Viewing file: baseplatform.py (13 KB) -rw-r--r-- Select action/file-type: (+) | (+) | (+) | Code (+) | Session (+) | (+) | SDB (+) | (+) | (+) | (+) | (+) | (+) |
"""Base class for platform implementations """ import ctypes from OpenGL.platform import ctypesloader import sys import OpenGL as top_level_module from OpenGL import logs
class _CheckContext( object ): def __init__( self, func, ccisvalid ): self.func = func self.ccisvalid = ccisvalid def __setattr__( self, key, value ): if key not in ('func','ccisvalid'): return setattr( self.func, key, value ) else: self.__dict__[key] = value def __getattr__( self, key ): if key != 'func': return getattr(self.func, key ) raise AttributeError( key ) def __call__( self, *args, **named ): if not self.ccisvalid(): from OpenGL import error raise error.NoContext( self.func, args, named ) return self.func( *args, **named )
class BasePlatform( object ): """Base class for per-platform implementations Attributes of note: EXPORTED_NAMES -- set of names exported via the platform module's namespace... GL, GLU, GLUT, GLE, OpenGL -- ctypes libraries DEFAULT_FUNCTION_TYPE -- used as the default function type for functions unless overridden on a per-DLL basis with a "FunctionType" member GLUT_GUARD_CALLBACKS -- if True, the GLUT wrappers will provide guarding wrappers to prevent GLUT errors with uninitialised GLUT. EXTENSIONS_USE_BASE_FUNCTIONS -- if True, uses regular dll attribute-based lookup to retrieve extension function pointers. """ EXPORTED_NAMES = [ 'GetCurrentContext','CurrentContextIsValid','safeGetError', 'createBaseFunction', 'createExtensionFunction', 'copyBaseFunction', 'GL','GLU','GLUT','GLE','OpenGL', 'getGLUTFontPointer', 'GLUT_GUARD_CALLBACKS', ]
DEFAULT_FUNCTION_TYPE = None GLUT_GUARD_CALLBACKS = False EXTENSIONS_USE_BASE_FUNCTIONS = False def install( self, namespace ): """Install this platform instance into the platform module""" for name in self.EXPORTED_NAMES: namespace[ name ] = getattr(self,name) namespace['PLATFORM'] = self return self def functionTypeFor( self, dll ): """Given a DLL, determine appropriate function type...""" if hasattr( dll, 'FunctionType' ): return dll.FunctionType else: return self.DEFAULT_FUNCTION_TYPE def errorChecking( self, func, dll ): """Add error checking to the function if appropriate""" from OpenGL import error if top_level_module.ERROR_CHECKING: if dll not in (self.GLUT,): #GLUT spec says error-checking is basically undefined... # there *may* be GL errors on GLUT calls that e.g. render # geometry, but that's all basically "maybe" stuff... func.errcheck = error.glCheckError return func def wrapContextCheck( self, func, dll ): """Wrap function with context-checking if appropriate""" if top_level_module.CONTEXT_CHECKING and dll is not self.GLUT: return _CheckContext( func, self.CurrentContextIsValid ) return func def wrapLogging( self, func ): """Wrap function with logging operations if appropriate""" return logs.logOnFail( func, logs.getLog( 'OpenGL.errors' )) def finalArgType( self, typ ): """Retrieve a final type for arg-type""" if typ == ctypes.POINTER( None ) and not getattr( typ, 'final',False): from OpenGL.arrays import ArrayDatatype return ArrayDatatype else: return typ def constructFunction( self, functionName, dll, resultType=ctypes.c_int, argTypes=(), doc = None, argNames = (), extension = None, deprecated = False, ): """Core operation to create a new base ctypes function raises AttributeError if can't find the procedure... """ if extension and not self.checkExtension( extension ): raise AttributeError( """Extension not available""" ) argTypes = [ self.finalArgType( t ) for t in argTypes ] if extension and not self.EXTENSIONS_USE_BASE_FUNCTIONS: # what about the VERSION values??? if self.checkExtension( extension ): pointer = self.getExtensionProcedure( functionName ) if pointer: func = self.functionTypeFor( dll )( resultType, *argTypes )( pointer ) else: raise AttributeError( """Extension %r available, but no pointer for function %r"""%(extension,functionName)) else: raise AttributeError( """No extension %r"""%(extension,)) else: func = ctypesloader.buildFunction( self.functionTypeFor( dll )( resultType, *argTypes ), functionName, dll, ) func.__doc__ = doc func.argNames = list(argNames or ()) func.__name__ = functionName func.DLL = dll func.extension = extension func.deprecated = deprecated func = self.wrapLogging( self.wrapContextCheck( self.errorChecking( func, dll ), dll, ) ) return func
def createBaseFunction( self, functionName, dll, resultType=ctypes.c_int, argTypes=(), doc = None, argNames = (), extension = None, deprecated = False, ): """Create a base function for given name Normally you can just use the dll.name hook to get the object, but we want to be able to create different bindings for the same function, so we do the work manually here to produce a base function from a DLL. """ from OpenGL import wrapper try: if top_level_module.FORWARD_COMPATIBLE_ONLY and dll is self.GL: if deprecated: return self.nullFunction( functionName, dll=dll, resultType=resultType, argTypes=argTypes, doc = doc, argNames = argNames, extension = extension, deprecated = deprecated, ) return self.constructFunction( functionName, dll, resultType=resultType, argTypes=argTypes, doc = doc, argNames = argNames, extension = extension, ) except AttributeError, err: return self.nullFunction( functionName, dll=dll, resultType=resultType, argTypes=argTypes, doc = doc, argNames = argNames, extension = extension, ) def checkExtension( self, name ): """Check whether the given extension is supported by current context""" if not name: return True context = self.GetCurrentContext() if context: from OpenGL import contextdata from OpenGL.raw.GL import GL_EXTENSIONS set = contextdata.getValue( GL_EXTENSIONS, context=context ) if set is None: set = {} contextdata.setValue( GL_EXTENSIONS, set, context=context, weak=False ) current = set.get( name ) if current is None: from OpenGL import extensions result = extensions.hasGLExtension( name ) set[name] = result return result return current else: return False createExtensionFunction = createBaseFunction
def copyBaseFunction( self, original ): """Create a new base function based on an already-created function This is normally used to provide type-specific convenience versions of a definition created by the automated generator. """ from OpenGL import wrapper, error if isinstance( original, _NullFunctionPointer ): return self.nullFunction( original.__name__, original.DLL, resultType = original.restype, argTypes= original.argtypes, doc = original.__doc__, argNames = original.argNames, extension = original.extension, deprecated = original.deprecated, ) elif hasattr( original, 'originalFunction' ): original = original.originalFunction return self.createBaseFunction( original.__name__, original.DLL, resultType=original.restype, argTypes=original.argtypes, doc = original.__doc__, argNames = original.argNames, extension = original.extension, deprecated = original.deprecated, ) def nullFunction( self, functionName, dll, resultType=ctypes.c_int, argTypes=(), doc = None, argNames = (), extension = None, deprecated = False, ): """Construct a "null" function pointer""" if deprecated: base = _DeprecatedFunctionPointer else: base = _NullFunctionPointer cls = type( functionName, (base,), { '__doc__': doc, 'deprecated': deprecated, } ) return cls( functionName, dll, resultType, argTypes, argNames, extension=extension, doc=doc, ) def GetCurrentContext( self ): """Retrieve opaque pointer for the current context""" raise NotImplementedError( """Platform does not define a GetCurrentContext function""" ) def CurrentContextIsValid( self ): """Return boolean of whether current context is valid""" raise NotImplementedError( """Platform does not define a CurrentContextIsValid function""" ) def getGLUTFontPointer(self, constant ): """Retrieve a GLUT font pointer for this platform""" raise NotImplementedError( """Platform does not define a GLUT font retrieval function""" ) def safeGetError( self ): """Safety-checked version of glError() call (checks for valid context first)""" raise NotImplementedError( """Platform does not define a safeGetError function""" )
class _NullFunctionPointer( object ): """Function-pointer-like object for undefined functions""" def __init__( self, name, dll, resultType, argTypes, argNames, extension=None, doc=None, deprecated=False ): from OpenGL import error self.__name__ = name self.DLL = dll self.argNames = argNames self.argtypes = argTypes self.errcheck = None self.restype = resultType self.extension = extension self.doc = doc self.deprecated = deprecated resolved = False def __nonzero__( self ): """Make this object appear to be NULL""" if self.extension and not self.resolved: self.load() return self.resolved def load( self ): """Attempt to load the function again, presumably with a context this time""" from OpenGL import platform if not platform.PLATFORM.checkExtension( self.extension ): return None try: func = platform.PLATFORM.constructFunction( self.__name__, self.DLL, resultType=self.restype, argTypes=self.argtypes, doc = self.doc, argNames = self.argNames, extension = self.extension, ) except AttributeError, err: return None else: # now short-circuit so that we don't need to check again... self.__class__.__call__ = staticmethod( func.__call__ ) self.resolved = True return func return None def __call__( self, *args, **named ): if self.load(): return self( *args, **named ) else: from OpenGL import error raise error.NullFunctionError( """Attempt to call an undefined function %s, check for bool(%s) before calling"""%( self.__name__, self.__name__, ) )
class _DeprecatedFunctionPointer( _NullFunctionPointer ): deprecated = True def __call__( self, *args, **named ): from OpenGL import error raise error.NullFunctionError( """Attempt to call a deprecated function %s while OpenGL in FORWARD_COMPATIBLE_ONLY mode. Set OpenGL.FORWARD_COMPATIBLE_ONLY to True to use legacy entry points"""%( self.__name__, ) )
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