Adjusted the converter to be robust against IDs being overwritten with zeros in the png. Sucessfully ran it.

converter/converter.cc

@@ -178,6 +178,34 @@ Converter::~Converter(){
 }
 
 std::vector<int> Converter::newComposition(int type, float posX, float posZ){
+    int oldIDGreen, oldIDBlue;
+    bool alreadyExists = false;
+    XMLElement* thisComposition = doc->FirstChildElement("composition");
+    for(; thisComposition; thisComposition=thisComposition->NextSiblingElement("composition")){
+        float xPos = queryFloat(thisComposition, "xPos");
+        float zPos = queryFloat(thisComposition, "zPos");
+        int typeID = queryInt(thisComposition, "typeID");
+        if(xPos == posX && zPos == posZ && typeID == type){
+            if(alreadyExists){
+                std::cout << "At the position " << xPos << "," << zPos << " multiple compositions with the ID " << typeID << " exist in the xml." << std::endl;
+                exit(-1);
+            }
+            oldIDGreen = queryInt(thisComposition, "idGreen");
+            oldIDBlue = queryInt(thisComposition, "idBlue");
+            alreadyExists = true;
+        }
+    }
+    if (alreadyExists){
+        if (! idUsed[oldIDGreen][oldIDBlue]){
+            std::cout << "The composition with ID " << oldIDGreen << "," << oldIDBlue << " exists in the xml but the converter thinks it does not." << std::endl;
+            exit(-1);
+        }
+        std::vector<int> oldID;
+        oldID.push_back(oldIDGreen);
+        oldID.push_back(oldIDBlue);
+        return oldID;
+    }
+    
     bool full = false;
     while(idUsed[nextID[0]][nextID[1]]){
         nextID[1] += 1;
@@ -194,6 +222,7 @@ std::vector<int> Converter::newComposition(int type, float posX, float posZ){
             }
         }
     }
+    
     XMLElement* newComposition = doc->NewElement("composition");
     XMLElement* typeID = doc->NewElement("typeID");
     XMLElement* idBlue = doc->NewElement("idBlue");
@@ -322,6 +351,28 @@ void Converter::save(){
     doc->SaveFile(charXmlFile);
 }
 
+float Converter::queryFloat(XMLElement* element, const char* attribute){
+    XMLElement* attributeElement = element->FirstChildElement(attribute);
+    if (attributeElement == NULL){
+        std::cout << "XMLError: Attribute " << attribute << " does not exist." << std::endl;
+        exit(-1);
+    }
+    float ret;
+    errorCheck(attributeElement->QueryFloatText(&ret));
+    return ret;
+}
+
+float Converter::queryFloat(XMLDocument*& element, const char* attribute){
+    XMLElement* attributeElement = element->FirstChildElement(attribute);
+    if (attributeElement == NULL){
+        std::cout << "XMLError: Attribute " << attribute << " does not exist." << std::endl;
+        exit(-1);
+    }
+    float ret;
+    errorCheck(attributeElement->QueryFloatText(&ret));
+    return ret;
+}
+
 int Converter::queryInt(XMLElement* element, const char* attribute){
     XMLElement* attributeElement = element->FirstChildElement(attribute);
     if (attributeElement == NULL){

converter/converter.hh

@@ -16,12 +16,13 @@ class Converter {
         void deleteComposition(int idG, int idB);
         void save(); //writes the xml to file
     private:
-        
         std::vector<int> nextID;
         bool idUsed[256][256];
         std::string xmlFile;
         XMLDocument* doc = new XMLDocument();
         XMLDocument* compositions = new XMLDocument();
+        float queryFloat(XMLElement* element, const char* attribute);
+        float queryFloat(XMLDocument*& element, const char* attribute);
         int queryInt(XMLElement* element, const char* attribute);
         int queryInt(XMLDocument*& element, const char* attribute);
         bool queryBool(XMLElement* element, const char* attribute);

data/levels/Level1.xml

@@ -1,3 +1,32 @@
+<composition>
+    <scale>1.0</scale>
+    <xRot>0.0</xRot>
+    <yRot>0.0</yRot>
+    <zRot>0.0</zRot>
+    <manualPos>false</manualPos>
+    <xPos>58.500000</xPos>
+    <yOffset>0.0</yOffset>
+    <zPos>-172.500000</zPos>
+    <idGreen>0</idGreen>
+    <idBlue>112</idBlue>
+    <typeID>221</typeID>
+    <trigger>
+        <name>-</name>
+        <xPosition>0</xPosition>
+        <yPosition>0</yPosition>
+        <zPosition>0</zPosition>
+        <targetIdGreen>-</targetIdGreen>
+        <targetIdBlue>-</targetIdBlue>
+        <distance>1.0</distance>
+        <isBiggerThan>false</isBiggerThan>
+        <objectNum>0</objectNum>
+        <luaScript>-</luaScript>
+        <toChangeIdGreen>0</toChangeIdGreen>
+        <toChangeIdBlue>0</toChangeIdBlue>
+        <toChangeObjNum>0</toChangeObjNum>
+    </trigger>
+</composition>
+
 <composition>
     <scale>1.0</scale>
     <xRot>0.0</xRot>