Push many textures
#include <s3d.h>
int s3d_push_textures(int object, const uint16_t *tbuf, uint16_t n);
As for vertices, you can push arrays of textures on the texture stack to have greater performance. The tbuf should contain n texture sizes which consist of 2 uint16_t values for width and height for each texture.
Simon Wunderlich
Author of s3d