sphere mapping problem

hi,everyone,i am working a program with opengl,but
now i have a problem. I draw a sphere with gluSphere function and map a texture on it with .bmp image,but when i spin the sphere with the mouse ,the texture lools like distorted,sometimes bigger ,someties samller and it is not a circle,what is the matter with i program

You need to map the texture coordinates appropriately. If you’re not happy with glutsphere and teh mapping of coordinates then make your own.

In general you need to consider how a texture might be mapped on any object, consider an image on a rubber sheet and a sphere, just how is any graphics system supposed to map that rubber sheet onto a sphere. Obviously there will be some stretching and shrinking of the sheet to make it fit.

You get to choose how best to fit the image on the object by specifying texture coordinates at each vertex.