# ----------------------------------------------------------------------------
# pyglet
# Copyright (c) 2006-2008 Alex Holkner
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#
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# modification, are permitted provided that the following conditions
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# * Redistributions of source code must retain the above copyright
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# $Id:$
'''Low-level graphics rendering.
This module provides an efficient low-level abstraction over OpenGL. It gives
very good performance for rendering OpenGL primitives; far better than the
typical immediate-mode usage and, on modern graphics cards, better than using
display lists in many cases. The module is used internally by other areas of
pyglet.
See the Programming Guide for details on how to use this graphics API.
Batches and groups
==================
Without even needing to understand the details on how to draw primitives with
the graphics API, developers can make use of `Batch` and `Group`
objects to improve performance of sprite and text rendering.
The `Sprite`, `Label` and `TextLayout` classes all accept a ``batch`` and
``group`` parameter in their constructors. A batch manages a set of objects
that will be drawn all at once, and a group describes the manner in which an
object is drawn.
The following example creates a batch, adds two sprites to the batch, and then
draws the entire batch::
batch = pyglet.graphics.Batch()
car = pyglet.sprite.Sprite(car_image, batch=batch)
boat = pyglet.sprite.Sprite(boat_image, batch=batch)
def on_draw()
batch.draw()
Drawing a complete batch is much faster than drawing the items in the batch
individually, especially when those items belong to a common group.
Groups describe the OpenGL state required for an item. This is for the most
part managed by the sprite and text classes, however you can also use groups
to ensure items are drawn in a particular order. For example, the following
example adds a background sprite which is guaranteed to be drawn before the
car and the boat::
batch = pyglet.graphics.Batch()
background = pyglet.graphics.OrderedGroup(0)
foreground = pyglet.graphics.OrderedGroup(1)
background = pyglet.sprite.Sprite(background_image,
batch=batch, group=background)
car = pyglet.sprite.Sprite(car_image, batch=batch, group=foreground)
boat = pyglet.sprite.Sprite(boat_image, batch=batch, group=foreground)
def on_draw()
batch.draw()
It's preferable to manage sprites and text objects within as few batches as
possible. If the drawing of sprites or text objects need to be interleaved
with other drawing that does not use the graphics API, multiple batches will
be required.
Data item parameters
====================
Many of the functions and methods in this module accept any number of ``data``
parameters as their final parameters. In the documentation these are notated
as ``*data`` in the formal parameter list.
A data parameter describes a vertex attribute format and an optional sequence
to initialise that attribute. Examples of common attribute formats are:
``"v3f"``
Vertex position, specified as three floats.
``"c4B"``
Vertex color, specifed as four unsigned bytes.
``"t2f"``
Texture coordinate, specified as two floats.
See `pyglet.graphics.vertexattribute` for the complete syntax of the vertex
format string.
When no initial data is to be given, the data item is just the format string.
For example, the following creates a 2 element vertex list with position and
color attributes::
vertex_list = pyglet.graphics.vertex_list(2, 'v2f', 'c4B')
When initial data is required, wrap the format string and the initial data in
a tuple, for example::
vertex_list = pyglet.graphics.vertex_list(2,
('v2f', (0.0, 1.0, 1.0, 0.0)),
('c4B', (255, 255, 255, 255) * 2))
Drawing modes
=============
Methods in this module that accept a ``mode`` parameter will accept any value
in the OpenGL drawing mode enumeration; for example, ``GL_POINTS``,
``GL_LINES``, ``GL_TRIANGLES``, etc.
Because of the way the graphics API renders multiple primitives with shared
state, ``GL_POLYGON``, ``GL_LINE_LOOP`` and ``GL_TRIANGLE_FAN`` cannot be used
--- the results are undefined.
When using ``GL_LINE_STRIP``, ``GL_TRIANGLE_STRIP`` or ``GL_QUAD_STRIP`` care
must be taken to insert degenrate vertices at the beginning and end of each
vertex list. For example, given the vertex list::
A, B, C, D
the correct vertex list to provide the vertex list is::
A, A, B, C, D, D
Alternatively, the ``NV_primitive_restart`` extension can be used if it is
present. This also permits use of ``GL_POLYGON``, ``GL_LINE_LOOP`` and
``GL_TRIANGLE_FAN``. Unfortunatley the extension is not provided by older
video drivers, and requires indexed vertex lists.
:since: pyglet 1.1
'''
__docformat__ = 'restructuredtext'
__version__ = '$Id: $'
import ctypes
import pyglet
from pyglet.gl import *
from pyglet import gl
from pyglet.graphics import vertexbuffer,vertexattribute,vertexdomain
_debug_graphics_batch = pyglet.options['debug_graphics_batch']
def draw(size, mode, *data):
'''Draw a primitive immediately.
:Parameters:
`size` : int
Number of vertices given
`mode` : int
OpenGL drawing mode, e.g. ``GL_TRIANGLES``
`data` : data items
Attribute formats and data. See the module summary for
details.
'''
glPushClientAttrib(GL_CLIENT_VERTEX_ARRAY_BIT)
buffers = []
for format, array in data:
attribute = vertexattribute.create_attribute(format)
assert size == len(array) // attribute.count, \
'Data for %s is incorrect length' % format
buffer = vertexbuffer.create_mappable_buffer(
size * attribute.stride, vbo=False)
attribute.set_region(buffer, 0, size, array)
attribute.enable()
attribute.set_pointer(buffer.ptr)
buffers.append(buffer)
glDrawArrays(mode, 0, size)
glFlush()
glPopClientAttrib()
def draw_indexed(size, mode, indices, *data):
'''Draw a primitive with indexed vertices immediately.
:Parameters:
`size` : int
Number of vertices given
`mode` : int
OpenGL drawing mode, e.g. ``GL_TRIANGLES``
`indices` : sequence of int
Sequence of integers giving indices into the vertex list.
`data` : data items
Attribute formats and data. See the module summary for details.
'''
glPushClientAttrib(GL_CLIENT_VERTEX_ARRAY_BIT)
buffers = []
for format, array in data:
attribute = vertexattribute.create_attribute(format)
assert size == len(array) // attribute.count, \
'Data for %s is incorrect length' % format
buffer = vertexbuffer.create_mappable_buffer(
size * attribute.stride, vbo=False)
attribute.set_region(buffer, 0, size, array)
attribute.enable()
attribute.set_pointer(buffer.ptr)
buffers.append(buffer)
if size <= 0xff:
index_type = GL_UNSIGNED_BYTE
index_c_type = ctypes.c_ubyte
elif size <= 0xffff:
index_type = GL_UNSIGNED_SHORT
index_c_type = ctypes.c_ushort
else:
index_type = GL_UNSIGNED_INT
index_c_type = ctypes.c_uint
index_array = (index_c_type * len(indices))(*indices)
glDrawElements(mode, len(indices), index_type, index_array)
glFlush()
glPopClientAttrib()
def _parse_data(data):
'''Given a list of data items, returns (formats, initial_arrays).'''
assert data, 'No attribute formats given'
# Return tuple (formats, initial_arrays).
formats = []
initial_arrays = []
for i, format in enumerate(data):
if isinstance(format, tuple):
format, array = format
initial_arrays.append((i, array))
formats.append(format)
formats = tuple(formats)
return formats, initial_arrays
def _get_default_batch():
shared_object_space = gl.current_context.object_space
try:
return shared_object_space.pyglet_graphics_default_batch
except AttributeError:
shared_object_space.pyglet_graphics_default_batch = Batch()
return shared_object_space.pyglet_graphics_default_batch
def vertex_list(count, *data):
'''Create a `VertexList` not associated with a batch, group or mode.
:Parameters:
`count` : int
The number of vertices in the list.
`data` : data items
Attribute formats and initial data for the vertex list. See the
module summary for details.
:rtype: `VertexList`
'''
# Note that mode=0 because the default batch is never drawn: vertex lists
# returned from this function are drawn directly by the app.
return _get_default_batch().add(count, 0, None, *data)
def vertex_list_indexed(count, indices, *data):
'''Create an `IndexedVertexList` not associated with a batch, group or mode.
:Parameters:
`count` : int
The number of vertices in the list.
`indices` : sequence
Sequence of integers giving indices into the vertex list.
`data` : data items
Attribute formats and initial data for the vertex list. See the
module summary for details.
:rtype: `IndexedVertexList`
'''
# Note that mode=0 because the default batch is never drawn: vertex lists
# returned from this function are drawn directly by the app.
return _get_default_batch().add_indexed(count, 0, None, indices, *data)
class Batch(object):
'''Manage a collection of vertex lists for batched rendering.
Vertex lists are added to a `Batch` using the `add` and `add_indexed`
methods. An optional group can be specified along with the vertex list,
which gives the OpenGL state required for its rendering. Vertex lists
with shared mode and group are allocated into adjacent areas of memory and
sent to the graphics card in a single operation.
Call `VertexList.delete` to remove a vertex list from thebatch. import
'''
def __init__(self):
'''Create a graphics batch.'''
# Mapping to find domain.
# group -> (attributes, mode, indexed) -> domain
self.group_map = {}
# Mapping of group to list of children.
self.group_children = {}
# List of top-level groups
self.top_groups = []
self._draw_list = []
self._draw_list_dirty = False
def add(self, count, mode, group, *data):
'''Add a vertex list to the batch.
:Parameters:
`count` : int
The number of vertices in the list.
`mode` : int
OpenGL drawing mode enumeration; for example, one of
``GL_POINTS``, ``GL_LINES``, ``GL_TRIANGLES``, etc.
See the module summary for additional information.
`group` : `Group`
Group of the vertex list, or ``None`` if no group is required.
`data` : data items
Attribute formats and initial data for the vertex list. See
the module summary for details.
:rtype: `VertexList`
'''
formats, initial_arrays = _parse_data(data)
domain = self._get_domain(False, mode, group, formats)
# Create vertex list and initialize
vlist = domain.create(count)
for i, array in initial_arrays:
vlist._set_attribute_data(i, array)
return vlist
def add_indexed(self, count, mode, group, indices, *data):
'''Add an indexed vertex list to the batch.
:Parameters:
`count` : int
The number of vertices in the list.
`mode` : int
OpenGL drawing mode enumeration; for example, one of
``GL_POINTS``, ``GL_LINES``, ``GL_TRIANGLES``, etc.
See the module summary for additional information.
`group` : `Group`
Group of the vertex list, or ``None`` if no group is required.
`indices` : sequence
Sequence of integers giving indices into the vertex list.
`data` : data items
Attribute formats and initial data for the vertex list. See
the module summary for details.
:rtype: `IndexedVertexList`
'''
formats, initial_arrays = _parse_data(data)
domain = self._get_domain(True, mode, group, formats)
# Create vertex list and initialize
vlist = domain.create(count, len(indices))
start = vlist.start
vlist._set_index_data(map(lambda i: i + start, indices))
for i, array in initial_arrays:
vlist._set_attribute_data(i, array)
return vlist
def migrate(self, vertex_list, mode, group, batch):
'''Migrate a vertex list to another batch and/or group.
`vertex_list` and `mode` together identify the vertex list to migrate.
`group` and `batch` are new owners of the vertex list after migration.
The results are undefined if `mode` is not correct or if `vertex_list`
does not belong to this batch (they are not checked and will not
necessarily throw an exception immediately).
`batch` can remain unchanged if only a group change is desired.
:Parameters:
`vertex_list` : `VertexList`
A vertex list currently belonging to this batch.
`mode` : int
The current GL drawing mode of the vertex list.
`group` : `Group`
The new group to migrate to.
`batch` : `Batch`
The batch to migrate to (or the current batch).
'''
formats = vertex_list.domain.__formats
domain = batch._get_domain(False, mode, group, formats)
vertex_list.migrate(domain)
def _get_domain(self, indexed, mode, group, formats):
if group is None:
group = null_group
# Batch group
if group not in self.group_map:
self._add_group(group)
domain_map = self.group_map[group]
# Find domain given formats, indices and mode
key = (formats, mode, indexed)
try:
domain = domain_map[key]
except KeyError:
# Create domain
if indexed:
domain = vertexdomain.create_indexed_domain(*formats)
else:
domain = vertexdomain.create_domain(*formats)
domain.__formats = formats
domain_map[key] = domain
self._draw_list_dirty = True
return domain
def _add_group(self, group):
self.group_map[group] = {}
if group.parent is None:
self.top_groups.append(group)
else:
if group.parent not in self.group_map:
self._add_group(group.parent)
if group.parent not in self.group_children:
self.group_children[group.parent] = []
self.group_children[group.parent].append(group)
self._draw_list_dirty = True
def _update_draw_list(self):
'''Visit group tree in preorder and create a list of bound methods
to call.
'''
def visit(group):
draw_list = []
# Draw domains using this group
domain_map = self.group_map[group]
for (formats, mode, indexed), domain in list(domain_map.items()):
# Remove unused domains from batch
if domain._is_empty():
del domain_map[(formats, mode, indexed)]
continue
draw_list.append(
(lambda d, m: lambda: d.draw(m))(domain, mode))
# Sort and visit child groups of this group
children = self.group_children.get(group)
if children:
children.sort()
for child in list(children):
draw_list.extend(visit(child))
if children or domain_map:
return [group.set_state] + draw_list + [group.unset_state]
else:
# Remove unused group from batch
del self.group_map[group]
if group.parent:
self.group_children[group.parent].remove(group)
try:
del self.group_children[group]
except KeyError:
pass
try:
self.top_groups.remove(group)
except ValueError:
pass
return []
self._draw_list = []
self.top_groups.sort()
for group in list(self.top_groups):
self._draw_list.extend(visit(group))
self._draw_list_dirty = False
if _debug_graphics_batch:
self._dump_draw_list()
def _dump_draw_list(self):
def dump(group, indent=''):
print indent, 'Begin group', group
domain_map = self.group_map[group]
for _, domain in domain_map.items():
print indent, ' ', domain
for start, size in zip(*domain.allocator.get_allocated_regions()):
print indent, ' ', 'Region %d size %d:' % (start, size)
for key, attribute in domain.attribute_names.items():
print indent, ' ',
try:
region = attribute.get_region(attribute.buffer,
start, size)
print key, region.array[:]
except:
print key, '(unmappable)'
for child in self.group_children.get(group, ()):
dump(child, indent + ' ')
print indent, 'End group', group
print 'Draw list for %r:' % self
for group in self.top_groups:
dump(group)
def draw(self):
'''Draw the batch.
'''
if self._draw_list_dirty:
self._update_draw_list()
for func in self._draw_list:
func()
def draw_subset(self, vertex_lists):
'''Draw only some vertex lists in the batch.
The use of this method is highly discouraged, as it is quite
inefficient. Usually an application can be redesigned so that batches
can always be drawn in their entirety, using `draw`.
The given vertex lists must belong to this batch; behaviour is
undefined if this condition is not met.
:Parameters:
`vertex_lists` : sequence of `VertexList` or `IndexedVertexList`
Vertex lists to draw.
'''
# Horrendously inefficient.
def visit(group):
group.set_state()
# Draw domains using this group
domain_map = self.group_map[group]
for (_, mode, _), domain in domain_map.items():
for list in vertex_lists:
if list.domain is domain:
list.draw(mode)
# Sort and visit child groups of this group
children = self.group_children.get(group)
if children:
children.sort()
for child in children:
visit(child)
group.unset_state()
self.top_groups.sort()
for group in self.top_groups:
visit(group)
class Group(object):
'''Group of common OpenGL state.
Before a vertex list is rendered, its group's OpenGL state is set; as are
that state's ancestors' states. This can be defined arbitrarily on
subclasses; the default state change has no effect, and groups vertex
lists only in the order in which they are drawn.
'''
def __init__(self, parent=None):
'''Create a group.
:Parameters:
`parent` : `Group`
Group to contain this group; its state will be set before this
state's.
'''
self.parent = parent
def set_state(self):
'''Apply the OpenGL state change.
The default implementation does nothing.'''
pass
def unset_state(self):
'''Repeal the OpenGL state change.
The default implementation does nothing.'''
pass
def set_state_recursive(self):
'''Set this group and its ancestry.
Call this method if you are using a group in isolation: the
parent groups will be called in top-down order, with this class's
`set` being called last.
'''
if self.parent:
self.parent.set_state_recursive()
self.set_state()
def unset_state_recursive(self):
'''Unset this group and its ancestry.
The inverse of `set_state_recursive`.
'''
self.unset_state()
if self.parent:
self.parent.unset_state_recursive()
class NullGroup(Group):
'''The default group class used when ``None`` is given to a batch.
This implementation has no effect.
'''
pass
#: The default group.
#:
#: :type: `Group`
null_group = NullGroup()
class TextureGroup(Group):
'''A group that enables and binds a texture.
Texture groups are equal if their textures' targets and names are equal.
'''
# Don't use this, create your own group classes that are more specific.
# This is just an example.
def __init__(self, texture, parent=None):
'''Create a texture group.
:Parameters:
`texture` : `Texture`
Texture to bind.
`parent` : `Group`
Parent group.
'''
super(TextureGroup, self).__init__(parent)
self.texture = texture
def set_state(self):
glEnable(self.texture.target)
glBindTexture(self.texture.target, self.texture.id)
def unset_state(self):
glDisable(self.texture.target)
def __hash__(self):
return hash((self.texture.target, self.texture.id, self.parent))
def __eq__(self, other):
return (self.__class__ is other.__class__ and
self.texture.target == other.texture.target and
self.texture.id == other.texture.id and
self.parent == other.parent)
def __repr__(self):
return '%s(id=%d)' % (self.__class__.__name__, self.texture.id)
class OrderedGroup(Group):
'''A group with partial order.
Ordered groups with a common parent are rendered in ascending order of
their ``order`` field. This is a useful way to render multiple layers of
a scene within a single batch.
'''
# This can be useful as a top-level group, or as a superclass for other
# groups that need to be ordered.
#
# As a top-level group it's useful because graphics can be composited in a
# known order even if they don't know about each other or share any known
# group.
def __init__(self, order, parent=None):
'''Create an ordered group.
:Parameters:
`order` : int
Order of this group.
`parent` : `Group`
Parent of this group.
'''
super(OrderedGroup, self).__init__(parent)
self.order = order
def __cmp__(self, other):
if isinstance(other, OrderedGroup):
return cmp(self.order, other.order)
return -1
def __eq__(self, other):
return (self.__class__ is other.__class__ and
self.order == other.order and
self.parent == other.parent)
def __hash__(self):
return hash((self.order, self.parent))
def __repr__(self):
return '%s(%d)' % (self.__class__.__name__, self.order)
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