from ctypes import c_void_p, byref
from typing import Dict, List, Optional, Sequence, TYPE_CHECKING, Union
import weakref
from pyglet import gl
from .buffer import Buffer
from .types import BufferDescription
from .program import Program
if TYPE_CHECKING: # handle import cycle caused by type hinting
from arcade.gl import Context
index_types = [None, gl.GL_UNSIGNED_BYTE, gl.GL_UNSIGNED_SHORT, None, gl.GL_UNSIGNED_INT]
[docs]class VertexArray:
"""Wrapper for Vertex Array Objects (VAOs).
This objects should not be instantiated from user code.
Use :py:class:`arcade.gl.Geometry` instead. It will create VAO instances for you
automatically. There is a lot of complex interaction between programs
and vertex arrays that will be done for you automatically.
"""
__slots__ = (
"_ctx",
"glo",
"_program",
"_content",
"_ibo",
"_index_element_size",
"_index_element_type",
"_content",
"_num_vertices",
"__weakref__",
)
# TODO: Resolve what VertexArray should actually store
def __init__(
self,
ctx: "Context",
program: Program,
content: Sequence[BufferDescription],
index_buffer: Buffer = None,
index_element_size: int = 4,
):
self._ctx = ctx
self._program = program
self._content = content
self.glo = glo = gl.GLuint()
self._num_vertices = -1
self._ibo = index_buffer
self._index_element_size = index_element_size
self._index_element_type = index_types[index_element_size]
self._build(program, content, index_buffer)
if self._ctx.gc_mode == "auto":
weakref.finalize(self, VertexArray.delete_glo, self.ctx, glo)
self.ctx.stats.incr("vertex_array")
def __repr__(self):
return f"<VertexArray {self.glo.value}>"
def __del__(self):
# Intercept garbage collection if we are using Context.gc()
if self._ctx.gc_mode == "context_gc" and self.glo.value > 0:
self._ctx.objects.append(self)
@property
def ctx(self) -> "Context":
"""
The Context this object belongs to
:type: :py:class:`arcade.gl.Context`
"""
return self._ctx
@property
def program(self) -> Program:
"""
The assigned program
:type: :py:class:`arcade.gl.Program`
"""
return self._program
@property
def ibo(self) -> Optional[Buffer]:
"""
Element/index buffer
:type: :py:class:`arcade.gl.Buffer`
"""
return self._ibo
@property
def num_vertices(self) -> int:
"""
The number of vertices
:type: int
"""
return self._num_vertices
[docs] def delete(self):
"""
Destroy the underlying OpenGL resource.
Don't use this unless you know exactly what you are doing.
"""
VertexArray.delete_glo(self._ctx, self.glo)
self.glo.value = 0
[docs] @staticmethod
def delete_glo(ctx: "Context", glo: gl.GLuint):
"""
Delete this object.
This is automatically called when this object is garbage collected.
"""
# If we have no context, then we are shutting down, so skip this
if gl.current_context is None:
return
if glo.value != 0:
gl.glDeleteVertexArrays(1, byref(glo))
glo.value = 0
ctx.stats.decr("vertex_array")
def _build(
self, program: Program, content: Sequence[BufferDescription], index_buffer
):
"""Build a vertex array compatible with the program passed in"""
gl.glGenVertexArrays(1, byref(self.glo))
gl.glBindVertexArray(self.glo)
if index_buffer is not None:
gl.glBindBuffer(gl.GL_ELEMENT_ARRAY_BUFFER, index_buffer.glo)
# Lookup dict for BufferDescription attrib names
# print(content)
descr_attribs = {
attr.name: (descr, attr) for descr in content for attr in descr.formats
}
# print('->', descr_attribs)
# Build the vao according to the shader's attribute specifications
for i, prog_attr in enumerate(program.attributes):
# print('prog_attr', prog_attr)
# Do we actually have an attribute with this name in buffer descriptions?
if prog_attr.name.startswith("gl_"):
continue
try:
buff_descr, attr_descr = descr_attribs[prog_attr.name]
except KeyError:
raise ValueError(
(
f"Program needs attribute '{prog_attr.name}', but is not present in buffer description. "
f"Buffer descriptions: {content}"
)
)
# TODO: Sanity check this
# if buff_descr.instanced and i == 0:
# raise ValueError("The first vertex attribute cannot be a per instance attribute.")
# Make sure components described in BufferDescription and in the shader match
if prog_attr.components != attr_descr.components:
raise ValueError(
(
f"Program attribute '{prog_attr.name}' has {prog_attr.components} components "
f"while the buffer description has {attr_descr.components} components. "
)
)
# TODO: Compare gltype between buffer descr and program attr
gl.glEnableVertexAttribArray(prog_attr.location)
gl.glBindBuffer(gl.GL_ARRAY_BUFFER, buff_descr.buffer.glo)
# TODO: Detect normalization
normalized = (
gl.GL_TRUE if attr_descr.name in buff_descr.normalized else gl.GL_FALSE
)
gl.glVertexAttribPointer(
prog_attr.location, # attrib location
attr_descr.components, # 1, 2, 3 or 4
attr_descr.gl_type, # GL_FLOAT etc
normalized, # normalize
buff_descr.stride,
c_void_p(attr_descr.offset),
)
# print((
# f"gl.glVertexAttribPointer(\n"
# f" {prog_attr.location}, # attrib location\n"
# f" {attr_descr.components}, # 1, 2, 3 or 4\n"
# f" {attr_descr.gl_type}, # GL_FLOAT etc\n"
# f" {normalized}, # normalize\n"
# f" {buff_descr.stride},\n"
# f" c_void_p({attr_descr.offset}),\n"
# ))
# TODO: Sanity check this
if buff_descr.instanced:
gl.glVertexAttribDivisor(prog_attr.location, 1)
[docs] def render(
self, mode: gl.GLenum, first: int = 0, vertices: int = 0, instances: int = 1
):
"""Render the VertexArray to the currently active framebuffer.
:param GLuint mode: Primitive type to render. TRIANGLES, LINES etc.
:param int first: The first vertex to render from
:param int vertices: Number of vertices to render
:param int instances: OpenGL instance, used in using vertices over and over
"""
gl.glBindVertexArray(self.glo)
if self._ibo is not None:
# HACK: re-bind index buffer just in case. pyglet rendering was somehow replacing the index buffer.
gl.glBindBuffer(gl.GL_ELEMENT_ARRAY_BUFFER, self._ibo.glo)
gl.glDrawElementsInstanced(
mode, vertices, self._index_element_type,
first * self._index_element_size, instances
)
else:
gl.glDrawArraysInstanced(mode, first, vertices, instances)
[docs] def render_indirect(self, buffer: Buffer, mode: gl.GLuint, count, first, stride):
"""
Render the VertexArray to the framebuffer using indirect rendering.
.. Warning:: This requires OpenGL 4.3
:param Buffer buffer: The buffer containing one or multiple draw parameters
:param GLuint mode: Primitive type to render. TRIANGLES, LINES etc.
:param int count: The number if indirect draw calls to run
:param int first: The first indirect draw call to start on
:param int stride: The byte stride of the draw command buffer.
Keep the default (0) if the buffer is tightly packed.
"""
# The default buffer stride for array and indexed
_stride = 20 if self._ibo is not None else 16
stride = stride or _stride
if stride % 4 != 0 or stride < 0:
raise ValueError(f"stride must be positive integer in multiples of 4, not {stride}.")
# The maximum number of draw calls in the buffer
max_commands = buffer.size // stride
if count < 0:
count = max_commands
elif (first + count) > max_commands:
raise ValueError(
"Attempt to issue rendering commands outside the buffer. "
f"first = {first}, count = {count} is reaching past "
f"the buffer end. The buffer have room for {max_commands} "
f"draw commands. byte size {buffer.size}, stride {stride}."
)
gl.glBindVertexArray(self.glo)
gl.glBindBuffer(gl.GL_DRAW_INDIRECT_BUFFER, buffer._glo)
if self._ibo:
gl.glMultiDrawElementsIndirect(mode, self._index_element_type, first * stride, count, stride)
else:
gl.glMultiDrawArraysIndirect(mode, first * stride, count, stride)
[docs]class Geometry:
"""A higher level abstraction of the VertexArray.
It generates VertexArray instances on the fly internally matching the incoming program.
This means we can render the same geometry with different programs as long as the
:py:class:`~arcade.gl.Program` and :py:class:`~arcade.gl.BufferDescription` have compatible attributes.
Geometry objects should be created through :py:meth:`arcade.gl.Context.geometry`
:param Contex ctx: The context this object belongs to
:param list content: List of BufferDescriptions
:param Buffer index_buffer: Index/element buffer
:param int mode: The default draw mode
"""
__slots__ = (
"_ctx",
"_content",
"_index_buffer",
"_index_element_size",
"_mode",
"_vao_cache",
"_num_vertices",
"__weakref__",
)
def __init__(
self,
ctx: "Context",
content: Optional[Sequence[BufferDescription]],
index_buffer: Buffer = None,
mode=None,
index_element_size: int = 4,
):
self._ctx = ctx
self._content = content or []
self._index_buffer = index_buffer
self._index_element_size = index_element_size
self._mode = mode if mode is not None else ctx.TRIANGLES
self._vao_cache = {} # type: Dict[str, VertexArray]
self._num_vertices = -1
"""
:param Contex ctx: The context this object belongs to
:param list content: List of BufferDescriptions
:param Buffer index_buffer: Index/element buffer
:param int mode: The default draw mode (optional)
:param int index_element_size: Byte size of the index buffer datatype. Can be 1, 2 or 4 (8, 16 or 32bit integer)
"""
if self._index_buffer and self._index_element_size not in (1, 2, 4):
raise ValueError("index_element_size must be 1, 2, or 4")
if content:
# Calculate vertices. Use the minimum for now
if self._index_buffer:
self._num_vertices = self._index_buffer.size // self._index_element_size
else:
self._num_vertices = content[0].num_vertices
for descr in self._content:
if descr.instanced:
continue
self._num_vertices = min(self._num_vertices, descr.num_vertices)
# No cleanup is needed, but we want to count them
weakref.finalize(self, Geometry._release, self._ctx)
self._ctx.stats.incr("geometry")
@property
def ctx(self) -> "Context":
"""
The context this geometry belongs to.
:type: :py:class:`~arcade.gl.Geometry`
"""
return self._ctx
@property
def index_buffer(self) -> Optional[Buffer]:
"""
Index/element buffer if supplied at creation.
:type: :py:class:`~arcade.gl.Buffer`
"""
return self._index_buffer
@property
def num_vertices(self) -> int:
"""
Get or set the number of vertices.
Be careful when modifying this properly
and be absolutely sure what you are doing.
:type: int
"""
# TODO: Calculate this better...
return self._num_vertices
@num_vertices.setter
def num_vertices(self, value: int):
self._num_vertices = value
[docs] def instance(self, program: Program) -> VertexArray:
"""
Get the :py:class:`arcade.gl.VertexArray` compatible with this program
"""
vao = self._vao_cache.get(program.attribute_key)
if vao:
return vao
return self._generate_vao(program)
[docs] def render(
self,
program: Program,
*,
mode: gl.GLenum = None,
first: int = 0,
vertices: int = None,
instances: int = 1,
) -> None:
"""Render the geometry with a specific program.
The geometry object will know how many vertices your buffers contains
so overriding vertices is not needed unless you have a special case
or have resized the buffers after the geometry instance was created.
:param Program program: The Program to render with
:param gl.GLenum mode: Override what primitive mode should be used
:param int first: Offset start vertex
:param int vertices: Override the number of vertices to render
:param int instances: Number of instances to render
"""
program.use()
vao = self.instance(program)
mode = self._mode if mode is None else mode
# If we have a geometry shader we need to sanity check that
# the primitive mode is supported
if program.geometry_vertices > 0:
if program.geometry_input == self._ctx.POINTS:
mode = program.geometry_input
if program.geometry_input == self._ctx.LINES:
if mode not in [self._ctx.LINES, self._ctx.LINE_STRIP, self._ctx.LINE_LOOP, self._ctx.LINES_ADJACENCY]:
raise ValueError(
"Geometry shader expects LINES, LINE_STRIP, LINE_LOOP or LINES_ADJACENCY as input")
if program.geometry_input == self._ctx.LINES_ADJACENCY:
if mode not in [self._ctx.LINES_ADJACENCY, self._ctx.LINE_STRIP_ADJACENCY]:
raise ValueError(
"Geometry shader expects LINES_ADJACENCY or LINE_STRIP_ADJACENCY as input")
if program.geometry_input == self._ctx.TRIANGLES:
if mode not in [self._ctx.TRIANGLES, self._ctx.TRIANGLE_STRIP, self._ctx.TRIANGLE_FAN]:
raise ValueError(
"Geometry shader expects GL_TRIANGLES, GL_TRIANGLE_STRIP or GL_TRIANGLE_FAN as input")
if program.geometry_input == self._ctx.TRIANGLES_ADJACENCY:
if mode not in [self._ctx.TRIANGLES_ADJACENCY, self._ctx.TRIANGLE_STRIP_ADJACENCY]:
raise ValueError(
"Geometry shader expects GL_TRIANGLES_ADJACENCY or GL_TRIANGLE_STRIP_ADJACENCY as input")
vao.render(
mode=mode,
first=first,
vertices=vertices or self._num_vertices,
instances=instances,
)
[docs] def render_indirect(
self,
program: Program,
buffer: Buffer,
*,
mode: gl.GLuint = None,
count: int = -1,
first: int = 0,
stride: int = 0,
):
"""
Render the VertexArray to the framebuffer using indirect rendering.
.. Warning:: This requires OpenGL 4.3
The following structs are expected for the buffer::
// Array rendering - no index buffer (16 bytes)
typedef struct {
uint count;
uint instanceCount;
uint first;
uint baseInstance;
} DrawArraysIndirectCommand;
// Index rendering - with index buffer 20 bytes
typedef struct {
GLuint count;
GLuint instanceCount;
GLuint firstIndex;
GLuint baseVertex;
GLuint baseInstance;
} DrawElementsIndirectCommand;
The ``stride`` is the byte stride between every redering command
in the buffer. By default we assume this is 16 for array rendering
(no index buffer) and 20 for indexed rendering (with index buffer)
:param Program program: The program to execute
:param Buffer buffer: The buffer containing one or multiple draw parameters
:param GLuint mode: Primitive type to render. TRIANGLES, LINES etc.
:param int count: The number if indirect draw calls to run.
If omitted all draw commands in the buffer will be executed.
:param int first: The first indirect draw call to start on
:param int stride: The byte stride of the draw command buffer.
Keep the default (0) if the buffer is tightly packed.
"""
program.use()
vao = self.instance(program)
mode = self._mode if mode is None else mode
vao.render_indirect(buffer, mode, count, first, stride)
[docs] def flush(self) -> None:
"""
Flush all the internally generated VertexArrays.
The Geometry instance will store a VertexArray
for every unique set of input attributes it
stumbles over when redering and transform calls
are issued. This data is usually pretty light weight
and usually don't need flushing.
"""
self._vao_cache = {}
def _generate_vao(self, program: Program) -> VertexArray:
"""Here we do the VertexArray building"""
# print(f"Generating vao for key {program.attribute_key}")
vao = VertexArray(
self._ctx,
program,
self._content,
index_buffer=self._index_buffer,
index_element_size=self._index_element_size,
)
self._vao_cache[program.attribute_key] = vao
return vao
@staticmethod
def _release(ctx):
"""Mainly here to count destroyed instances"""
ctx.stats.decr("geometry")