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I am on latest Raspian release with latest Qt5 pkgs and related OpenGL + MESA pkgs installed from the standard Raspian repo.

I am attempting to build a C++ program (not mine) that relies on Qt5 and OpenGL.

The compiler is complaining as follows:

error: ‘glGetTexImage’ was not declared in this scope
     glGetTexImage(GL_TEXTURE_2D, 0, GL_RED, GL_UNSIGNED_BYTE, (unsigned char *)memoryObject[0].constPointer());

Yet, immediately above that there are two other OpenGL calls that "resolve" fine:

glBindTexture(GL_TEXTURE_2D, frameBufferObjectA->texture());
glPixelStorei(GL_PACK_ALIGNMENT, 1);

Digging around, I see that glGetTexImage() is mentioned in the Qt5 provided header files which are (apparently) exposed via:

#include <QOpenGLFunctions>

I also have:

#include <QOpenGLBuffer>
#include <QOpenGLTexture>
#include <QOpenGLShaderProgram>
#include <QOpenGLVertexArrayObject>
#include <QOpenGLFramebufferObject>

In my experience, the compiler complaint usually points to a missing #include, but so far I am not finding it.

Any pointers?

What should I look at next?

Is this related to OpenGL "desktop" vs SE2?

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I found an answer as to why the code doesn't build when using the OOB Raspbian OpenGL:

$ glxinfo | grep -i version
server glx version string: 1.4
client glx version string: 1.4
GLX version: 1.4
    Version: 13.0.6
    Max core profile version: 0.0
    Max compat profile version: 2.1
    Max GLES1 profile version: 1.1
    Max GLES[23] profile version: 2.0
OpenGL version string: 2.1 Mesa 13.0.6
OpenGL shading language version string: 1.20
OpenGL ES profile version string: OpenGL ES 2.0 Mesa 13.0.6
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 1.0.16

And according to the following post, OpenGL ES 2 doesn't include an implementation of glGetTexImage():

StackOverflow: opengl es 2.0 android c++ glGetTexImage alternative

SOLUTION: Will either need to re-write the code, or build the full desktop version of OpenGL.

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