Initial email from Tim : "I've implemented using a timestamp, available with ARB_timer_query and OpenGL 3.3, to gather GPU stats. This is nice because it can accurately fix the GPU draw time with respect to the other times on the stats graph, rather than having to estimate the wall time of the end of GPU drawing. This also prevents anomalies like the GPU phase starting before the draw phase..."
Changes to Tim's submission by Robert: Removal of need for swap buffer callback in ViewerBase.cpp, by
integrating a osg::State::frameCompleted() method that does the stats timing collection. Introduction of a
GraphicsContext::swapBuffersCallbackOrImplementation() method that calls the State::frameCompleted() and
the swap buffers callback or the swapImplementation as required.
The win32 pbuffer implementation returned an error unless both the
WGL_ARB_pbuffer and the WGL_ARB_render_texture functions were present.
This was too restrictive, as a pbuffer can usefully be created without
render-to-texture, e.g. for use with glReadPixels. The osg 1.2/Producer
pbuffers worked without RTT, and osgUtil::RenderStage has all the code to
handle both RTT and non-RTT pbuffers, doing a read and copy in the
latter case.
With these changes I have successfully tested the osgprerender example
on a graphics card which supports RTT, and one which doesn't. Plus
tested in my own application.
In order to aid diagnostics I have also added more function status
return checks, and associated error messages. I have included the win32
error text in all error messages output. And there were some errors
with multi-threaded handling of "bind to texture" and a temporary window
context which I have corrected.
These is one (pre-existing) problem with multi-threaded use of pbuffers
in osgViewer & osgprerender, which I have not been able to fix. A win32
device context (HDC) can only be destroyed from the thread that created
it. The pbuffers for pre-render cameras are created in
osgUtil::RenderStage::runCameraSetUp, from the draw thread. But
closeImplementation is normally invoked from the destructor in the main
application thread. With the additional error messages I have added,
osgprerender will now output a couple of warnings from
osgViewer::PixelBufferWin32::closeImplementation() at exit, after
running multi-threaded on windows. I think that is a good thing, to
highlight the problem. I looked into fixing it in osgViewer::Renderer &
osgUtil::RenderStage, but it was too involved for me. My own
application requirements are only single-threaded.
Unrelated fix - an uninitialised variable in
osg::GraphicsThread::FlushDeletedGLObjectsOperation().
"
local function pointer to avoid compiler warnings related to case void*.
Moved various OSG classes across to using setGLExtensions instead of getGLExtensions,
and changed them to use typedef declarations in the headers rather than casts in
the .cpp.
Updated wrappers
Created a new GraphicsThread subclass from OperationThread which allows the
GraphicsContext specific calls to be moved out of the base OperationThread class.
Updated the rest of the OSG to respect these changes.
* Fix for the aspect ratio not being properly set when screens have
different aspect ratios.
* Minor fix for makeCurrentImplementation being called directly instead of
makeCurrent() causing the owning thread pointer not being tracked
* Fix for osglauncher so that it sets its update text regions to DYNAMIC to
prevent multi-threading issues.
as osg::GraphicsOperation. Unpdated parts of OSG depending upon these.
Added a virtaul bool valid() method to osg::GraphicsContext to allow apps to
test whether a valid graphis context has been created or not.
added frame stamp updating and update traversal to osgViewer::Scene/Viewer.
Updated osgcamera example to use new Viewer API calls instead of using local
rendering calls.
the names of the operations to be logged for stats purposes, or used when
do searches of the operation list. The keep member variable tells the graphics
thread run loop wether to remove the entry from the list once its been called.
