python: remove the black magic from magnum.platform.

Implicitly importing whole toolkits was not a good idea.

doc/python/magnum.platform.rst

@@ -25,18 +25,16 @@
 
 .. py:module:: magnum.platform
 
-    While concrete implementations of :py:`Application` and
+    Concrete implementations of :py:`Application` and :py:`WindowlessApplication`
-    :py:`WindowlessApplication` classes are available in the submodules,
+    classes are available in submodules, and it's up to you which one you
-    there's a convenience logic importing the most fitting implementation
+    choose. For example:
-    that's available directly into the `platform` module, meaning you can do
-    just this without having to think about a particular implementation, for
-    example:
 
     .. code:: py
 
         from magnum import platform
+        import magnum.platform.sdl2
 
-        class MyApp(platform.Application): # platform.sdl2.Application
+        class MyApp(platform.sdl2.Application):
             ...
 
     The same goes for :py:`WindowlessApplication` implementations, for example:
@@ -44,11 +42,16 @@
     .. code:: py
 
         from magnum import platform
+        import magnum.platform.egl
 
-        class MyApp(platform.WindowlessApplication): # platform.egl.WindowlessApp
+        class MyApp(platform.egl.WindowlessApplication):
             ...
 
-    .. block-warning:: Subject to change
+    Alternatively, if you want to narrow down the mention of a particular
+    toolkit to just one line, you can also do:
 
-        At the moment, there's no way to specify a different priority order or
+    .. code:: py
-        disable the auto-import altogether.
+
+        from magnum.platform.sdl2 import Application
+
+        class MyApp(Application):

src/python/magnum/__init__.py

@@ -43,21 +43,6 @@ if 'platform' in globals():
     for i in ['glfw', 'sdl2', 'glx', 'wgl', 'egl']:
         if hasattr(platform, i): sys.modules['magnum.platform.' + i] = getattr(platform, i)
 
-    # Bring one application implementation directly into the platform module.
-    # The same logic is duplicated in platform/__init__.py.
-    if hasattr(platform, 'sdl2'):
-        platform.Application = platform.sdl2.Application
-    elif hasattr(platform, 'glfw'):
-        platform.Application = platform.glfw.Application
-
-    # Same for windowless apps
-    if hasattr(platform, 'glx'):
-        platform.WindowlessApplication = platform.glx.WindowlessApplication
-    elif hasattr(platform, 'wgl'):
-        platform.WindowlessApplication = platform.wgl.WindowlessApplication
-    elif hasattr(platform, 'egl'):
-        platform.WindowlessApplication = platform.egl.WindowlessApplication
-
 # Scenegraph has subpackages
 if 'scenegraph' in globals():
     for i in ['matrix', 'trs']:

src/python/magnum/platform/__init__.py

@@ -24,25 +24,3 @@
 #
 
 """Platform-specific application and context creation"""
-
-# This logic is repeated in magnum's main __init__.py for static builds as
-# there magnum.platform is a submodule inside the native _magnum module.
-
-try:
-    from .glx import WindowlessApplication
-except ImportError: # pragma: no cover
-    try:
-        from .wgl import WindowlessApplication
-    except ImportError:
-        try:
-            from .egl import WindowlessApplication
-        except ImportError:
-            pass
-
-try:
-    from .sdl2 import Application
-except ImportError: # pragma: no cover
-    try:
-        from .glfw import Application
-    except ImportError:
-        pass

src/python/magnum/test/__init__.py

@@ -33,10 +33,22 @@ sys.path = [os.path.join(os.path.dirname(__file__), os.environ.get('CMAKE_BINARY
 from magnum import *
 from magnum import gl, platform
 
+try:
+    from magnum.platform.glx import WindowlessApplication
+except ImportError:
+    try:
+        from magnum.platform.wgl import WindowlessApplication
+    except ImportError:
+        try:
+            from magnum.platform.egl import WindowlessApplication
+        except ImportError:
+            WindowlessApplication = None
+
 def setUpModule():
     if os.environ.get('MAGNUM_SKIP_GL_TESTS') == 'ON':
         raise unittest.SkipTest('GL tests skipped')
-    if not hasattr(platform, 'WindowlessApplication'): # pragma: no cover
+
+    if not WindowlessApplication:
         raise unittest.SkipTest('no WindowlessApplication found')
 
 class GLTestCase(unittest.TestCase):
@@ -45,7 +57,7 @@ class GLTestCase(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         if not GLTestCase.app:
-            GLTestCase.app = platform.WindowlessApplication()
+            GLTestCase.app = WindowlessApplication()
 
     def assertNoGLError(self):
         self.assertEqual(gl.Renderer.error, gl.Renderer.Error.NO_ERROR)