[solved] using two or three threads

ogopa

Hey guys,
I have a gui that outputs a sine wave and square wave with user input frequency and amplitude. My code to produce both the square and sine wave is tested and works successfully.
My problem is: I have the sine wave working. I used threads to start and eliminate(from click of pushButtons) the generation of the sine wave. I am trying to do the same for the square wave, but when I click the pushButton, it generates the sine wave again.
I am not sure where I am going wrong. Any help would be appreciated. Code snippets below:

wave.cpp:
@wave::wave(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::wave)
{
ui->setupUi(this);
setup();
thread = new MyThread();
thread2 = new MyThread();

}
wave::~wave()
{
delete ui;
delete thread;
delete thread2;
}

void wave::on_pushButton_clicked()
{
//Generate
freq = ui->frequency->text().toDouble();
ampl = ui->amplitude->text().toDouble();
thread->start();
ui->pushButton->setEnabled(false);
ui->pushButton->setStyleSheet("background-color: gray");
ui->pushButton_2->setStyleSheet("background-color: rgb(255, 192, 192);"
"color: red;");
ui->pushButton_2->setEnabled(true);
}

void wave::on_pushButton_2_clicked()
{
//Terminate
thread->terminate();
ui->pushButton_2->setEnabled(false);
ui->pushButton_2->setStyleSheet("background-color: gray");
ui->pushButton->setStyleSheet("background-color: rgb(192, 255, 208);"
"color: green;");
ui->pushButton->setEnabled(true);

}

void wave::on_pushButton_3_clicked()
{
freq = ui->frequency->text().toDouble();
ampl = ui->amplitude->text().toDouble();
thread2->start();
ui->pushButton_3->setEnabled(false);
ui->pushButton_3->setStyleSheet("background-color: gray");
ui->pushButton_4->setStyleSheet("background-color: rgb(255, 192, 192);"
"color: red;");
ui->pushButton_4->setEnabled(true);
}

void wave::on_pushButton_4_clicked()
{
thread2->terminate();
ui->pushButton_4->setEnabled(false);
ui->pushButton_4->setStyleSheet("background-color: gray");
ui->pushButton_3->setStyleSheet("background-color: rgb(192, 255, 208);"
"color: green;");
ui->pushButton_3->setEnabled(true);
}@

wave.h:
@#ifndef WAVE_H
#define WAVE_H
#include "ui_wave.h"
#include <alsa/asoundlib.h>
#include <QMainWindow>
#include <QObject>
#include "mythread.h"

namespace Ui {
class wave;
}

class wave : public QMainWindow
{
Q_OBJECT
MyThread *thread;
MyThread *thread2;

public:
explicit wave(QWidget *parent = 0);
~wave();

private slots:
void on_pushButton_clicked();
void on_pushButton_2_clicked();

void on_pushButton_3_clicked();

void on_pushButton_4_clicked();

private:
Ui::wave *ui;

};

void onWriteLoopSine();
void onWriteLoopSquare();

#endif // WAVE_H@

mythread.h:
@#ifndef MYTHREAD_H
#define MYTHREAD_H

#include <QThread>

class MyThread : public QThread
{
Q_OBJECT

protected:
void run();

public:
explicit MyThread(QObject *parent = 0);

};

#endif // MYTHREAD_H@

mythread.cpp:
@#include "wave.h"
#include "mythread.h"

MyThread::MyThread(QObject *parent) :
QThread(parent)
{
}

void MyThread::run()
{
onWriteLoopSine();
onWriteLoopSquare();
}
@

mlong

What tells each thread whether to generate a square or sine wave?

ogopa

The function MyThread::run()? I'm not really sure how to do that..

ogopa

[quote author="mlong" date="1313524604"]What tells each thread whether to generate a square or sine wave?

[/quote]
The function MyThread::run()? I’m not really sure how to do that..

mlong

If onWriteLoopSine() is called before onWriteLoopSquare(), onWriteLoopSine will be executed first. And if it runs forever (as implied by previous posts), onWriteLoopSquare will never get called.

mlong

You should tell the thread what kind of wave to use. You could use an enum for the wave types, or something.

This is a rough example that just uses a boolean flag to determine whether to use sine or not. I haven't tested it or anything.

in mythread.h:
@
protected:
void run();

bool m_is_sine;

public:
explicit MyThread(QObject *parent = 0);
void setSine(bool useSine) { m_is_sine = useSine; }
@

in mythread.cpp:
@

MyThread::MyThread(QObject *parent) :
QThread(parent), m_is_sine(false)
{
}

void MyThread::run()
{
if (m_is_sine)
onWriteLoopSine();
else
onWriteLoopSquare();
}
@

in wave.cpp:
@
wave::wave(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::wave)
{
ui->setupUi(this);
setup();
thread = new MyThread();
thread->setSine(true);
thread2 = new MyThread();
thread2->setSine(false);
}
@

ogopa

Wow. Thanks alot again. I was just trying to use booleans, but i was doing it all wrong again.
This didn't quite work. The second thread which produces a square wave is producing square wave which run in the motion of sine waves. i'm checking my whole program again to see if there is anything wrong with it.

ogopa

ogopa

[quote author="mlong" date="1313525638"]You should tell the thread what kind of wave to use. You could use an enum for the wave types, or something.

This is a rough example that just uses a boolean flag to determine whether to use sine or not. I haven't tested it or anything.

in mythread.h:
@
protected:
void run();

bool m_is_sine;

public:
explicit MyThread(QObject *parent = 0);
void setSine(bool useSine) { m_is_sine = useSine; }
@

in mythread.cpp:
@

MyThread::MyThread(QObject *parent) :
QThread(parent), m_is_sine(false)
{
}

void MyThread::run()
{
if (m_is_sine)
onWriteLoopSine();
else
onWriteLoopSquare();
}
@

in wave.cpp:
@
wave::wave(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::wave)
{
ui->setupUi(this);
setup();
thread = new MyThread();
thread->setSine(true);
thread2 = new MyThread();
thread2->setSine(false);
}
@[/quote]

What if I had three threads, so I would need three conditions instead of 2?

mlong

The big picture is this...

You need some way to tell the thread what kind of wave to generate. Think of it as a property of the thread class.

I already suggested you could use an "enum":http://cplus.about.com/od/introductiontoprogramming/p/enumeration.htm to do it.

But figuring out how you want to do it is up to you.

ogopa

Thanks mlong. I just included a second boolean.:)

Here's the solution:
mythread.cpp:
@#include "wave.h"
#include "mythread.h"

MyThread::MyThread(QObject *parent) :
QThread(parent), is_sine(true), is_square(true)
{
}

void MyThread::run()
{
if (is_sine) onWriteLoopSine();
else {
if(is_square) onWriteLoopSquare();
else onWriteLoopTri();
}
}@

mythread.h:
@#ifndef MYTHREAD_H
#define MYTHREAD_H

#include <QThread>

class MyThread : public QThread
{
Q_OBJECT

protected:
void run();
bool is_sine;
bool is_square;

public:
explicit MyThread(QObject *parent = 0);
void setSine(bool useSine) { is_sine = useSine;}
void setSquare(bool useSquare) { is_square = useSquare;}

};

#endif // MYTHREAD_H@

wave.cpp:
@wave::wave(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::wave)
{
ui->setupUi(this);
setup();
sinethread = new MyThread();
sinethread->setSine(true);
squarethread = new MyThread();
squarethread->setSine(false);
squarethread->setSquare(true);
trithread = new MyThread();
trithread->setSine(false);
trithread->setSquare(false);

}@