Howdy!
In the frame of a VR app, I split the screen in two halves. Each half renders the scene with a different camera position. I set the Config.viewportOffsetX to 0.0f for the left eye and 1.0f for the right eye.
Everything is working like a charm.
I tried to add a reticle in the center of each half screen by blitting a texture but it appears only on the left part of the screen. I understand that it is the same framebuffer that is rendered twice, but I can't figure out a way to do this (I assume I would have the same issue using an Overlay).
My code in onDrawFrame is:
[...]

        //LEFT EYE
        scn.update();
        fb.clear(back);
        //The 2 following rotations of the camera
        //are needed to set the JPCT camera as it is in Blender.
        cam.rotateAxis(cam.getXAxis(), (float) Math.PI/2);
        cam.rotateAxis(cam.getYAxis(), (float) Math.PI/2);

        //Position left eye
        cam.setPosition(new SimpleVector(0.0f+eyeDistance, 0.0f, 1.3f));
        //Rendering in the left viewport
        com.threed.jpct.Config.viewportOffsetX = 0.0f;
        world.renderScene(fb);
        world.draw(fb);
        //Left reticle
        fb.blit(reticleTex, 0, 0, fb.getWidth()/2, fb.getHeight()/2, 256, 256 ,128, 128, 2, false);

        //RIGHT EYE
        cam.setPosition(new SimpleVector(0.0f-eyeDistance, 0.0f, 1.3f));
        com.threed.jpct.Config.viewportOffsetX = 1.0f;
        world.renderScene(fb);
        world.draw(fb);
        // /!\
        // Right reticle
        // This one appears cut in half by the limit of the (left drawn) framebuffer
        fb.blit(reticleTex, 0, 0, fb.getWidth()/2+290, fb.getHeight()/2, 256, 256 ,64, 64, 2, false);
        fb.display();

Does someone could give me any advice on how to do this ? This would make my night

And also, I noticed that the reticle is not well centered. It's a bit off-centered and it surprised me since I used the width and height of the framebuffer divided by two. I saw a deprecated method, getOutputWidth/Height, so maybe for some reasons getWidth/Height might not return the right values. Someone knows where I could have some details about this please ? Thank you!
 
Fixta.