Add support for start position via level XML for CLI playtesting

As already described in cc61194bed, as
well as Ved's commits from the last almost two weeks, starting VVVVVV
from Ved for playtesting could be made a lot faster by "preloading" the
game - letting it do all its asset loading in the background without
creating a window - and then waiting until the level is passed in via
stdin. There's only one problem left with this approach: VVVVVV
currently expects the starting position to be passed via command line
arguments, which isn't known yet at the time we'd like to start VVVVVV.
Therefore, this commit allows passing the starting position via the
level XML, instead of via arguments.

The extra XML looks like this, and is added next to the <Data> tag:

    <Playtest>
        <playx>214</playx>
        <playy>112</playy>
        <playrx>100</playrx>
        <playry>100</playry>
        <playgc>0</playgc>
        <playmusic>4</playmusic>
    </Playtest>

This is handled similarly to how the equivalent arguments are handled:
when the level metadata is loaded for CLI playtesting, we also try to
find this tag, and if it exists, it sets the same variables that the
arguments would have otherwise set.

desktop_version/src/CustomLevels.cpp

@@ -201,6 +201,15 @@ TAG_FINDER(find_desc2, "Desc2")
 TAG_FINDER(find_desc3, "Desc3")
 TAG_FINDER(find_website, "website")
 
+/* For CliPlaytestArgs */
+TAG_FINDER(find_playtest, "Playtest")
+TAG_FINDER(find_playx, "playx")
+TAG_FINDER(find_playy, "playy")
+TAG_FINDER(find_playrx, "playrx")
+TAG_FINDER(find_playry, "playry")
+TAG_FINDER(find_playgc, "playgc")
+TAG_FINDER(find_playmusic, "playmusic")
+
 #undef TAG_FINDER
 
 static void levelMetaDataCallback(const char* filename)
@@ -245,7 +254,7 @@ void customlevelclass::getDirectoryData(void)
     }
 
 }
-bool customlevelclass::getLevelMetaData(const std::string& _path, LevelMetaData& _data )
+bool customlevelclass::getLevelMetaDataAndPlaytestArgs(const std::string& _path, LevelMetaData& _data, CliPlaytestArgs* pt_args)
 {
     unsigned char *uMem;
     FILESYSTEM_loadFileToMemory(_path.c_str(), &uMem, NULL, true);
@@ -273,10 +282,34 @@ bool customlevelclass::getLevelMetaData(const std::string& _path, LevelMetaData&
     _data.Desc3 = find_desc3(buf);
     _data.website = find_website(buf);
 
+    if (pt_args != NULL)
+    {
+        const std::string playtest = find_playtest(buf);
+        if (playtest == "")
+        {
+            pt_args->valid = false;
+        }
+        else
+        {
+            pt_args->valid = true;
+            pt_args->x = help.Int(find_playx(playtest).c_str());
+            pt_args->y = help.Int(find_playy(playtest).c_str());
+            pt_args->rx = help.Int(find_playrx(playtest).c_str());
+            pt_args->ry = help.Int(find_playry(playtest).c_str());
+            pt_args->gc = help.Int(find_playgc(playtest).c_str());
+            pt_args->music = help.Int(find_playmusic(playtest).c_str());
+        }
+    }
+
     _data.filename = _path;
     return true;
 }
 
+bool customlevelclass::getLevelMetaData(const std::string& _path, LevelMetaData& _data)
+{
+    return getLevelMetaDataAndPlaytestArgs(_path, _data, NULL);
+}
+
 void customlevelclass::reset(void)
 {
     version=2; //New smaller format change is 2

desktop_version/src/CustomLevels.h

@@ -60,6 +60,17 @@ struct LevelMetaData
     int version;
 };
 
+struct CliPlaytestArgs
+{
+    int x;
+    int y;
+    int rx;
+    int ry;
+    int gc;
+    int music;
+    bool valid;
+};
+
 
 extern std::vector<CustomEntity> customentities;
 
@@ -80,7 +91,8 @@ public:
 
     void loadZips(void);
     void getDirectoryData(void);
-    bool getLevelMetaData(const std::string& filename, LevelMetaData& _data );
+    bool getLevelMetaDataAndPlaytestArgs(const std::string& filename, LevelMetaData& _data, CliPlaytestArgs* pt_args);
+    bool getLevelMetaData(const std::string& filename, LevelMetaData& _data);
 
     void reset(void);
     const int* loadlevel(int rxi, int ryi);

desktop_version/src/main.cpp

@@ -634,12 +634,13 @@ int main(int argc, char *argv[])
         game.menustart = true;
 
         LevelMetaData meta;
-        if (cl.getLevelMetaData(playtestname, meta)) {
+        CliPlaytestArgs pt_args;
+        if (cl.getLevelMetaDataAndPlaytestArgs(playtestname, meta, &pt_args)) {
             cl.ListOfMetaData.clear();
             cl.ListOfMetaData.push_back(meta);
         } else {
             cl.loadZips();
-            if (cl.getLevelMetaData(playtestname, meta)) {
+            if (cl.getLevelMetaDataAndPlaytestArgs(playtestname, meta, &pt_args)) {
                 cl.ListOfMetaData.clear();
                 cl.ListOfMetaData.push_back(meta);
             } else {
@@ -648,6 +649,17 @@ int main(int argc, char *argv[])
             }
         }
 
+        if (pt_args.valid)
+        {
+            savefileplaytest = true;
+            savex = pt_args.x;
+            savey = pt_args.y;
+            saverx = pt_args.rx;
+            savery = pt_args.ry;
+            savegc = pt_args.gc;
+            savemusic = pt_args.music;
+        }
+
         game.loadcustomlevelstats();
         game.customleveltitle=cl.ListOfMetaData[game.playcustomlevel].title;
         game.customlevelfilename=cl.ListOfMetaData[game.playcustomlevel].filename;