Linking glew

OpenGL OpenGL: Basic Coding
1

Hi,

I’m trying to add glew library on my project Qt but I don’t understand why, it didn’t find some functions.

Here’s my .pro:


#-------------------------------------------------
#
# Project created by QtCreator 2011-03-22T23:49:11
#
#-------------------------------------------------

QT       += core gui opengl
QT       += webkit

TARGET = Teste
TEMPLATE = app


SOURCES += main.cpp\
        menuprincipal.cpp \
    glwidget.cpp \
    box.cpp \
    point.cpp \
    arraylist.cpp \
    arraylist.operators.cpp \
    xml.cpp \
    tinyxmlparser.cpp \
    tinyxmlerror.cpp \
    tinyxml.cpp \
    tinystr.cpp \
    robot.cpp \
    joint.cpp \
    vertex.cpp \
    properties.cpp \
    face.cpp \
    matrixcalculator.cpp

HEADERS  += menuprincipal.h \
    glwidget.h \
    box.h \
    point.h \
    arraylist.h \
    xml.h \
    tinyxml.h \
    tinystr.h \
    robot.h \
    joint.h \
    vertex.h \
    properties.h \
    face.h \
    matrixcalculator.h \
    tree.hh

FORMS    += menuprincipal.ui
LIBS     += -lglew32

I don’t have problems calling code = glewInit(); but when I try to call other functions like glGenVertexArrays, I have this error:
undefined reference to `_imp____glewGenVertexArrays’

I read the instructions of how to set this library here but nothing. I have put the header <GL/glew.h> in the right place but stills not working.
Any idea?

2

When you program links successfully and runs there shouldnt be a problem with the installation of the lib.

What does glewinit return? Does it return GLEW_OK?
Are you sure that your OpenGL version support glGenVertexArrays? Read here how to check for this:
Glew Basic Usage

Also remember to install a proper OpenGL supporting graphics driver.

3

It returns 0, is the right value true?

I update my drivers yesterday

4

0 should equal GLEW_OK, so it seems ok.
However, you should check if your OpenGL version is at least 3.0 and that GLEW supports the command glGenVertexArrays as described in the link i gave you.

What other gl-commands do not work?

What hardware/system are you on?

5

With glewIsSupported(…) I check the version, I’m on openGL 3.3 (weird because as I said, I update yesterday :S)

Others call that don’t work:
glBindVertexArray
glGenVertexArrays
glGenBuffers
glBindBuffer
glBufferData
and the constant “GLEW_VERSION_3_3”

This is all that I tryied for the moment.

System: Windows XP
Hardware:
NVIDIA Quadro FX1700 (version of driver: 6.14.0012.7536)
Intel 2Quad Q9300

6

http://www.opengl.org/wiki/Extension_Loading_Library

7

If I understand what you’re trying to say, I need to put glewExperimental=TRUE; on my code?

Still not working.

8

Did you try one of the examples?
http://www.opengl.org/wiki/Tutorial1:_Rendering_shapes_with_glDrawRangeElements,_VAO,_VBO,_shaders_(C%2B%2B_/_freeGLUT)

And if that doesn’t work, try getting the function pointers yourself.
You can then trace into the GLEW code to see why it fails.

9

V-man is right, you should check if you can retrieve the OpenGL function pointers for the non-working functions directly from windows using wglGetProcAdress… see here .

Also, since your graphics card is not a standard consumer model, you might to try to compile the code on another machine to ensure your code is fine.

10

The problem is solved, it was the graphic card. Now I m on another nVidia graphic card (more comercial) but I have another problem, check this post