1 files changed, 72 insertions, 0 deletions
diff --git a/cmake/FindGLESv2.cmake b/cmake/FindGLESv2.cmake
new file mode 100644
index 0000000000..49e757ef55
--- /dev/null
+++ b/cmake/FindGLESv2.cmake
@@ -0,0 +1,72 @@
+include(CheckCXXSourceCompiles)
+
+# No library linkage is necessary to use GLESv2 with Emscripten. The headers are also
+# system headers, so we don't need to search for them.
+if(EMSCRIPTEN)
+    set(HAVE_GLESv2 ON)
+else()
+    find_library(GLESv2_LIBRARY NAMES GLESv2 OpenGLES)
+    find_path(GLESv2_INCLUDE_DIR NAMES "GLES2/gl2.h" "OpenGLES/ES2/gl.h" DOC "The OpenGLES 2 include path")
+    set(_libraries "${CMAKE_REQUIRED_LIBRARIES}")
+    list(APPEND CMAKE_REQUIRED_LIBRARIES "${GLESv2_LIBRARY}")
+    set(_includes "${CMAKE_REQUIRED_INCLUDES}")
+    list(APPEND CMAKE_REQUIRED_INCLUDES "${GLESv2_INCLUDE_DIR}")
+
+    check_cxx_source_compiles("
+#ifdef __APPLE__
+#  include <OpenGLES/ES2/gl.h>
+#else
+#  define GL_GLEXT_PROTOTYPES
+#  include <GLES2/gl2.h>
+#endif
+
+int main(int argc, char *argv[]) {
+    glUniform1f(1, GLfloat(1.0));
+    glClear(GL_COLOR_BUFFER_BIT);
+}" HAVE_GLESv2)
+
+    set(CMAKE_REQUIRED_LIBRARY "${_libraries}")
+    unset(_libraries)
+    set(CMAKE_REQUIRED_INCLUDES "${_includes}")
+    unset(_includes)
+    set(package_args GLESv2_INCLUDE_DIR GLESv2_LIBRARY HAVE_GLESv2)
+endif()
+
+# Framework handling partially inspired by FindGLUT.cmake.
+if(GLESv2_LIBRARY MATCHES "/([^/]+)\\.framework$")
+    # TODO: Might need to handle non .tbd suffixes, but didn't find an
+    # example like that.
+    # TODO: Might need to handle INTERFACE_INCLUDE_DIRECTORIES differently.
+    set(_library_imported_location "${GLESv2_LIBRARY}/${CMAKE_MATCH_1}.tbd")
+    if(NOT EXISTS "${_library_imported_location}")
+        set(_library_imported_location "")
+    endif()
+else()
+    set(_library_imported_location "${GLESv2_LIBRARY}")
+endif()
+set(GLESv2_LIBRARY "${_library_imported_location}")
+
+list(APPEND package_args HAVE_GLESv2)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(GLESv2 DEFAULT_MSG ${package_args})
+
+mark_as_advanced(${package_args})
+
+if(GLESv2_FOUND AND NOT TARGET GLESv2::GLESv2)
+    if(EMSCRIPTEN OR APPLE_UIKIT)
+        add_library(GLESv2::GLESv2 INTERFACE IMPORTED)
+        if(APPLE_UIKIT)
+            # For simulator_and_device builds we can't specify the full library path, because
+            # it's specific to either the device or the simulator. Resort to passing a link
+            # flag instead.
+            set_target_properties(GLESv2::GLESv2 PROPERTIES
+                INTERFACE_LINK_LIBRARIES "-framework OpenGLES")
+        endif()
+    else()
+        add_library(GLESv2::GLESv2 UNKNOWN IMPORTED)
+        set_target_properties(GLESv2::GLESv2 PROPERTIES
+            IMPORTED_LOCATION "${GLESv2_LIBRARY}"
+            INTERFACE_INCLUDE_DIRECTORIES "${GLESv2_INCLUDE_DIR}")
+    endif()
+endif()