[Qt+OpenGL]

appdev

Hey,

I tried to modify the cube example in Qt by adding a coordinate system and changing the texture.
These are the line codes to draw the frame:
void MainWidget::draw_frame()
{ glLineWidth(8.0f);

     glBegin(GL_LINES);
      //X_axis
     glColor3f( (1.0, 0.0, 0.0);
     glVertex3f(0.0, 0.0, 0.0);
     glVertex3f(4.0, 0.0, 0.0);
     // arrow
     glVertex3f(4.0, 0.0f, 0.0f);
     glVertex3f(3.75, 0.25f, 0.0f);

     glVertex3f(4.0, 0.0f, 0.0f);
     glVertex3f(3.75, -0.25f, 0.0f);
     //Y_axis
     glColor3f (0.0, 1.0, 0.0);
     glVertex3f(0.0, 0.0, 0.0);
     glVertex3f(0.0, 4.0, 0.0);
     // arrow
     glVertex3f(0.0, 4.0f, 0.0f);
     glVertex3f(0.25, 3.75f, 0.0f);

     glVertex3f(0.0, 4.0f, 0.0f);
     glVertex3f(-0.25, 3.75f, 0.0f);

     //Z_axis
     glColor3f (0.0, 0.0, 1.0);
     glVertex3f(0.0, 0.0, 0.0);
     glVertex3f(0.0, 0.0, 4.0);
     // arrow


     glVertex3f(0.0, 0.0f ,4.0f );
     glVertex3f(0.0, 0.25f ,3.75f );

     glVertex3f(0.0, 0.0f ,4.0f );
     glVertex3f(0.0, -0.25f ,3.75f );
     glEnd();

}

Each axis is supposed to have a specific color ( for example x: red, y: green, z:blue).
However the axes have the same color as the cube texture.

Any idea on how to fix the problem ?

appdev

Update: I used texture->release() function to unbind it from the currently active texture unit. Now the frame is all black

appdev

Update: Problem solved.
If you ever face this problem, Please tell me, I can help :D

Petross404_Petros S

@appdev Eerr, care to share with us now?

appdev

Sure with great pleasure,

After disabling texture and shader program, you should specify the matrix mode in glMatrixMode:

glMatrixMode(GL_PROJECTION) then load the projection matrix you used (call glLoadMatrixf)
glMatrixMode(GL_MODELVIEW) then load the modelview matrix. Transform it to identity.
Finally you can draw the coordinate system or any other object. In this case, the texture of the first object won't have any effect on any other object rendered after. ^^