[Opensg-users] Multipass Rendering with computation between passes

[Oliver Kutter]

Hi, I want to do some data (non effects) computation on the gpu by glsl with multipass rendering. I put the data on the gpu by textures. For the way back from the gpu to my application, I want to use an object (like a plane or a quad) on the framebuffer and I want to read the pixel values of this object. My first question: Is there a way to create an object on the framebuffer (in 2D or with parallel projection) like the ImageForeground object and set some shader on it? Or do I have to manage this manually? My second Question: I want to compute my results by the fragment shader in the first pass. Then I want to get the computed pixels (my results) back to my application with glReadPixels() and store them for further computation. Then, in the second pass, I want to clear the object, because the rest of the scene should be visible without it. And then, I want to render the whole opengl scene. Is there a way to do it? I read something about a MultiPassMaterialRender, but I don't think, that I can use this, because I can't pause between the first and the second pass, or am I wrong? I think, it would even work, if the objects first pass is rendered to the back buffer, and then the object will be cleared in the second pass while rendering the whole scene, but I don't know how to do it. thanks, Oliver ------------------------------------------------------- SF.Net email is Sponsored by the Better Software Conference & EXPO September 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices Agile & Plan-Driven Development * Managing Projects & Teams * Testing & QA Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf _______________________________________________ Opensg-users mailing list Opensg-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/opensg-users