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;
}
