Qt isn't generating .h and .cpp files for QOpenGLWidget

mrjj

@stevereine
Hi
The promotion dialog asked what Class to "promote to" and in which .h file it can find that class. But i can see if you are not sure what that features does it could look like it asked what to call it and where to put it :)

Yes you are right the class is called MyGLWidget so main.cpp is wrong. Good catch.

Did you fix the constructor error ?

stevereine

I have not been able to solve the constructor problem. I'll be honest with you, I'm a decent C++ guy but some of the nomenclature I see around contructors does confuse me. There might be something very obvious here that I don't understand. Here is the definition and the implementation. I didn't change anything, just cut and pasted from the example code.

definition:

public:
MyGLWidget(QWidget *parent) : QOpenGLWidget(parent) { }

implementation:

MyGLWidget::MyGLWidget()
: m_program(0), m_shader(0), m_texture(0)
{
// No OpenGL resource initialization is done here.
}

The brackets at the end of the implementation don't look right to me. I did try removing them, but just got different error.

thank you again!

mrjj

@stevereine
It seems you have 2 constructors
one that is fully defined in .h
the
MyGLWidget(QWidget *parent) : QOpenGLWidget(parent) { }

And then in .cpp you have another one that has no definition in .h and i think thats
what the "out of bounds " was talking about.

what about just doing
MyGLWidget(QWidget *parent) : m_program(0), m_shader(0), m_texture(0), QOpenGLWidget(parent) { }

and get rid of
MyGLWidget::MyGLWidget()
: m_program(0), m_shader(0), m_texture(0)
{
// No OpenGL resource initialization is done here.
}

as that takes no parent which we want for a QWidget so we would not use this anyway.

update:
maybe do it right so its
.h
MyGLWidget(QWidget *parent);
and .cpp
MyGLWidget::MyGLWidget(QWidget *parent) : m_program(0), m_shader(0), m_texture(0), QOpenGLWidget(parent) { }

stevereine

I'm one step ahead of you. I did try this earlier. When I comment out what you suggest, I get the following errors;

definition of implicitly declared destructor

no matching constructor for initialization of 'MyGLWidget'

MyGLWidget: no appropriate default constructor available

To fix at least part of this, I tried commenting out the destructor. Note I'm pasting the destructor from the example code here as well.

MyGLWidget::~MyGLWidget()
{
// Make sure the context is current and then explicitly
// destroy all underlying OpenGL resources.
makeCurrent();

delete m_texture;
delete m_shader;
delete m_program;

m_vbo.destroy();
m_vao.destroy();

doneCurrent();

}

When I comment out the destructor, I am left with two errors. I think it's really one error, both related to the constructor. Here are the errors:

error: no matching constructor for initialization of 'MyGLWidget'

error: C2512: 'MyGLWidget': no appropriate default constructor available

Regardless, I think we are close to solving this.

mrjj

@stevereine
Hi
"MyGLWidget: no appropriate default constructor available"
Sounds to me like you create one without giving it a parent?
like
MyGLWidget widget;
so fix is to do
MyGLWidget widget(nullptr);
(not giving it a parent will make it a window but i guess that is fine)
I assume its still the same main as in example ?

stevereine

One more comment, it doesn't seem like it's recognizing that line of code as a constructor:

public:
MyGLWidget(QWidget *parent) : QOpenGLWidget(parent) {}

mrjj

@stevereine
The : QOpenGLWidget(parent) should go to .cpp
as it dont like it in .h

so .h
MyGLWidget(QWidget *parent);
and in cpp
MyGLWidget::MyGLWidget(QWidget *parent) : QOpenGLWidget(parent) {

}

stevereine

Yes! That worked. It makes sense, but I never would have figured out by myself. I can now initialize the background to whichever color I want.

I've moved on now to adding the shaders and the init code for the shaders, getting an assert error when using;

attributeLocation("posAttr");m_posAttr = m_program->attributeLocation("posAttr");

The problem that I started this thread with is solved. Should I start a new query for this new assert error?

mrjj

@stevereine
Hi
Well i also forgot it has to be .cpp for the ctor initialiser list. 😋

I would make this as solved and open a new one for the shader issue simply
to make sure people see the actually issue right away.

stevereine

will do, thank you!