Hi Chris, I think that
the use of FBO in place of pbuffer, and use of async read pixels see my message https://www.mail-archive.com/[email protected]/msg50831.html could improve speed a bit in your case. Regards Sergey On Fri, Aug 22, 2014 at 11:55 AM, Chris Hidden <[email protected]> wrote: > Ok, with your pushes in the right direction I have finally managed to get > this working! :D. Its not very performance friendly but that I can > optimize later. > > Ill break it down so that people who are looking to do somethings similar > can see what I did and suggest betters ways of doing it if they want :D. > > The first step is to take a look at dhpowares code. His open GL layered > window example is the basis for a lot of what I did. > http://www.dhpoware.com/demos/glLayeredWindows.html > > Dhpoware defines a bunch of constants to help set up the OpenGL and OpenGL > Extensions in his code. A lot of these we don't need however as OSG takes > care of a lot of this for us. We also don't need the methods: > > > Code: > > InitChekerPatternTexture(); > InitGLExtensions(); > InitPBuffer(); > InitGL(); > > > > > These methods do things that OSG takes care of for us. We can also remove > the Struct called Vertex and the Vertex object g_cube as we are using our > own models. > > I changed the Image struct to Scene instead of image just to make things > easier for myself. The struct itself remains the same: > > > Code: > > typedef struct > { > int width; > int height; > int pitch; > HDC hdc; > HBITMAP hBitmap; > BITMAPINFO info; > BYTE *pPixels; > } Scene; > > > > > I also added a few global variables to make things easier while I was > trying to figure this out: > > > Code: > > /** > * Handle to the current Instance > */ > HINSTANCE g_hInst; > /** > * Screen Horizontal x > */ > int sLeft; > /** > * Screen Vertical y > */ > int sTop; > /** > * Width of the screen > */ > int sWidth; > /** > * Height of the screen > */ > int sHeight; > > /** > * Viewer for the OSG engine > */ > osg::ref_ptr<osgViewer::Viewer> g_viewer; > /** > * Image for the off screen pbuffer for the osg Scene > */ > osg::ref_ptr<osg::Image> g_image; > /** > * OSG camera object for our scene > */ > osg::ref_ptr<osg::Camera> g_camera; > > > > > > With WinMain we establish the layered window as shown in the example > except I use sTop, sLeft, sWidth and sHeight to set the createWindow > x,y,width and height attriubutes: > > > Code: > > g_hWnd = CreateWindowEx( > WS_EX_LAYERED | WS_EX_TOPMOST, // 32 bit value declaring > the extended window style > wcl.lpszClassName, // Null > terminated string. Class name. > _T("GL Layered Window Demo"), // Null terminated > string. Window Name. > WS_POPUP, // > 32 but value declaring the style of the window. > sLeft, // > int x pos of window > sTop, // > int y pos of window. > sWidth, // > int width of window > sHeight, // > int height of window. > 0, > // HWND handle to parent window, 0 if none. > 0, > // HMENU handle to menu > wcl.hInstance, // > HINSTANCE handle to the instance of the module. > 0); > > > > > Then I built a small method to set the full screen: > > > Code: > > void SetToFullScreen() > { > RECT desktop; > > const HWND hDesk = GetDesktopWindow(); > GetWindowRect(hDesk, &desktop); > > sLeft = desktop.left; > sTop = desktop.top; > sWidth = desktop.right - sLeft; > sHeight = desktop.bottom - sTop; > } > > > > > Now that the window is full screen and the layered window is established > we need to set up the WindowProc method to handle messages: > > > Code: > > LRESULT CALLBACK WindowProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM > lParam) > { > static TCHAR szBuffer[32] = { 0 }; > > switch (msg) > { > case WM_CREATE: > initOSG(hWnd); > return 0; > > case WM_DESTROY: > PostQuitMessage(0); > return 0; > > case WM_KEYDOWN: > if (wParam == VK_ESCAPE) > { > SendMessage(hWnd, WM_CLOSE, 0, 0); > return 0; > } > break; > > default: > break; > } > > return DefWindowProc(hWnd, msg, wParam, lParam); > } > > > > > This looks a bit different as I didn't need the timer functionality any > more and in WM_CREATE I used the function initOSG to init the OSG engine. > > I also took away the functionality to move around the window as its > unnecessary in full screen. > > initOSG builds off of the forum post that Sergey so kindly provided me: > > > > > > see discussion here http://forum.openscenegraph.org/viewtopic.php?t=7202 > > > > > > Code: > > void initOSG(HWND &hWnd) > { > osg::ref_ptr<osg::Referenced> windata = new > osgViewer::GraphicsWindowWin32::WindowData(hWnd); > > g_viewer = new osgViewer::Viewer(); > g_camera = new osg::Camera; > g_camera = g_viewer->getCamera(); > > osg::ref_ptr<osg::GraphicsContext::Traits> traits = new > osg::GraphicsContext::Traits; > > initOSGTraits(*traits, windata); > > osg::ref_ptr<osg::GraphicsContext> gc = > osg::GraphicsContext::createGraphicsContext(traits.get()); > > g_camera->setGraphicsContext (gc); > g_camera->setDrawBuffer > (GL_FRONT); > g_camera->setProjectionMatrixAsPerspective (30.0f, > (double)traits->width / (double)traits->height, 1.0, 1000.0); > g_camera->setViewport > (new osg::Viewport(0, 0, traits->width, traits->height)); > g_viewer->setSceneData > (osgDB::readNodeFile("cessna.osg")); > g_camera->setClearColor > (osg::Vec4f(0, 0, 0, 0)); > > g_viewer->setCameraManipulator(new osgGA::TrackballManipulator); > g_image = new osg::Image(); // Needed to establish off screen > rendering. > > g_viewer->setRunMaxFrameRate(30); > } > > > > > I also like to split my code up a lot so I establish the traits in a > separate method. Its important here to set the pbuffer to true. As well as > the alpha if you want the background to be completely transparent. > > > Code: > > void initOSGTraits(osg::GraphicsContext::Traits &traits, > osg::ref_ptr<osg::Referenced> &windata) > { > traits.x = sWidth / > 2; > traits.y = sHeight / > 2; > traits.width = sWidth; > traits.height = sHeight; > traits.windowDecoration = false; > traits.doubleBuffer = true; > traits.pbuffer = true; > traits.alpha = true; > traits.inheritedWindowData = windata; > } > > > > > Now to DrawFrame() which gets called every time we move through the > message loop in WinMain where WM_QUIT is not true. > > Here is the bit that got it all working for me. First we need to call > attach on our camera to link the image to the scene. Or I think thats how > it works anyways. Im still quite new to OSG. Then we realize and draw our > frame. > > Now I use dhpoweras CopyPBufferToImage method to create an offscreen > render of our frame: > > > Code: > > void CopyPBufferToImage() > { > > g_image->readPixels(0, 0, sWidth, sHeight, GL_BGRA_EXT, > GL_UNSIGNED_BYTE); > > > for (int i = 0; i < g_image->t(); ++i) > { > memcpy(&g_scene.pPixels[g_scene.pitch * i], > &g_image->data()[((sHeight - 1) - i) * (sWidth * > 4)], > sWidth * 4); > } > > > } > > > > > I took out everything from this method except for the loop that handles > copying over the image from the pbuffer to the scene struct we have > declared earlier. This way it does exactly what dhpoware did except that > we use OSG to handle readPixels. So instead of passing in a byte array we > use osg::IMAGE data property to get the byte array. And memcpy it to our > struct. Notice here that I don't use a threading method as we want > everything to exist in the same thread as the layered window so that we can > actually access our image and copy it to the current window context. > > Dhpowares redrawLayeredWindow() and ImagePreMultAlpha take care of the > nitty gritty redrawing process that I don't fully fuly understand yet. > > And voila! Full screen with a model and no background! Very awesome. > Now I need to fix a LOT of performance issues as this takes a crap ton of > resources, but this is the basic idea anyways. Don't forget to include > the osg headers you need and process.h. > > PLEASE FEEL FREE to criticize the shit out my methods. I want to make this > as performance low and well written as possible. Like I said, I just > started using OSG 2 weeks ago so Im stil learning. > > Cheers![/code] > > ------------------ > Read this topic online here: > http://forum.openscenegraph.org/viewtopic.php?p=60738#60738 > > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >
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