stbimage

A single compiled instantiation of stb_image and stb_image_write.

stb_image.h and stb_image_write.h are single-header libraries: exactly one translation unit in a program is allowed to define STB_IMAGE_IMPLEMENTATION / STB_IMAGE_WRITE_IMPLEMENTATION, and every function they declare has external linkage unless that translation unit also defines STB_IMAGE_STATIC / STB_IMAGE_WRITE_STATIC. Both Ghoul and SGCT need stb_image/stb_image_write, and both are linked into the same OpenSpace executable, so each independently compiling its own implementation is a duplicate-symbol/ODR hazard. This repository compiles each implementation exactly once instead, as two separate objects (read and write; see "CMake targets" below) so a consumer that already has a stb_image read implementation from elsewhere (e.g. assimp) can link only the write half.

CMake targets

This package exports three targets, all namespaced unofficial:: because this CMake package is authored by this repository, not by the upstream stb project:

• unofficial::stbimage::stbimage — an interface target with just the stb_image/stb_image_write declarations. Link this from any library that calls stbi_* functions but does not itself need to satisfy those symbols (e.g. Ghoul, SGCT); it never compiles anything.
• unofficial::stbimage::stbimage-read-impl — compiles just the stb_image (read) functions, such as stbi_load. Link this from an executable that needs those symbols resolved, unless something else already links a different stb_image read implementation (e.g. assimp vendors its own copy, and linking both would be a duplicate-symbol conflict).
• unofficial::stbimage::stbimage-write-impl — compiles just the stb_image_write (write) functions, such as stbi_write_png. Link this from an executable that needs those symbols resolved.

The read and write halves are split into separate targets/objects so that a program which already gets stb_image's read functions from elsewhere (like assimp) can link only the write half instead of pulling in a second, conflicting copy of the read functions.

Consuming stbimage

A vcpkg port lives in support/vcpkg/ports/stbimage and builds the enclosing checkout. Ghoul, SGCT, and the OpenSpace superproject each maintain their own overlay port (support/vcpkg/ports/stbimage in each of their own checkouts) that instead fetches this repository directly from GitHub via vcpkg_from_github, pinned to a commit here. None of them consume this repository as a git submodule.

Either way:

find_package(stbimage CONFIG REQUIRED)
target_link_libraries(mylib PRIVATE unofficial::stbimage::stbimage)
target_link_libraries(myexe PRIVATE unofficial::stbimage::stbimage-read-impl)
target_link_libraries(myexe PRIVATE unofficial::stbimage::stbimage-write-impl)