Qt OpenGL rendering doesn't work

Xav12358

Hello,

I made a program in CPP using Qt and QTOpenGL to render mesh objects.
When I use in CPP example it works properly this is my example.cpp . Now I want to connect to a python wrapper to be able to use it in python.

Here is my python setuptools application: setup.py

import glob
import os

from setuptools import setup, Extension

# sources = glob.glob("**/**/*.cpp", recursive=True)
sources = glob.glob("../pyboost_converter/**/*.cpp", recursive=True)

setup(
    name='vmpbcvt',
    version='1.0',
    description='Python Package with Hello World C++ Extension',
    ext_modules=[
        Extension(
            'vmpbcvt',
            sources=['pyboost_converter/pyboost_converter.cpp', 'pyboost_converter/pbcvt_module.cpp'],
            # sources=sources,
            include_dirs=["/usr/include/numpy",
                          "/usr/include/opencv4",
                          "/usr/include/x86_64-linux-gnu/qt5/QtGui/",
                          "/usr/include/x86_64-linux-gnu/qt5/",
                          "/opt/ros/noetic/include",
                          "/usr/include/x86_64-linux-gnu/qt5/QtWidgets",
                          "/usr/include/x86_64-linux-gnu/qt5/QtCore",
                          "/usr/include/x86_64-linux-gnu/qt5/QtOpenGL",
                          ],
            libraries=['opencv_core', 'opencv_highgui', 'opencv_videoio', 'boost_python38', 'boost_system', "OpenGL",
                       "cv_bridge",
                       "roscpp",
                       "rosbag",
                       "image_transport",
                       "roscpp_serialization",
                       "Qt5Core",
                       "Qt5Widgets",
                       ],
            library_dirs=["/home/me/dev/3003/catkin_ws/devel/lib/", "/opt/ros/noetic/lib/"],
            extra_compile_args=['-std=c++2a', '-v'],
            # package_dir={'vision_module_pkg': '/home/me/dev/3003/catkin_ws/devel/lib/'},
            # package_data={'vision_module_pkg': ['libvision_module.so']},
            py_limited_api=False)
    ],
)

I put in a cpp python wrapper the sample content of my example.cpp file:

#define PY_ARRAY_UNIQUE_SYMBOL vmpbcvt_ARRAY_API

#include <boost/python.hpp>
#include <pyboost_converter/pyboost_converter.hpp>

#include <QApplication>



#include <filesystem>
#include <opencv2/core.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgcodecs.hpp>
#include <opencv2/imgproc.hpp>
#include <opencv2/opencv.hpp>
#include <sstream>
#include <typeinfo>
int IMG_FORMAT = CV_8UC3;

namespace pbcvt {

using namespace boost::python;

std::shared_ptr<VisionModuleManager> vision_module_manager;

bool pbcvt_module_core_init(std::string vision_module_path) {
 /*********************** 
  * 
  * My example.cpp content here
  * */
  return true;
}


#if (PY_VERSION_HEX >= 0x03000000)
#ifndef NUMPY_IMPORT_ARRAY_RETVAL
#define NUMPY_IMPORT_ARRAY_RETVAL NULL
#endif
static void *init_ar() {
#else
#ifndef NUMPY_IMPORT_ARRAY_RETVAL
#define NUMPY_IMPORT_ARRAY_RETVAL
#endif
static void init_ar() {
#endif
  Py_Initialize();

  import_array();
  return NUMPY_IMPORT_ARRAY_RETVAL;
}

BOOST_PYTHON_MODULE(vmpbcvt) {
  // using namespace XM;
  init_ar();

  // initialize converters
  to_python_converter<cv::Mat, pbcvt::matToNDArrayBoostConverter>();
  matFromNDArrayBoostConverter();
  // expose module-level functions
  def("init", pbcvt_module_core_init);

}

} // end namespace pbcvt

On my example.cpp, the rendering works fine but in the wrapped example, it doesn't work. Is it an error in my setup.py file?

SGaist

Hi,

Based solely on your code, there's nothing related to OpenGL rendering that would allow to understand how your code is working and why it would not it python.

An other question is: why do you need to wrap CPP since jt seems that you are using libraries that are also available through Python.

SGaist

Here is a basic example that I hope will get you going:

import sys

from OpenGL import GL
from PySide6.QtCore import QTimer
from PySide6.QtGui import QMatrix4x4
from PySide6.QtGui import QOpenGLFunctions
from PySide6.QtGui import QSurfaceFormat
from PySide6.QtOpenGL import QOpenGLShader
from PySide6.QtOpenGL import QOpenGLShaderProgram
from PySide6.QtOpenGLWidgets import QOpenGLWidget
from PySide6.QtWidgets import QApplication

vertext_shader_source = """
    attribute highp vec4 posAttr;
    attribute lowp vec4 colAttr;
    varying lowp vec4 col;
    uniform highp mat4 matrix;
    void main() {
       col = colAttr;
       gl_Position = matrix * posAttr;
    }
"""

fragment_shader_source = """
    varying lowp vec4 col;
    void main() {
       gl_FragColor = col;
    }
"""


class OpenGLWidget(QOpenGLWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.gl = QOpenGLFunctions()

        self._animating = False

        self._posAttr = 0
        self._colAttr = 0
        self._matrix_uniform = 0

        self._program = None
        self._frame = 0

        self._timer = QTimer()
        self._timer.timeout.connect(self.update)

    def initializeGL(self):
        self.gl.initializeOpenGLFunctions()

        self._program = QOpenGLShaderProgram(self)
        success = self._program.addShaderFromSourceCode(
            QOpenGLShader.Vertex, vertext_shader_source
        )
        assert success
        success = self._program.addShaderFromSourceCode(
            QOpenGLShader.Fragment, fragment_shader_source
        )
        assert success
        success = self._program.link()
        assert success

        self._posAttr = self._program.attributeLocation("posAttr")
        assert self._posAttr != -1
        self._colAttr = self._program.attributeLocation("colAttr")
        assert self._colAttr != -1
        self._matrix_uniform = self._program.uniformLocation("matrix")
        assert self._matrix_uniform != -1

    def paintGL(self):
        retinaScale = self.devicePixelRatio()
        self.gl.glViewport(
            0, 0, self.width() * retinaScale, self.height() * retinaScale
        )

        self.gl.glClear(GL.GL_COLOR_BUFFER_BIT)

        self._program.bind()

        matrix = QMatrix4x4()
        matrix.perspective(60.0, 4.0 / 3.0, 0.1, 100.0)
        matrix.translate(0, 0, -2)
        matrix.rotate(100.0 * self._frame / self.screen().refreshRate(), 0, 1, 0)

        self._program.setUniformValue(self._matrix_uniform, matrix)

        vertices = [0.0, 0.707, -0.5, -0.5, 0.5, -0.5]

        colors = [1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0]

        GL.glVertexAttribPointer(
            self._posAttr, 2, GL.GL_FLOAT, GL.GL_FALSE, 0, vertices
        )
        GL.glVertexAttribPointer(self._colAttr, 3, GL.GL_FLOAT, GL.GL_FALSE, 0, colors)

        self.gl.glEnableVertexAttribArray(self._posAttr)
        self.gl.glEnableVertexAttribArray(self._colAttr)

        self.gl.glDrawArrays(GL.GL_TRIANGLES, 0, 3)

        self.gl.glDisableVertexAttribArray(self._colAttr)
        self.gl.glDisableVertexAttribArray(self._posAttr)

        self._program.release()

        self._frame += 1

    def setAnimating(self, animating: bool):
        self._animating = animating

        if animating:
            self._timer.start(25)


if __name__ == "__main__":
    app = QApplication(sys.argv)

    format = QSurfaceFormat()
    format.setSamples(16)

    QSurfaceFormat.setDefaultFormat(format)

    widget = OpenGLWidget()
    widget.setAnimating(True)
    widget.show()
    sys.exit(app.exec())