DMU API: Added property DMU_ARCHIVE_INDEX

The archive index is the position of the relevant data and/or
definition for the map element in the "archived" map. The archive
in this context is original source of the map element (e.g., from
an id Tech 1 format map).

For example, in the case of a DMU_SIDE element that is produced
from an id tech 1 format map, the archive index will be the index
of the definition in the SIDEDEFS data lump.

Todo: This info should be used when translating legacy indexes,
such as those used in the Doom ver 1.9 save game reader.

doomsday/api/api_map.h

@@ -30,6 +30,8 @@
 #include <de/aabox.h>
 #include <de/mathutil.h>
 
+#define DMT_ARCHIVE_INDEX DDVT_INT
+
 #define DMT_VERTEX_ORIGIN DDVT_DOUBLE
 
 #define DMT_HEDGE_SIDE DDVT_PTR

doomsday/api/dd_share.h

@@ -328,6 +328,9 @@ enum {
 
     DMU_NONE = 0,
 
+    /*
+     * Element types:
+     */
     DMU_FIRST_ELEMENT_TYPE_ID = 1,
     DMU_VERTEX = DMU_FIRST_ELEMENT_TYPE_ID,
     DMU_HEDGE,
@@ -341,12 +344,20 @@ enum {
     DMU_MATERIAL,
     DMU_LAST_ELEMENT_TYPE_ID = DMU_MATERIAL,
 
+    /*
+     * Selection methods:
+     */
     DMU_LINE_BY_TAG,
     DMU_SECTOR_BY_TAG,
 
     DMU_LINE_BY_ACT_TAG,
     DMU_SECTOR_BY_ACT_TAG,
 
+    /*
+     * Element properties:
+     */
+    DMU_ARCHIVE_INDEX, ///< Relevant data/definition position in the "archived" map.
+
     DMU_X,
     DMU_Y,
     DMU_XY,

doomsday/client/src/map/mapelement.cpp

@@ -56,9 +56,19 @@ MapElement &MapElement::operator = (MapElement const &other)
 
 int MapElement::property(setargs_t &args) const
 {
-    /// @throw UnknownPropertyError  The requested property is not readable.
-    throw UnknownPropertyError(QString("%1::property").arg(DMU_Str(_type)),
-                               QString("Property '%1' is unknown/not readable").arg(DMU_Str(args.prop)));
+    switch(args.prop)
+    {
+    case DMU_ARCHIVE_INDEX:
+        DMU_GetValue(DMT_ARCHIVE_INDEX, &_indexInArchive, &args, 0);
+        break;
+
+    default:
+        /// @throw UnknownPropertyError  The requested property is not readable.
+        throw UnknownPropertyError(QString("%1::property").arg(DMU_Str(_type)),
+                                   QString("Property '%1' is unknown/not readable").arg(DMU_Str(args.prop)));
+    }
+
+    return false; // Continue iteration.
 }
 
 int MapElement::setProperty(setargs_t const &args)

doomsday/client/src/map/p_dmu.cpp

@@ -90,6 +90,7 @@ char const *DMU_Str(uint prop)
         { DMU_SECTOR_BY_TAG, "DMU_SECTOR_BY_TAG" },
         { DMU_LINE_BY_ACT_TAG, "DMU_LINE_BY_ACT_TAG" },
         { DMU_SECTOR_BY_ACT_TAG, "DMU_SECTOR_BY_ACT_TAG" },
+        { DMU_ARCHIVE_INDEX, "DMU_ARCHIVE_INDEX" },
         { DMU_X, "DMU_X" },
         { DMU_Y, "DMU_Y" },
         { DMU_XY, "DMU_XY" },