glPrimitiveRestartIndex not present when writing code in Qt Creator

[Olivier Ronat]

The glPrimitiveRestartIndex function is unknown by the compiler while glEnable(GL_PRIMITIVE_RESTART_INDEX) is valid.
The <QOpenGLFunctions_4_3_Core> is included (and I have noticed in the documentation the existence of that function)
Is this OpengL feature included in QT 5.4 or what must I do to activate it?
Thank you for your answer

[SGaist]

Hi and welcome to devnet,

Can you show how you are using QOpenGLFunctions_4_3_Core ?

[Olivier Ronat]

I want to draw a cube as a pair of triangle strips separated by a primitive restart index.
GLfloat cubePositions []={
-1.0f, 1.0f, -1.0f // Summit 0
, 1.0f, 1.0f, -1.0f // Summit 1
, -1.0f,1.0f, 1.0f // Summit 2
, 1.0f, 1.0f, 1.0f // Summit 3
, -1.0f,-1.0f,-1.0f // Summit 4
, 1.0f, -1.0f,-1.0f // Summit 5
, -1.0f,-1.0f,1.0f // Summit 6
, 1.0f,-1.0f,1.0f // Summit 7 };
GLushort cube_indices[] =
{
1, 5, 0, 4, 2, 6, 3, 7 , // First strip
0xFFFF, // <<- - This is the restart index
6, 4, 7, 5, 3, 1, 2, 0 // Second strip
};
Normally when all is well defined and allocated we must do the following
glEnable(GL_PRIMITIVE_RESTART); // OK it is working
glPrimitiveRestartIndex(0xFFFF); // This procedure is not recognized by Qt although it is documented.
glDrawElements(GL_TRIANGLE_STRIP, 17, GL_UNSIGNED_SHORT, NULL);

Of course I can call 2 draw commands without primitive restart as follow:
glDrawElements(GL_TRIANGLE_STRIP, 8, GL_UNSIGNED_SHORT, NULL);
glDrawElements(GL_TRIANGLE_STRIP, 8, GL_UNSIGNED_SHORT, (const GLvoid *)(9 * sizeof(GLushort)));

But I was testing advanced features and I have a problem with primitive restart when declaring which index is the restarting index
Thank you for your help

[SGaist]

Sorry, I meant: how are you declaring/initializing your class with QOpenGLFunctions_4_3_Core ?

[Olivier Ronat]

@SGaist
Thank you your question solves the problem. In fact I have derived my new class with QOpenGLFunctions and not QOpenGLFunctions_4_3_Core. So now glPrimitiveRestartIndex appears.
For the GL functions initialisation can I use initializeOpenGLFunctions(); or must I add something else?

[SGaist]

No, nothing else, that's the only thing you need to do to initialize QOpenGLFunctions