On 24 February 2012 14:26, Henrik Johansen <[email protected]> wrote: > > On Feb 24, 2012, at 2:04 PM, Igor Stasenko wrote: > >> On 24 February 2012 11:22, Henrik Johansen <[email protected]> >> wrote: >>> On Feb 24, 2012, at 4:05 AM, Igor Stasenko wrote: >>> >>>> >>>> Anyways, i don't like the fact that it copying the rendered stuff from >>>> video memory back to main memory, >>>> and then copying stuff back to video memory (but this time by morphic + >>>> VM). >>>> But this was a cheap way to get demo working and morphic integration. >>>> >>>> If i would be making app which using opengl for rendering, i would >>>> never copy things like that, >>>> because it just a waste of cycles causing a big impact to frame rate. >>>> What works for demo, is not really applicable in serious application. :) >>>> In serious app, i'd rather copy morphic Display form into separate >>>> texture and then render it along with other stuff, which is already >>>> in video memory. >>>> But this approach needs more time investments, which currently i don't >>>> have, and actually heavily depends >>>> on what you want from your app. >>> >>> I think you'd have to ditch the idea of rendering the Display bitmap >>> entirely, if you want to write GL windows to screen directly. >>> Otherwise, you would _never_ get compositing correct, think translucent >>> morphs on top of the GL window for example. >>> >> Yes, but this is for cases if i want to make opengl stuff embedded >> into morphic world. But if i don't want it, i don't need to care :) >> >>> As such, you'd need to rewrite the entire compositing window manager using >>> GL buffers, and only as a side-effect flush the rendering results to a >>> Display there for purely backwards-compatability reasons. >>> >> >> If we would have an easy control of host windows, i.e. a way to create >> new windows and create GL contexts for them in a way we want. >> But today's VMs having little for that. What needs to be done first is >> to make image to be in direct control of host windows, so then >> we can control GL & Display in a way we want. >> Because right now, VM doing "magic" with main window by binding >> Display form to it , and the code which updates it also there, so you >> simply >> cannot do any compositing et all , since the code you need to modify >> is on VM side. > > Multiple window support is orthogonal to compositing OGL/Morphic correctly > through writing a window manager (badly worded, I meant composition manager) > for the current way display is handled. >
Unfortunately, if i would control creation of main window (and hence creation of GL context for it ), then it would be much easier to sidestep all VM functionality and use flicker-free things like swapBuffers, when update to window is required. So, it is not quite orthogonal, because if you look at Mac VMs, its using opengl by its own and it means that it creating own gl context and managing it behind the scenes (see sqSqueakOSXNSView.m in platforms/iOS/vm). > You'd theoretically only need two things from the VM to do so; a handle to > the context of the current window; and a way to modify the Display that does > not automatically trigger a "built-in" redisplay. > The compositing in that window could all use VBO/FBO's (bound to said context > of course), and display done directly by the (written in smalltalk, using OGL > to display) composition manager, sidestepping all VM logic. (well, and > ensuring you redraw *after* VM logic triggers automatically, like when window > is resized) > As long as the Display bitmap is updated accordingly as well, external users > shouldn't even be affected. > what would be really nice is to have callbacks to language side when request to update is received. Then i can decide what to do in order to update the window. But right now i'd rather avoid investing too much effort in "seamless" integration of morphic and GL, because without changing the VM interface the implementation will be cumbersome and will contain many different bells and whistles... The central part of OpenGL game is controlling creation of context and its various parameters. Without such control you often cannot ensure that you will have certain hardware functionality accessible, because depending on the way how you creating a context OS may block it and provide oldish or even software-based renderer for you. -- Best regards, Igor Stasenko.
