使用自定义 QSurfaceFormat 时出现 PySide2 OpenGL 错误

Question

我使用QSurfaceFormat 明确定义OpenGL 核心配置文件 并设置次要/主要版本。问题是，自定义表面格式的分配给了我以下错误：

Traceback (most recent call last):
  File "/home/artem/PycharmProjects/PolyEdit3D/PolyEdit3D/Widgets/PlyViewport.py", line 22, in initializeGL
    gl.glEnable(gl.GL_COLOR_BUFFER_BIT)
  File "/home/artem/.local/lib/python3.7/site-packages/OpenGL/platform/baseplatform.py", line 415, in __call__
    return self( *args, **named )
  File "src/errorchecker.pyx", line 58, in OpenGL_accelerate.errorchecker._ErrorChecker.glCheckError
OpenGL.error.GLError: GLError(
    err = 1280,
    description = b'invalid enumerant',
    baseOperation = glEnable,
    cArguments = (GL_COLOR_BUFFER_BIT,)
)
Traceback (most recent call last):
  File "/home/artem/PycharmProjects/PolyEdit3D/PolyEdit3D/Widgets/PlyViewport.py", line 69, in paintGL
    gl.glDrawElements(gl.GL_TRIANGLES, 6, gl.GL_UNSIGNED_INT, ctypes.c_void_p(0))
  File "src/latebind.pyx", line 39, in OpenGL_accelerate.latebind.LateBind.__call__
  File "src/wrapper.pyx", line 318, in OpenGL_accelerate.wrapper.Wrapper.__call__
  File "src/wrapper.pyx", line 311, in OpenGL_accelerate.wrapper.Wrapper.__call__
  File "/home/artem/.local/lib/python3.7/site-packages/OpenGL/platform/baseplatform.py", line 415, in __call__
    return self( *args, **named )
  File "src/errorchecker.pyx", line 58, in OpenGL_accelerate.errorchecker._ErrorChecker.glCheckError
OpenGL.error.GLError: GLError(
    err = 1282,
    description = b'invalid operation',
    baseOperation = glDrawElements,
    pyArgs = (
        GL_TRIANGLES,
        6,
        GL_UNSIGNED_INT,
        c_void_p(None),
    ),
    cArgs = (
        GL_TRIANGLES,
        6,
        GL_UNSIGNED_INT,
        c_void_p(None),
    ),
    cArguments = (
        GL_TRIANGLES,
        6,
        GL_UNSIGNED_INT,
        c_void_p(None),
    )
)

如您所见，gl.glEnable(gl.GL_COLOR_BUFFER_BIT) 和其他简单的事情有一个错误。如果不指定QSurfaceFormat，一切都会像魅力一样发挥作用。

这是我的表面格式类：

class GLSurfaceFormat(QtGui.QSurfaceFormat):
    def __init__(self):
        super(GLSurfaceFormat, self).__init__()
        self.__initSurface()

    def __initSurface(self):
        self.setRenderableType(QtGui.QSurfaceFormat.OpenGL)
        self.setMinorVersion(3)
        self.setMajorVersion(4)
        self.setProfile(QtGui.QSurfaceFormat.CoreProfile)
        self.setColorSpace(QtGui.QSurfaceFormat.sRGBColorSpace)
        self.setSwapBehavior(QtGui.QSurfaceFormat.DoubleBuffer)

我是这样分配的：

    QApplication.setAttribute(Qt.AA_UseDesktopOpenGL)
    QSurfaceFormat.setDefaultFormat(GLSurfaceFormat())

    app = QApplication(sys.argv)
    ...

您能告诉我，QSurfaceFormat 的用法有什么错误吗？还是有其他问题？

！更新！ 这是一个简单的示例，您可以在其中重现相同的行为：

from PySide2 import QtCore, QtGui, QtWidgets
from OpenGL import GL as gl
from OpenGL.GL.shaders import compileProgram, compileShader
import numpy as np
import ctypes
import sys
import glm

class PlyViewportWidget(QtWidgets.QOpenGLWidget):
    def __init__(self):
        super(PlyViewportWidget, self).__init__(parent=None)
        self.vao = None
        self.vbo = None
        self.ebo = None
        self.shaderProg = None
        self.isWireframe = False

    def initializeGL(self):
        gl.glEnable(gl.GL_COLOR_BUFFER_BIT)
        gl.glClearColor(0.4, 0.4, 0.4, 1)

        with open("fragment.glsl", 'r') as f:
            fragment = compileShader(f.read(), gl.GL_FRAGMENT_SHADER)
        with open("vertex.glsl", "r") as f:
            vertex = compileShader(f.read(), gl.GL_VERTEX_SHADER)
        self.shaderProg = compileProgram(vertex, fragment)

        vertices = np.array(
            [
                0.5, 0.5, 0.0,
                0.5, -0.5, 0.0,
                -0.5, -0.5, 0.0,
                -0.5, 0.5, 0.0
            ], dtype=ctypes.c_float
        )
        indices = np.array(
            [
                0, 1, 3,
                1, 2, 3
            ], dtype=ctypes.c_uint
        )

        self.vbo = gl.glGenBuffers(1)
        self.ebo = gl.glGenBuffers(1)

        gl.glBindBuffer(gl.GL_ARRAY_BUFFER, self.vbo)
        gl.glBufferData(gl.GL_ARRAY_BUFFER, vertices.nbytes, vertices, gl.GL_STATIC_DRAW)

        gl.glBindBuffer(gl.GL_ELEMENT_ARRAY_BUFFER, self.ebo)
        gl.glBufferData(gl.GL_ELEMENT_ARRAY_BUFFER, indices.nbytes, indices, gl.GL_STATIC_DRAW)

        gl.glEnableVertexAttribArray(0)
        gl.glVertexAttribPointer(0, 3, gl.GL_FLOAT, gl.GL_FALSE, 3 * ctypes.sizeof(ctypes.c_float), ctypes.c_void_p(0))

        gl.glBindBuffer(gl.GL_ARRAY_BUFFER, 0)
        gl.glBindVertexArray(0)

        gl.glUseProgram(self.shaderProg)

    def paintGL(self):
        gl.glClearColor(0.4, 0.4, 0.4, 1.0)
        gl.glClear(gl.GL_COLOR_BUFFER_BIT)

        trans = self.getTransformMatrix()
        #u_transform = gl.glGetUniformLocation(self.shaderProg, "u_transform")
        #gl.glUniformMatrix4fv(u_transform, 1, gl.GL_FALSE, u_transform)

        gl.glBindVertexArray(self.vao)
        gl.glDrawElements(gl.GL_TRIANGLES, 6, gl.GL_UNSIGNED_INT, ctypes.c_void_p(0))

    def resizeGL(self, w:int, h:int):
        gl.glViewport(0, 0, w, h)

    def keyPressEvent(self, event:QtGui.QKeyEvent):
        self.makeCurrent()
        if event.key() == QtCore.Qt.Key_Z and not self.isWireframe:
            gl.glPolygonMode(gl.GL_FRONT_AND_BACK, gl.GL_LINE)
            self.isWireframe = True
            self.update()
        elif event.key() == QtCore.Qt.Key_Z and self.isWireframe:
            gl.glPolygonMode(gl.GL_FRONT_AND_BACK, gl.GL_FILL)
            self.isWireframe = False
            self.update()

        event.accept()

    def getTransformMatrix(self):
        return glm.rotate(glm.mat4(1.0), glm.radians(90.0), glm.vec3(1.0, 0.0, 0.0))


class GLSurfaceFormat(QtGui.QSurfaceFormat):
    def __init__(self):
        super(GLSurfaceFormat, self).__init__()
        self.__initSurface()

    def __initSurface(self):
        self.setRenderableType(QtGui.QSurfaceFormat.OpenGL)
        self.setMinorVersion(3)
        self.setMajorVersion(4)
        self.setProfile(QtGui.QSurfaceFormat.CoreProfile)
        self.setColorSpace(QtGui.QSurfaceFormat.sRGBColorSpace)
        self.setSwapBehavior(QtGui.QSurfaceFormat.DoubleBuffer)


if __name__ == '__main__':

    QtWidgets.QApplication.setAttribute(QtCore.Qt.AA_UseDesktopOpenGL)
    # Uncomment to get this damn error!!!
    #QtGui.QSurfaceFormat.setDefaultFormat(GLSurfaceFormat())

    app = QtWidgets.QApplication(sys.argv)
    window = PlyViewportWidget()
    window.show()
    sys.exit(app.exec_())

vertex.glsl

#version 330 core

layout (location = 0) in vec3 aPos;

void main()
{
    gl_Position = vec4(aPos, 1.0);
}

fragment.glsl

#version 330 core

out vec4 FragColor;

void main()
{
    FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);
} 

Answer 1

GL_COLOR_BUFFER_BIT 不是glEnable 的有效枚举常量，但它是glClear 的正确参数。
调用glClear，在glClearColor设置清除颜色后：

class PlyViewportWidget(QtWidgets.QOpenGLWidget):
    # [...]

    def initializeGL(self):
        
        #gl.glEnable(gl.GL_COLOR_BUFFER_BIT) <---- DELETE
        
        gl.glClearColor(0.4, 0.4, 0.4, 1)

        gl.glClear(gl.GL_COLOR_BUFFER_BIT) # <---- ADD

---

你错过了创建命名Vertex Array Object：

class PlyViewportWidget(QtWidgets.QOpenGLWidget):
    # [...]

    def initializeGL(self):
        # [...]

        self.vao = gl.glGenVertexArrays(1) # <--- 
        gl.glBindVertexArray(self.vao)     # <--- 

        self.vbo = gl.glGenBuffers(1)
        self.ebo = gl.glGenBuffers(1)

        gl.glBindBuffer(gl.GL_ARRAY_BUFFER, self.vbo)
        gl.glBufferData(gl.GL_ARRAY_BUFFER, vertices.nbytes, vertices, gl.GL_STATIC_DRAW)

        gl.glBindBuffer(gl.GL_ELEMENT_ARRAY_BUFFER, self.ebo)
        gl.glBufferData(gl.GL_ELEMENT_ARRAY_BUFFER, indices.nbytes, indices, gl.GL_STATIC_DRAW)

        gl.glEnableVertexAttribArray(0)
        gl.glVertexAttribPointer(0, 3, gl.GL_FLOAT, gl.GL_FALSE, 3 * ctypes.sizeof(ctypes.c_float), ctypes.c_void_p(0))

        gl.glBindBuffer(gl.GL_ARRAY_BUFFER, 0)
        gl.glBindVertexArray(0)