8000 Extremely WIP protocol based abstraction of arcade.gl · pythonarcade/arcade@6fec97d · GitHub
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Extremely WIP protocol based abstraction of arcade.gl
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‎arcade/gl/backends/gl/__init__.py

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from .context import GLContext
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from .buffer import GLBuffer

‎arcade/gl/backends/gl/buffer.py

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from __future__ import annotations
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import weakref
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from ctypes import byref, string_at
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from typing import TYPE_CHECKING
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from pyglet import gl
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from arcade.types import BufferProtocol
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from arcade.gl.new import Buffer, Context
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from .utils import data_to_ctypes
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if TYPE_CHECKING:
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from arcade.gl.backends.gl import GLContext
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class GLBuffer(Buffer):
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"""OpenGL buffer object. Buffers store byte data and upload it
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to graphics memory so shader programs can process the data.
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They are used for storage of vertex data,
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element data (vertex indexing), uniform block data etc.
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The ``data`` parameter can be anything that implements the
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`Buffer Protocol <https://docs.python.org/3/c-api/buffer.html>`_.
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This includes ``bytes``, ``bytearray``, ``array.array``, and
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more. You may need to use typing workarounds for non-builtin
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types. See :ref:`prog-guide-gl-buffer-protocol-typing` for more
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information.
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.. warning:: Buffer objects should be created using :py:meth:`arcade.gl.Context.buffer`
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Args:
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ctx:
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The context this buffer belongs to
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data:
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The data this buffer should contain. It can be a ``bytes`` instance or any
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object supporting the buffer protocol.
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reserve:
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Create a buffer of a specific byte size
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usage:
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A hit of this buffer is ``static`` or ``dynamic`` (can mostly be ignored)
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"""
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__slots__ = "_ctx", "_glo", "_size", "_usage", "__weakref__"
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_usages = {
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"static": gl.GL_STATIC_DRAW,
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"dynamic": gl.GL_DYNAMIC_DRAW,
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"stream": gl.GL_STREAM_DRAW,
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}
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def __init__(
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self,
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ctx: Context,
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data: BufferProtocol | None = None,
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reserve: int = 0,
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usage: str = "static",
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) -> None:
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assert isinstance(ctx, GLContext)
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self._ctx = ctx
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self._glo = glo = gl.GLuint()
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self._size = -1
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self._usage = GLBuffer._usages[usage]
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gl.glGenBuffers(1, byref(self._glo))
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# print(f"glGenBuffers() -> {self._glo.value}")
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if self._glo.value == 0:
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raise RuntimeError("Cannot create Buffer object.")
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# print(f"glBindBuffer({self._glo.value})")
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gl.glBindBuffer(gl.GL_ARRAY_BUFFER, self._glo)
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# print(f"glBufferData(gl.GL_ARRAY_BUFFER, {self._size}, data, {self._usage})")
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if data is not None and len(data) > 0: # type: ignore
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self._size, data = data_to_ctypes(data)
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gl.glBufferData(gl.GL_ARRAY_BUFFER, self._size, data, self._usage)
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elif reserve > 0:
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self._size = reserve
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# populate the buffer with zero byte values
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data = (gl.GLubyte * self._size)()
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gl.glBufferData(gl.GL_ARRAY_BUFFER, self._size, data, self._usage)
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else:
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raise ValueError("Buffer takes byte data or number of reserved bytes")
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if self._ctx.gc_mode == "auto":
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weakref.finalize(self, GLBuffer.delete_glo, self.ctx, glo)
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self._ctx.stats.incr("buffer")
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def __repr__(self):
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return f"<Buffer {self._glo.value}>"
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def __del__(self):
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# Intercept garbage collection if we are using Context.gc()
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if self._ctx.gc_mode == "context_gc" and self._glo.value > 0:
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self._ctx.objects.append(self)
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@property
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def size(self) -> int:
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"""The byte size of the buffer."""
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return self._size
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@property
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def ctx(self) -> GLContext:
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"""The context this resource belongs to."""
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return self._ctx
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@property
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def glo(self) -> gl.GLuint:
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"""The OpenGL resource id."""
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return self._glo
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def delete(self) -> None:
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"""
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Destroy the underlying OpenGL resource.
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.. warning:: Don't use this unless you know exactly what you are doing.
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"""
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GLBuffer.delete_glo(self._ctx, self._glo)
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self._glo.value = 0
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@staticmethod
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def delete_glo(ctx: GLContext, glo: gl.GLuint):
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"""
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Release/delete open gl buffer.
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This is automatically called when the object is garbage collected.
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Args:
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ctx:
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The context the buffer belongs to
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glo:
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The OpenGL buffer id
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"""
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# If we have no context, then we are shutting down, so skip this
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if gl.current_context is None:
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return
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if glo.value != 0:
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gl.glDeleteBuffers(1, byref(glo))
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glo.value = 0
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ctx.stats.decr("buffer")
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def read(self, size: int = -1, offset: int = 0) -> bytes:
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"""Read data from the buffer.
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Args:
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size:
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The bytes to read. -1 means the entire buffer (default)
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offset:
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Byte read offset
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"""
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if size == -1:
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size = self._size - offset
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# Catch this before confusing INVALID_OPERATION is raised
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if size < 1:
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raise ValueError(
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"Attempting to read 0 or less bytes from buffer: "
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f"buffer size={self._size} | params: size={size}, offset={offset}"
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)
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# Manually detect this so it doesn't raise a confusing INVALID_VALUE error
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if size + offset > self._size:
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raise ValueError(
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(
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"Attempting to read outside the buffer. "
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f"Buffer size: {self._size} "
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f"Reading from {offset} to {size + offset}"
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)
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)
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gl.glBindBuffer(gl.GL_ARRAY_BUFFER, self._glo)
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ptr = gl.glMapBufferRange(gl.GL_ARRAY_BUFFER, offset, size, gl.GL_MAP_READ_BIT)
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data = string_at(ptr, size=size)
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gl.glUnmapBuffer(gl.GL_ARRAY_BUFFER)
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return data
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def write(self, data: BufferProtocol, offset: int = 0):
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"""Write byte data to the buffer from a buffer protocol object.
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The ``data`` value can be anything that implements the
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`Buffer Protocol <https://docs.python.org/3/c-api/buffer.html>`_.
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This includes ``bytes``, ``bytearray``, ``array.array``, and
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more. You may need to use typing workarounds for non-builtin
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types. See :ref:`prog-guide-gl-buffer-protocol-typing` for more
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information.
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If the supplied data is larger than the buffer, it will be
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truncated to fit. If the supplied data is smaller than the
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buffer, the remaining bytes will be left unchanged.
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Args:
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data:
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The byte data to write. This can be bytes or any object
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supporting the buffer protocol.
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offset:
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The byte offset
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"""
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gl.glBindBuffer(gl.GL_ARRAY_BUFFER, self._glo)
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size, data = data_to_ctypes(data)
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# Ensure we don't write outside the buffer
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size = min(size, self._size - offset)
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if size < 0:
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raise ValueError("Attempting to write negative number bytes to buffer")
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gl.glBufferSubData(gl.GL_ARRAY_BUFFER, gl.GLintptr(offset), size, data)
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def copy_from_buffer(self, source: Buffer, size=-1, offset=0, source_offset=0) -> None:
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"""Copy data into this buffer from another buffer.
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Args:
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source:
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The buffer to copy from
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size:
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The amount of bytes to copy
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offset:
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The byte offset to write the data in this buffer
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source_offset:
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The byte offset to read from the source buffer
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"""
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assert isinstance(source, GLBuffer)
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# Read the entire source buffer into this buffer
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if size == -1:
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size = source.size
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# TODO: Check buffer bounds
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if size + source_offset > source.size:
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raise ValueError("Attempting to read outside the source buffer")
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if size + offset > self._size:
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raise ValueError("Attempting to write outside the buffer")
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gl.glBindBuffer(gl.GL_COPY_READ_BUFFER, source.glo)
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gl.glBindBuffer(gl.GL_COPY_WRITE_BUFFER, self._glo)
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gl.glCopyBufferSubData(
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gl.GL_COPY_READ_ F438 BUFFER,
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gl.GL_COPY_WRITE_BUFFER,
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gl.GLintptr(source_offset), # readOffset
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gl.GLintptr(offset), # writeOffset
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size, # size (number of bytes to copy)
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)
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def orphan(self, size: int = -1, double: bool = False):
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"""
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Re-allocate the entire buffer memory. This can be used to resize
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a buffer or for re-specification (orphan the buffer to avoid blocking).
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If the current buffer is busy in rendering operations
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it will be deallocated by OpenGL when completed.
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Args:
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size:
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New size of buffer. -1 will retain the current size.
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Takes precedence over ``double`` parameter if specified.
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double:
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Is passed in with `True` the buffer size will be doubled
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from its current size.
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"""
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if size > 0:
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self._size = size
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elif double is True:
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self._size *= 2
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gl.glBindBuffer(gl.GL_ARRAY_BUFFER, self._glo)
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gl.glBufferData(gl.GL_ARRAY_BUFFER, self._size, None, self._usage)
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def bind_to_uniform_block(self, binding: int = 0, offset: int = 0, size: int = -1):
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"""Bind this buffer to a uniform block location.
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In most cases it will be sufficient to only provide a binding location.
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Args:
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binding:
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The binding location
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offset:
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Byte offset
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size:
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Size of the buffer to bind.
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""&qu AD16 ot;
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if size < 0:
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size = self.size
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gl.glBindBufferRange(gl.GL_UNIFORM_BUFFER, binding, self._glo, offset, size)
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def bind_to_storage_buffer(self, binding: int = 0, offset: int = 0, size: int = -1) -> None:
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"""
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Bind this buffer as a shader storage buffer.
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Args:
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binding:
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The binding location
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offset:
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Byte offset in the buffer
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size:
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The size in bytes. The entire buffer will be mapped by default.
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"""
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if size < 0:
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size = self.size
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gl.glBindBufferRange(gl.GL_SHADER_STORAGE_BUFFER, binding, self._glo, offset, size)

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