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# 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()
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