Change almost all other uses of qrand() to QRandomGenerator

The vast majority is actually switched to QRandomGenerator::bounded(),
which gives a mostly uniform distribution over the [0, bound)
range. There are very few floating point cases left, as many of those
that did use floating point did not need to, after all. (I did leave
some that were too ugly for me to understand)

This commit also found a couple of calls to rand() instead of qrand().

This commit does not include changes to SSL code that continues to use
qrand() (job for someone else):
  src/network/ssl/qsslkey_qt.cpp
  src/network/ssl/qsslsocket_mac.cpp
  tests/auto/network/ssl/qsslsocket/tst_qsslsocket.cpp

Change-Id: Icd0e0d4b27cb4e5eb892fffd14b5285d43f4afbf
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

6 files changed, 30 insertions, 23 deletions

diff --git a/examples/opengl/hellowindow/hellowindow.cpp b/examples/opengl/hellowindow/hellowindow.cpp
index 048190d766..a978e19b79 100644
--- a/examples/opengl/hellowindow/hellowindow.cpp
+++ b/examples/opengl/hellowindow/hellowindow.cpp
@@ -52,6 +52,7 @@
 
 #include <QOpenGLContext>
 #include <QOpenGLFunctions>
+#include <QRandomGenerator>
 #include <qmath.h>
 
 Renderer::Renderer(const QSurfaceFormat &format, Renderer *share, QScreen *screen)
@@ -68,9 +69,9 @@ Renderer::Renderer(const QSurfaceFormat &format, Renderer *share, QScreen *scree
     m_context->create();
 
     m_backgroundColor = QColor::fromRgbF(0.1f, 0.1f, 0.2f, 1.0f);
-    m_backgroundColor.setRed(qrand() % 64);
-    m_backgroundColor.setGreen(qrand() % 128);
-    m_backgroundColor.setBlue(qrand() % 256);
+    m_backgroundColor.setRed(QRandomGenerator::global()->bounded(64));
+    m_backgroundColor.setGreen(QRandomGenerator::global()->bounded(128));
+    m_backgroundColor.setBlue(QRandomGenerator::global()->bounded(256));
 }
 
 HelloWindow::HelloWindow(const QSharedPointer<Renderer> &renderer, QScreen *screen)
diff --git a/examples/opengl/legacy/overpainting/bubble.cpp b/examples/opengl/legacy/overpainting/bubble.cpp
index afc50117d0..352e359cf9 100644
--- a/examples/opengl/legacy/overpainting/bubble.cpp
+++ b/examples/opengl/legacy/overpainting/bubble.cpp
@@ -50,6 +50,8 @@
 
 #include "bubble.h"
 
+#include <QRandomGenerator>
+
 Bubble::Bubble(const QPointF &position, qreal radius, const QPointF &velocity)
     : position(position), vel(velocity), radius(radius)
 {
@@ -80,10 +82,10 @@ void Bubble::drawBubble(QPainter *painter)
 
 QColor Bubble::randomColor()
 {
-    int red = int(205 + 50.0*qrand()/(RAND_MAX+1.0));
-    int green = int(205 + 50.0*qrand()/(RAND_MAX+1.0));
-    int blue = int(205 + 50.0*qrand()/(RAND_MAX+1.0));
-    int alpha = int(91 + 100.0*qrand()/(RAND_MAX+1.0));
+    int red = int(205 + QRandomGenerator::global()->bounded(50));
+    int green = int(205 + QRandomGenerator::global()->bounded(50));
+    int blue = int(205 + QRandomGenerator::global()->bounded(50));
+    int alpha = int(91 + QRandomGenerator::global()->bounded(100));
 
     return QColor(red, green, blue, alpha);
 }
diff --git a/examples/opengl/legacy/overpainting/glwidget.cpp b/examples/opengl/legacy/overpainting/glwidget.cpp
index 7e9f4a5beb..1ec7bd731c 100644
--- a/examples/opengl/legacy/overpainting/glwidget.cpp
+++ b/examples/opengl/legacy/overpainting/glwidget.cpp
@@ -53,6 +53,7 @@
 #include "glwidget.h"
 
 #include <QMouseEvent>
+#include <QRandomGenerator>
 #include <QTime>
 
 #include <math.h>
@@ -67,7 +68,6 @@ GLWidget::GLWidget(QWidget *parent)
     : QGLWidget(QGLFormat(QGL::SampleBuffers), parent)
 {
     QTime midnight(0, 0, 0);
-    qsrand(midnight.secsTo(QTime::currentTime()));
 
     logo = 0;
     xRot = 0;
@@ -234,11 +234,11 @@ QSize GLWidget::sizeHint() const
 void GLWidget::createBubbles(int number)
 {
     for (int i = 0; i < number; ++i) {
-        QPointF position(width()*(0.1 + (0.8*qrand()/(RAND_MAX+1.0))),
-                        height()*(0.1 + (0.8*qrand()/(RAND_MAX+1.0))));
-        qreal radius = qMin(width(), height())*(0.0125 + 0.0875*qrand()/(RAND_MAX+1.0));
-        QPointF velocity(width()*0.0125*(-0.5 + qrand()/(RAND_MAX+1.0)),
-                        height()*0.0125*(-0.5 + qrand()/(RAND_MAX+1.0)));
+        QPointF position(width()*(0.1 + QRandomGenerator::global()->bounded(0.8)),
+                        height()*(0.1 + QRandomGenerator::global()->bounded(0.8)));
+        qreal radius = qMin(width(), height())*(0.0125 + QRandomGenerator::global()->bounded(0.0875));
+        QPointF velocity(width()*0.0125*(-0.5 + QRandomGenerator::global()->bounded(1.0)),
+                        height()*0.0125*(-0.5 + QRandomGenerator::global()->bounded(1.0)));
 
         bubbles.append(new Bubble(position, radius, velocity));
     }
diff --git a/examples/opengl/qopenglwidget/bubble.cpp b/examples/opengl/qopenglwidget/bubble.cpp
index adf5742f6a..dbaf460f6f 100644
--- a/examples/opengl/qopenglwidget/bubble.cpp
+++ b/examples/opengl/qopenglwidget/bubble.cpp
@@ -109,10 +109,10 @@ void Bubble::drawBubble(QPainter *painter)
 
 QColor Bubble::randomColor()
 {
-    int red = int(185 + 70.0*qrand()/(RAND_MAX+1.0));
-    int green = int(185 + 70.0*qrand()/(RAND_MAX+1.0));
-    int blue = int(205 + 50.0*qrand()/(RAND_MAX+1.0));
-    int alpha = int(91 + 100.0*qrand()/(RAND_MAX+1.0));
+    int red = int(185 + QRandomGenerator::global()->bounded(70));
+    int green = int(185 + QRandomGenerator::global()->bounded(70));
+    int blue = int(205 + QRandomGenerator::global()->bounded(50));
+    int alpha = int(91 + QRandomGenerator::global()->bounded(100));
 
     return QColor(red, green, blue, alpha);
 }
diff --git a/examples/opengl/qopenglwidget/glwidget.cpp b/examples/opengl/qopenglwidget/glwidget.cpp
index 40a1258dd5..3fe919f94b 100644
--- a/examples/opengl/qopenglwidget/glwidget.cpp
+++ b/examples/opengl/qopenglwidget/glwidget.cpp
@@ -53,6 +53,7 @@
 #include <QPaintEngine>
 #include <QOpenGLShaderProgram>
 #include <QOpenGLTexture>
+#include <QRandomGenerator>
 #include <QCoreApplication>
 #include <qmath.h>
 
@@ -420,11 +421,11 @@ void GLWidget::paintGL()
 void GLWidget::createBubbles(int number)
 {
     for (int i = 0; i < number; ++i) {
-        QPointF position(width()*(0.1 + (0.8*qrand()/(RAND_MAX+1.0))),
-                         height()*(0.1 + (0.8*qrand()/(RAND_MAX+1.0))));
-        qreal radius = qMin(width(), height())*(0.0175 + 0.0875*qrand()/(RAND_MAX+1.0));
-        QPointF velocity(width()*0.0175*(-0.5 + qrand()/(RAND_MAX+1.0)),
-                         height()*0.0175*(-0.5 + qrand()/(RAND_MAX+1.0)));
+        QPointF position(width()*(0.1 + QRandomGenerator::global()->bounded(0.8)),
+                         height()*(0.1 + QRandomGenerator::global()->bounded(0.8)));
+        qreal radius = qMin(width(), height())*(0.0175 + QRandomGenerator::global()->bounded(0.0875));
+        QPointF velocity(width()*0.0175*(-0.5 + QRandomGenerator::global()->bounded(1.0)),
+                         height()*0.0175*(-0.5 + QRandomGenerator::global()->bounded(1.0)));
 
         m_bubbles.append(new Bubble(position, radius, velocity));
     }
diff --git a/examples/opengl/qopenglwidget/mainwindow.cpp b/examples/opengl/qopenglwidget/mainwindow.cpp
index 1bb2aa2bf0..4bd123628f 100644
--- a/examples/opengl/qopenglwidget/mainwindow.cpp
+++ b/examples/opengl/qopenglwidget/mainwindow.cpp
@@ -56,6 +56,7 @@
 #include <QSlider>
 #include <QLabel>
 #include <QCheckBox>
+#include <QRandomGenerator>
 #include <QSpinBox>
 #include <QScrollArea>
 
@@ -155,7 +156,9 @@ void MainWindow::addNew()
 {
     if (m_nextY == 4)
         return;
-    GLWidget *w = new GLWidget(this, false, qRgb(qrand() % 256, qrand() % 256, qrand() % 256));
+    GLWidget *w = new GLWidget(this, false, qRgb(QRandomGenerator::global()->bounded(256),
+                                                 QRandomGenerator::global()->bounded(256),
+                                                 QRandomGenerator::global()->bounded(256)));
     m_glWidgets << w;
     connect(m_timer, &QTimer::timeout, w, QOverload<>::of(&QWidget::update));
     m_layout->addWidget(w, m_nextY, m_nextX, 1, 1);