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'''Unit test for QOpenGLContext, QOpenGLTexture, QOpenGLWindow and related classes'''

import sys
import unittest

from helper import UsesQApplication

from PySide2.QtCore import QSize, QTimer, Qt
from PySide2.QtGui import (QColor, QGuiApplication, QImage, QOpenGLContext,
    QOpenGLTexture, QSurfaceFormat, QOpenGLWindow)

try:
    from OpenGL import GL
except ImportError:
    print("Skipping test due to missing OpenGL module")
    sys.exit(0)

class OpenGLWindow(QOpenGLWindow):
    def __init__(self):
        super(OpenGLWindow, self).__init__()

        self.m_functions = None
        self.m_texture = None
        self.visibleChanged.connect(self.slotVisibleChanged)

    def slotVisibleChanged(self, visible):
        if not visible and self.m_texture is not None and self.context().makeCurrent(self):
            self.m_texture = None
            self.context().doneCurrent()

    def initializeGL(self):
        self.m_functions = self.context().functions()
        self.m_functions.initializeOpenGLFunctions()
        image = QImage(QSize(200, 200), QImage.Format_RGBA8888)
        image.fill(QColor(Qt.red))
        self.m_texture = QOpenGLTexture(image)

    def paintGL(self):
        GL.glMatrixMode(GL.GL_MODELVIEW);
        GL.glLoadIdentity();

        GL.glMatrixMode(GL.GL_PROJECTION);
        GL.glLoadIdentity();
        GL.glOrtho(0, 1, 1, 0, -1, 1);

        self.m_functions.glClear(GL.GL_COLOR_BUFFER_BIT)
        self.m_functions.glEnable(GL.GL_TEXTURE_2D);
        self.m_texture.bind()

        d = 0.5
        GL.glBegin(GL.GL_QUADS)
        GL.glTexCoord2f(0, 0)
        GL.glVertex2f(0, 0)
        GL.glTexCoord2f(d, 0)
        GL.glVertex2f(d, 0)
        GL.glTexCoord2f(d, d)
        GL.glVertex2f(d, d)
        GL.glTexCoord2f(0, d)
        GL.glVertex2f(0, d)
        GL.glEnd()
        self.m_texture.release()

    def resizeGL(self, w, h):
        self.m_functions.glViewport(0, 0, self.width(), self.height())

class QOpenGLWindowTest(UsesQApplication):
    # On macOS, glClear(), glViewport() are rejected due to GLbitfield/GLint not being resolved properly
    def test(self):
        openGlWindow = OpenGLWindow()
        openGlWindow.resize(640, 480)
        openGlWindow.show()
        QTimer.singleShot(100, openGlWindow.close)
        self.app.exec_()

if __name__ == '__main__':
    unittest.main()
