from typing import List
import numpy
import moderngl
import moderngl_window as mglw
from moderngl_window.opengl import types
# For sanity checking draw modes when creating the VAO
DRAW_MODES = {
moderngl.TRIANGLES: 'TRIANGLES',
moderngl.TRIANGLE_FAN: 'TRIANGLE_FAN',
moderngl.TRIANGLE_STRIP: 'TRIANGLE_STRIP',
moderngl.TRIANGLES_ADJACENCY: 'TRIANGLES_ADJACENCY',
moderngl.TRIANGLE_STRIP_ADJACENCY: 'TRIANGLE_STRIP_ADJACENCY',
moderngl.POINTS: 'POINTS',
moderngl.LINES: 'LINES',
moderngl.LINE_STRIP: 'LINE_STRIP',
moderngl.LINE_LOOP: 'LINE_LOOP',
moderngl.LINES_ADJACENCY: 'LINES_ADJACENCY',
}
class BufferInfo:
"""Container for a vbo with additional information"""
def __init__(self, buffer: moderngl.Buffer, buffer_format: str, attributes=None, per_instance=False):
"""
:param buffer: The vbo object
:param format: The format of the buffer
"""
self.buffer = buffer
self.attrib_formats = types.parse_attribute_formats(buffer_format)
self.attributes = attributes
self.per_instance = per_instance
# Sanity check byte size
if self.buffer.size % self.vertex_size != 0:
raise VAOError("Buffer with type {} has size not aligning with {}. Remainder: {}".format(
buffer_format, self.vertex_size, self.buffer.size % self.vertex_size
))
self.vertices = self.buffer.size // self.vertex_size
@property
def vertex_size(self) -> int:
return sum(f.bytes_total for f in self.attrib_formats)
def content(self, attributes: List[str]):
"""Build content tuple for the buffer"""
formats = []
attrs = []
for attrib_format, attrib in zip(self.attrib_formats, self.attributes):
if attrib not in attributes:
formats.append(attrib_format.pad_str())
continue
formats.append(attrib_format.format)
attrs.append(attrib)
attributes.remove(attrib)
if not attrs:
return None
return (
self.buffer,
"{}{}".format(" ".join(formats), '/i' if self.per_instance else ''),
*attrs
)
def has_attribute(self, name):
return name in self.attributes
[docs]class VAO:
"""
Represents a vertex array object.
This is a wrapper class over ``moderngl.VertexArray`` to make interactions
with programs/shaders simpler. Named buffers are added correspoding with
attribute names in a vertex shader. When rendering the VAO an internal
```moderngl.VertextArray`` is created by automatically creating a buffer
mapping compatible with the supplied program. This program is cached
internally.
The shader program doesn't need to use all the buffers registered in
this wrapper. When a subset is used only the used buffers are mapped
and the approproate padding is calculated when iterleaved data is used.
There is no requirements to use this class, but most methods in the
system creating vertexbuffers will return this type. You can obtain
a single ```moderngl.VertexBuffer`` instance by calling :py:meth:`VAO.instance`
method if you prefer to work directly on moderngl instances.
Example::
# Separate buffers
vao = VAO(name="test", mode=moderngl.POINTS)
vao.buffer(positions, '3f', ['in_position'])
vao.buffer(velocities, '3f', ['in_velocities'])
# Interleaved
vao = VAO(name="test", mode=moderngl.POINTS)
vao.buffer(interleaved_data, '3f 3f', ['in_position', 'in_velocities'])
.. code:: glsl
# GLSL vertex shader in attributes
in vec3 in_position;
in vec3 in_velocities;
"""
[docs] def __init__(self, name="", mode=moderngl.TRIANGLES):
"""Create and empty VAO with a name and default render mode.
Example::
VAO(name="cube", mode=moderngl.TRIANGLES)
Keyword Args:
name (str): Optional name for debug purposes
mode (int): Default draw mode
"""
self.name = name
self.mode = mode
try:
DRAW_MODES[self.mode]
except KeyError:
raise VAOError("Invalid draw mode. Options are {}".format(DRAW_MODES.values()))
self._buffers = []
self._index_buffer = None
self._index_element_size = None
self.vertex_count = 0
self.vaos = {}
@property
def ctx(self):
"""moderngl.Context: The actite moderngl context"""
return mglw.ctx()
[docs] def render(self, program: moderngl.Program, mode=None, vertices=-1, first=0, instances=1):
"""Render the VAO.
An internal ``moderngl.VertexBuffer`` with compatible buffer bindings
is automatically created on the fly and cached internally.
Args:
program: The ``moderngl.Program``
Keyword Args:
mode: Override the draw mode (``TRIANGLES`` etc)
vertices (int): The number of vertices to transform
first (int): The index of the first vertex to start with
instances (int): The number of instances
"""
vao = self.instance(program)
if mode is None:
mode = self.mode
vao.render(mode, vertices=vertices, first=first, instances=instances)
[docs] def render_indirect(self, program: moderngl.Program, buffer, mode=None, count=-1, *, first=0):
"""The render primitive (mode) must be the same as the input primitive of the GeometryShader.
The draw commands are 5 integers: (count, instanceCount, firstIndex, baseVertex, baseInstance).
Args:
program: The ``moderngl.Program``
buffer: The ``moderngl.Buffer`` containing indirect draw commands
Keyword Args:
mode (int): By default :py:data:`TRIANGLES` will be used.
count (int): The number of draws.
first (int): The index of the first indirect draw command.
"""
vao = self.instance(program)
if mode is None:
mode = self.mode
vao.render_indirect(buffer, mode=mode, count=count, first=first)
[docs] def buffer(self, buffer, buffer_format: str, attribute_names: List[str]):
"""Register a buffer/vbo for the VAO. This can be called multiple times.
adding multiple buffers (interleaved or not).
Args:
buffer: The buffer data. Can be ``numpy.array``, ``moderngl.Buffer`` or ``bytes``.
buffer_format (str): The format of the buffer. (eg. ``3f 3f`` for interleaved positions and normals).
attribute_names: A list of attribute names this buffer should map to.
Returns:
The ``moderngl.Buffer`` instance object. This is handy when providing ``bytes`` and ``numpy.array``.
"""
if not isinstance(attribute_names, list):
attribute_names = [attribute_names, ]
if not type(buffer) in [moderngl.Buffer, numpy.ndarray, bytes]:
raise VAOError(
(
"buffer parameter must be a moderngl.Buffer, numpy.ndarray or bytes instance"
"(not {})".format(type(buffer))
)
)
if isinstance(buffer, numpy.ndarray):
buffer = self.ctx.buffer(buffer.tobytes())
if isinstance(buffer, bytes):
buffer = self.ctx.buffer(data=buffer)
formats = buffer_format.split()
if len(formats) != len(attribute_names):
raise VAOError("Format '{}' does not describe attributes {}".format(buffer_format, attribute_names))
self._buffers.append(BufferInfo(buffer, buffer_format, attribute_names))
self.vertex_count = self._buffers[-1].vertices
return buffer
[docs] def index_buffer(self, buffer, index_element_size=4):
"""Set the index buffer for this VAO.
Args:
buffer: ``moderngl.Buffer``, ``numpy.array`` or ``bytes``
Keyword Args:
index_element_size (int): Byte size of each element. 1, 2 or 4
"""
if not type(buffer) in [moderngl.Buffer, numpy.ndarray, bytes]:
raise VAOError("buffer parameter must be a moderngl.Buffer, numpy.ndarray or bytes instance")
if isinstance(buffer, numpy.ndarray):
buffer = self.ctx.buffer(buffer.tobytes())
if isinstance(buffer, bytes):
buffer = self.ctx.buffer(data=buffer)
self._index_buffer = buffer
self._index_element_size = index_element_size
[docs] def instance(self, program: moderngl.Program) -> moderngl.VertexArray:
"""Obtain the ``moderngl.VertexArray`` instance for the program.
The instance is only created once and cached internally.
Args:
program (moderngl.Program): The program
Returns:
``moderngl.VertexArray``: instance
"""
vao = self.vaos.get(program.glo)
if vao:
return vao
program_attributes = [name for name, attr in program._members.items() if isinstance(attr, moderngl.Attribute)]
# Make sure all attributes are covered
for attrib_name in program_attributes:
# Ignore built in attributes for now
if attrib_name.startswith('gl_'):
continue
# Do we have a buffer mapping to this attribute?
if not sum(buffer.has_attribute(attrib_name) for buffer in self._buffers):
raise VAOError("VAO {} doesn't have attribute {} for program {}".format(
self.name, attrib_name, program))
vao_content = []
# Pick out the attributes we can actually map
for buffer in self._buffers:
content = buffer.content(program_attributes)
if content:
vao_content.append(content)
# Any attribute left is not accounted for
if program_attributes:
for attrib_name in program_attributes:
if attrib_name.startswith('gl_'):
continue
raise VAOError("Did not find a buffer mapping for {}".format([n for n in program_attributes]))
# Create the vao
if self._index_buffer:
vao = self.ctx.vertex_array(
program, vao_content,
self._index_buffer, self._index_element_size,
)
else:
vao = self.ctx.vertex_array(program, vao_content)
self.vaos[program.glo] = vao
return vao
[docs] def release(self, buffer=True):
"""Destroy all iternally cached vaos and release all buffers.
Keyword Args:
buffers (bool): also release buffers
"""
for _, vao in self.vaos.items():
vao.release()
if buffer:
for buff in self._buffers:
buff.buffer.release()
if self._index_buffer:
self._index_buffer.release()
[docs] def get_buffer_by_name(self, name: str) -> BufferInfo:
"""Get the BufferInfo associated with a specific attribute name
If no buffer is associated with the name `None` will be returned.
Args:
name (str): Name of the mapped attribute
Returns:
BufferInfo: BufferInfo instance
"""
for buffer in self._buffers:
if name in buffer.attributes:
return buffer
return None
class VAOError(Exception):
pass