# ----------------------------------------------------------------------------
# pyglet
# Copyright (c) 2006-2008 Alex Holkner
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# ----------------------------------------------------------------------------
# $Id:$
'''Byte abstractions of Vertex Buffer Objects and vertex arrays.
Use `create_buffer` or `create_mappable_buffer` to create a Vertex Buffer
Object, or a vertex array if VBOs are not supported by the current context.
Buffers can optionally be created "mappable" (incorporating the
`AbstractMappable` mix-in). In this case the buffer provides a ``get_region``
method which provides the most efficient path for updating partial data within
the buffer.
'''
__docformat__ = 'restructuredtext'
__version__ = '$Id: $'
import ctypes
import sys
import pyglet
from pyglet.gl import *
from pyglet.gl import gl_info
_enable_vbo = pyglet.options['graphics_vbo']
# Enable workaround permanently if any VBO is created on a context that has
# this workaround. (On systems with multiple contexts where one is
# unaffected, the workaround will be enabled unconditionally on all of the
# contexts anyway. This is completely unlikely anyway).
_workaround_vbo_finish = False
def create_buffer(size,
target=GL_ARRAY_BUFFER,
usage=GL_DYNAMIC_DRAW,
vbo=True):
'''Create a buffer of vertex data.
:Parameters:
`size` : int
Size of the buffer, in bytes
`target` : int
OpenGL target buffer
`usage` : int
OpenGL usage constant
`vbo` : bool
True if a `VertexBufferObject` should be created if the driver
supports it; otherwise only a `VertexArray` is created.
:rtype: `AbstractBuffer`
'''
from pyglet import gl
if (vbo and
gl_info.have_version(1, 5) and
_enable_vbo and
not gl.current_context._workaround_vbo):
return VertexBufferObject(size, target, usage)
else:
return VertexArray(size)
def create_mappable_buffer(size,
target=GL_ARRAY_BUFFER,
usage=GL_DYNAMIC_DRAW,
vbo=True):
'''Create a mappable buffer of vertex data.
:Parameters:
`size` : int
Size of the buffer, in bytes
`target` : int
OpenGL target buffer
`usage` : int
OpenGL usage constant
`vbo` : bool
True if a `VertexBufferObject` should be created if the driver
supports it; otherwise only a `VertexArray` is created.
:rtype: `AbstractBuffer` with `AbstractMappable`
'''
from pyglet import gl
if (vbo and
gl_info.have_version(1, 5) and
_enable_vbo and
not gl.current_context._workaround_vbo):
return MappableVertexBufferObject(size, target, usage)
else:
return VertexArray(size)
class AbstractBuffer(object):
'''Abstract buffer of byte data.
:Ivariables:
`size` : int
Size of buffer, in bytes
`ptr` : int
Memory offset of the buffer, as used by the ``glVertexPointer``
family of functions
`target` : int
OpenGL buffer target, for example ``GL_ARRAY_BUFFER``
`usage` : int
OpenGL buffer usage, for example ``GL_DYNAMIC_DRAW``
'''
ptr = 0
size = 0
def bind(self):
'''Bind this buffer to its OpenGL target.'''
raise NotImplementedError('abstract')
def unbind(self):
'''Reset the buffer's OpenGL target.'''
raise NotImplementedError('abstract')
def set_data(self, data):
'''Set the entire contents of the buffer.
:Parameters:
`data` : sequence of int or ctypes pointer
The byte array to set.
'''
raise NotImplementedError('abstract')
def set_data_region(self, data, start, length):
'''Set part of the buffer contents.
:Parameters:
`data` : sequence of int or ctypes pointer
The byte array of data to set
`start` : int
Offset to start replacing data
`length` : int
Length of region to replace
'''
raise NotImplementedError('abstract')
def map(self, invalidate=False):
'''Map the entire buffer into system memory.
The mapped region must be subsequently unmapped with `unmap` before
performing any other operations on the buffer.
:Parameters:
`invalidate` : bool
If True, the initial contents of the mapped block need not
reflect the actual contents of the buffer.
:rtype: ``POINTER(ctypes.c_ubyte)``
:return: Pointer to the mapped block in memory
'''
raise NotImplementedError('abstract')
def unmap(self):
'''Unmap a previously mapped memory block.'''
raise NotImplementedError('abstract')
def resize(self, size):
'''Resize the buffer to a new size.
:Parameters:
`size` : int
New size of the buffer, in bytes
'''
def delete(self):
'''Delete this buffer, reducing system resource usage.'''
raise NotImplementedError('abstract')
class AbstractMappable(object):
def get_region(self, start, size, ptr_type):
'''Map a region of the buffer into a ctypes array of the desired
type. This region does not need to be unmapped, but will become
invalid if the buffer is resized.
Note that although a pointer type is required, an array is mapped.
For example::
get_region(0, ctypes.sizeof(c_int) * 20, ctypes.POINTER(c_int * 20))
will map bytes 0 to 80 of the buffer to an array of 20 ints.
Changes to the array may not be recognised until the region's
`AbstractBufferRegion.invalidate` method is called.
:Parameters:
`start` : int
Offset into the buffer to map from bytes import
`size` : int
Size of the buffer region to map, in bytes
`ptr_type` : ctypes pointer type
Pointer type describing the array format to create
:rtype: `AbstractBufferRegion`
'''
raise NotImplementedError('abstract')
class VertexArray(AbstractBuffer, AbstractMappable):
'''A ctypes implementation of a vertex array.
Many of the methods on this class are effectively no-op's, such as `bind`,
`unbind`, `map`, `unmap` and `delete`; they exist in order to present
a consistent interface with `VertexBufferObject`.
This buffer type is also mappable, and so `get_region` can be used.
'''
def __init__(self, size):
self.size = size
self.array = (ctypes.c_byte * size)()
self.ptr = ctypes.cast(self.array, ctypes.c_void_p).value
def bind(self):
pass
def unbind(self):
pass
def set_data(self, data):
ctypes.memmove(self.ptr, data, self.size)
def set_data_region(self, data, start, length):
ctypes.memmove(self.ptr + start, data, length)
def map(self, invalidate=False):
return self.array
def unmap(self):
pass
def get_region(self, start, size, ptr_type):
array = ctypes.cast(self.ptr + start, ptr_type).contents
return VertexArrayRegion(array)
def delete(self):
pass
def resize(self, size):
array = (ctypes.c_byte * size)()
ctypes.memmove(array, self.array, min(size, self.size))
self.size = size
self.array = array
self.ptr = ctypes.cast(self.array, ctypes.c_void_p).value
class VertexBufferObject(AbstractBuffer):
'''Lightweight representation of an OpenGL VBO.
The data in the buffer is not replicated in any system memory (unless it
is done so by the video driver). While this can improve memory usage and
possibly performance, updates to the buffer are relatively slow.
This class does not implement `AbstractMappable`, and so has no
``get_region`` method. See `MappableVertexBufferObject` for a VBO class
that does implement ``get_region``.
'''
def __init__(self, size, target, usage):
self.size = size
self.target = target
self.usage = usage
self._context = pyglet.gl.current_context
id = GLuint()
glGenBuffers(1, id)
self.id = id.value
glPushClientAttrib(GL_CLIENT_VERTEX_ARRAY_BIT)
glBindBuffer(target, self.id)
glBufferData(target, self.size, None, self.usage)
glPopClientAttrib()
global _workaround_vbo_finish
if pyglet.gl.current_context._workaround_vbo_finish:
_workaround_vbo_finish = True
def bind(self):
glBindBuffer(self.target, self.id)
def unbind(self):
glBindBuffer(self.target, 0)
def set_data(self, data):
glPushClientAttrib(GL_CLIENT_VERTEX_ARRAY_BIT)
glBindBuffer(self.target, self.id)
glBufferData(self.target, self.size, data, self.usage)
glPopClientAttrib()
def set_data_region(self, data, start, length):
glPushClientAttrib(GL_CLIENT_VERTEX_ARRAY_BIT)
glBindBuffer(self.target, self.id)
glBufferSubData(self.target, start, length, data)
glPopClientAttrib()
def map(self, invalidate=False):
glPushClientAttrib(GL_CLIENT_VERTEX_ARRAY_BIT)
glBindBuffer(self.target, self.id)
if invalidate:
glBufferData(self.target, self.size, None, self.usage)
ptr = ctypes.cast(glMapBuffer(self.target, GL_WRITE_ONLY),
ctypes.POINTER(ctypes.c_byte * self.size)).contents
glPopClientAttrib()
return ptr
def unmap(self):
glPushClientAttrib(GL_CLIENT_VERTEX_ARRAY_BIT)
glUnmapBuffer(self.target)
glPopClientAttrib()
def __del__(self):
try:
if self.id is not None:
self._context.delete_buffer(self.id)
except:
pass
def delete(self):
id = GLuint(self.id)
glDeleteBuffers(1, id)
self.id = None
def resize(self, size):
# Map, create a copy, then reinitialize.
temp = (ctypes.c_byte * size)()
glPushClientAttrib(GL_CLIENT_VERTEX_ARRAY_BIT)
glBindBuffer(self.target, self.id)
data = glMapBuffer(self.target, GL_READ_ONLY)
ctypes.memmove(temp, data, min(size, self.size))
glUnmapBuffer(self.target)
self.size = size
glBufferData(self.target, self.size, temp, self.usage)
glPopClientAttrib()
class MappableVertexBufferObject(VertexBufferObject, AbstractMappable):
'''A VBO with system-memory backed store.
Updates to the data via `set_data`, `set_data_region` and `map` will be
held in local memory until `bind` is called. The advantage is that fewer
OpenGL calls are needed, increasing performance.
There may also be less performance penalty for resizing this buffer.
Updates to data via `map` are committed immediately.
'''
def __init__(self, size, target, usage):
super(MappableVertexBufferObject, self).__init__(size, target, usage)
self.data = (ctypes.c_byte * size)()
self.data_ptr = ctypes.cast(self.data, ctypes.c_void_p).value
self._dirty_min = sys.maxint
self._dirty_max = 0
def bind(self):
# Commit pending data
super(MappableVertexBufferObject, self).bind()
size = self._dirty_max - self._dirty_min
if size > 0:
if size == self.size:
glBufferData(self.target, self.size, self.data, self.usage)
else:
glBufferSubData(self.target, self._dirty_min, size,
self.data_ptr + self._dirty_min)
self._dirty_min = sys.maxint
self._dirty_max = 0
def set_data(self, data):
super(MappableVertexBufferObject, self).set_data(data)
ctypes.memmove(self.data, data, self.size)
self._dirty_min = 0
self._dirty_max = self.size
def set_data_region(self, data, start, length):
ctypes.memmove(self.data_ptr + start, data, length)
self._dirty_min = min(start, self._dirty_min)
self._dirty_max = max(start + length, self._dirty_max)
def map(self, invalidate=False):
self._dirty_min = 0
self._dirty_max = self.size
return self.data
def unmap(self):
pass
def get_region(self, start, size, ptr_type):
array = ctypes.cast(self.data_ptr + start, ptr_type).contents
return VertexBufferObjectRegion(self, start, start + size, array)
def resize(self, size):
data = (ctypes.c_byte * size)()
ctypes.memmove(data, self.data, min(size, self.size))
self.data = data
self.data_ptr = ctypes.cast(self.data, ctypes.c_void_p).value
self.size = size
glPushClientAttrib(GL_CLIENT_VERTEX_ARRAY_BIT)
glBindBuffer(self.target, self.id)
glBufferData(self.target, self.size, self.data, self.usage)
glPopClientAttrib()
self._dirty_min = sys.maxint
self._dirty_max = 0
class AbstractBufferRegion(object):
'''A mapped region of a buffer.
Buffer regions are obtained using `AbstractMappable.get_region`.
:Ivariables:
`array` : ctypes array
Array of data, of the type and count requested by ``get_region``.
'''
def invalidate(self):
'''Mark this region as changed.
The buffer may not be updated with the latest contents of the
array until this method is called. (However, it may not be updated
until the next time the buffer is used, for efficiency).
'''
pass
class VertexBufferObjectRegion(AbstractBufferRegion):
'''A mapped region of a VBO.'''
def __init__(self, buffer, start, end, array):
self.buffer = buffer
self.start = start
self.end = end
self.array = array
def invalidate(self):
buffer = self.buffer
buffer._dirty_min = min(buffer._dirty_min, self.start)
buffer._dirty_max = max(buffer._dirty_max, self.end)
class VertexArrayRegion(AbstractBufferRegion):
'''A mapped region of a vertex array.
The `invalidate` method is a no-op but is provided in order to present
a consistent interface with `VertexBufferObjectRegion`.
'''
def __init__(self, array):
self.array = array
class IndirectArrayRegion(AbstractBufferRegion):
'''A mapped region in which data elements are not necessarily contiguous.
This region class is used to wrap buffer regions in which the data
must be accessed with some stride. For example, in an interleaved buffer
this region can be used to access a single interleaved component as if the
data was contiguous.
'''
def __init__(self, region, size, component_count, component_stride):
'''Wrap a buffer region.
Use the `component_count` and `component_stride` parameters to specify
the data layout of the encapsulated region. For example, if RGBA
data is to be accessed as if it were packed RGB, ``component_count``
would be set to 3 and ``component_stride`` to 4. If the region
contains 10 RGBA tuples, the ``size`` parameter is ``3 * 10 = 30``.
:Parameters:
`region` : `AbstractBufferRegion`
The region with interleaved data
`size` : int
The number of elements that this region will provide access to.
`component_count` : int
The number of elements that are contiguous before some must
be skipped.
`component_stride` : int
The number of elements of interleaved data separating
the contiguous sections.
'''
self.region = region
self.size = size
self.count = component_count
self.stride = component_stride
self.array = self
def __repr__(self):
return 'IndirectArrayRegion(size=%d, count=%d, stride=%d)' % (
self.size, self.count, self.stride)
def __getitem__(self, index):
count = self.count
if not isinstance(index, slice):
elem = index // count
j = index % count
return self.region.array[elem * self.stride + j]
start = index.start or 0
stop = index.stop
step = index.step or 1
if start < 0:
start = self.size + start
if stop is None:
stop = self.size
elif stop < 0:
stop = self.size + stop
assert step == 1 or step % count == 0, \
'Step must be multiple of component count'
data_start = (start // count) * self.stride + start % count
data_stop = (stop // count) * self.stride + stop % count
data_step = step * self.stride
# TODO stepped getitem is probably wrong, see setitem for correct.
value_step = step * count
# ctypes does not support stepped slicing, so do the work in a list
# and copy it back.
data = self.region.array[:]
value = [0] * ((stop - start) // step)
stride = self.stride
for i in range(count):
value[i::value_step] = \
data[data_start + i:data_stop + i:data_step]
return value
def __setitem__(self, index, value):
count = self.count
if not isinstance(index, slice):
elem = index // count
j = index % count
self.region.array[elem * self.stride + j] = value
return
start = index.start or 0
stop = index.stop
step = index.step or 1
if start < 0:
start = self.size + start
if stop is None:
stop = self.size
elif stop < 0:
stop = self.size + stop
assert step == 1 or step % count == 0, \
'Step must be multiple of component count'
data_start = (start // count) * self.stride + start % count
data_stop = (stop // count) * self.stride + stop % count
# ctypes does not support stepped slicing, so do the work in a list
# and copy it back.
data = self.region.array[:]
if step == 1:
data_step = self.stride
value_step = count
for i in range(count):
data[data_start + i:data_stop + i:data_step] = \
value[i::value_step]
else:
data_step = (step // count) * self.stride
data[data_start:data_stop:data_step] = value
self.region.array[:] = data
def invalidate(self):
self.region.invalidate()
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