Hello,
we don't have two projectors but a 3d monitor that expects side by side
stereo images.
I already tried to use two viewports beside each other. We received a
side by side image that was not fully satisfying.
If we have a monitor with resolution 1920x1080 the approach produced 1
image of that resolution including 2 half images with resolution of
960x1080 each. The monitor separates the 2 images and scales each of
them horizontally up from 960 to 1920 pixels.
To receive a correct result I would expect that each half image needs to
be distorted horizontally by factor 0.5, to be able to be upscaled
correctly afterwards. I tried this by implementing a seperate
cameradecorator that multiplies the appropriate projection matrix by:
0.5 0 0 0
0 1 0 0
0 0 1 0
0 0 0 1
Don't know if this was a good approach. The problem was that text images
(including relatively thin features/lines) in the scene were unreadable
after that.
I think it may be better to produce a image that has resolution
(2x1920)x1080. Is that somehow feasible?
Other ideas?
Thanks,
Michael
Am 24.02.2011 17:00, schrieb Hall, Theodore:
> Hi Michael.
>
> We support several stereo modes, including none, anaglyph, side-by-
> side, and active.
>
> For side-by-side, we simply create two viewports in one window. In
> width, one viewport extends from 0.0 to 0.5, the other extends from 0.5
> to 1.0.
>
> For a 16x9 projection surface, we create a 32x9 window with side-by-
> side 16x9 viewports. The window spans across two projectors with
> polarizing filters, aligned to project each 16x9 viewport onto the
> same surface.
>
> Here's some code:
>
> // Create an OpenSG PassiveBackground and PassiveWindow that don't mess
> with
> // the GL state. This allows us to implement alternative stereo modes
> and
> // custom render features.
> //
> // In OpenSg 2.0, PassiveWindow derives from NativeWindow, which is a
> // typedef for the system-specific window class -- e.g., WIN32Window.
> int width, height;
> glfwGetWindowSize (&width,&height);
> m_Background = OSG::PassiveBackground::create();
> m_Window = OSG::PassiveWindow::create();
> m_Window->resize (width, height);
>
> #ifdef WIN32
> m_Window->setHwnd (m_HWND);
> m_Window->setHdc (m_HDC);
> m_Window->setHglrc (m_HGLRC);
> #endif
>
> // Determine the viewport bounds and the stereo camera separation.
> //
> // NOTE: The OSG::PassiveViewport isn't passive enough! Its render()
> // function calls glGetIntegerv(GL_VIEWPORT, vp) to reset the OSG
> viewport
> // limits. If we don't explicitly call glViewport() ourselves before
> each
> // render(), it sets the viewport to the entire window. In contrast,
> the
> // basic OSG::Viewport preserves the viewport boundaries that we set
> here.
> // Its activateSize() function calls glViewport() for us.
> float left_min, left_max, right_min, right_max;
> switch (m_StereoMode)
> {
> case ACTIVE_STEREO:
> case ANAGLYPH_STEREO:
> left_min = right_min = 0.0f;
> left_max = right_max = 1.0f;
> break;
>
> case SPLIT_LR_STEREO:
> left_min = 0.0f;
> left_max = 0.5f;
> right_min = 0.5f;
> right_max = 1.0f;
> break;
>
> case SPLIT_RL_STEREO: // for cross-eyed stereo.
> left_min = 0.5f;
> left_max = 1.0f;
> right_min = 0.0f;
> right_max = 0.5f;
> break;
>
> case NO_STEREO:
> default:
> m_StereoMode = NO_STEREO;
> stereo_sep = 0.0f;
> left_min = right_min = 0.0f;
> left_max = right_max = 1.0f;
> break;
> }
>
> // The SceneManager defines the user transform relative to the camera.
> OSG::NodeRefPtr user = SceneManager::getUserTransform (camera);
>
> // Get the corners of the display surface.
> const gmtl::Point3f * corners = m_DisplaySurface.getCorners();
> OSG::MFPnt3f * deco_surface;
>
> // Create the camera decorator and viewport for the mono or left eye.
> m_CameraDecoratorLeft = OSG::ProjectionCameraDecorator::create();
> m_CameraDecoratorLeft->setUser (user);
> m_CameraDecoratorLeft->setDecoratee (camera);
> m_CameraDecoratorLeft->setLeftEye (true);
> m_CameraDecoratorLeft->setEyeSeparation (stereo_sep);
> deco_surface = m_CameraDecoratorLeft->editMFSurface();
> deco_surface->clear();
> deco_surface->push_back (toOSG (corners[0]));
> deco_surface->push_back (toOSG (corners[1]));
> deco_surface->push_back (toOSG (corners[2]));
> deco_surface->push_back (toOSG (corners[3]));
> m_ViewportLeft = OSG::Viewport::create();
> m_ViewportLeft->setBackground (m_Background);
> m_ViewportLeft->setSize (left_min, 0.f, left_max, 1.f);
> m_ViewportLeft->setRoot (root);
> m_ViewportLeft->setCamera (m_CameraDecoratorLeft);
> m_Window->addPort (m_ViewportLeft);
>
> // Create the camera decorator and viewport for the right eye.
> if (m_StereoMode != NO_STEREO)
> {
> m_CameraDecoratorRight =
> OSG::ProjectionCameraDecorator::create();
> m_CameraDecoratorRight->setUser (user);
> m_CameraDecoratorRight->setDecoratee (camera);
> m_CameraDecoratorRight->setLeftEye (false);
> m_CameraDecoratorRight->setEyeSeparation (stereo_sep);
> deco_surface = m_CameraDecoratorRight->editMFSurface();
> deco_surface->clear();
> deco_surface->push_back (toOSG (corners[0]));
> deco_surface->push_back (toOSG (corners[1]));
> deco_surface->push_back (toOSG (corners[2]));
> deco_surface->push_back (toOSG (corners[3]));
> m_ViewportRight = OSG::Viewport::create();
> m_ViewportRight->setBackground (m_Background);
> m_ViewportRight->setSize (right_min, 0.f, right_max, 1.f);
> m_ViewportRight->setRoot (root);
> m_ViewportRight->setCamera (m_CameraDecoratorRight);
> m_Window->addPort (m_ViewportRight);
> }
> m_Window->init();
>
>
>
> Hope this helps.
>
> -- Ted
>
>
> -----Original Message-----
> From: Michael Raab [mailto:michael-r...@gmx.de]
> Sent: Thursday, February 24, 2011 07:38
> To: opensg-users@lists.sourceforge.net
> Subject: [Opensg-users] OpenSG1.8 - Side by Side Stereo
>
> Hi all,
>
> we're thinking about implementing side by side stereo output format for our
> OpenSG based application. Our approach would be to render left eye and right
> eye each in a separate FBO, map the two resulting textures on a quad (left
> eye 0.0->0.5 and right eye 0.5->1.0) and render this with a orthographic
> camera to receive the final output.
> First question, has someone tried to implement side by side before? Are there
> any proven (or better) ways of doing this with OpenSG?
> A special condition is that we're using OpenSG shadows (by
> osg::ShadowViewport) in our application. Is it possible to render shadowed
> scenes to an OpenSG FBOViewport? At the moment I don't see how.
>
> Thanks& Best regards,
> Michael
>
>
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