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#############################################################################
##
## Copyright (C) 2021 The Qt Company Ltd.
## Contact: http://www.qt.io/licensing/
##
## This file is part of the Qt for Python examples of the Qt Toolkit.
##
## $QT_BEGIN_LICENSE:BSD$
## You may use this file under the terms of the BSD license as follows:
##
## "Redistribution and use in source and binary forms, with or without
## modification, are permitted provided that the following conditions are
## met:
## * Redistributions of source code must retain the above copyright
## notice, this list of conditions and the following disclaimer.
## * Redistributions in binary form must reproduce the above copyright
## notice, this list of conditions and the following disclaimer in
## the documentation and/or other materials provided with the
## distribution.
## * Neither the name of The Qt Company Ltd nor the names of its
## contributors may be used to endorse or promote products derived
## from this software without specific prior written permission.
##
##
## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
## LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
## OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
## SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
## LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
## DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
## THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
##
## $QT_END_LICENSE$
##
#############################################################################
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()
self.profile = QOpenGLVersionProfile()
self.gl = None
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
or rif.graphicsApi() == QSGRendererInterface.OpenGLRhy
)
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()
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