I am currently having problems sharing texture objects between several (currently two) different QGLWidgets. I first create a custom QGLWidget and I override its initializeGL() function and do texture initialization in there. Here is the following code:

Qt Code: 
  1. SharedGLWidget::SharedGLWidget(QWidget *parent) :
  2.     QGLWidget(QGLFormat(QGL::DoubleBuffer | QGL::Rgba | QGL::DepthBuffer), parent)
  3. {
  4. }
  5.  
  6. void SharedGLWidget::initializeGL()
  7. {
  8.     GLbyte *pBytes;
  9.     GLint iWidth, iHeight, iComponents;
  10.     GLenum eFormat;
  11.  
  12.     // Load texture
  13.     glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
  14.     pBytes = gltLoadTGA("../SharedTest/stone.tga", &iWidth, &iHeight, &iComponents, &eFormat);
  15.     glTexImage2D(GL_TEXTURE_2D, 0, iComponents, iWidth, iHeight, 0, eFormat, GL_UNSIGNED_BYTE, pBytes);
  16.     free(pBytes);
  17.  
  18.     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  19.     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  20.     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  21.     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  22.  
  23.     glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
  24.     glEnable(GL_TEXTURE_2D);
  25. }
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Then I create a second QGLWidget and do normal Qt rendering stuff with the exception of loading the textures again.

Qt Code: 
  1. GLWidget::GLWidget(QWidget *parent, const QGLWidget *sharedWidget, Qt::WindowFlags f)
  2.     : QGLWidget(QGLFormat(QGL::DoubleBuffer | QGL::Rgba | QGL::DepthBuffer), parent, sharedWidget, f)
  3.     , xRot(0.0f)
  4.     , yRot(0.0f)
  5. {
  6. }
  7.  
  8. void GLWidget::initializeGL()
  9. {
  10.     // Light values and coordinates
  11.     GLfloat  whiteLight[] = { 0.05f, 0.05f, 0.05f, 1.0f };
  12.     GLfloat  sourceLight[] = { 0.25f, 0.25f, 0.25f, 1.0f };
  13.     GLfloat	 lightPos[] = { -10.f, 5.0f, 5.0f, 1.0f };
  14.  
  15.     glEnable(GL_DEPTH_TEST);	// Hidden surface removal
  16.     glFrontFace(GL_CCW);		// Counter clock-wise polygons face out
  17.     glEnable(GL_CULL_FACE);		// Do not calculate inside of jet
  18.  
  19.     // Enable lighting
  20.     glEnable(GL_LIGHTING);
  21.  
  22.     // Setup and enable light 0
  23.     glLightModelfv(GL_LIGHT_MODEL_AMBIENT,whiteLight);
  24.     glLightfv(GL_LIGHT0,GL_AMBIENT,sourceLight);
  25.     glLightfv(GL_LIGHT0,GL_DIFFUSE,sourceLight);
  26.     glLightfv(GL_LIGHT0,GL_POSITION,lightPos);
  27.     glEnable(GL_LIGHT0);
  28.  
  29.     // Enable color tracking
  30.     glEnable(GL_COLOR_MATERIAL);
  31.  
  32.     // Set Material properties to follow glColor values
  33.     glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE);
  34.  
  35.     // Black blue background
  36.     glClearColor(0.0f, 0.0f, 0.0f, 1.0f );
  37.  
  38.     glEnable(GL_TEXTURE_2D);
  39. }
  40.  
  41. void GLWidget::paintGL()
  42. {
  43.     M3DVector3f vNormal;
  44.     M3DVector3f vCorners[5] = { { 0.0f, .80f, 0.0f },     // Top           0
  45.                               { -0.5f, 0.0f, -.50f },    // Back left     1
  46.                               { 0.5f, 0.0f, -0.50f },    // Back right    2
  47.                               { 0.5f, 0.0f, 0.5f },      // Front right   3
  48.                               { -0.5f, 0.0f, 0.5f }};    // Front left    4
  49.  
  50.     // Clear the window with current clearing color
  51.     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  52.  
  53.     // Save the matrix state and do the rotations
  54.     glPushMatrix();
  55.         // Move object back and do in place rotation
  56.         glTranslatef(0.0f, -0.25f, -4.0f);
  57.         glRotatef(xRot, 1.0f, 0.0f, 0.0f);
  58.         glRotatef(yRot, 0.0f, 1.0f, 0.0f);
  59.  
  60.         // Draw the Pyramid
  61.         glColor3f(1.0f, 1.0f, 1.0f);
  62.         glBegin(GL_TRIANGLES);
  63.             // Bottom section - two triangles
  64.             glNormal3f(0.0f, -1.0f, 0.0f);
  65.             glTexCoord2f(1.0f, 1.0f);
  66.             glVertex3fv(vCorners[2]);
  67.  
  68.             glTexCoord2f(0.0f, 0.0f);
  69.             glVertex3fv(vCorners[4]);
  70.  
  71.             glTexCoord2f(0.0f, 1.0f);
  72.             glVertex3fv(vCorners[1]);
  73.  
  74.  
  75.             glTexCoord2f(1.0f, 1.0f);
  76.             glVertex3fv(vCorners[2]);
  77.  
  78.             glTexCoord2f(1.0f, 0.0f);
  79.             glVertex3fv(vCorners[3]);
  80.  
  81.             glTexCoord2f(0.0f, 0.0f);
  82.             glVertex3fv(vCorners[4]);
  83.  
  84.             // Front Face
  85.             m3dFindNormal(vNormal, vCorners[0], vCorners[4], vCorners[3]);
  86.             glNormal3fv(vNormal);
  87.             glTexCoord2f(0.5f, 1.0f);
  88.             glVertex3fv(vCorners[0]);
  89.             glTexCoord2f(0.0f, 0.0f);
  90.             glVertex3fv(vCorners[4]);
  91.             glTexCoord2f(1.0f, 0.0f);
  92.             glVertex3fv(vCorners[3]);
  93.  
  94.             // Left Face
  95.             m3dFindNormal(vNormal, vCorners[0], vCorners[1], vCorners[4]);
  96.             glNormal3fv(vNormal);
  97.             glTexCoord2f(0.5f, 1.0f);
  98.             glVertex3fv(vCorners[0]);
  99.             glTexCoord2f(0.0f, 0.0f);
  100.             glVertex3fv(vCorners[1]);
  101.             glTexCoord2f(1.0f, 0.0f);
  102.             glVertex3fv(vCorners[4]);
  103.  
  104.             // Back Face
  105.             m3dFindNormal(vNormal, vCorners[0], vCorners[2], vCorners[1]);
  106.             glNormal3fv(vNormal);
  107.             glTexCoord2f(0.5f, 1.0f);
  108.             glVertex3fv(vCorners[0]);
  109.  
  110.             glTexCoord2f(0.0f, 0.0f);
  111.             glVertex3fv(vCorners[2]);
  112.  
  113.             glTexCoord2f(1.0f, 0.0f);
  114.             glVertex3fv(vCorners[1]);
  115.  
  116.             // Right Face
  117.             m3dFindNormal(vNormal, vCorners[0], vCorners[3], vCorners[2]);
  118.             glNormal3fv(vNormal);
  119.             glTexCoord2f(0.5f, 1.0f);
  120.             glVertex3fv(vCorners[0]);
  121.             glTexCoord2f(0.0f, 0.0f);
  122.             glVertex3fv(vCorners[3]);
  123.             glTexCoord2f(1.0f, 0.0f);
  124.             glVertex3fv(vCorners[2]);
  125.         glEnd();
  126.  
  127.  
  128.     // Restore the matrix state
  129.     glPopMatrix();
  130.  
  131.     // Buffer swap
  132.     swapBuffers();
  133. }
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In my main.cpp I pass the first QGLWidget with just the texture initialization as the sharedWidget for the second QGLWidget:

Qt Code: 
  1. int main(int argc, char* argv[])
  2. {
  3.     QApplication app(argc, argv);
  4.  
  5.     SharedGLWidget* glwidget1 = new SharedGLWidget;
  6.  
  7.     GLWidget* widget = new GLWidget(0, glwidget1);
  8.     widget->show();
  9.  
  10.     app.exec();
  11. }
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I am not sure what I am missing but when widget is shown the texture isn't showing up (the pyramid is drawn but with no texturing). I am wondering what I am missing and if anyone has any idea as to how I can do this. I am only creating one texture object thus I was trying to not use glGenBuffers for texture objects but if this is something that has to be done I will try to do it while I wait for some responses. I am curious if I do go that route, how the glBind call would be preformed in the rendering widget. Thanks for any help!