why is texture bitmap deformated when being rotated

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C++

graphics

3D

lately i am tring to drawing texture bitmap on the 3d object, with the same drawing texture interface, i used double-buffering both in directx and DrawDibDraw. it performs in the right way when to rotate texture object with directx, while when it comes to DrawDibDraw, i put back buffer in drawdibdraw, texture bitmap will be deformated when being rotated.

pseudo-code:

DrawDibDraw;

load_bitmap_file(file->buffer, bitmap);

load_image_bitmap(lpobj->buffer, file->buffer);

draw_texture(back_buffer, lpobj->buffer);

DrawDibDraw(hdc, back_buffer);

DirectX

load_bitmap_file(file->buffer, bitmap);

load_image_bitmap(lpobj->buffer, file->buffer);

draw_texture(back_buffer, lpobj->buffer);

DDraw_Lock_Back_Surface()

DDraw_Unlock_Back_Surface()

DDraw_Flip()