Provide CMake package

[cNoNim]

Closes #452

[cNoNim]

I tested on Windows and Linux.

tested by

• installing the module via

pip install .

• manually copying GladConfig.cmake to $PREFIX/lib/cmake/Glad

find_package(Glad REQUIRED)

glad_add_library(glad_gl_core_33 REPRODUCIBLE API gl:core=3.3)

Also tested by

• manual copy sources to ${PROJECT_SOURCE_DIR}/external/glad/ of sample project

set(GLAD_SOURCES_DIR "${PROJECT_SOURCE_DIR}/external/glad/")
add_subdirectory("${GLAD_SOURCES_DIR}/cmake" glad_cmake)

glad_add_library(glad_gl_core_33 REPRODUCIBLE API gl:core=3.3)

All works

[spnda]

When using the following CMake snippet in my local project, CMake will fail saying it can't find glad_add_library. Though, interestingly enough, this only happens for the CMake configurations which use MSVC as the compiler.

add_subdirectory("${FASTGLTF_DEPS_DIR}/glad/cmake" glad_cmake)

# Let the glad script generate the glad headers
glad_add_library(fg_glad_gl46 REPRODUCIBLE EXCLUDE_FROM_ALL LOADER API gl:core=4.6)

However, if I change the cmake/CMakeLists.txt file like this, it works again as it did before.

-list(APPEND CMAKE_PREFIX_PATH ${GLAD_SOURCES_DIR})
-find_package(Glad REQUIRED)
+include(./GladConfig.cmake)

Should I make this into an issue or provide the PR to fix this? Note that I am on Windows using CLion and CMake 3.27.8.

[cNoNim]

Consider opening an issue.
The logic described in the wiki suggests the need to set GLAD_SOURCES_DIR, but it may not be necessary.
If it is unnecessary, it can be fixed as you suggest. Keep in mind that GLAD_SOURCES_DIR defines the working directory.

"Directory containing glad sources (python modules), used as working directory. Must be absolute."

[cNoNim]

set(GLAD_SOURCES_DIR "${FASTGLTF_DEPS_DIR}/glad")
add_subdirectory("${GLAD_SOURCES_DIR}/cmake" glad_cmake)

I assume this is how it will work.

[cNoNim]

I now understand why everything worked without specifying the path.
In this case, replacing 'find_package' with 'include' seems correct.
I apologize for the regression.

[spnda]

set(GLAD_SOURCES_DIR "${FASTGLTF_DEPS_DIR}/glad")
add_subdirectory("${GLAD_SOURCES_DIR}/cmake" glad_cmake)

I assume this is how it will work.

That would not have made any difference because glad's CMakeLists.txt defines it too. So setting it or not setting it should make absolutely no difference as far as I can tell.

I now understand why everything worked without specifying the path.
In this case, replacing 'find_package' with 'include' seems correct.
I apologize for the regression.

Shall I open a pull request? Are you 100% positive it doesn't induce any other issues?

[cNoNim]

I thought that find_package and CMAKE_PREFIX_PATH were the same as include.
However, exist issue https://gitlab.kitware.com/cmake/cmake/-/issues/16644.
Therefore, using include is more consistent with the previous behavior.

I don't mind PR. I guess @Dav1dde feels the same way.

And thanks.