8. Special Effects
This chapter introduces three techniques for adding apparent detail to 3D applications without dramatically increasing the number of vertices processed. Each technique uses 2D images designed to fool the eye even when moving and panning within a 3D scene. The first, a skybox, encloses the rendered scene in a cube with textures on all six sides. The textures make it seem like geometry extends all the way to an imaginary horizon. The second effect, particles, efficiently simulates explosions, water flowing, or smoke billowing. Finally, billboards take advantage of textured triangles aligned with the point of view to conceal the absence of depth.
Figure 8.1 shows a partially unfolded skybox and a screenshot of a scene rendered ...