"""VertexBufferObject helper class Basic usage: my_data = numpy.array( data, 'f') my_vbo = vbo.VBO( my_data ) ... my_vbo.bind() try: ... glVertexPointer( my_vbo, ... ) ... glNormalPointer( my_vbo + 12, ... ) finally: my_vbo.unbind() or with my_vbo: ... glVertexPointer( my_vbo, ... ) ... glNormalPointer( my_vbo + 12, ... ) See the OpenGLContext shader tutorials for a gentle introduction on the usage of VBO objects: http://pyopengl.sourceforge.net/context/tutorials/shader_intro.xhtml This implementation will choose either the ARB or Core (OpenGL 1.5) implementation of the VBO functions. """ from OpenGL.arrays.arraydatatype import ArrayDatatype from OpenGL.arrays.formathandler import FormatHandler from OpenGL.raw.GL import _types from OpenGL import error from OpenGL._bytes import bytes,unicode,as_8_bit import ctypes,logging _log = logging.getLogger( 'OpenGL.arrays.vbo' ) from OpenGL._bytes import long, integer_types import weakref __all__ = ('VBO','VBOHandler','mapVBO') class Implementation( object ): """Abstraction point for the various implementations that can be used """ IMPLEMENTATION_CLASSES = [] CHOSEN = None @classmethod def register( cls ): cls.IMPLEMENTATION_CLASSES.append( cls ) @classmethod def get_implementation( cls, *args ): if cls.CHOSEN is None: for possible in cls.IMPLEMENTATION_CLASSES: implementation = possible() if possible: Implementation.CHOSEN = implementation break return cls.CHOSEN EXPORTED_NAMES = '''glGenBuffers glBindBuffer glBufferData glBufferSubData glDeleteBuffers glMapBuffer glUnmapBuffer GL_STATIC_DRAW GL_STATIC_READ GL_STATIC_COPY GL_DYNAMIC_DRAW GL_DYNAMIC_READ GL_DYNAMIC_COPY GL_STREAM_DRAW GL_STREAM_READ GL_STREAM_COPY GL_ARRAY_BUFFER GL_ELEMENT_ARRAY_BUFFER GL_UNIFORM_BUFFER GL_TEXTURE_BUFFER GL_TRANSFORM_FEEDBACK_BUFFER'''.split() available = False def _arbname( self, name ): return ( (name.startswith( 'gl' ) and name.endswith( 'ARB' )) or (name.startswith( 'GL_' ) and name.endswith( 'ARB' )) ) and (name != 'glInitVertexBufferObjectARB') def basename( self, name ): if name.endswith( '_ARB' ): return name[:-4] elif name.endswith( 'ARB' ): return name[:-3] else: return name def __nonzero__( self ): return self.available __bool__ = __nonzero__ def deleter( self, buffers, key): """Produce a deleter callback to delete the given buffer""" # these values are stored here to avoid them being cleaned up # to non during module deletion and causing errors to be raised nfe = error.NullFunctionError gluint = _types.GLuint def doBufferDeletion( *args, **named ): while buffers: try: buffer = buffers.pop() except IndexError as err: break else: try: # Note that to avoid ERROR_ON_COPY issues # we have to pass an array-compatible type here... buf = gluint( buffer ) self.glDeleteBuffers(1, buf) except (AttributeError, nfe, TypeError) as err: pass try: self._DELETERS_.pop( key ) except KeyError as err: pass return doBufferDeletion _DELETERS_ = {} get_implementation = Implementation.get_implementation from OpenGL import acceleratesupport VBO = None if acceleratesupport.ACCELERATE_AVAILABLE: try: from OpenGL_accelerate.vbo import ( VBO,VBOOffset,VBOHandler,VBOOffsetHandler, ) except ImportError as err: _log.warning( "Unable to load VBO accelerator from OpenGL_accelerate" ) if VBO is None: class VBO( object ): """Instances can be passed into array-handling routines You can check for whether VBOs are supported by accessing the implementation: if bool(vbo.get_implementation()): # vbo version of code else: # fallback version of code """ copied = False _no_cache_ = True # do not cache in context data arrays def __init__( self, data, usage='GL_DYNAMIC_DRAW', target='GL_ARRAY_BUFFER', size=None, ): """Initialize the VBO object data -- PyOpenGL-compatible array-data structure, numpy arrays, ctypes arrays, etc. usage -- OpenGL usage constant describing expected data-flow patterns (this is a hint to the GL about where/how to cache the data) GL_STATIC_DRAW_ARB GL_STATIC_READ_ARB GL_STATIC_COPY_ARB GL_DYNAMIC_DRAW_ARB GL_DYNAMIC_READ_ARB GL_DYNAMIC_COPY_ARB GL_STREAM_DRAW_ARB GL_STREAM_READ_ARB GL_STREAM_COPY_ARB DRAW constants suggest to the card that the data will be primarily used to draw on the card. READ that the data will be read back into the GL. COPY means that the data will be used both for DRAW and READ operations. STATIC suggests that the data will only be written once (or a small number of times). DYNAMIC suggests that the data will be used a small number of times before being discarded. STREAM suggests that the data will be updated approximately every time that it is used (that is, it will likely only be used once). target -- VBO target to which to bind (array or indices) GL_ARRAY_BUFFER -- array-data binding GL_ELEMENT_ARRAY_BUFFER -- index-data binding GL_UNIFORM_BUFFER -- used to pass mid-size arrays of data packed into a buffer GL_TEXTURE_BUFFER -- used to pass large arrays of data as a pseudo-texture GL_TRANSFORM_FEEDBACK_BUFFER -- used to receive transformed vertices for processing size -- if not provided, will use arrayByteCount to determine the size of the data-array, thus this value (number of bytes) is required when using opaque data-structures, (such as ctypes pointers) as the array data-source. """ self.usage = usage self.set_array( data, size ) self.target = target self.buffers = [] self._copy_segments = [] _I_ = None implementation = property( get_implementation, ) def resolve( self, value ): """Resolve string constant to constant""" if isinstance( value, (bytes,unicode)): return getattr( self.implementation, self.implementation.basename( value ) ) return value def set_array( self, data, size=None ): """Update our entire array with new data data -- PyOpenGL-compatible array-data structure, numpy arrays, ctypes arrays, etc. size -- if not provided, will use arrayByteCount to determine the size of the data-array, thus this value (number of bytes) is required when using opaque data-structures, (such as ctypes pointers) as the array data-source. """ self.data = data self.copied = False if size is not None: self.size = size elif self.data is not None: self.size = ArrayDatatype.arrayByteCount( self.data ) def __setitem__( self, slice, array): """Set slice of data on the array and vbo (if copied already) slice -- the Python slice object determining how the data should be copied into the vbo/array array -- something array-compatible that will be used as the source of the data, note that the data-format will have to be the same as the internal data-array to work properly, if not, the amount of data copied will be wrong. This is a reasonably complex operation, it has to have all sorts of state-aware changes to correctly map the source into the low-level OpenGL view of the buffer (which is just bytes as far as the GL is concerned). """ if slice.step and not slice.step == 1: raise NotImplemented( """Don't know how to map stepped arrays yet""" ) # TODO: handle e.g. mapping character data into an integer data-set data = ArrayDatatype.asArray( array ) data_length = ArrayDatatype.arrayByteCount( array ) start = (slice.start or 0) stop = (slice.stop or len(self.data)) if start < 0: start += len(self.data) start = max((start,0)) if stop < 0: stop += len(self.data) stop = max((stop,0)) self.data[ slice ] = data if self.copied and self.buffers: if start-stop == len(self.data): # re-copy the whole data-set self.copied = False elif len(data): # now the fun part, we need to make the array match the # structure of the array we're going to copy into and make # the "size" parameter match the value we're going to copy in, # note that a 2D array (rather than a 1D array) may require # multiple mappings to copy into the memory area... # find the step size from the dimensions and base size... size = ArrayDatatype.arrayByteCount( self.data[0] ) #baseSize = ArrayDatatype.unitSize( data ) # now create the start and distance values... start *= size stop *= size # wait until the last moment (bind) to copy the data... self._copy_segments.append( (start,(stop-start), data) ) def __len__( self ): """Delegate length/truth checks to our data-array""" return len( self.data ) def __getattr__( self, key ): """Delegate failing attribute lookups to our data-array""" if key not in ('data','usage','target','buffers', 'copied','_I_','implementation','_copy_segments' ): return getattr( self.data, key ) else: raise AttributeError( key ) def create_buffers( self ): """Create the internal buffer(s)""" assert not self.buffers, """Already created the buffer""" self.buffers = [ long(self.implementation.glGenBuffers(1)) ] self.target = self.resolve( self.target ) self.usage = self.resolve( self.usage ) self.implementation._DELETERS_[ id(self) ] = weakref.ref( self, self.implementation.deleter( self.buffers, id(self) )) return self.buffers def copy_data( self ): """Copy our data into the buffer on the GL side (if required) Ensures that the GL's version of the data in the VBO matches our internal view of the data, either by copying the entire data-set over with glBufferData or by updating the already-transferred data with glBufferSubData. """ assert self.buffers, """Should do create_buffers before copy_data""" if self.copied: if self._copy_segments: while self._copy_segments: start,size,data = self._copy_segments.pop(0) dataptr = ArrayDatatype.voidDataPointer( data ) self.implementation.glBufferSubData(self.target, start, size, dataptr) else: if self.data is not None and self.size is None: self.size = ArrayDatatype.arrayByteCount( self.data ) self.implementation.glBufferData( self.target, self.size, self.data, self.usage, ) self.copied = True def delete( self ): """Delete this buffer explicitly""" if self.buffers: while self.buffers: try: self.implementation.glDeleteBuffers(1, self.buffers.pop(0)) except (AttributeError,error.NullFunctionError) as err: pass def __int__( self ): """Get our VBO id""" if not self.buffers: self.create_buffers() return self.buffers[0] def bind( self ): """Bind this buffer for use in vertex calls If we have not yet created our implementation-level VBO, then we will create it before binding. Once bound, calls self.copy_data() """ if not self.buffers: buffers = self.create_buffers() self.implementation.glBindBuffer( self.target, self.buffers[0]) self.copy_data() def unbind( self ): """Unbind the buffer (make normal array operations active)""" self.implementation.glBindBuffer( self.target,0 ) def __add__( self, other ): """Add an integer to this VBO (create a VBOOffset)""" if hasattr( other, 'offset' ): other = other.offset assert isinstance( other, integer_types ), """Only know how to add integer/long offsets""" return VBOOffset( self, other ) __enter__ = bind def __exit__( self, exc_type=None, exc_val=None, exc_tb=None ): """Context manager exit""" self.unbind() return False # do not supress exceptions... class VBOOffset( object ): """Offset into a VBO instance This class is normally instantiated by doing a my_vbo + int operation, it can be passed to VBO requiring operations and will generate the appropriate integer offset value to be passed in. """ def __init__( self, vbo, offset ): """Initialize the offset with vbo and offset (unsigned integer)""" self.vbo = vbo self.offset = offset def __getattr__( self, key ): """Delegate any undefined attribute save vbo to our vbo""" if key != 'vbo': return getattr( self.vbo, key ) raise AttributeError( 'No %r key in VBOOffset'%(key,)) def __add__( self, other ): """Allow adding integers or other VBOOffset instances returns a VBOOffset to the this VBO with other.offset + self.offset or, if other has no offset, returns VBOOffset with self.offset + other """ if hasattr( other, 'offset' ): other = other.offset return VBOOffset( self.vbo, self.offset + other ) class VBOHandler( FormatHandler ): """Handles VBO instances passed in as array data This FormatHandler is registered with PyOpenGL on import of this module to provide handling of VBO objects as array data-sources """ vp0 = ctypes.c_void_p( 0 ) def dataPointer( self, instance ): """Retrieve data-pointer from the instance's data Is always NULL, to indicate use of the bound pointer """ return 0 def from_param( self, instance, typeCode=None ): """Always returns c_void_p(0)""" return self.vp0 def zeros( self, dims, typeCode ): """Not implemented""" raise NotImplemented( """Don't have VBO output support yet""" ) ones = zeros def asArray( self, value, typeCode=None ): """Given a value, convert to array representation""" return value def arrayToGLType( self, value ): """Given a value, guess OpenGL type of the corresponding pointer""" return ArrayDatatype.arrayToGLType( value.data ) def arrayByteCount( self, value ): return ArrayDatatype.arrayByteCount( value.data ) def arraySize( self, value, typeCode = None ): """Given a data-value, calculate dimensions for the array""" return ArrayDatatype.arraySize( value.data ) def unitSize( self, value, typeCode=None ): """Determine unit size of an array (if possible)""" return ArrayDatatype.unitSize( value.data ) def dimensions( self, value, typeCode=None ): """Determine dimensions of the passed array value (if possible)""" return ArrayDatatype.dimensions( value.data ) class VBOOffsetHandler( VBOHandler ): """Handles VBOOffset instances passed in as array data Registered on module import to provide support for VBOOffset instances as sources for array data. """ def dataPointer( self, instance ): """Retrieve data-pointer from the instance's data returns instance' offset """ return instance.offset def from_param( self, instance, typeCode=None ): """Returns a c_void_p( instance.offset )""" return ctypes.c_void_p( instance.offset ) _cleaners = {} def _cleaner( vbo ): """Construct a mapped-array cleaner function to unmap vbo.target""" def clean( ref ): try: _cleaners.pop( vbo ) except Exception as err: pass else: vbo.implementation.glUnmapBuffer( vbo.target ) return clean def mapVBO( vbo, access=0x88BA ): # GL_READ_WRITE """Map the given buffer into a numpy array... Method taken from: http://www.mail-archive.com/numpy-discussion@lists.sourceforge.net/msg01161.html This should be considered an *experimental* API, it is not guaranteed to be available in future revisions of this library! Simplification to use ctypes cast from comment by 'sashimi' on my blog... """ from numpy import frombuffer vp = vbo.implementation.glMapBuffer( vbo.target, access ) # TODO: obviously this is not the right way to do this should allow each format # handler to convert the pointer in their own way... vp_array = ctypes.cast(vp, ctypes.POINTER(ctypes.c_byte*vbo.size) ) # Note: we could have returned the raw ctypes.c_byte array instead... array = frombuffer( vp_array, 'B' ) _cleaners[vbo] = weakref.ref( array, _cleaner( vbo )) return array