Setting up a cross-platform SDL project
One of the benefits of SDL is portability. You can drop in a couple of SDL headers and start writing code that renders images to the screen, captures input, and emits audio, like magic. The only problem is that when you take your code and try to build it on a different OS you may find the process a little confusing. Let’s take a look at how to set up a C++ project with SDL you can build just about anywhere.
macOS and Linux
Let’s start with a POSIX environment like macOS or a Linux distribution. If you’re running on macOS you wont have a package manager by default, but Homebrew is a common choice and easy to use. Once installed. Once your environment has a package manager you can go ahead and install all of the SDL development libraries.
$ brew install sdl2 sdl2_image sdl2_mixer sdl2_net sdl2_ttf
Great, now we can begin. We’ll use a simple Makefile for our project:
CXX=g++
SDL2CFLAGS=-I/usr/local/include/SDL2 -D_THREAD_SAFE
CXXFLAGS=-O2 -c --std=c++14 -Wall $(SDL2CFLAGS)
LDFLAGS=-L/usr/local/lib -lSDL2
exec: main.o
$(CXX) $(LDFLAGS) -o exec main.o
main.o: main.cpp
$(CXX) $(CXXFLAGS) main.cpp
The process here is simple, we build our main.cpp file into an object using our SDL2 headers, then link it against the SDL2 dynamic libraries. In main.cpp we can access SDL_* functions with a simple #include <SDL2/SDL.h> directive. The header files will tell the compiler how the API works, and the dynamic libraries will tell the linker how they’re implemented.
But where did we get the SDL2CFLAGS and LDFLAGS values? Well we installed the SDL libraries we also got access to sdl2-config. You can use it like this:
$ sdl2-config --cflags
$ sdl2-config --libs
It’s a handy way to find out where your package manager installed the files. Now, assuming you’ve got a C++ compiler, you can go ahead and run make exec to build your program.
Windows
So we’ve got an SDL program that we wrote on macOS or Linux, and we want to share it with our friends running Windows. How do we make a build for them? Well we could install MinGW which provides us with g++ and make, but for my project I found that the version of g++ included here was lacking. It didn’t support std::thread after installation. So much for standardization.
That leaves us with Visual Studio, specifically Visual C++, or MSVC. Microsoft isn’t good with naming these things. It’s an IDE and a C++ compiler, tightly coupled. The process here is a little finnicky. You need to open your SDL project as a project without a “Solution” (which is going to replace our Makefile on Windows) so that VS can generate one for us. Skip past all of the dialogue (when prompted, indicate you’re building a command line app) so that we can start configuring things.
Without a package manager on Windows you need to manually make your way here and download the development libraries for Visual C++. Unzip those to a folder you’ll remember later. As a tip, alter the SDL2 include folder structure to place all headers in a dir called SDL2. For some reason the Windows distribution of this package doesn’t do that, which would mean your includes would look like #include <SDL.h> instead of #include <SDL2/SDL.h>.
Okay, last step. We need to tell VS how to use the libraries we just downloaded. Go to Project -> Properties -> Configuration Properties -> VC++ Directories -> Include Directories -> Edit and add the path to the include subdir from the SDL2 package you unzipped earlier. These are the header files. Then go to Linker -> Additional Dependencies -> Edit and add SDL2.lib; SDL2main.lib;. These are the dynamic libraries, but we still need to tell VS where those blobs are, so go to VC++ Directories -> Include Directories -> Edit and add the path to the lib/x64 (or x86 for 32-bit builds) subdir from the SDL2 package you unzipped earlier. Finally, save everything and build your project.
With that, you can sleep safely knowing your project will build just about anywhere. When you want to release on macOS or Linux, use the Makefile, and when you want to release on Windows, use the Visual Studio solution.