Bumpmapping is an advanced multitexture blending technique that can be used to render the appearance of rough, bumpy surfaces. The bump map itself is a texture that stores the perturbation data. Bumpmapping requires two textures, actually.

Direct3D+9.0+SDK.zip 帮助文件，使用查询起来非常方便。-Direct3D+9.0+SDK.zip help file, use Query very convenient.