本篇是游戲中物件的定義與使用（2）的續篇。
MIL編輯器的使用
快速且容易地創建物件的需求誕生了MIL編輯器，MIL編輯器不過是一個windows應用程序，它允許玩家操控物件列表，編輯每個想要的物件的屬性特征。可以保存和加載MIL，但是物件屬性的列表將保持固定不變（直到根據自己的意圖重編它們）。
如下圖所示，該對話框由一個包含所有物件的列表框，以及編輯物件信息，保存和加載物件列表的按鈕組成。列表提供了1024個物件的空間，這意味著可以使用一個16位的變量去存儲物件的編號（范圍從0
- 1023）。
To begin using the Master Item List Editor, locate and execute the
MILEdit.exe file.
At the Master Item List Editor dialog box, you can perform the
following steps to add
or edit items, and then save them to disk:
1. Select an item from the Item List by double-clicking the item (or selecting
the item and clicking the Edit button), or add an item by clicking the Add
button. The Modify Item dialog box appears.
2. Edit the appropriate fields in the Modify Item dialog box.
3. When you finish editing, click OK to apply the changes and return to the
Master Item List Editor dialog.
4. To make the changes permanent, click Save on the Master Item List Editor
dialog box, and in the Save MIL File dialog box, enter a filename and save
the MIL to disk.
The MIL Editor uses the same
version of the sItem structure shown earlier, but I added
some extra item categories. Those extra categories are Shield, Healing, and
Container (a container object
such as a backpack). Here these extra categories are added to the ItemCategories
enum list, shown previously
in the section “Items Categories and Values”:
enum
ItemCategories
{
MONEY = 0, WEAPON, ARMOR,
SHIELD, ACCESSORY, EDIBLE,
HEALING, COLLECTION, TRANSPORTATION,
CONTAINER, OTHER
};
If you decide to modify the MIL
Editor to use different item attributes or categories,
modify the sItem structure as well. When you’re ready, you can start using
the item data you created in your game project.
Accessing Items from the MIL
Once you have a MIL, you can load the entire list into an array of sItem
structures
using the following code:
sItem
Items[1024]; // Array of sItem structures
// Open the Default.mil file
FILE *fp = fopen(“Default.mil”, “rb”);
// Read in all items
for(short i=0;i<1024;i++)
fread(&Items[i], 1, sizeof(sItem), fp);
// Close file
fclose(fp);
At this point, I’m assuming
that your item structure is relatively small and that you
are using no more than 1,024 items in your MIL. What happens if you extend each
item’s sItem structure or you begin storing more items in the MIL? We’re talking
about some serious memory usage.
To avoid loading each and every single item in memory from the MIL at once, you
can access individual items directly from the MIL. Because the size of each item
structure is fixed, you can access each item’s data by moving the file pointer
to the
appropriate position and reading in the structure, as in the following code bit:
//
ItemNum = reference # of item to load
sItem Item;
// Open the MIL file titled items.mil
FILE *fp=fopen(“items.mil”, “rb”);
// Seek to the appropriate position in file
// based on the size of the sItem structure and
// the number of the item to load.
fseek(fp, sizeof(sItem) * ItemNum, SEEK_SET);
// Read in the item structure
fread(&Item, 1, sizeof(sItem), fp);
// Close the file
fclose(fp);
And there you go—quick and easy access to every item in the MIL! Now, it’s time
to do something with those items.