#!/usr/bin/env python


#############################################################################
##
## Copyright (C) 2018 Riverbank Computing Limited.
## Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
## All rights reserved.
##
## This file is part of the examples of PyQt.
##
## $QT_BEGIN_LICENSE:BSD$
## 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 Nokia Corporation and its Subsidiary(-ies) 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
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## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
## $QT_END_LICENSE$
##
#############################################################################


import sys

from PyQt5.QtCore import pyqtSignal, QFileInfo, QPoint, QSize, Qt, QTimer
from PyQt5.QtGui import (QColor, QImage, QMatrix4x4, QOpenGLShader,
        QOpenGLShaderProgram, QOpenGLTexture, QOpenGLVersionProfile,
        QSurfaceFormat)
from PyQt5.QtWidgets import QApplication, QGridLayout, QOpenGLWidget, QWidget


class GLWidget(QOpenGLWidget):

    clicked = pyqtSignal()

    PROGRAM_VERTEX_ATTRIBUTE, PROGRAM_TEXCOORD_ATTRIBUTE = range(2)

    vsrc = """
attribute highp vec4 vertex;
attribute mediump vec4 texCoord;
varying mediump vec4 texc;
uniform mediump mat4 matrix;
void main(void)
{
    gl_Position = matrix * vertex;
    texc = texCoord;
}
"""

    fsrc = """
uniform sampler2D texture;
varying mediump vec4 texc;
void main(void)
{
    gl_FragColor = texture2D(texture, texc.st);
}
"""

    coords = (
        (( +1, -1, -1 ), ( -1, -1, -1 ), ( -1, +1, -1 ), ( +1, +1, -1 )),
        (( +1, +1, -1 ), ( -1, +1, -1 ), ( -1, +1, +1 ), ( +1, +1, +1 )),
        (( +1, -1, +1 ), ( +1, -1, -1 ), ( +1, +1, -1 ), ( +1, +1, +1 )),
        (( -1, -1, -1 ), ( -1, -1, +1 ), ( -1, +1, +1 ), ( -1, +1, -1 )),
        (( +1, -1, +1 ), ( -1, -1, +1 ), ( -1, -1, -1 ), ( +1, -1, -1 )),
        (( -1, -1, +1 ), ( +1, -1, +1 ), ( +1, +1, +1 ), ( -1, +1, +1 ))
    )

    def __init__(self, parent=None):
        super(GLWidget, self).__init__(parent)

        self.clearColor = QColor(Qt.black)
        self.xRot = 0
        self.yRot = 0
        self.zRot = 0
        self.program = None

        self.lastPos = QPoint()

    def minimumSizeHint(self):
        return QSize(50, 50)

    def sizeHint(self):
        return QSize(200, 200)

    def rotateBy(self, xAngle, yAngle, zAngle):
        self.xRot += xAngle
        self.yRot += yAngle
        self.zRot += zAngle
        self.update()

    def setClearColor(self, color):
        self.clearColor = color
        self.update()

    def initializeGL(self):
        version_profile = QOpenGLVersionProfile()
        version_profile.setVersion(2, 0)
        self.gl = self.context().versionFunctions(version_profile)
        self.gl.initializeOpenGLFunctions()

        self.makeObject()

        self.gl.glEnable(self.gl.GL_DEPTH_TEST)
        self.gl.glEnable(self.gl.GL_CULL_FACE)

        vshader = QOpenGLShader(QOpenGLShader.Vertex, self)
        vshader.compileSourceCode(self.vsrc)

        fshader = QOpenGLShader(QOpenGLShader.Fragment, self)
        fshader.compileSourceCode(self.fsrc)

        self.program = QOpenGLShaderProgram()
        self.program.addShader(vshader)
        self.program.addShader(fshader)
        self.program.bindAttributeLocation('vertex',
                self.PROGRAM_VERTEX_ATTRIBUTE)
        self.program.bindAttributeLocation('texCoord',
                self.PROGRAM_TEXCOORD_ATTRIBUTE)
        self.program.link()

        self.program.bind()
        self.program.setUniformValue('texture', 0)

        self.program.enableAttributeArray(self.PROGRAM_VERTEX_ATTRIBUTE)
        self.program.enableAttributeArray(self.PROGRAM_TEXCOORD_ATTRIBUTE)
        self.program.setAttributeArray(self.PROGRAM_VERTEX_ATTRIBUTE,
                self.vertices)
        self.program.setAttributeArray(self.PROGRAM_TEXCOORD_ATTRIBUTE,
                self.texCoords)

    def paintGL(self):
        self.gl.glClearColor(self.clearColor.redF(), self.clearColor.greenF(),
                self.clearColor.blueF(), self.clearColor.alphaF())
        self.gl.glClear(
                self.gl.GL_COLOR_BUFFER_BIT | self.gl.GL_DEPTH_BUFFER_BIT)

        m = QMatrix4x4()
        m.ortho(-0.5, 0.5, 0.5, -0.5, 4.0, 15.0)
        m.translate(0.0, 0.0, -10.0)
        m.rotate(self.xRot / 16.0, 1.0, 0.0, 0.0)
        m.rotate(self.yRot / 16.0, 0.0, 1.0, 0.0)
        m.rotate(self.zRot / 16.0, 0.0, 0.0, 1.0)

        self.program.setUniformValue('matrix', m)

        for i, texture in enumerate(self.textures):
            texture.bind()
            self.gl.glDrawArrays(self.gl.GL_TRIANGLE_FAN, i * 4, 4)

    def resizeGL(self, width, height):
        side = min(width, height)
        self.gl.glViewport((width - side) // 2, (height - side) // 2, side,
                side)

    def mousePressEvent(self, event):
        self.lastPos = event.pos()

    def mouseMoveEvent(self, event):
        dx = event.x() - self.lastPos.x()
        dy = event.y() - self.lastPos.y()

        if event.buttons() & Qt.LeftButton:
            self.rotateBy(8 * dy, 8 * dx, 0)
        elif event.buttons() & Qt.RightButton:
            self.rotateBy(8 * dy, 0, 8 * dx)

        self.lastPos = event.pos()

    def mouseReleaseEvent(self, event):
        self.clicked.emit()

    def makeObject(self):
        self.textures = []
        self.texCoords = []
        self.vertices = []

        root = QFileInfo(__file__).absolutePath()

        for i in range(6):
            self.textures.append(
                    QOpenGLTexture(
                            QImage(root + ('/images/side%d.png' % (i + 1))).mirrored()))

            for j in range(4):
                self.texCoords.append(((j == 0 or j == 3), (j == 0 or j == 1)))

                x, y, z = self.coords[i][j]
                self.vertices.append((0.2 * x, 0.2 * y, 0.2 * z))


class Window(QWidget):
    NumRows = 2
    NumColumns = 3

    def __init__(self):
        super(Window, self).__init__()

        self.glWidgets = []

        mainLayout = QGridLayout()

        for i in range(Window.NumRows):
            row = []

            for j in range(Window.NumColumns):
                clearColor = QColor()
                clearColor.setHsv(((i * Window.NumColumns) + j) * 255
                                  / (Window.NumRows * Window.NumColumns - 1),
                                  255, 63)

                widget = GLWidget()
                widget.setClearColor(clearColor)
                widget.rotateBy(+42 * 16, +42 * 16, -21 * 16)
                mainLayout.addWidget(widget, i, j)

                widget.clicked.connect(self.setCurrentGlWidget)

                row.append(widget)

            self.glWidgets.append(row)

        self.setLayout(mainLayout)

        self.currentGlWidget = self.glWidgets[0][0]

        timer = QTimer(self)
        timer.timeout.connect(self.rotateOneStep)
        timer.start(20)

        self.setWindowTitle("Textures")

    def setCurrentGlWidget(self):
        self.currentGlWidget = self.sender()

    def rotateOneStep(self):
        if self.currentGlWidget:
            self.currentGlWidget.rotateBy(+2 * 16, +2 * 16, -1 * 16)


if __name__ == '__main__':

    app = QApplication(sys.argv)

    format = QSurfaceFormat()
    format.setDepthBufferSize(24)
    QSurfaceFormat.setDefaultFormat(format)

    window = Window()
    window.show()
    sys.exit(app.exec_())