void grabImage(OSG::Image *img) { OSG::UInt8* data = img->editData(); // for this example, just fill it with random junk if(changeOnlyPart) { // Just change a small rectangular area OSG::UInt32 x = rand() % (img->getWidth() - 100); OSG::UInt32 y = rand() % (img->getHeight() - 100); OSG::UInt32 w = rand() % 100; OSG::UInt32 h = rand() % 100; OSG::UInt32 bpp = img->getBpp(); OSG::UInt32 bpl = img->getWidth() * bpp; OSG::UInt32 bytes = w * bpp; data += y * bpl + x * bpp; OSG::UInt8 val = ((rand() & 0x7f) + 0x80); for(OSG::UInt32 i = h; i > 0; --i, data += bpl) { OSG::UInt8 *d = data; for(OSG::UInt32 j = bytes; j > 0; --j) *d++ = val; } // If only a part of the image changed, only that part needs to // be updated. The speed of the update operation is pretty // directly dependent on the amount of data changed. texObj->imageContentChanged(x, x + w, y, y + h); } else { // Fill the whole picture for(OSG::UInt32 i = img->getHeight(); i > 0; --i) { OSG::UInt8 val = ((rand() & 0x3f) + 0x80); for(OSG::UInt32 j = img->getWidth() * img->getBpp(); j > 0; --j) *data++ = val; } // Everything changed texObj->imageContentChanged(); } }
// Initialize GLUT & OpenSG and set up the scene int main(int argc, char **argv) { // OSG init OSG::osgInit(argc,argv); // GLUT init int winid = setupGLUT(&argc, argv); { // the connection between GLUT and OpenSG OSG::GLUTWindowRefPtr gwin = OSG::GLUTWindow::create(); gwin->setGlutId(winid); gwin->init(); // create the scene OSG::NodeRefPtr torus = OSG::makeTorus( .5, 2, 16, 32 ); OSG::NodeRefPtr scene = OSG::Node::create(); trans = OSG::Transform::create(); scene->setCore(trans); scene->addChild(torus); // Create the parts needed for the video background OSG::UInt32 width = 640; OSG::UInt32 height = 480; // get the desired size from the command line if(argc >= 3) { width = atoi(argv[1]); height = atoi(argv[2]); } // To check OpenGL extensions, the Window needs to have run through // frameInit at least once. This automatically happens when rendering, // but we can't wait for that here. gwin->activate (); gwin->frameInit(); // Now we can check for OpenGL extensions hasNPOT = gwin->hasExtension("GL_ARB_texture_non_power_of_two"); // Print what we've got SLOG << "Got " << (isPOT?"":"non-") << "power-of-two images and " << (hasNPOT?"can":"cannot") << " use NPOT textures, changing " << (changeOnlyPart?"part":"all") << " of the screen" << std::endl; // Ok, now for the meat of the code... // first we need an Image to hold the picture(s) to show image = OSG::Image::create(); // set the image's size and type, and allocate memory // this example uses RGB. On some systems (e.g. Windows) BGR // or BGRA might be faster, it depends on how the images are // acquired image->set(OSG::Image::OSG_RGB_PF, width, height); // Now create the texture to be used for the background texObj = OSG::TextureObjChunk::create(); // Associate image and texture texObj->setImage(image); // Set filtering modes. LINEAR is cheap and good if the image size // changes very little (i.e. the window is about the same size as // the images). texObj->setMinFilter(GL_LINEAR); texObj->setMagFilter(GL_LINEAR); // Set the wrapping modes. We don't need repetition, it might actually // introduce artifactes at the borders, so switch it off. texObj->setWrapS(GL_CLAMP_TO_EDGE); texObj->setWrapT(GL_CLAMP_TO_EDGE); // Newer versions of OpenGL can handle NPOT textures directly. // OpenSG will do that internally automatically. // // Older versions need POT textures. By default OpenSG // will scale an NPOT texture to POT while defining it. // For changing textures that's too slow. // So tell OpenSG not to scale the image and adjust the texture // coordinates used by the TextureBackground (see below). texObj->setScale(false); // Create the background OSG::TextureBackgroundRefPtr back = OSG::TextureBackground::create(); // Set the texture to use back->setTexture(texObj); // if the image is NPOT and we don't have hardware support for it // adjust the texture coordinates. if(isPOT == false && hasNPOT == false) { OSG::UInt32 potWidth = OSG::osgNextPower2(width ); OSG::UInt32 potHeight = OSG::osgNextPower2(height); OSG::Real32 tcRight = OSG::Real32(width ) / OSG::Real32(potWidth ); OSG::Real32 tcTop = OSG::Real32(height) / OSG::Real32(potHeight); back->editMFTexCoords()->push_back(OSG::Vec2f( 0.f, 0.f)); back->editMFTexCoords()->push_back(OSG::Vec2f(tcRight, 0.f)); back->editMFTexCoords()->push_back(OSG::Vec2f(tcRight, tcTop)); back->editMFTexCoords()->push_back(OSG::Vec2f( 0.f, tcTop)); } OSG::commitChanges(); // create the SimpleSceneManager helper mgr = OSG::SimpleSceneManager::create(); // tell the manager what to manage mgr->setWindow(gwin ); mgr->setRoot (scene); mgr->setStatistics(true); // replace the background // This has to be done after the viewport has been created, which the // SSM does in setRoot(). OSG::ViewportRefPtr vp = gwin->getPort(0); vp->setBackground(back); } // show the whole scene mgr->showAll(); // GLUT main loop glutMainLoop(); return 0; }