qt5base-lts/examples/opengl/hellowindow/hellowindow.cpp

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#include "hellowindow.h"
#include <QWindowContext>
#include <QTimer>
#include <qmath.h>
HelloWindow::HelloWindow()
: colorIndex(0)
{
setSurfaceType(OpenGLSurface);
QWindowFormat format;
format.setDepthBufferSize(16);
format.setSamples(4);
setWindowFormat(format);
setGeometry(QRect(10, 10, 640, 480));
create();
initialize();
QTimer *timer = new QTimer(this);
timer->start(10);
connect(timer, SIGNAL(timeout()), this, SLOT(render()));
}
void HelloWindow::mousePressEvent(QMouseEvent *)
{
updateColor();
}
void HelloWindow::updateColor()
{
float colors[][4] =
{
{ 0.4, 1.0, 0.0, 0.0 },
{ 0.0, 0.4, 1.0, 0.0 }
};
glContext()->makeCurrent();
program.bind();
program.setUniformValue(colorUniform, colors[colorIndex][0], colors[colorIndex][1], colors[colorIndex][2], colors[colorIndex][3]);
program.release();
colorIndex++;
if (colorIndex >= sizeof(colors) / sizeof(colors[0]))
colorIndex = 0;
}
void HelloWindow::render()
{
glContext()->makeCurrent();
glClearColor(0.1f, 0.1f, 0.2f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glFrontFace(GL_CW);
glCullFace(GL_FRONT);
glEnable(GL_CULL_FACE);
glEnable(GL_DEPTH_TEST);
QMatrix4x4 modelview;
modelview.rotate(m_fAngle, 0.0f, 1.0f, 0.0f);
modelview.rotate(m_fAngle, 1.0f, 0.0f, 0.0f);
modelview.rotate(m_fAngle, 0.0f, 0.0f, 1.0f);
modelview.translate(0.0f, -0.2f, 0.0f);
program.bind();
program.setUniformValue(matrixUniform, modelview);
paintQtLogo();
program.release();
glDisable(GL_DEPTH_TEST);
glDisable(GL_CULL_FACE);
glContext()->swapBuffers();
m_fAngle += 1.0f;
}
void HelloWindow::paintQtLogo()
{
program.enableAttributeArray(normalAttr);
program.enableAttributeArray(vertexAttr);
program.setAttributeArray(vertexAttr, vertices.constData());
program.setAttributeArray(normalAttr, normals.constData());
glDrawArrays(GL_TRIANGLES, 0, vertices.size());
program.disableAttributeArray(normalAttr);
program.disableAttributeArray(vertexAttr);
}
void HelloWindow::initialize()
{
glContext()->makeCurrent();
glClearColor(0.1f, 0.1f, 0.2f, 1.0f);
QGLShader *vshader = new QGLShader(QGLShader::Vertex, this);
const char *vsrc =
"attribute highp vec4 vertex;\n"
"attribute mediump vec3 normal;\n"
"uniform mediump mat4 matrix;\n"
"uniform lowp vec4 sourceColor;\n"
"varying mediump vec4 color;\n"
"void main(void)\n"
"{\n"
" vec3 toLight = normalize(vec3(0.0, 0.3, 1.0));\n"
" float angle = max(dot(normal, toLight), 0.0);\n"
" vec3 col = sourceColor.rgb;\n"
" color = vec4(col * 0.2 + col * 0.8 * angle, 1.0);\n"
" color = clamp(color, 0.0, 1.0);\n"
" gl_Position = matrix * vertex;\n"
"}\n";
vshader->compileSourceCode(vsrc);
QGLShader *fshader = new QGLShader(QGLShader::Fragment, this);
const char *fsrc =
"varying mediump vec4 color;\n"
"void main(void)\n"
"{\n"
" gl_FragColor = color;\n"
"}\n";
fshader->compileSourceCode(fsrc);
program.addShader(vshader);
program.addShader(fshader);
program.link();
vertexAttr = program.attributeLocation("vertex");
normalAttr = program.attributeLocation("normal");
matrixUniform = program.uniformLocation("matrix");
colorUniform = program.uniformLocation("sourceColor");
m_fAngle = 0;
createGeometry();
updateColor();
}
void HelloWindow::createGeometry()
{
vertices.clear();
normals.clear();
qreal x1 = +0.06f;
qreal y1 = -0.14f;
qreal x2 = +0.14f;
qreal y2 = -0.06f;
qreal x3 = +0.08f;
qreal y3 = +0.00f;
qreal x4 = +0.30f;
qreal y4 = +0.22f;
quad(x1, y1, x2, y2, y2, x2, y1, x1);
quad(x3, y3, x4, y4, y4, x4, y3, x3);
extrude(x1, y1, x2, y2);
extrude(x2, y2, y2, x2);
extrude(y2, x2, y1, x1);
extrude(y1, x1, x1, y1);
extrude(x3, y3, x4, y4);
extrude(x4, y4, y4, x4);
extrude(y4, x4, y3, x3);
const qreal Pi = 3.14159f;
const int NumSectors = 100;
for (int i = 0; i < NumSectors; ++i) {
qreal angle1 = (i * 2 * Pi) / NumSectors;
qreal x5 = 0.30 * qSin(angle1);
qreal y5 = 0.30 * qCos(angle1);
qreal x6 = 0.20 * qSin(angle1);
qreal y6 = 0.20 * qCos(angle1);
qreal angle2 = ((i + 1) * 2 * Pi) / NumSectors;
qreal x7 = 0.20 * qSin(angle2);
qreal y7 = 0.20 * qCos(angle2);
qreal x8 = 0.30 * qSin(angle2);
qreal y8 = 0.30 * qCos(angle2);
quad(x5, y5, x6, y6, x7, y7, x8, y8);
extrude(x6, y6, x7, y7);
extrude(x8, y8, x5, y5);
}
for (int i = 0;i < vertices.size();i++)
vertices[i] *= 2.0f;
}
void HelloWindow::quad(qreal x1, qreal y1, qreal x2, qreal y2, qreal x3, qreal y3, qreal x4, qreal y4)
{
vertices << QVector3D(x1, y1, -0.05f);
vertices << QVector3D(x2, y2, -0.05f);
vertices << QVector3D(x4, y4, -0.05f);
vertices << QVector3D(x3, y3, -0.05f);
vertices << QVector3D(x4, y4, -0.05f);
vertices << QVector3D(x2, y2, -0.05f);
QVector3D n = QVector3D::normal
(QVector3D(x2 - x1, y2 - y1, 0.0f), QVector3D(x4 - x1, y4 - y1, 0.0f));
normals << n;
normals << n;
normals << n;
normals << n;
normals << n;
normals << n;
vertices << QVector3D(x4, y4, 0.05f);
vertices << QVector3D(x2, y2, 0.05f);
vertices << QVector3D(x1, y1, 0.05f);
vertices << QVector3D(x2, y2, 0.05f);
vertices << QVector3D(x4, y4, 0.05f);
vertices << QVector3D(x3, y3, 0.05f);
n = QVector3D::normal
(QVector3D(x2 - x4, y2 - y4, 0.0f), QVector3D(x1 - x4, y1 - y4, 0.0f));
normals << n;
normals << n;
normals << n;
normals << n;
normals << n;
normals << n;
}
void HelloWindow::extrude(qreal x1, qreal y1, qreal x2, qreal y2)
{
vertices << QVector3D(x1, y1, +0.05f);
vertices << QVector3D(x2, y2, +0.05f);
vertices << QVector3D(x1, y1, -0.05f);
vertices << QVector3D(x2, y2, -0.05f);
vertices << QVector3D(x1, y1, -0.05f);
vertices << QVector3D(x2, y2, +0.05f);
QVector3D n = QVector3D::normal
(QVector3D(x2 - x1, y2 - y1, 0.0f), QVector3D(0.0f, 0.0f, -0.1f));
normals << n;
normals << n;
normals << n;
normals << n;
normals << n;
normals << n;
}