Here you go:

Code:
void draw_rotated_bbox(ENTITY* ent)
{
	VECTOR c1,c2,c3,c4,c5,c6,c7,c8;  
		
	vec_set(c1,vector(ent.min_x,ent.min_y,ent.min_z));    
	vec_rotate(c1,ent.pan);
	vec_add(c1,ent.x);
		
	vec_set(c2,vector(ent.max_x,ent.min_y,ent.min_z));    
	vec_rotate(c2,ent.pan);
	vec_add(c2,ent.x);
		
	vec_set(c3,vector(ent.max_x,ent.max_y,ent.min_z));    
	vec_rotate(c3,ent.pan);
	vec_add(c3,ent.x);
		
	vec_set(c4,vector(ent.min_x,ent.max_y,ent.min_z));    
	vec_rotate(c4,ent.pan);
	vec_add(c4,ent.x);
		
	vec_set(c5,vector(ent.min_x,ent.min_y,ent.max_z));    
	vec_rotate(c5,ent.pan);
	vec_add(c5,ent.x);
		
	vec_set(c6,vector(ent.max_x,ent.min_y,ent.max_z));    
	vec_rotate(c6,ent.pan);
	vec_add(c6,ent.x);
		
	vec_set(c7,vector(ent.max_x,ent.max_y,ent.max_z));    
	vec_rotate(c7,ent.pan);
	vec_add(c7,ent.x);
		
	vec_set(c8,vector(ent.min_x,ent.max_y,ent.max_z));    
	vec_rotate(c8,ent.pan);
	vec_add(c8,ent.x);	
		
	draw_line3d(c1,NULL,100); 
	draw_line3d(c2,vector(0,255,0),100);
	draw_line3d(c3,vector(0,255,0),100);
	draw_line3d(c4,vector(0,255,0),100);
	draw_line3d(c1,vector(0,255,0),100);
		
	draw_line3d(c5,NULL,100);
	draw_line3d(c6,vector(0,255,0),100);
	draw_line3d(c7,vector(0,255,0),100);
	draw_line3d(c8,vector(0,255,0),100);
	draw_line3d(c5,vector(0,255,0),100);

	draw_line3d(c1,NULL,100);
	draw_line3d(c5,vector(0,255,0),100);
		
	draw_line3d(c2,NULL,100);
	draw_line3d(c6,vector(0,255,0),100);
		
	draw_line3d(c3,NULL,100);
	draw_line3d(c7,vector(0,255,0),100);
		
	draw_line3d(c4,NULL,100);
	draw_line3d(c8,vector(0,255,0),100);
}