Add import/build instructions to the README

README.md

@@ -1,3 +1,60 @@
 # SDL_image
 
-This is [SDL_image](https://github.com/libsdl-org/SDL_image) packaged for [Zig](https://ziglang.org).
+This is [SDL_image][1] packaged for [Zig][2].
+
+To use SDL_image along with [SDL][3], do the following in the project you want
+them in:
+
+1. zig fetch both projects to save the dependencies to your `build.zig.zon`:
+```sh
+zig fetch --save git+https://github.com/allyourcodebase/SDL
+zig fetch --save git+https://github.com/allyourcodebase/SDL_image
+```
+
+2. Then do this in `build.zig`:
+```zig
+// build.zig
+// ...
+    const sdl_dep = b.dependency("sdl", .{
+        .optimize = optimize,
+        .target = target,
+    });
+    const sdl_lib = sdl_dep.artifact("SDL3");
+    exe.root_module.linkLibrary(sdl_lib);
+
+    const sdl_image_dep = b.dependency("SDL_image", .{
+        .optimize = optimize,
+        .target = target,
+    });
+    const sdl_image_lib = sdl_image_dep.artifact("SDL3_image");
+    exe.root_module.linkLibrary(sdl_image_lib);
+
+    const translate_c = b.addTranslateC(.{
+        .root_source_file = b.addWriteFiles().add("stub.h",
+            \\#include <SDL3/SDL.h>
+            \\#include <SDL3_image/SDL_image.h>
+        ),
+        .target = target,
+        .optimize = optimize,
+    });
+    translate_c.addIncludePath(sdl_lib.getEmittedIncludeTree());
+    translate_c.addIncludePath(sdl_image_lib.getEmittedIncludeTree());
+    exe.root_module.addImport("sdl-bundle", translate_c.createModule());
+// ...
+```
+
+This will bundle SDL and SDL_image in a single module and allow cross-using the
+objects between the two libraries.
+
+3. Finally, you can use the two libraries like this in your project:
+
+```zig
+const sdl = @import("sdl-bundle");
+
+const surface = sdl.IMG_Load("foo.png");
+const texture = sdl.SDL_CreateTextureFromSurface(renderer, surface);
+```
+
+[1]: https://github.com/libsdl-org/SDL_image
+[2]: https://ziglang.org
+[3]: https://github.com/allyourcodebase/SDL