Question about multi target project

The target i would like to achieve is to create a multi platform project, but i would like to work with Visual Studio for the development phase.
I build the engine for Vs2015 and for emscripten, and i am now trying to compile my simple project to visual studio.
The engine complain that my Urho home is indeed the emscripten one, so i did change the home and build the project.
Everything works good.

Did i have to change Uhro home everytime i need to create a project?
Is this the correct approach? Or did i miss some steps?

Thank you.

multi platform target? this means multiple build environments, yes generally this means more projects, at worst, one for each build target. But your source code does not change, well never a lot, just the requirements and settings for the various targets.
I’ve built across multiple targets and it’s always been somewhat of a pain - but it can be done, some game engines actively support this concept more than others… mostly because they are commercial, and well-funded.

I am not worried about that, i was just asking if this is the correct way to handle this.

Generally, and without specific knowledge of your preferred IDE or build platform, yes this is the right way for targetting multiple platforms.

this is usually where things like cmake come in - cmake can wrap your project code for a given target platform, sometimes.

my base app tree:

(3.5.3_Default) max:myApp tree -L 5
.
├── CMake -> /usr/local/Urho/Urho3D/CMake
├── CMakeLists.txt -> /Users/max/Developer/Setup/urho/playground/my1.7/CMakeLists.txt
├── bin
│   ├── CoreData -> /usr/local/Urho/Urho3D/bin/CoreData
│   ├── Data -> /usr/local/Urho/Urho3D/bin/Data
│   └── GameData
│       ├── Scenes
│       │   └── BaseThreeLights.xml
│       ├── UI
│       │   └── UIWindowAndButton.xml
│       └── dummy.txt
├── build
│   ├── android
│   │   ├── app
│   │   │   ├── CMakeLists.txt
│   │   │   ├── LIBRARIES.txt
│   │   │   ├── SOURCES.txt
│   │   │   ├── VARS.txt
│   │   │   ├── build
│   │   │   │   ├── generated
│   │   │   │   ├── intermediates
│   │   │   │   ├── outputs
│   │   │   │   └── tmp
│   │   │   ├── build.gradle
│   │   │   └── src
│   │   │       └── main
│   │   ├── bin
│   │   │   ├── CoreData -> /Users/max/Developer/Stage/Workspace/Urho/myApp/bin/CoreData
│   │   │   ├── Data -> /Users/max/Developer/Stage/Workspace/Urho/myApp/bin/Data
│   │   │   └── GameData -> /Users/max/Developer/Stage/Workspace/Urho/myApp/bin/GameData
│   │   ├── build
│   │   │   └── android-profile
│   │   │       ├── profile-2018-12-17-19-15-13-678.json
│   │   │       └── profile-2018-12-17-19-15-13-678.rawproto
│   │   ├── build.gradle
│   │   ├── gradle
│   │   │   └── wrapper
│   │   │       ├── gradle-wrapper.jar
│   │   │       └── gradle-wrapper.properties
│   │   ├── gradle.properties
│   │   ├── gradlew
│   │   ├── gradlew.bat
│   │   ├── local.properties
│   │   └── settings.gradle
│   └── emscripten
│       └── Debug
│           ├── CMakeCache.txt
│           ├── CMakeFiles
│           │   ├── 3.14.0
│           │   ├── CMakeDirectoryInformation.cmake
│           │   ├── CMakeOutput.log
│           │   ├── CMakeRelink.dir
│           │   ├── CMakeRuleHashes.txt
│           │   ├── CMakeTmp
│           │   ├── Makefile.cmake
│           │   ├── Makefile2
│           │   ├── RESOURCE_CHECK.dir
│           │   ├── TargetDirectories.txt
│           │   ├── cmake.check_cache
│           │   ├── myApp.dir
│           │   └── progress.marks
│           ├── CTestTestfile.cmake
│           ├── Makefile
│           ├── Source
│           │   └── shell.html
│           ├── bin
│           │   ├── CoreData -> /Users/max/Developer/Stage/Workspace/Urho/myApp/bin/CoreData
│           │   ├── CoreData.pak
│           │   ├── Data -> /Users/max/Developer/Stage/Workspace/Urho/myApp/bin/Data
│           │   ├── Data.pak
│           │   ├── GameData -> /Users/max/Developer/Stage/Workspace/Urho/myApp/bin/GameData
│           │   ├── GameData.pak
│           │   ├── myApp.data
│           │   ├── myApp.html
│           │   ├── myApp.html.map
│           │   └── myApp.js
│           ├── cmake_install.cmake
│           └── compile_commands.json
├── cmake_clean.sh -> /usr/local/Urho/Urho3D/cmake_clean.sh
├── cmake_emscripten.sh -> /usr/local/Urho/Urho3D/cmake_emscripten.sh
├── cmake_generic.sh -> /usr/local/Urho/Urho3D/cmake_generic.sh
├── setup
└── src
    ├── MyApp.cpp
    ├── MyApp.h
    ├── Sample.h
    └── Sample.inl

40 directories, 47 files
(3.5.3_Default) max:myApp 

one source, mutiple builds per system

I use an ad-hoc bash scripting system, but you can use the default scaffolding system with rake for generating quick project setup…