[Flightgear-devel] Getting the right View position and orientation
Hi Jim, It may help for you to explain more about what you are trying to do. Is this exhaust smoke from a moving aircraft model? Probably I'm the one to help you since I rewrote most of the viewer a couple years ago, but I just don't understand what you are asking. This is may not help, since I am guessing about what you are trying to do, but take a look at the code in SimGear/scene/model to see how to place an ssg object (ssgBranch) in the scene. This can be used for both stationary and moving objects. I'm trying to add the smoke like the one of the acrobatic aircrafts (for example, the Frecce Tricolori). To do that I've used a modified version of the ssgaParticleSystem. I'm able to correctly place the objects - they appear inside the aircraft - and their position doesn't change when the aircraft moves (in the first attempt, I've add the particle system to the aircraft node into the nodegraph of PLIB, but this doesn't work right). Instead, I've add a function that moves randmly the particles into the 3D space. My main problem is that the particles doesn't rotate to follow the point of view of the user so they are visible only when their normal points to the user. I've watched the code that rotates the particles into the ssgaParticleSystem.cxx file and I've found that the tecnique used rotates the objects using the data stored into the GL_MODELVIEW matrix. I've printed it on the screen and, in FlightGear this matrix is always the identity matrix: I've found the problem, but I'm not able to find a solution. I've watched the code of the billboard animation, the viewer manager and the viewer files, but I'n not able to get the rotation and the position of the point of view into the space. If I could get this data, I'll able to create a matrix like the GL_MODELVIEW and use it to rotate the objects. Thanks, Luca Navighi a 2 MEGA e i primi 3 mesi sono GRATIS. Scegli Libero Adsl Flat senza limiti su http://www.libero.it ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
[Flightgear-devel] Getting the right View position and orientation
Hi everyone, I've added a particle system to FlightGear that simulates the smoke via a PLIB object (I adapted the class ssgaParticleSystem to meet some requirements). However, I've in trouble with billboarding. Used alone, with a PLIB's example, the code that rotates the particles following the user movement's works right. In FlightGear, instead, that code doesn't works and the particles follows the user only within a small range of rotations (they move like the lens flare...). I think that the bug is into the code of rotation: it uses the MODELVIEW matrix, that maybe doesn't works with the lookAt and lookFrom. There's a way to get the position and the rotation of the view (I've tried about all the methods into the class FGViewer, but even when the view is rotated the data doesn't change). If I could get them maybe I'll able to correctly rotate the particles. Hi, Luca 6X velocizzare la tua navigazione a 56k? 6X Web Accelerator di Libero! Scaricalo su INTERNET GRATIS 6X http://www.libero.it ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] Getting the right View position and orientation
Luca Masera said: Hi everyone, I've added a particle system to FlightGear that simulates the smoke via a PLIB object (I adapted the class ssgaParticleSystem to meet some requirements). However, I've in trouble with billboarding. Used alone, with a PLIB's example, the code that rotates the particles following the user movement's works right. In FlightGear, instead, that code doesn't works and the particles follows the user only within a small range of rotations (they move like the lens flare...). I think that the bug is into the code of rotation: it uses the MODELVIEW matrix, that maybe doesn't works with the lookAt and lookFrom. There's a way to get the position and the rotation of the view (I've tried about all the methods into the class FGViewer, but even when the view is rotated the data doesn't change). If I could get them maybe I'll able to correctly rotate the particles. Hi Luca, It may help for you to explain more about what you are trying to do. Is this exhaust smoke from a moving aircraft model? Probably I'm the one to help you since I rewrote most of the viewer a couple years ago, but I just don't understand what you are asking. This is may not help, since I am guessing about what you are trying to do, but take a look at the code in SimGear/scene/model to see how to place an ssg object (ssgBranch) in the scene. This can be used for both stationary and moving objects. Is there anyone on the list who can translate to and from italian? Maybe that would help. Best, Jim ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
