Difference between revisions of "SCUMM/Technical Reference/Script resources"

SCUMM/Technical Reference/Script resources (view source)

Revision as of 14:40, 15 May 2009

977 bytes added , 14:40, 15 May 2009

Added info to v3/4 script blocks, clarified table entries & other bits.

Jestar jokin

126

edits

@@ Line 58: / Line 58: @@
 == Object Scripts V5+ (OBCD) ==
-These are scripts that correspond to VERB actions. VERBs are predefined activities at the bottom of the screen, e.g. "Open", "Look", "Give" etc. For each named object in a room, the game designer could define responses to the players actions. Starting with version 5, the whole code can be found in an [[Object resources|Object Resource]].
+These are scripts that correspond to VERB actions. VERBs are predefined activities at the bottom of the screen, e.g. "Open", "Look", "Give" etc. For each named object in a room, the game designer could define responses to the players actions. A single VERB block contains the code for all possible player actions on the object. Starting with version 5, the whole code can be found in an [[Object resources|Object Resource]].
   OBCD
@@ Line 73: / Line 73: @@
        Block name    4 bytes ("VERB")
        Block size    4 bytes
-       offset table  variable
+       offset table  variable {
-      verb          1 byte (0xFF is default)
+       verb          1 byte (0xFF is default)
-      offset        2 bytes
+       offset        2 bytes
-       table end     1 byte(must be 0)
+      }
+       table end     1 byte (must be 0x00)
        object code   variable
+    OBNA
+      Block name    4 bytes ("OBNA")
+      Block size    4 bytes
+      object name   null-terminated string
@@ Line 85: / Line 91: @@
   OC
-    Block size        4 bytes
+    Block size        4 bytes (LE)
     Block name        2 bytes ("OC")
-    Object ID         1 byte (?)
+    Object ID         2 bytes (LE)
-   unknown           12 bytes
+   unknown           3 bytes
+   image width / 8   1 byte
+   unknown           5 bytes
+   height & 0xF8     1 byte
+   name offset       1 byte
+   offset table      variable {
+    verb             1 byte (0xFF is default)
+    offset           2 bytes
+   }
+   table end         1 byte (must be 0x00)
+   object name       null-terminated string
+   object code       variable
+This block contains all object data except for the actual image bitmap. Compare this to V5+ objects, where metadata is split into seperate CDHD and OBNA blocks.
-Now starts a variable block similar to the VERB block in later games, which contains the verb identifier (1 byte) and the offset. The table end is marked with 0. Directly behind the object name is stored followed by the object code:
+Image width is given in strips, which are 8 pixels wide. Name offset is the absolute offset of object name (or, if you prefer, the position after table end).
-   verb               1 byte
+The offset table is a variable block like that used in the VERB block in later games, which contains the verb identifier (1 byte) and the absolute offset (2 bytes). The table end is marked with 0x00. Next is the object's name, which is a standard null-terminated string. After this follows the actual object code. Note that unlike other script types, because there are multiple entry points (one for each supported verb), there are also multiple exit points (or "stopObjectCode" instructions).
-   offset             2 bytes
-   table end          1 byte (must be 0)
-   object name        0 terminated string
-   object code        variable