Source code for arcade.texture_atlas

Texture atlas for SpriteList

The long term goal is to rely on pyglet's texture atlas, but
it's still unclear what features we need supported in arcade
so need to prototype something to get started.

We're still building on pyglet's allocator.

Pyglet atlases are located here:

import math
import time
import logging
from typing import Dict, List, Tuple, Sequence, TYPE_CHECKING
from array import array

import PIL
from PIL import Image, ImageDraw
from import Framebuffer
from collections import deque
from contextlib import contextmanager

import arcade

from pyglet.image.atlas import (

    from arcade import ArcadeContext, Texture
    from import Texture as GLTexture

# How many texture coordinates to store
# The amount of pixels we increase the atlas when scanning for a reasonable size.
# It must divide. Must be a power of two number like 64, 256, 512 etx
LOG = logging.getLogger(__name__)

[docs]class AtlasRegion: """ Stores information about where a texture is located :param str atlas: The atlas this region belongs to :param str texture: The arcade texture :param int x: The x position of the texture :param int y: The y position of the texture :param int width: The width of the texture in pixels :param int height: The height of the texture in pixels """ __slots__ = ( "atlas", "texture", "x", "y", "width", "height", "texture_coordinates", "texture_coordinates_buffer", "texture_id", ) def __init__( self, atlas: "TextureAtlas", texture: "Texture", x: int, y: int, width: int, height: int, ): self.atlas = atlas self.texture = texture self.x = x self.y = y self.width = width self.height = height # start_x, start_y, normalized_width, normalized_height self.texture_coordinates = ( self.x / self.atlas.width, (self.atlas.height - self.y - self.height) / self.atlas.height, self.width / self.atlas.width, self.height / self.atlas.height, )
[docs] def verify_image_size(self): """ Verify the image has the right size. The internal image of a texture can be tampered with at any point causing an atlas update to fail. """ if self.texture.image.size != (self.width, self.height): raise ValueError(( f"Texture '{}' change their internal image " f"size from {self.width}x{self.height} to " f"{self.texture.image.size[0]}x{self.texture.image.size[1]}. " "It's not possible to fit this into the old allocated area in the atlas. " ))
[docs]class TextureAtlas: """ A texture atlas with a size in a context. A texture atlas is a large texture containing several textures so OpenGL can easily batch draw thousands or hundreds of thousands of sprites on one draw operation. This is a fairly simple atlas that stores horizontal strips were the height of the strip is the texture/image with the larges height. Adding a texture to this atlas generates a texture id. This id is used the sprite list vertex data to reference what texture each sprite is using. The actual texture coordinates are located in a float32 texture this atlas is responsible for keeping up to date. :param Tuple[int, int] size: The width and height of the atlas in pixels :param int border: Currently no effect; Should always be 1 to avoid textures bleeding :param Sequence[arcade.Texture] textures: The texture for this atlas :param bool auto_resize: Automatically resize the atlas when full :param Context ctx: The context for this atlas (will use window context if left empty) """ def __init__( self, size: Tuple[int, int], *, border: int = 1, textures: Sequence["Texture"] = None, auto_resize: bool = True, ctx: "ArcadeContext" = None, ): self._ctx = ctx or arcade.get_window().ctx self._max_size = self._size: Tuple[int, int] = size self._border: int = 1 self._allocator = Allocator(*self._size) self._auto_resize = auto_resize self._check_size(self._size) self._texture = self._ctx.texture(size, components=4) # Creating an fbo makes us able to clear the texture self._fbo = self._ctx.framebuffer(color_attachments=[self._texture]) # A dictionary of all the allocated regions # The key is the cache name for a texture self._atlas_regions: Dict[str, AtlasRegion] = dict() # A set of textures this atlas contains for fast lookups + set operations self._textures: List["Texture"] = [] # Texture containing texture coordinates self._uv_texture = self._ctx.texture( (TEXCOORD_BUFFER_SIZE, 1), components=4, dtype="f4" ) self._uv_texture.filter = self._ctx.NEAREST, self._ctx.NEAREST self._uv_data = array("f", [0] * TEXCOORD_BUFFER_SIZE * 4) # Free slots in the texture coordinate texture self._uv_slots_free = deque(i for i in range(0, TEXCOORD_BUFFER_SIZE)) # Map texture names to slots self._uv_slots: Dict[str, int] = dict() self._uv_data_changed = True # Add all the textures for tex in textures or []: self.add(tex) @property def width(self) -> int: """ The width of the texture atlas in pixels :rtype: int """ return self._size[0] @property def height(self) -> int: """ The height of the texture atlas in pixels :rtype: int """ return self._size[1] @property def size(self) -> Tuple[int, int]: """ The width and height of the texture atlas in pixels :rtype: Tuple[int,int] """ return self._size @property def max_width(self) -> int: """ The maximum width of the atlas in pixels :rtype: int """ return self._max_size[0] @property def max_height(self) -> int: """ The maximum height of the atlas in pixels :rtype: int """ return self._max_size[1] @property def max_size(self) -> Tuple[int, int]: """ The maximum size of the atlas in pixels (x, y) :rtype: Tuple[int,int] """ return self._max_size @property def auto_resize(self) -> bool: """ Get or set the auto resize flag for the atlas. If enabled the atlas will resize itself when full. :rtype: bool """ return self._auto_resize @auto_resize.setter def auto_resize(self, value: bool): self._auto_resize = value @property def border(self) -> int: """ The texture border in pixels :rtype: int """ return self._border @property def texture(self) -> "GLTexture": """ The atlas texture :rtype: Texture """ return self._texture @property def uv_texture(self) -> "GLTexture": """ Texture coordinate texture. :rtype: Texture """ return self._uv_texture @property def fbo(self) -> Framebuffer: """The framebuffer object for this atlas""" return self._fbo
[docs] def add(self, texture: "Texture") -> Tuple[int, AtlasRegion]: """ Add a texture to the atlas. :param Texture texture: The texture to add :return: texture_id, AtlasRegion tuple """ if self.has_texture(texture): slot = self.get_texture_id( region = self.get_region_info( return slot, region"Attempting to add texture: %s", try: x, y, slot, region = self.allocate(texture) except AllocatorException:"[%s] No room for %s size %s", id(self),, texture.image.size) if self._auto_resize: width = min(self.width * 2, self.max_width) height = min(self.height * 2, self.max_height) if self._size == (width, height): raise self.resize((width, height)) return self.add(texture) else: raise self.write_texture(texture, x, y) return slot, region
[docs] def allocate(self, texture: "Texture") -> Tuple[int, int, int, AtlasRegion]: """ Attempts to allocate space for a texture in the atlas. This doesn't write the texture to the atlas texture itself. It only allocates space. :return: The x, y texture_id, TextureRegion """ # Allocate space for texture try: x, y = self._allocator.alloc( texture.image.width + self.border * 2, texture.image.height + self.border * 2, ) except AllocatorException: raise AllocatorException( f"No more space for texture {} size={texture.image.size}" ) LOG.debug("Allocated new space for texture %s : %s %s",, x, y) # Store a texture region for this allocation region = AtlasRegion( self, texture, x + self._border, y + self._border, texture.image.width, texture.image.height, ) self._atlas_regions[] = region # Get the existing slot for this texture or grab a new one. # Existing slots for textures will only happen when re-building # the atlas since we want to keep the same slots to avoid # re-building the sprite list existing_slot = self._uv_slots.get( slot = existing_slot if existing_slot is not None else self._uv_slots_free.popleft() self._uv_slots[] = slot self._uv_data[slot * 4] = region.texture_coordinates[0] self._uv_data[slot * 4 + 1] = region.texture_coordinates[1] self._uv_data[slot * 4 + 2] = region.texture_coordinates[2] self._uv_data[slot * 4 + 3] = region.texture_coordinates[3] self._uv_data_changed = True self._textures.append(texture) return x, y, slot, region
[docs] def write_texture(self, texture: "Texture", x: int, y: int): """ Writes an arcade texture to a subsection of the texture atlas """ # NOTE: We convert to RGBA when padding the image data # if texture.image.mode != "RGBA": # LOG.warning(f"TextureAtlas: Converting texture '{}' to RGBA") # texture.image = texture.image.convert("RGBA") self.write_image(texture.image, x, y)
[docs] def write_image(self, image: PIL.Image.Image, x: int, y: int) -> None: """ Write a PIL image to the atlas in a specific region. :param PIL.Image.Image image: The pillow image :param int x: The x position to write the texture :param int y: The y position to write the texture """ # NOTE: We assume border is at least 1 here # Write into atlas at the allocated location + a 1 pixel border viewport = ( x + self._border - 1, y + self._border - 1, image.width + 2, image.height + 2, ) # print(image.size, viewport,"|", x, y, self._border) # Pad the 1-pixel border with repeating data tmp ='RGBA', (image.width + 2, image.height + 2)) tmp.paste(image, (1, 1)) tmp.paste(tmp.crop((1 , 1 , image.width+1, 2 )), (1 , 0 )) # noqa tmp.paste(tmp.crop((1 , image.height, image.width+1, image.height+1)), (1 , image.height+1)) # noqa tmp.paste(tmp.crop((1 , 0 , 2, image.height+2)), (0 , 0 )) # noqa tmp.paste(tmp.crop((image.width, 0 , image.width+1, image.height+2)), (image.width+1, 0 )) # noqa # Write the image directly to graphics memory in the allocated space self._texture.write(tmp.tobytes(), 0, viewport=viewport)
[docs] def remove(self, texture: "Texture") -> None: """ Remove a texture from the atlas. This doesn't remove the image from the underlying texture. To physically remove the data you need to ``rebuild()``. :param Texture texture: The texture to remove """ self._textures.remove(texture) del self._atlas_regions[] # Reclaim the uv slot slot = self._uv_slots[] del self._uv_slots[] self._uv_slots_free.appendleft(slot)
[docs] def update_texture_image(self, texture: "Texture"): """ Updates the internal image of a texture in the atlas texture. The new image needs to be the exact same size as the original one meaning the texture already need to exist in the atlas. This can be used in cases were the image is manipulated in some way and we need a quick way to sync these changes to graphics memory. This operation is fairly expensive, but still orders of magnitude faster than removing the old texture, adding the new one and re-building the entire atlas. :param Texture texture: The texture to update """ region = self._atlas_regions[] region.verify_image_size() viewport = ( region.x, region.y, region.width, region.height, ) self._texture.write(texture.image.tobytes(), 0, viewport=viewport)
[docs] def get_region_info(self, name: str) -> AtlasRegion: """ Get the region info for a texture :return: The AtlasRegion for the given texture name """ return self._atlas_regions[name]
[docs] def get_texture_id(self, name: str) -> int: """ Get the uv slot for a texture name :return: The texture id for the given texture name """ return self._uv_slots[name]
[docs] def has_texture(self, texture: "Texture") -> bool: """Check if a texture is already in the atlas""" return in self._atlas_regions
# TODO: Possibly let user decide the resize function # def resize(self, size: Tuple[int, int]) -> None: # """ # Resize the texture atlas. # This will cause a full rebuild. # :param Tuple[int,int]: The new size # """ # # if size == self._size: # # return # self._check_size(size) # self._size = size # self._texture = None # self._fbo = None # gc.collect() # Try to force garbage collection of the gl resource asap # self._texture = self._ctx.texture(size, components=4) # self._fbo = self._ctx.framebuffer(color_attachments=[self._texture]) # self.rebuild()
[docs] def resize(self, size: Tuple[int, int]) -> None: """ Resize the atlas on the gpu. This will copy the pixel data from the old to the new atlas retaining the exact same data. This is useful if the atlas was rendered into directly and we don't have to transfer each texture individually from system memory to graphics memory. :param Tuple[int,int] size: The new size """"[%s] Resizing atlas from %s to %s", id(self), self._size, size) if size == self._size: return resize_start = time.perf_counter() self._check_size(size) self._size = size # Keep the old atlas texture and uv texture uv_texture_old = self._uv_texture texture_old = self._texture self._uv_texture.write(self._uv_data, 0) # Create new atlas texture and uv texture + fbo self._uv_texture = self._ctx.texture( (TEXCOORD_BUFFER_SIZE, 1), components=4, dtype="f4" ) self._texture = self._ctx.texture(size, components=4) self._fbo = self._ctx.framebuffer(color_attachments=[self._texture]) textures = self._textures self.clear(texture_ids=False, texture=False) for texture in sorted(textures, key=lambda x: x.image.size[1]): self.allocate(texture) # Write the new UV data self._uv_texture.write(self._uv_data, 0) self._uv_data_changed = False # Bind textures for atlas copy shader texture_old.use(0) self._texture.use(1) uv_texture_old.use(2) self._uv_texture.use(3) self._ctx.atlas_resize_program["projection"] = arcade.create_orthogonal_projection( 0, self.width, self.height, 0, ) with self._fbo.activate(): self._ctx.disable(self._ctx.BLEND) self._ctx.atlas_geometry.render( self._ctx.atlas_resize_program, mode=self._ctx.POINTS, vertices=TEXCOORD_BUFFER_SIZE, )"[%s] Atlas resize took %s seconds", id(self), time.perf_counter() - resize_start)
[docs] def rebuild(self) -> None: """Rebuild the underlying atlas texture. This method also tries to organize the textures more efficiently ordering them by size. The texture ids will persist so the sprite list don't need to be rebuilt. """ # Hold a reference to the old textures textures = self._textures # Clear the atlas but keep the uv slot mapping self.clear(texture_ids=False) # Add textures back sorted by height to potentially make more room for texture in sorted(textures, key=lambda x: x.image.size[1]): self.add(texture)
[docs] def clear(self, texture_ids: bool = True, texture: bool = True) -> None: """ Clear and reset the texture atlas. Note that also clearing "texture_ids" makes the atlas lose track of the old texture ids. This means the sprite list must be rebuild from scratch. :param bool texture_ids: Clear the assigned texture ids :param bool texture: Clear the contents of the atlas texture itself """ if texture: self._fbo.clear() self._textures = [] self._atlas_regions = dict() self._allocator = Allocator(*self._size) if texture_ids: self._uv_slots_free = deque(i for i in range(TEXCOORD_BUFFER_SIZE)) self._uv_slots = dict()
[docs] def use_uv_texture(self, unit: int = 0) -> None: """ Bind the texture coordinate texture to a channel. In addition this method writes the texture coordinate to the texture if the data is stale. This is to avoid a full update every time a texture is added to the atlas. :param int unit: The texture unit to bind the uv texture """ if self._uv_data_changed: self._uv_texture.write(self._uv_data, 0) self._uv_data_changed = False self._uv_texture.use(unit)
[docs] @contextmanager def render_into( self, texture: "Texture", projection: Tuple[float, float, float, float] = None, ): """ Render directly into a sub-section of the atlas. The sub-section is defined by the already allocated space of the texture supplied in this method. By default the projection will be set to match the texture area size were `0, 0` is the lower left corner and `width, height` (of texture) is the upper right corner. This method should should be used with the ``with`` statement:: with atlas.render_into(texture): # Draw commands here # Specify projection with atlas.render_into(texture, projection=(0, 100, 0, 100)) # Draw geometry :param Texture texture: The texture area to render into :param Tuple[float,float,float,float] projection: The ortho projection to render with. This parameter can be left blank if no projection changes are needed. The tuple values are: (left, right, button, top) """ region = self._atlas_regions[] proj_prev = self._ctx.projection_2d # Use provided projection or default projection = projection or (0, region.width, 0, region.height) # Flip the top and bottom because we need to render things upside down projection = projection[0], projection[1], projection[3], projection[2] self._ctx.projection_2d = projection with self._fbo.activate() as fbo: fbo.viewport = region.x, region.y, region.width, region.height try: yield fbo finally: fbo.viewport = 0, 0, *self._fbo.size self._ctx.projection_2d = proj_prev
[docs] @classmethod def create_from_texture_sequence(cls, textures: Sequence["Texture"], border: int = 1) -> "TextureAtlas": """ Create a texture atlas of a reasonable size from a sequence of textures. :param Sequence[Texture] textures: A sequence of textures (list, set, tuple, generator etc.) :param int border: The border for the atlas in pixels (space between each texture) """ textures = sorted(set(textures), key=lambda x: x.image.size[1]) size = TextureAtlas.calculate_minimum_size(textures) return TextureAtlas(size, textures=textures, border=border)
[docs] @classmethod def calculate_minimum_size(cls, textures: Sequence["Texture"], border: int = 1): """ Calculate the minimum atlas size needed to store the the provided sequence of textures :param Sequence[Texture] textures: Sequence of textures :param border: :return: An estimated minimum size as a (width, height) tuple """ # Try to guess some sane minimum size to reduce the brute force iterations total_area = sum(t.image.size[0] * t.image.size[1] for t in textures) sqrt_size = int(math.sqrt(total_area)) start_size = sqrt_size or RESIZE_STEP if start_size % RESIZE_STEP: start_size = sqrt_size + (64 - sqrt_size % RESIZE_STEP) # For now we just brute force a solution by gradually # increasing the atlas size using the allocator as a guide. for size in range(start_size, 16385, RESIZE_STEP): allocator = Allocator(size, size) try: for texture in textures: allocator.alloc( texture.image.width + border * 2, texture.image.height + border * 2, ) except AllocatorException: continue break else: raise ValueError("Too many textures to fit into one atlas") return size, size
[docs] def to_image( self, flip: bool = False, components: int = 4, draw_borders: bool = False, border_color: Tuple[int, int, int] = (255, 0, 0), ) -> Image.Image: """ Convert the atlas to a Pillow image :param bool flip: Flip the image horizontally :param int components: Number of components. (3 = RGB, 4 = RGBA) :param bool draw_borders: Draw region borders into image :param color: RGB color of the borders :return: A pillow image containing the atlas texture """ if components == 4: mode = "RGBA" elif components == 3: mode = "RGB" else: raise ValueError(f"Components must be 3 or 4, not {components}") image = Image.frombytes( mode, self._texture.size, bytes(, ) if self.border == 1 and draw_borders: draw = ImageDraw.Draw(image) for rg in self._atlas_regions.values(): p1 = rg.x - 1, rg.y - 1 p2 = rg.x + rg.width, rg.y + rg.height draw.rectangle([p1, p2], outline=border_color, width=1) if flip: image = image.transpose(Image.FLIP_TOP_BOTTOM) return image
[docs] def show( self, flip: bool = False, components: int = 4, draw_borders: bool = False, border_color: Tuple[int, int, int] = (255, 0, 0), ) -> None: """ Show the texture atlas using Pillow :param bool flip: Flip the image horizontally :param int components: Number of components. (3 = RGB, 4 = RGBA) :param bool draw_borders: Draw region borders into image :param color: RGB color of the borders """ self.to_image( flip=flip, components=components, draw_borders=draw_borders, border_color=border_color, ).show()
[docs] def save( self, path: str, flip: bool = False, components: int = 4, draw_borders: bool = False, border_color: Tuple[int, int, int] = (255, 0, 0), ) -> None: """ Save the texture atlas to a png. :param str path: The path to save the atlas on disk :param bool flip: Flip the image horizontally :param int components: Number of components. (3 = RGB, 4 = RGBA) :param color: RGB color of the borders :return: A pillow image containing the atlas texture """ self.to_image( flip=flip, components=components, draw_borders=draw_borders, border_color=border_color, ).save(path, format="png")
def _check_size(self, size: Tuple[int, int]) -> None: """Check it the atlas exceeds the hardware limitations""" if size[0] > self._max_size[0] or size[1] > self._max_size[1]: raise ValueError( "Attempting to create or resize an atlas to " f"{size} past its maximum size of {self._max_size}" )