to shift to the left; (c) A positive pitch (looking upward) causes the box to shift upward; (d) In this case, the yaw is too large and there is no rasterized data to use for part of the image (this region is shown as a black rectangle).