Fix include paths in FindOpenAL.cmake/FindOpenGL.cmake (#16840)

Also add a test that uses both of these modules.

Fixes: #16833

cmake/Modules/FindOpenAL.cmake

@@ -11,15 +11,15 @@ if (NOT OPENAL_FOUND)
 	SET(OPENAL_FOUND TRUE)
 
 	# For Emscripten-compiled apps in the test suite (test_alut), this is expected...
-	SET(OPENAL_INCLUDE_DIR "${EMSCRIPTEN_ROOT_PATH}/system/include")
+	SET(OPENAL_INCLUDE_DIR "${EMSCRIPTEN_SYSROOT}/include")
 	# ... but the stock FindOpenAL.cmake would have returned this.
 	#SET(OPENAL_INCLUDE_DIR "${EMSCRIPTEN_ROOT_PATH}/system/include/AL")
 
 	# Returning "-lopenal" is now considered mandatory
 	SET(OPENAL_LIBRARY "-lopenal")
 	SET(OPENAL_LIB "-lopenal")
 
-	set(CMAKE_INCLUDE_PATH ${CMAKE_INCLUDE_PATH} "${EMSCRIPTEN_ROOT_PATH}/system/include" "${EMSCRIPTEN_ROOT_PATH}/system/include/AL")
+	set(CMAKE_INCLUDE_PATH ${CMAKE_INCLUDE_PATH} "${OPENAL_INCLUDE_DIR}" "${OPENAL_INCLUDE_DIR}/AL")
 
 	MARK_AS_ADVANCED(OPENAL_LIBRARY OPENAL_INCLUDE_DIR)
 endif()

cmake/Modules/FindOpenGL.cmake

@@ -19,13 +19,11 @@ SET(OPENGL_GLU_FOUND TRUE)
 SET(OPENGL_XMESA_FOUND FALSE)
 
 # This is the path where <GL/gl.h> is found
-SET(OPENGL_INCLUDE_DIR "${EMSCRIPTEN_ROOT_PATH}/system/include")
+SET(OPENGL_INCLUDE_DIR "${EMSCRIPTEN_SYSROOT}/include")
 
-# No library to link against for OpenGL, since Emscripten picks it up automatically from library_webgl.js,
-# but need to report something, or CMake thinks we failed in the search.
-SET(OPENGL_LIBRARIES "nul")
-SET(OPENGL_gl_LIBRARY "nul")
-SET(OPENGL_glu_LIBRARY "nul")
+SET(OPENGL_gl_LIBRARY "GL")
+SET(OPENGL_glu_LIBRARY "GLU")
+SET(OPENGL_LIBRARIES ${OPENGL_gl_LIBRARY} ${OPENGL_glu_LIBRARY})
 
 mark_as_advanced(
   OPENGL_INCLUDE_DIR

src/library_openal.js

@@ -3055,13 +3055,6 @@ var LibraryOpenAL = {
   alGetString__proxy: 'sync',
   alGetString__sig: 'ii',
   alGetString: function(param) {
-    if (!AL.currentCtx) {
-#if OPENAL_DEBUG
-      err('alGetString() called without a valid context');
-#endif
-      return 0;
-    }
-
     if (AL.stringCache[param]) {
       return AL.stringCache[param];
     }
@@ -3104,7 +3097,13 @@ var LibraryOpenAL = {
       ret = ret.trim();
       break;
     default:
-      AL.currentCtx.err = 0xA002 /* AL_INVALID_ENUM */;
+      if (AL.currentCtx) {
+        AL.currentCtx.err = 0xA002 /* AL_INVALID_ENUM */;
+      } else {
+  #if OPENAL_DEBUG
+        err('alGetString() called without a valid context');
+  #endif
+      }
       return 0;
     }
 

tests/cmake/find_modules/CMakeLists.txt

@@ -0,0 +1,20 @@
+cmake_minimum_required(VERSION 3.0)
+project(find_modules)
+
+add_executable(test_prog test.c)
+
+find_package(OpenGL REQUIRED)
+include_directories(${OPENGL_INCLUDE_DIR})
+target_link_libraries(test_prog ${OPENGL_LIBRARIES})
+message(" test: OPENGL_LIBRARIES: ${OPENGL_LIBRARIES}")
+
+find_package(OpenAL REQUIRED)
+include_directories(${OPENAL_INCLUDE_DIR})
+target_link_libraries(test_prog ${OPENAL_LIBRARY})
+message(" test: OPENGL_LIBRARIES: ${OPENAL_LIBRARIES}")
+
+find_package(SDL2 REQUIRED)
+include_directories(${SDL2_INCLUDE_DIRS})
+target_link_libraries(test_prog SDL2::SDL2)
+message(" test: SDL2_LIBRARIES: ${SDL2_LIBRARIES}")
+message(" test: SDL2_INCLUDE_DIRS: ${SDL2_INCLUDE_DIRS}")

tests/cmake/find_modules/test.c

@@ -0,0 +1,16 @@
+// Invlude emscripten/version.h to ensure that the in-tree
+// include directory has not been added to the include path.
+#include <emscripten/version.h>
+#include <stdio.h>
+#include <AL/al.h>
+#include <GL/gl.h>
+#include <SDL.h>
+
+int main() {
+  SDL_version compiled;
+  SDL_VERSION(&compiled);
+  SDL_Log("SDL version: %d.%d.%d\n", compiled.major, compiled.minor, compiled.patch);
+
+  printf("AL_VERSION: %s\n", alGetString(AL_VERSION));
+  return 0;
+}

tests/test_other.py

@@ -789,11 +789,12 @@ def test_cmake_install(self):
     self.assertContained('foo: 42\n', self.run_js('build2/Bar.js'))
     self.run_process(['cmake', '--build', 'build2', '--target', 'install'])
 
-  def test_cmake_find_sdl2(self):
-    os.mkdir('build')
-    self.run_process([EMCMAKE, 'cmake', test_file('cmake/find_sdl2')], cwd='build')
-    self.run_process(['cmake', '--build', 'build'])
-    self.assertContained('SDL version: 2.0.', self.run_js('build/sdl2.js'))
+  def test_cmake_find_modules(self):
+    self.run_process([EMCMAKE, 'cmake', test_file('cmake/find_modules')])
+    self.run_process(['cmake', '--build', '.'])
+    output = self.run_js('test_prog.js')
+    self.assertContained('AL_VERSION: 1.1', output)
+    self.assertContained('SDL version: 2.0.', output)
 
   def test_system_include_paths(self):
     # Verify that all default include paths are within `emscripten/system`