Stefano wrote: > Hi there, > I'm trying to implement a simple glow effect with OpenSG. Has anyone > already > made it? > > I have already: > - used a TextureGrabForeground to take the 2D rendering of the scene; > - used a PolygonForegroundPtr with a shader material to obtain the glow > effect on the whole scene; Sounds good. > > Which obviously is not what I want, as I only want some objects in my > scene > to glow. For what I know, what I have to do is to mask out the parts > of the > scene that do not glow, turning them black in the glow source > rendering, use > the glowing shader material on this texture, and then alpha blend the > result > over the ordinary rendering. Am I right? Yup. But you need to define what parts should glow (i.e. have a light value larger than 1) somehow. > > How can I achieve all this stuff with OpenSG? No different than OpenGL in general. I suggest reading some papers/tutorials on glow/bloom and High Dynamics Rendering, HDR.
Anyway, the two most common approaches are: * Store material glow "amount" in frambuffer alpha channel, multiply scene rgb with alpha in glow effect shader to get glow amount, * Render to floating point texture/buffer with values > 1 denoting "really bright lights". Just filter all that together and compress into 0..1 by various values (depending on how bright your scene is and how much glow you want) Cheers, /Marcus ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Opensg-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/opensg-users
