1 files changed, 99 insertions, 0 deletions
diff --git a/examples/quick/scenegraph/openglunderqml/squirclerenderer.py b/examples/quick/scenegraph/openglunderqml/squirclerenderer.py
new file mode 100644
index 000000000..5d1759251
--- /dev/null
+++ b/examples/quick/scenegraph/openglunderqml/squirclerenderer.py
@@ -0,0 +1,99 @@
+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+from textwrap import dedent
+
+import numpy as np
+from OpenGL.GL import (GL_ARRAY_BUFFER, GL_BLEND, GL_DEPTH_TEST, GL_FLOAT,
+                       GL_ONE, GL_SRC_ALPHA, GL_TRIANGLE_STRIP)
+from PySide6.QtCore import QSize, Slot
+from PySide6.QtGui import QOpenGLFunctions
+from PySide6.QtOpenGL import (QOpenGLShader, QOpenGLShaderProgram,
+                              QOpenGLVersionProfile)
+from PySide6.QtQuick import QQuickWindow, QSGRendererInterface
+
+VERTEX_SHADER = dedent(
+    """\
+    attribute highp vec4 vertices;
+    varying highp vec2 coords;
+    void main() {
+        gl_Position = vertices;
+        coords = vertices.xy;
+    }
+    """
+)
+FRAGMENT_SHADER = dedent(
+    """\
+    uniform lowp float t;
+    varying highp vec2 coords;
+    void main() {
+        lowp float i = 1. - (pow(abs(coords.x), 4.) + pow(abs(coords.y), 4.));
+        i = smoothstep(t - 0.8, t + 0.8, i);
+        i = floor(i * 20.) / 20.;
+        gl_FragColor = vec4(coords * .5 + .5, i, i);
+    }
+    """
+)
+
+
+class SquircleRenderer(QOpenGLFunctions):
+    def __init__(self):
+        QOpenGLFunctions.__init__(self)
+        self._viewport_size = QSize()
+        self._t = 0.0
+        self._program = None
+        self._window = QQuickWindow()
+
+    def setT(self, t):
+        self._t = t
+
+    def setViewportSize(self, size):
+        self._viewport_size = size
+
+    def setWindow(self, window):
+        self._window = window
+
+    @Slot()
+    def init(self):
+        if not self._program:
+            rif = self._window.rendererInterface()
+            assert (rif.graphicsApi() == QSGRendererInterface.OpenGL)
+            self.initializeOpenGLFunctions()
+            self._program = QOpenGLShaderProgram()
+            self._program.addCacheableShaderFromSourceCode(QOpenGLShader.Vertex, VERTEX_SHADER)
+            self._program.addCacheableShaderFromSourceCode(QOpenGLShader.Fragment, FRAGMENT_SHADER)
+            self._program.bindAttributeLocation("vertices", 0)
+            self._program.link()
+
+    @Slot()
+    def paint(self):
+        # Play nice with the RHI. Not strictly needed when the scenegraph uses
+        # OpenGL directly.
+        self._window.beginExternalCommands()
+
+        self._program.bind()
+
+        self._program.enableAttributeArray(0)
+
+        values = np.array([-1, -1, 1, -1, -1, 1, 1, 1], dtype="single")
+
+        # This example relies on (deprecated) client-side pointers for the vertex
+        # input. Therefore, we have to make sure no vertex buffer is bound.
+        self.glBindBuffer(GL_ARRAY_BUFFER, 0)
+
+        self._program.setAttributeArray(0, GL_FLOAT, values, 2)
+        self._program.setUniformValue1f("t", self._t)
+
+        self.glViewport(0, 0, self._viewport_size.width(), self._viewport_size.height())
+
+        self.glDisable(GL_DEPTH_TEST)
+
+        self.glEnable(GL_BLEND)
+        self.glBlendFunc(GL_SRC_ALPHA, GL_ONE)
+
+        self.glDrawArrays(GL_TRIANGLE_STRIP, 0, 4)
+
+        self._program.disableAttributeArray(0)
+        self._program.release()
+
+        self._window.endExternalCommands()