error LNK2019: unresolved external symbol __imp_glBegin referenced in ... (I have both Qt OpenGL & QtOpenGLWidget modules included)

[enjoysmath]

This is in Visual Studio Community 2022 (64-bit) - Current. The C++ Version is Visual C++ 2022. I'm using the latest C++ release version (so past C++ 20).

Here is a screenshot of my module selection:

Here is glviewwidget.h:

#pragma once
#include <QOpenGLWidget>
#include <QOpenGLFunctions>
#include "glgraphicsitem.h"
#include <QColor>
#include <QList>


class GLViewWidget : public QOpenGLWidget, protected QOpenGLFunctions
{
public:
	GLViewWidget(QWidget* parent = nullptr);

protected:
	void initializeGL() override;
	void paintGL() override;
	void resizeGL(int w, int h) override;
	void perspective(GLdouble fovy, GLdouble aspect, GLdouble zNear, GLdouble zFar);
	void setBackgroundColor(char r, char g, char b, char a);
	QColor backgroundColor() const { return bgColor; }
	void addItem(GLGraphicsItem* gfxItem);

private slots:
	void updateRequestedByItem() { update(); }

private:
	QList<GLGraphicsItem*> graphicsItems;
	QColor bgColor;
};

And its implementation glviewwidget.cpp:
#include "glviewwidget.h":

GLViewWidget::GLViewWidget(QWidget* parent)
	: QOpenGLWidget(parent)
{
}

void GLViewWidget::initializeGL()
{
	initializeOpenGLFunctions();	
	glEnable(GL_DEPTH_TEST);
}

void GLViewWidget::paintGL()
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glLoadIdentity();

	foreach(auto const& item, graphicsItems)
	{
		item->paintGL();
	}
}

void GLViewWidget::resizeGL(int w, int h)
{
	glViewport(0, 0, w, h);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	// The below line replaces gluPerspective(45.0, (float)w / (float)h, 0.1, 100.0);
	// TODO: are the params correct? -ddj
	perspective(45.0, 1.0f, 0.1, 100.0);
	glMatrixMode(GL_MODELVIEW);
}

void GLViewWidget::perspective(GLdouble fovy, GLdouble aspect, GLdouble zNear, GLdouble zFar)
{
	GLdouble top = zNear * tan(fovy * M_PI / 360.0);
	GLdouble right = top * aspect;
	glFrustum(-right, right, -top, top, zNear, zFar);
}

void GLViewWidget::setBackgroundColor(char r, char g, char b, char a)
{
	bgColor.setRed(r);
	bgColor.setGreen(g);
	bgColor.setBlue(b);
	bgColor.setAlpha(a);
}

void GLViewWidget::addItem(GLGraphicsItem* gfxItem)
{
	graphicsItems.append(gfxItem);
	connect(gfxItem, &GLGraphicsItem::update, this, &GLViewWidget::updateRequestedByItem);
	update();
}

The errors I'm getting are linker errors:

1>glgriditem.obj : error LNK2019: unresolved external symbol __imp_glBegin referenced in function "protected: virtual void __cdecl GLGridItem::paintGL(void)" (?paintGL@GLGridItem@@MEAAXXZ)
1>glgriditem.obj : error LNK2019: unresolved external symbol __imp_glEnd referenced in function "protected: virtual void __cdecl GLGridItem::paintGL(void)" (?paintGL@GLGridItem@@MEAAXXZ)
1>glgriditem.obj : error LNK2019: unresolved external symbol __imp_glVertex3f referenced in function "protected: virtual void __cdecl GLGridItem::paintGL(void)" (?paintGL@GLGridItem@@MEAAXXZ)
1>glviewwidget.obj : error LNK2019: unresolved external symbol __imp_glFrustum referenced in function "protected: void __cdecl GLViewWidget::perspective(double,double,double,double)" (?perspective@GLViewWidget@@IEAAXNNNN@Z)
1>glviewwidget.obj : error LNK2019: unresolved external symbol __imp_glLoadIdentity referenced in function "protected: virtual void __cdecl GLViewWidget::paintGL(void)" (?paintGL@GLViewWidget@@MEAAXXZ)
1>glviewwidget.obj : error LNK2019: unresolved external symbol __imp_glMatrixMode referenced in function "protected: virtual void __cdecl GLViewWidget::resizeGL(int,int)" (?resizeGL@GLViewWidget@@MEAAXHH@Z)
1>debug\\cuberhiwidget.exe : fatal error LNK1120: 6 unresolved externals
1>Done building project "cuberhiwidget.vcxproj" -- FAILED.
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
========== Build completed at 9:38 AM and took 38.090 seconds ==========

I know I'm coding this using the "old GL style", if you recommend using the "new GL style" or even Qt3D, I will try to learn those. But if I could simply get these linker errors fixed, I would prefer that. It's not a very complex scene that I'm rendering. Something like: a floor grid, a bounding box, and a scatter plot of up to 1000 points, all in 3D, with a camera to rotate around the scatter plot.

Thanks for your help, in advance!

[Christian Ehrlicher]

You need to link against the opengl libraries. Opemgl32.lib on windows.

[enjoysmath]

@Christian-Ehrlicher Where do we find those libs?

[enjoysmath]

@Christian-Ehrlicher thanks. That worked! Here is a screenshot for future users of where to add it: