Revision control
++ // Copyright (C) 2016 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
++
++ #include "glwidget.h"
++ #include <QOpenGLShaderProgram>
++ #include <QOpenGLTexture>
++ #include <QMouseEvent>
++
++ GLWidget::~GLWidget()
++ {
++ makeCurrent();
++ vbo.destroy();
++ for (int i = 0; i < 6; ++i)
++ delete textures[i];
++ delete program;
++ doneCurrent();
++ }
++
++ QSize GLWidget::minimumSizeHint() const
++ {
++ return QSize(50, 50);
++ }
++
++ QSize GLWidget::sizeHint() const
++ {
++ return QSize(200, 200);
++ }
++
++ void GLWidget::rotateBy(int xAngle, int yAngle, int zAngle)
++ {
++ xRot += xAngle;
++ yRot += yAngle;
++ zRot += zAngle;
++ update();
++ }
++
++ void GLWidget::setClearColor(const QColor &color)
++ {
++ clearColor = color;
++ update();
++ }
++
++ void GLWidget::initializeGL()
++ {
++ initializeOpenGLFunctions();
++
++ makeObject();
++
++ #define PROGRAM_VERTEX_ATTRIBUTE 0
++ #define PROGRAM_TEXCOORD_ATTRIBUTE 1
++
++ QOpenGLShader *vshader = new QOpenGLShader(QOpenGLShader::Vertex, this);
++ const char *vsrc =
++ "attribute highp vec4 vertex;\n"
++ "attribute mediump vec4 texCoord;\n"
++ "varying mediump vec4 texc;\n"
++ "uniform mediump mat4 matrix;\n"
++ "void main(void)\n"
++ "{\n"
++ " gl_Position = matrix * vertex;\n"
++ " texc = texCoord;\n"
++ "}\n";
++ vshader->compileSourceCode(vsrc);
++
++ QOpenGLShader *fshader = new QOpenGLShader(QOpenGLShader::Fragment, this);
++ const char *fsrc =
++ "uniform sampler2D texture;\n"
++ "varying mediump vec4 texc;\n"
++ "void main(void)\n"
++ "{\n"
++ " gl_FragColor = texture2D(texture, texc.st);\n"
++ "}\n";
++ fshader->compileSourceCode(fsrc);
++
++ program = new QOpenGLShaderProgram;
++ program->addShader(vshader);
++ program->addShader(fshader);
++ program->bindAttributeLocation("vertex", PROGRAM_VERTEX_ATTRIBUTE);
++ program->bindAttributeLocation("texCoord", PROGRAM_TEXCOORD_ATTRIBUTE);
++ program->link();
++
++ program->bind();
++ program->setUniformValue("texture", 0);
++ }
++
++ void GLWidget::paintGL()
++ {
++ glClearColor(clearColor.redF(), clearColor.greenF(), clearColor.blueF(), clearColor.alphaF());
++ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
++
++ glEnable(GL_DEPTH_TEST);
++ glEnable(GL_CULL_FACE);
++
++ QMatrix4x4 m;
++ m.ortho(-0.5f, +0.5f, +0.5f, -0.5f, 4.0f, 15.0f);
++ m.translate(0.0f, 0.0f, -10.0f);
++ m.rotate(xRot / 16.0f, 1.0f, 0.0f, 0.0f);
++ m.rotate(yRot / 16.0f, 0.0f, 1.0f, 0.0f);
++ m.rotate(zRot / 16.0f, 0.0f, 0.0f, 1.0f);
++
++ vbo.bind();
++ program->bind();
++ program->setUniformValue("matrix", m);
++ program->enableAttributeArray(PROGRAM_VERTEX_ATTRIBUTE);
++ program->enableAttributeArray(PROGRAM_TEXCOORD_ATTRIBUTE);
++ program->setAttributeBuffer(PROGRAM_VERTEX_ATTRIBUTE, GL_FLOAT, 0, 3, 5 * sizeof(GLfloat));
++ program->setAttributeBuffer(PROGRAM_TEXCOORD_ATTRIBUTE, GL_FLOAT, 3 * sizeof(GLfloat), 2, 5 * sizeof(GLfloat));
++
++ for (int i = 0; i < 6; ++i) {
++ textures[i]->bind();
++ glDrawArrays(GL_TRIANGLE_FAN, i * 4, 4);
++ }
++ }
++ void GLWidget::resizeGL(int width, int height)
++ {
++ int side = qMin(width, height);
++ glViewport((width - side) / 2, (height - side) / 2, side, side);
++ }
++
++ void GLWidget::mousePressEvent(QMouseEvent *event)
++ {
++ lastPos = event->position().toPoint();
++ }
++
++ void GLWidget::mouseMoveEvent(QMouseEvent *event)
++ {
++ int dx = event->position().toPoint().x() - lastPos.x();
++ int dy = event->position().toPoint().y() - lastPos.y();
++
++ if (event->buttons() & Qt::LeftButton) {
++ rotateBy(8 * dy, 8 * dx, 0);
++ } else if (event->buttons() & Qt::RightButton) {
++ rotateBy(8 * dy, 0, 8 * dx);
++ }
++ lastPos = event->position().toPoint();
++ }
++
++ void GLWidget::mouseReleaseEvent(QMouseEvent * /* event */)
++ {
++ emit clicked();
++ }
++
++ void GLWidget::makeObject()
++ {
++ static const int coords[6][4][3] = {
++ { { +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 } }
++ };
++
++ for (int j = 0; j < 6; ++j)
++ textures[j] = new QOpenGLTexture(QImage(QString(":/images/side%1.png").arg(j + 1)).flipped());
++
++ QList<GLfloat> vertData;
++ for (int i = 0; i < 6; ++i) {
++ for (int j = 0; j < 4; ++j) {
++ // vertex position
++ vertData.append(0.2 * coords[i][j][0]);
++ vertData.append(0.2 * coords[i][j][1]);
++ vertData.append(0.2 * coords[i][j][2]);
++ // texture coordinate
++ vertData.append(j == 0 || j == 3);
++ vertData.append(j == 0 || j == 1);
++ }
++ }
++
++ vbo.create();
++ vbo.bind();
++ vbo.allocate(vertData.constData(), vertData.count() * sizeof(GLfloat));
++ }