为什么在使用 GTKGLArea 时在 PyOpenGL 中未定义 glGenVertexArrays
Why is glGenVertexArrays undefined in PyOpenGL when using GTKGLArea
我在下面有下面的测试代码，我试图让一个基本的 opengl Gtk3 GLArea 示例工作。
下面的错误目前是我的症结所在，从我读到的内容来看，这可能意味着这些功能在上下文中不可用，但阅读有关 GLArea 的信息时，它似乎不允许您选择上下文，听起来应该是默认的到正确的那个。
不幸的是，问题可能出在 GLArea 或 PyOpenGL 上，目前我可以处理的所有示例都在 C 中，非常适合在 python.
中获得一个基本示例
无论如何花了很多时间试图解决这个问题，所以如果有人能帮助解决至少这个错误，那就太好了。
Traceback (most recent call last):
File "gtkglarea.py", line 91, in on_configure_event
self.vertex_array_object = glGenVertexArrays(1)
File "/usr/lib/python3/dist-packages/OpenGL/platform/baseplatform.py", line 407, in call
self.name, self.name,
OpenGL.error.NullFunctionError: Attempt to call an undefined function glGenVertexArrays, check for bool(glGenVertexArrays) before calling
例如，它也是一个要点https://gist.github.com/olymk2/5b3e49ac83130e580bd9983f2e5d49c3
#!/usr/bin/python
import os
import sys
from OpenGL.GLU import *
from OpenGL import GLX
from OpenGL import GL as GL
from ctypes import *
import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk, Gdk
from OpenGL.arrays import vbo
from OpenGL.GL import shaders
from OpenGL.raw.GL.ARB.vertex_array_object import glGenVertexArrays, \
glBindVertexArray
from numpy import array
import numpy as np
VERTEX_SHADER = """
#version 330
in vec4 position;
void main()
{
gl_Position = position;
}"""
FRAGMENT_SHADER = """
#version 330
out vec4 fragColor;
void main()
{
fragColor = vec4(1.0, 0.0, 0.0, 1.0);
}
"""
class application_gui:
"""Tutorial 01 Create and destroy a window"""
# glwrap = gtkglarea()
def __init__(self):
self.window = Gtk.Window()
self.canvas = Gtk.GLArea()
self.canvas.set_required_version(3, 3)
self.test_features()
self.vertices = [
0.6, 0.6, 0.0, 1.0,
-0.6, 0.6, 0.0, 1.0,
0.0, -0.6, 0.0, 1.0]
self.vertices = np.array(self.vertices, dtype=np.float32)
self.canvas.connect('realize', self.on_configure_event)
self.canvas.connect('render', self.on_draw)
self.canvas.set_double_buffered(False)
self.window.connect('delete_event', Gtk.main_quit)
self.window.connect('destroy', lambda quit: Gtk.main_quit())
self.window.add(self.canvas)
self.window.show_all()
self.on_configure_event(self.canvas)
def test_features(self):
print('Testing features')
print('glGenVertexArrays Available %s' % bool(glGenVertexArrays))
print('Alpha Available %s' % bool(self.canvas.get_has_alpha()))
print('Depth buffer Available %s' % bool(self.canvas.get_has_depth_buffer()))
def on_configure_event(self, widget):
print('realize event')
widget.make_current()
# widget.attach_buffers()
context = widget.get_context()
print('is legacy context %s' % Gdk.GLContext.is_legacy(context))
print('configure errors')
print(widget.get_error())
vs = shaders.compileShader(VERTEX_SHADER, GL.GL_VERTEX_SHADER)
fs = shaders.compileShader(FRAGMENT_SHADER, GL.GL_FRAGMENT_SHADER)
self.shader = shaders.compileProgram(vs, fs)
self.vertex_array_object = glGenVertexArrays(1)
GL.glBindVertexArray( self.vertex_array_object )
# Generate buffers to hold our vertices
self.vertex_buffer = GL.glGenBuffers(1)
GL.glBindBuffer(GL.GL_ARRAY_BUFFER, self.vertex_buffer)
# Get the position of the 'position' in parameter of our shader and bind it.
self.position = GL.glGetAttribLocation(self.shader, 'position')
GL.glEnableVertexAttribArray(self.position)
# Describe the position data layout in the buffer
GL.glVertexAttribPointer(self.position, 4, GL.GL_FLOAT, False, 0, ctypes.c_void_p(0))
# Send the data over to the buffer
GL.glBufferData(GL.GL_ARRAY_BUFFER, 48, self.vertices, GL.GL_STATIC_DRAW)
# Unbind the VAO first (Important)
GL.glBindVertexArray( 0 )
# Unbind other stuff
GL.glDisableVertexAttribArray(self.position)
GL.glBindBuffer(GL.GL_ARRAY_BUFFER, 0)
print('errors')
print(widget.get_error())
return True
def on_draw(self, widget, *args):
print('render event')
print(widget.get_error())
#Create the VBO
widget.attach_buffers()
GL.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT)
GL.glUseProgram(self.shader)
GL.glBindVertexArray( self.vertex_array_object )
GL.glDrawArrays(GL.GL_TRIANGLES, 0, 3)
GL.glBindVertexArray( 0 )
GL.glUseProgram(0)
glFlush()
return True
application = application_gui()
Gtk.main()
下面是完整的工作示例，在@derhass 的评论之后我做了一些搜索并发现Gdk.Screen为什么我以前发现的示例中没有使用它我不知道。
这 3 行缺少的拼图
screen = Gdk.Screen.get_default()
visual = Gdk.Screen.get_rgba_visual(screen)
self.window = Gtk.Window()
Gtk.Widget.set_visual(self.window, visual)
完整的工作示例，应该在 window 中显示基本三角形，如下所示。
#!/usr/bin/python
# noqa: E402
import gi
gi.require_version('Gtk', '3.0')
import numpy as np
from gi.repository import Gtk, Gdk
from OpenGL.GLU import *
from OpenGL import GL as GL
from OpenGL.GL import shaders
from OpenGL.raw.GL.ARB.vertex_array_object import glGenVertexArrays, \
glBindVertexArray
# from numpy import array
VERTEX_SHADER = """
#version 330
in vec4 position;
void main()
{
gl_Position = position;
}"""
FRAGMENT_SHADER = """
#version 330
out vec4 fragColor;
void main()
{
fragColor = vec4(1.0, 0.0, 0.0, 1.0);
}
"""
class application_gui:
"""Tutorial 01 Create and destroy a window"""
# glwrap = gtkglarea()
def __init__(self):
screen = Gdk.Screen.get_default()
visual = Gdk.Screen.get_rgba_visual(screen)
print('is composite %s' % Gdk.Screen.is_composited(screen))
self.window = Gtk.Window()
Gtk.Widget.set_visual(self.window, visual)
self.canvas = Gtk.GLArea()
self.canvas.set_required_version(3, 3)
self.test_features()
self.vertices = [
0.6, 0.6, 0.0, 1.0,
-0.6, 0.6, 0.0, 1.0,
0.0, -0.6, 0.0, 1.0]
self.vertices = np.array(self.vertices, dtype=np.float32)
self.canvas.connect('realize', self.on_configure_event)
self.canvas.connect('render', self.on_draw)
self.canvas.set_double_buffered(False)
self.window.connect('delete_event', Gtk.main_quit)
self.window.connect('destroy', lambda quit: Gtk.main_quit())
self.window.add(self.canvas)
self.window.show_all()
def test_features(self):
print('Testing features')
print('glGenVertexArrays Available %s' % bool(glGenVertexArrays))
print('Alpha Available %s' % bool(self.canvas.get_has_alpha()))
print('Depth buffer Available %s' % bool(self.canvas.get_has_depth_buffer()))
def on_configure_event(self, widget):
print('realize event')
widget.make_current()
print(widget.get_error())
vs = shaders.compileShader(VERTEX_SHADER, GL.GL_VERTEX_SHADER)
fs = shaders.compileShader(FRAGMENT_SHADER, GL.GL_FRAGMENT_SHADER)
self.shader = shaders.compileProgram(vs, fs)
# Create a new Vertex Array Object
self.vertex_array_object = GL.glGenVertexArrays(1)
GL.glBindVertexArray(self.vertex_array_object )
# Generate a new array buffers for our vertices
self.vertex_buffer = GL.glGenBuffers(1)
GL.glBindBuffer(GL.GL_ARRAY_BUFFER, self.vertex_buffer)
# Get position variable form the shader and store
self.position = GL.glGetAttribLocation(self.shader, 'position')
GL.glEnableVertexAttribArray(self.position)
# describe the data layout
GL.glVertexAttribPointer(self.position, 4, GL.GL_FLOAT, False, 0, ctypes.c_void_p(0))
# Copy data to the buffer
GL.glBufferData(GL.GL_ARRAY_BUFFER, 48, self.vertices, GL.GL_STATIC_DRAW)
# Unbind buffers once done
GL.glBindVertexArray( 0 )
GL.glDisableVertexAttribArray(self.position)
GL.glBindBuffer(GL.GL_ARRAY_BUFFER, 0)
return True
def on_draw(self, widget, *args):
print('render event')
print(widget.get_error())
# clear screen and select shader for drawing
GL.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT)
GL.glUseProgram(self.shader)
# bind and draw vertices
GL.glBindVertexArray(self.vertex_array_object)
GL.glDrawArrays(GL.GL_TRIANGLES, 0, 3)
GL.glBindVertexArray(0)
GL.glUseProgram(0)
GL.glFlush()
return True
application = application_gui()
Gtk.main()
对我来说，问题似乎与 Wayland 下的 运行 有关。似乎如果 PyOpenGL 在 Wayland 下 运行 并且有一个 X11 服务器 运行，它将使用 GLX 而不是 Wayland 的 EGL 支持。关于 GtkGLArea 如何设置 GL 上下文的一些事情意味着 GLX 可以工作但没有任何 GL 扩展，其中包括 VAO。这似乎是 PyOpenGL 中的错误。
有两种方法可以解决此问题：
设置PYOPENGL_PLATFORM强制PyOpenGL使用EGL而不是GLX。
例如在导入 OpenGL 之前：
if 'WAYLAND_DISPLAY' in os.environ and 'PYOPENGL_PLATFORM' not in os.environ:
os.environ['PYOPENGL_PLATFORM'] = 'egl'
取消设置 WAYLAND_DISPLAY 以强制 Gtk 使用 GLX 而不是 EGL。
例如在导入 Gtk 之前：
if 'WAYLAND_DISPLAY' in os.environ:
del os.environ['WAYLAND_DISPLAY']
运行 在使用 PyOpenGL 和 glfw 时出现此错误，修复是 glfw.make_context_current(window)。
我在下面有下面的测试代码，我试图让一个基本的 opengl Gtk3 GLArea 示例工作。
下面的错误目前是我的症结所在，从我读到的内容来看，这可能意味着这些功能在上下文中不可用，但阅读有关 GLArea 的信息时，它似乎不允许您选择上下文，听起来应该是默认的到正确的那个。
不幸的是，问题可能出在 GLArea 或 PyOpenGL 上，目前我可以处理的所有示例都在 C 中，非常适合在 python.
中获得一个基本示例无论如何花了很多时间试图解决这个问题，所以如果有人能帮助解决至少这个错误，那就太好了。
Traceback (most recent call last):
File "gtkglarea.py", line 91, in on_configure_event
self.vertex_array_object = glGenVertexArrays(1)
File "/usr/lib/python3/dist-packages/OpenGL/platform/baseplatform.py", line 407, in call
self.name, self.name,
OpenGL.error.NullFunctionError: Attempt to call an undefined function glGenVertexArrays, check for bool(glGenVertexArrays) before calling
例如，它也是一个要点https://gist.github.com/olymk2/5b3e49ac83130e580bd9983f2e5d49c3
#!/usr/bin/python
import os
import sys
from OpenGL.GLU import *
from OpenGL import GLX
from OpenGL import GL as GL
from ctypes import *
import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk, Gdk
from OpenGL.arrays import vbo
from OpenGL.GL import shaders
from OpenGL.raw.GL.ARB.vertex_array_object import glGenVertexArrays, \
glBindVertexArray
from numpy import array
import numpy as np
VERTEX_SHADER = """
#version 330
in vec4 position;
void main()
{
gl_Position = position;
}"""
FRAGMENT_SHADER = """
#version 330
out vec4 fragColor;
void main()
{
fragColor = vec4(1.0, 0.0, 0.0, 1.0);
}
"""
class application_gui:
"""Tutorial 01 Create and destroy a window"""
# glwrap = gtkglarea()
def __init__(self):
self.window = Gtk.Window()
self.canvas = Gtk.GLArea()
self.canvas.set_required_version(3, 3)
self.test_features()
self.vertices = [
0.6, 0.6, 0.0, 1.0,
-0.6, 0.6, 0.0, 1.0,
0.0, -0.6, 0.0, 1.0]
self.vertices = np.array(self.vertices, dtype=np.float32)
self.canvas.connect('realize', self.on_configure_event)
self.canvas.connect('render', self.on_draw)
self.canvas.set_double_buffered(False)
self.window.connect('delete_event', Gtk.main_quit)
self.window.connect('destroy', lambda quit: Gtk.main_quit())
self.window.add(self.canvas)
self.window.show_all()
self.on_configure_event(self.canvas)
def test_features(self):
print('Testing features')
print('glGenVertexArrays Available %s' % bool(glGenVertexArrays))
print('Alpha Available %s' % bool(self.canvas.get_has_alpha()))
print('Depth buffer Available %s' % bool(self.canvas.get_has_depth_buffer()))
def on_configure_event(self, widget):
print('realize event')
widget.make_current()
# widget.attach_buffers()
context = widget.get_context()
print('is legacy context %s' % Gdk.GLContext.is_legacy(context))
print('configure errors')
print(widget.get_error())
vs = shaders.compileShader(VERTEX_SHADER, GL.GL_VERTEX_SHADER)
fs = shaders.compileShader(FRAGMENT_SHADER, GL.GL_FRAGMENT_SHADER)
self.shader = shaders.compileProgram(vs, fs)
self.vertex_array_object = glGenVertexArrays(1)
GL.glBindVertexArray( self.vertex_array_object )
# Generate buffers to hold our vertices
self.vertex_buffer = GL.glGenBuffers(1)
GL.glBindBuffer(GL.GL_ARRAY_BUFFER, self.vertex_buffer)
# Get the position of the 'position' in parameter of our shader and bind it.
self.position = GL.glGetAttribLocation(self.shader, 'position')
GL.glEnableVertexAttribArray(self.position)
# Describe the position data layout in the buffer
GL.glVertexAttribPointer(self.position, 4, GL.GL_FLOAT, False, 0, ctypes.c_void_p(0))
# Send the data over to the buffer
GL.glBufferData(GL.GL_ARRAY_BUFFER, 48, self.vertices, GL.GL_STATIC_DRAW)
# Unbind the VAO first (Important)
GL.glBindVertexArray( 0 )
# Unbind other stuff
GL.glDisableVertexAttribArray(self.position)
GL.glBindBuffer(GL.GL_ARRAY_BUFFER, 0)
print('errors')
print(widget.get_error())
return True
def on_draw(self, widget, *args):
print('render event')
print(widget.get_error())
#Create the VBO
widget.attach_buffers()
GL.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT)
GL.glUseProgram(self.shader)
GL.glBindVertexArray( self.vertex_array_object )
GL.glDrawArrays(GL.GL_TRIANGLES, 0, 3)
GL.glBindVertexArray( 0 )
GL.glUseProgram(0)
glFlush()
return True
application = application_gui()
Gtk.main()
下面是完整的工作示例，在@derhass 的评论之后我做了一些搜索并发现Gdk.Screen为什么我以前发现的示例中没有使用它我不知道。
这 3 行缺少的拼图
screen = Gdk.Screen.get_default()
visual = Gdk.Screen.get_rgba_visual(screen)
self.window = Gtk.Window()
Gtk.Widget.set_visual(self.window, visual)
完整的工作示例，应该在 window 中显示基本三角形，如下所示。
#!/usr/bin/python
# noqa: E402
import gi
gi.require_version('Gtk', '3.0')
import numpy as np
from gi.repository import Gtk, Gdk
from OpenGL.GLU import *
from OpenGL import GL as GL
from OpenGL.GL import shaders
from OpenGL.raw.GL.ARB.vertex_array_object import glGenVertexArrays, \
glBindVertexArray
# from numpy import array
VERTEX_SHADER = """
#version 330
in vec4 position;
void main()
{
gl_Position = position;
}"""
FRAGMENT_SHADER = """
#version 330
out vec4 fragColor;
void main()
{
fragColor = vec4(1.0, 0.0, 0.0, 1.0);
}
"""
class application_gui:
"""Tutorial 01 Create and destroy a window"""
# glwrap = gtkglarea()
def __init__(self):
screen = Gdk.Screen.get_default()
visual = Gdk.Screen.get_rgba_visual(screen)
print('is composite %s' % Gdk.Screen.is_composited(screen))
self.window = Gtk.Window()
Gtk.Widget.set_visual(self.window, visual)
self.canvas = Gtk.GLArea()
self.canvas.set_required_version(3, 3)
self.test_features()
self.vertices = [
0.6, 0.6, 0.0, 1.0,
-0.6, 0.6, 0.0, 1.0,
0.0, -0.6, 0.0, 1.0]
self.vertices = np.array(self.vertices, dtype=np.float32)
self.canvas.connect('realize', self.on_configure_event)
self.canvas.connect('render', self.on_draw)
self.canvas.set_double_buffered(False)
self.window.connect('delete_event', Gtk.main_quit)
self.window.connect('destroy', lambda quit: Gtk.main_quit())
self.window.add(self.canvas)
self.window.show_all()
def test_features(self):
print('Testing features')
print('glGenVertexArrays Available %s' % bool(glGenVertexArrays))
print('Alpha Available %s' % bool(self.canvas.get_has_alpha()))
print('Depth buffer Available %s' % bool(self.canvas.get_has_depth_buffer()))
def on_configure_event(self, widget):
print('realize event')
widget.make_current()
print(widget.get_error())
vs = shaders.compileShader(VERTEX_SHADER, GL.GL_VERTEX_SHADER)
fs = shaders.compileShader(FRAGMENT_SHADER, GL.GL_FRAGMENT_SHADER)
self.shader = shaders.compileProgram(vs, fs)
# Create a new Vertex Array Object
self.vertex_array_object = GL.glGenVertexArrays(1)
GL.glBindVertexArray(self.vertex_array_object )
# Generate a new array buffers for our vertices
self.vertex_buffer = GL.glGenBuffers(1)
GL.glBindBuffer(GL.GL_ARRAY_BUFFER, self.vertex_buffer)
# Get position variable form the shader and store
self.position = GL.glGetAttribLocation(self.shader, 'position')
GL.glEnableVertexAttribArray(self.position)
# describe the data layout
GL.glVertexAttribPointer(self.position, 4, GL.GL_FLOAT, False, 0, ctypes.c_void_p(0))
# Copy data to the buffer
GL.glBufferData(GL.GL_ARRAY_BUFFER, 48, self.vertices, GL.GL_STATIC_DRAW)
# Unbind buffers once done
GL.glBindVertexArray( 0 )
GL.glDisableVertexAttribArray(self.position)
GL.glBindBuffer(GL.GL_ARRAY_BUFFER, 0)
return True
def on_draw(self, widget, *args):
print('render event')
print(widget.get_error())
# clear screen and select shader for drawing
GL.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT)
GL.glUseProgram(self.shader)
# bind and draw vertices
GL.glBindVertexArray(self.vertex_array_object)
GL.glDrawArrays(GL.GL_TRIANGLES, 0, 3)
GL.glBindVertexArray(0)
GL.glUseProgram(0)
GL.glFlush()
return True
application = application_gui()
Gtk.main()
对我来说，问题似乎与 Wayland 下的 运行 有关。似乎如果 PyOpenGL 在 Wayland 下 运行 并且有一个 X11 服务器 运行，它将使用 GLX 而不是 Wayland 的 EGL 支持。关于 GtkGLArea 如何设置 GL 上下文的一些事情意味着 GLX 可以工作但没有任何 GL 扩展，其中包括 VAO。这似乎是 PyOpenGL 中的错误。
有两种方法可以解决此问题：
设置
PYOPENGL_PLATFORM强制PyOpenGL使用EGL而不是GLX。例如在导入 OpenGL 之前：
if 'WAYLAND_DISPLAY' in os.environ and 'PYOPENGL_PLATFORM' not in os.environ: os.environ['PYOPENGL_PLATFORM'] = 'egl'取消设置
WAYLAND_DISPLAY以强制 Gtk 使用 GLX 而不是 EGL。例如在导入 Gtk 之前：
if 'WAYLAND_DISPLAY' in os.environ: del os.environ['WAYLAND_DISPLAY']
运行 在使用 PyOpenGL 和 glfw 时出现此错误，修复是 glfw.make_context_current(window)。