creating texture from RGB raw data

I am receiving an screen-shot Palette over the network. Next, I convert the Palette indices to their relevant RGB using my matrix containing different colors.
The problem I have with the code is I cannot create a texture out of this rgb image I receive successfully. I would thank if you inform me if I am making a mistake anywhere in the code.

Code:

void GlWidget::createTextureFromBitmap(QByteArray btmp)
{
    //==============================================
    //********** currently using ***************
    //==============================================
    bytes.clear();
    bytes.resize(size * sizeof(unsigned char) * 3);
    bytes = btmp;
    int iRow = 0, iCol = 0;
    for(int i = 2; i < 800*600; i++)
    {
        iCol = i % 800;
        iRow = i / 800;
 
        bytes[(800-iCol)*1800 + 3 * iRow    ] = rgbPaletteSystem[btmp[i]][0] ;
        bytes[(800-iCol)*1800 + 3 * iRow - 1] = rgbPaletteSystem[btmp[i]][2] ;
        bytes[(800-iCol)*1800 + 3 * iRow - 2] = rgbPaletteSystem[btmp[i]][1];
    }
    //    updateGL();
    //==============================================
    //********** currently using ***************
    //==============================================
 
 
     //==========================================
     //********** creating texture *********
     //=====================================
    /* create a 800 bye 600 texture from bitmap */
    tex.buf = new unsigned char[bytes.size()];
    memcpy(tex.buf, bytes.constData(), bytes.size());
    glGenTextures( 1, &tex.id);
    glBindTexture(GL_TEXTURE_2D, tex.id);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_LINEAR);
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
    glTexImage2D(     GL_TEXTURE_2D, 0, GL_RGB, 0, 0, 0, GL_RGB, GL_3_BYTES, tex.buf);
    gluBuild2DMipmaps(GL_TEXTURE_2D, GL_RGB, 800, 600, GL_RGB, GL_3_BYTES, tex.buf);
    delete [] tex.buf;
    tex.buf = NULL;
    updateGL();
}
 
void GlWidget::paintGL()
{
    QMatrix4x4 mMatrix;
    QMatrix4x4 vMatrix;
 
    QMatrix4x4 cameraTransformation;
    cameraTransformation.rotate(alpha, 0, 1, 0);
    cameraTransformation.rotate(beta, 1, 0, 0);
 
    QVector3D cameraPosition = cameraTransformation * QVector3D(0, 0, distance);
    QVector3D cameraUpDirection = cameraTransformation * QVector3D(0, 1, 0);
 
    vMatrix.lookAt(cameraPosition, QVector3D(0, 0, 0), cameraUpDirection);
 
    //    //! [6]
    shaderProgram.bind();
    shaderProgram.setUniformValue("mvpMatrix", pMatrix * vMatrix * mMatrix);
    shaderProgram.setUniformValue("texture", 0);
 
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, tex.id);
    glActiveTexture(0);
 
    shaderProgram.setAttributeArray("vertex", vertices.constData());
    shaderProgram.enableAttributeArray("vertex");
    shaderProgram.setAttributeArray("textureCoordinate", textureCoordinates.constData());
    shaderProgram.enableAttributeArray("textureCoordinate");
 
    glDrawArrays(GL_TRIANGLES, 0, vertices.size());
 
    shaderProgram.disableAttributeArray("vertex");
    shaderProgram.disableAttributeArray("textureCoordinate");
    shaderProgram.release();
}