Difficult-Rocket/bin/pyglet/image/atlas.py
2021-04-02 23:31:04 +08:00

280 lines
9.8 KiB
Python

# ----------------------------------------------------------------------------
# pyglet
# Copyright (c) 2006-2008 Alex Holkner
# Copyright (c) 2008-2020 pyglet contributors
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in
# the documentation and/or other materials provided with the
# distribution.
# * Neither the name of pyglet nor the names of its
# contributors may be used to endorse or promote products
# derived from this software without specific prior written
# permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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# POSSIBILITY OF SUCH DAMAGE.
# ----------------------------------------------------------------------------
"""Group multiple small images into larger textures.
This module is used by :py:mod:`pyglet.resource` to efficiently pack small
images into larger textures. :py:class:`~pyglet.image.atlas.TextureAtlas` maintains one texture;
:py:class:`TextureBin` manages a collection of atlases of a given size.
Example usage::
# Load images from disk
car_image = pyglet.image.load('car.png')
boat_image = pyglet.image.load('boat.png')
# Pack these images into one or more textures
bin = TextureBin()
car_texture = bin.add(car_image)
boat_texture = bin.add(boat_image)
The result of :py:meth:`TextureBin.add` is a :py:class:`TextureRegion`
containing the image. Once added, an image cannot be removed from a bin (or an
atlas); nor can a list of images be obtained from a given bin or atlas -- it is
the application's responsibility to keep track of the regions returned by the
``add`` methods.
.. versionadded:: 1.1
"""
import pyglet
from pyglet.gl import GL_RGBA
class AllocatorException(Exception):
"""The allocator does not have sufficient free space for the requested
image size."""
pass
class _Strip:
__slots__ = 'x', 'y', 'max_height', 'y2'
def __init__(self, y, max_height):
self.x = 0
self.y = y
self.max_height = max_height
self.y2 = y
def add(self, width, height):
assert width > 0 and height > 0
assert height <= self.max_height
x, y = self.x, self.y
self.x += width
self.y2 = max(self.y + height, self.y2)
return x, y
def compact(self):
self.max_height = self.y2 - self.y
class Allocator:
"""Rectangular area allocation algorithm.
Initialise with a given ``width`` and ``height``, then repeatedly
call `alloc` to retrieve free regions of the area and protect that
area from future allocations.
`Allocator` uses a fairly simple strips-based algorithm. It performs best
when rectangles are allocated in decreasing height order.
"""
__slots__ = 'width', 'height', 'strips', 'used_area'
def __init__(self, width, height):
"""Create an `Allocator` of the given size.
:Parameters:
`width` : int
Width of the allocation region.
`height` : int
Height of the allocation region.
"""
assert width > 0 and height > 0
self.width = width
self.height = height
self.strips = [_Strip(0, height)]
self.used_area = 0
def alloc(self, width, height):
"""Get a free area in the allocator of the given size.
After calling `alloc`, the requested area will no longer be used.
If there is not enough room to fit the given area `AllocatorException`
is raised.
:Parameters:
`width` : int
Width of the area to allocate.
`height` : int
Height of the area to allocate.
:rtype: int, int
:return: The X and Y coordinates of the bottom-left corner of the
allocated region.
"""
for strip in self.strips:
if self.width - strip.x >= width and strip.max_height >= height:
self.used_area += width * height
return strip.add(width, height)
if self.width >= width and self.height - strip.y2 >= height:
self.used_area += width * height
strip.compact()
newstrip = _Strip(strip.y2, self.height - strip.y2)
self.strips.append(newstrip)
return newstrip.add(width, height)
raise AllocatorException('No more space in %r for box %dx%d' % (self, width, height))
def get_usage(self):
"""Get the fraction of area already allocated.
This method is useful for debugging and profiling only.
:rtype: float
"""
return self.used_area / float(self.width * self.height)
def get_fragmentation(self):
"""Get the fraction of area that's unlikely to ever be used, based on
current allocation behaviour.
This method is useful for debugging and profiling only.
:rtype: float
"""
# The total unused area in each compacted strip is summed.
if not self.strips:
return 0.0
possible_area = self.strips[-1].y2 * self.width
return 1.0 - self.used_area / float(possible_area)
class TextureAtlas:
"""Collection of images within a texture."""
def __init__(self, width=2048, height=2048):
"""Create a texture atlas of the given size.
:Parameters:
`width` : int
Width of the underlying texture.
`height` : int
Height of the underlying texture.
"""
max_texture_size = pyglet.image.get_max_texture_size()
width = min(width, max_texture_size)
height = min(height, max_texture_size)
self.texture = pyglet.image.Texture.create(width, height, GL_RGBA, rectangle=True)
self.allocator = Allocator(width, height)
def add(self, img, border=0):
"""Add an image to the atlas.
This method will fail if the given image cannot be transferred
directly to a texture (for example, if it is another texture).
:py:class:`~pyglet.image.ImageData` is the usual image type for this method.
`AllocatorException` will be raised if there is no room in the atlas
for the image.
:Parameters:
`img` : `~pyglet.image.AbstractImage`
The image to add.
`border` : int
Leaves specified pixels of blank space around
each image added to the Atlas.
:rtype: :py:class:`~pyglet.image.TextureRegion`
:return: The region of the atlas containing the newly added image.
"""
x, y = self.allocator.alloc(img.width + border*2, img.height + border*2)
self.texture.blit_into(img, x+border, y+border, 0)
return self.texture.get_region(x+border, y+border, img.width, img.height)
class TextureBin:
"""Collection of texture atlases.
:py:class:`~pyglet.image.atlas.TextureBin` maintains a collection of texture atlases, and creates new
ones as necessary to accommodate images added to the bin.
"""
def __init__(self, texture_width=2048, texture_height=2048):
"""Create a texture bin for holding atlases of the given size.
:Parameters:
`texture_width` : int
Width of texture atlases to create.
`texture_height` : int
Height of texture atlases to create.
`border` : int
Leaves specified pixels of blank space around
each image added to the Atlases.
"""
max_texture_size = pyglet.image.get_max_texture_size()
self.texture_width = min(texture_width, max_texture_size)
self.texture_height = min(texture_height, max_texture_size)
self.atlases = []
def add(self, img, border=0):
"""Add an image into this texture bin.
This method calls `TextureAtlas.add` for the first atlas that has room
for the image.
`AllocatorException` is raised if the image exceeds the dimensions of
``texture_width`` and ``texture_height``.
:Parameters:
`img` : `~pyglet.image.AbstractImage`
The image to add.
`border` : int
Leaves specified pixels of blank space around
each image added to the Atlas.
:rtype: :py:class:`~pyglet.image.TextureRegion`
:return: The region of an atlas containing the newly added image.
"""
for atlas in list(self.atlases):
try:
return atlas.add(img, border)
except AllocatorException:
# Remove atlases that are no longer useful (this is so their
# textures can later be freed if the images inside them get
# collected).
if img.width < 64 and img.height < 64:
self.atlases.remove(atlas)
atlas = TextureAtlas(self.texture_width, self.texture_height)
self.atlases.append(atlas)
return atlas.add(img, border)