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// 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();
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE);
#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);
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);
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)).mirrored());
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));
}
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