Feature/virtualproperty (#286)

* Add virtual property owner to OpenSpaceEngine

* Ability to add and remove virtual properties

* Do not try to render empty PropertyOwner name
Compile fix for iswaComponent
Add example in default.scene

* Delete virtual properties also in the OpenSpaceEngine dtor

* Make RenderablePlanet not crash if the nighttextures are not present

* - Add VirtualPropertyManager to manage ownership of virtual properties
- Only execute regex when it was necessary
-

src/engine/openspaceengine_lua.inl

@@ -32,13 +32,14 @@ namespace luascriptfunctions {
  * reached
  */
 int toggleShutdown(lua_State* L) {
-    int nArguments = lua_gettop(L);
-    if (nArguments != 0)
+    const int nArguments = lua_gettop(L);
+    if (nArguments != 0) {
         return luaL_error(L, "Expected %i arguments, got %i", 0, nArguments);
+    }
 
     OsEng.toggleShutdownMode();
 
-    return 1;
+    return 0;
 }
 
 /**
@@ -47,13 +48,92 @@ int toggleShutdown(lua_State* L) {
 * Writes out documentation files
 */
 int writeDocumentation(lua_State* L) {
-    int nArguments = lua_gettop(L);
-    if (nArguments != 0)
+    const int nArguments = lua_gettop(L);
+    if (nArguments != 0) {
         return luaL_error(L, "Expected %i arguments, got %i", 0, nArguments);
+    }
 
     OsEng.writeDocumentation();
 
-    return 1;
+    return 0;
+}
+
+/**
+ * \ingroup LuaScripts
+ * addVirtualProperty():
+ * Adds a virtual property that will set a group of properties
+ */
+int addVirtualProperty(lua_State* L) {
+    using namespace properties;
+
+    const int nArguments = lua_gettop(L);
+    if (nArguments != 6) {
+        return luaL_error(L, "Expected %i arguments, got %i", 6, nArguments);
+    }
+
+    const std::string type = lua_tostring(L, -6);
+    const std::string name = lua_tostring(L, -5);
+    const std::string identifier = lua_tostring(L, -4);
+
+    std::unique_ptr<Property> prop;
+    if (type == "BoolProperty") {
+        bool v = lua_toboolean(L, -3);
+        prop = std::make_unique<BoolProperty>(identifier, name, v);
+    }
+    else if (type == "IntProperty") {
+        int v = static_cast<int>(lua_tonumber(L, -3));
+        int min = static_cast<int>(lua_tonumber(L, -2));
+        int max = static_cast<int>(lua_tonumber(L, -1));
+
+        prop = std::make_unique<IntProperty>(identifier, name, v, min, max);
+    }
+    else if (type == "FloatProperty") {
+        float v = static_cast<float>(lua_tonumber(L, -3));
+        float min = static_cast<float>(lua_tonumber(L, -2));
+        float max = static_cast<float>(lua_tonumber(L, -1));
+
+        prop = std::make_unique<FloatProperty>(identifier, name, v, min, max);
+    }
+    else if (type == "TriggerProperty") {
+        prop = std::make_unique<TriggerProperty>(identifier, name);
+    }
+    else {
+        return luaL_error(L, "Unknown property type '%s'", type.c_str());
+    }
+
+    OsEng.virtualPropertyManager().addProperty(std::move(prop));
+    return 0;
+}
+
+/**
+* \ingroup LuaScripts
+* removeVirtualProperty():
+* Removes a previously added virtual property
+*/
+int removeVirtualProperty(lua_State* L) {
+    const int nArguments = lua_gettop(L);
+    if (nArguments != 1) {
+        return luaL_error(L, "Expected %i arguments, got %i", 1, nArguments);
+    }
+
+    const std::string name = lua_tostring(L, -1);
+    properties::Property* p = OsEng.virtualPropertyManager().property(name);
+    OsEng.virtualPropertyManager().removeProperty(p);
+    return 0;
+}
+
+/**
+* \ingroup LuaScripts
+* removeAllVirtualProperties():
+* Remove all registered virtual properties
+*/
+int removeAllVirtualProperties(lua_State* L) {
+    std::vector<properties::Property*> ps = OsEng.virtualPropertyManager().properties();
+    for (properties::Property* p : ps) {
+        OsEng.virtualPropertyManager().removeProperty(p);
+        delete p;
+    }
+    return 0;
 }