DDS texture compression technic was added to directx in 2000 and the game was already in dev for 2 years when directx 7 was released. GPG did not have the time to add it to their engine being already late because of the move from opengl to direct3D.
There must be a way to add DDS to ds1 but that must be quite a hard work. But if you still want to look at it. You can try to reverse engineer the game hook the functions about texture parsing and add DDS compatibility.
DDS texture compression technic was added to directx in 2000 and the game was already in dev for 2 years when directx 7 was released. GPG did not have the time to add it to their engine being already late because of the move from opengl to direct3D.
There must be a way to add DDS to ds1 but that must be quite a hard work. But if you still want to look at it. You can try to reverse engineer the game hook the functions about texture parsing and add DDS compatibility.