Hey,

I'm just trying to setup a minimal example trying to draw a textured quad and already failing on this one. Code looks like this:

Qt Code: 
  1. class Foo : public QGLWidget
  2. {
  3. public:
  4.   Foo( QWidget* parent ) : QGLWidget( parent )
  5.   {
  6.   }
  7.  
  8.   void initializeGL( )
  9.   {
  10.     glDisable( GL_LIGHTING );
  11.     glEnable( GL_TEXTURE_2D );
  12.     glViewport( 0, 0, width( ), height( ) );
  13.  
  14.     glMatrixMode( GL_PROJECTION );
  15.     glLoadIdentity( );
  16.  
  17.     gluPerspective( 45.0f, (GLfloat)width( ) / (GLfloat)height( ), 0.1f, 100.0f );
  18.  
  19.     glMatrixMode( GL_MODELVIEW );
  20.     glLoadIdentity( );
  21.  
  22.     texId = bindTexture( "test.png" );
  23.   }
  24.  
  25.   void paintGL( ) override
  26.   {
  27.     glClearColor( 1.0f, 1.0f, 1.0f, 1.0f );
  28.     glClear( GL_COLOR_BUFFER_BIT );    
  29.  
  30.     glLoadIdentity();
  31.     glTranslatef( 0.0f, 0.0f, -6.0f );
  32.     //drawTexture( rect( ), texId);
  33.     glBegin( GL_QUADS );
  34.       glTexCoord2f( 0.0f, 0.0f );
  35.       glVertex3f( -1.0f, 1.0f, 0.0f );
  36.       glTexCoord2f( 1.0f, 0.0f );
  37.       glVertex3f( 1.0f, 1.0f, 0.0f );
  38.       glTexCoord2f( 1.0f, 1.0f );
  39.       glVertex3f( 1.0f, -1.0f, 0.0f );
  40.       //glColor3f( 0.0f, 1.0f, 0.0f );
  41.       glTexCoord2f( 0.0f, 1.0f );
  42.       glVertex3f( -1.0f, -1.0f, 0.0f );
  43.     glEnd( );
  44.   }
  45.  
  46. private:
  47.   GLuint texId;
  48. };
  49.  
  50. /*
  51.  * Application entry point.
  52.  */
  53. int main( int argc, char **argv )
  54. {
  55.   QApplication app(argc, argv);
  56.  
  57.   QMainWindow *window = new QMainWindow( );
  58.   window->setFixedSize( 800, 600 );
  59.   window->setWindowTitle( QString::fromUtf8( "test" ) );
  60.  
  61.   QWidget *centralWidget = new QWidget( window );
  62.   QVBoxLayout* layout = new QVBoxLayout( centralWidget );
  63.   Foo* foo = new Foo( centralWidget );
  64.   layout->addWidget( foo );
  65.  
  66.   window->setCentralWidget( centralWidget );
  67.   window->show( );
  68.  
  69.   return app.exec( );
  70. }
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I've also tried to manually bind the texture with glGenTexture, glBindTexture and converting the QImage to a OpenGL format and I've tried to experiment with drawTexture but nothing works. If I comment in the glColor line, my quad is rendered green, so it's definitely in my viewport. Am I maybe missing some other state variable or might this be a GL context problem?

Can I somehow double check that bindTexture worked as expected? Because texId will be 0 no matter if I input a valid or invalid filename. Are there any constraits about the texture's size? Because mine is 609x731.