i find the code for the item drop
void CreateItem(ITEM_t *ip,BYTE *Item,vec3_t Position,int CreateFlag)
{
int Type = ConvertItemType(Item);
ITEM *n = &ip->Item;
n->Type = Type;
if(Type==ITEM_POTION+15)
{
n->Level = (Item[1]<<16)+(Item[2]<<8)+(Item[4])...