Deferred rendering is now the de-facto standard rendering technique in many modern game engines, hence I think it is important to have this technique demonstrated in an osg code example.
This particular sample adds soft shadows as well as bump mapping into the rendering pipeline. The image files whitemetal_diffuse.jpg and whitemetal_normal.jpg from OpenSceneGraph-Data images folder are required (The OSG_FILE_PATH environment variable must be set correctly)
Two additional osgt models are included with the demo (best to also put them into OpenSceneGraph-Data, I think.
The shaders are currently defined in separate .frag and .vert files.
implementations being registered at the same time.
One usage case for this functionality to support usage of Wayland and X11 in the same version of the osgViewer.
As part of the new functionality there is now a osg::GraphicsContext::Traits::windowingSystemPreferrence string
that default to empty, but if defined will ensure that a specific WindowingSystemInterface is utilized when
you do a generic call like osg::createGraphicsContext().
Also implemented is standard proxy object for registering the new contexts and removing them automatically, and
declaration of standard graphicswindow_name() C entry point to help with static build linking.
"From I think that this piece of code in StateSet::setTextureAttributeAndModes is a copy&paste mistake:
OSG_NOTICE<<"Warning: non texture attribute '"<<attribute->className()<<"' passed to setTextureAttributeAndModes(unit,attr,value), "<<std::endl;
OSG_NOTICE<<" assuming setAttributeAndModes(attr,value) instead."<<std::endl;
OSG_NOTICE<<" please change calling code to use appropriate call."<<std::endl;
setAttribute(attribute,value);
As per the warning message it should be calling setAttributeAndModes(attribute,value); ."
Font::getKerning(...), Font::getGlyph3D(...) doesn't ask for a font resolution so it uses the last font resolution requested by Font:: getGlyph(...).
This can leads to different results depending of the precedent call to Font::getGlyph(...).
See http://lists.openscenegraph.org/pipermail/osg-users-openscenegraph.org/2016-January/271952.html for more infos.
This fix adds a font resolution parameter to Font::getKerning(...), Font::getGlyph3D(...) and to the font implementations.
This was made under the base revision r15182."
forcing users to use osgDB::readRef*File() methods. The later is preferable as it closes a potential threading bug when using paging databases in conjunction
with the osgDB::Registry Object Cache. This threading bug occurs when one thread gets an object from the Cache via an osgDB::read*File() call where only
a pointer to the object is passed back, so taking a reference to the object is delayed till it gets reassigned to a ref_ptr<>, but at the same time another
thread calls a flush of the Object Cache deleting this object as it's referenceCount is now zero. Using osgDB::readREf*File() makes sure the a ref_ptr<> is
passed back and the referenceCount never goes to zero.
To ensure the OSG builds when OSG_PROVIDE_READFILE is to OFF the many cases of osgDB::read*File() usage had to be replaced with a ref_ptr<> osgDB::readRef*File()
usage. The avoid this change causing lots of other client code to be rewritten to handle the use of ref_ptr<> in place of C pointer I introduced a serious of
templte methods in various class to adapt ref_ptr<> to the underly C pointer to be passed to old OSG API's, example of this is found in include/osg/Group:
bool addChild(Node* child); // old method which can only be used with a Node*
tempalte<class T> bool addChild(const osg::ref_ptr<T>& child) { return addChild(child.get()); } // adapter template method
These changes together cover 149 modified files, so it's a large submission. This extent of changes are warrent to make use of the Object Cache
and multi-threaded loaded more robust.
git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@15164 16af8721-9629-0410-8352-f15c8da7e697
This approach unifies much of the code handling the clean up of OpenGL graphics data, avoids lots of local mutexes and static variables that were previously required,
and enables the clean up scheme to be easily extended by users providing their own GraphicsObjectManager subclasses.
git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@15130 16af8721-9629-0410-8352-f15c8da7e697
Added osgText::Bevel::s/getRoundedConcaveJunctions(bool) to control how the bevel should be tessellated around concave junctions on the glyph boundary.
git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14871 16af8721-9629-0410-8352-f15c8da7e697
enum ResizeMask
{
RESIZE_VIEWPORT=1,
RESIZE_ATTACHMENTS=2,
RESIZE_PROJECTIONMATRIX=4,
RESIZE_DEFAULT=RESIZE_VIEWPORT|RESIZE_ATTACHMENTS
};
/** Resize, to the specified width and height, the viewport, attachments and projection matrix according to the resizeMask provided.
* Note, the adjustment of the projection matrix is done if the RESIZE_PROJECTIONMATRIX mask to set and according to the rules specified in the ProjectionResizePolicy. */
void resize(int width, int height, int resizeMask=RESIZE_DEFAULT);
git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14811 16af8721-9629-0410-8352-f15c8da7e697
geometry is clipped as soon as it is tessellated. The clipping is
probably caused by rounding errors because it is only in one spot. The
clipping disappears when the camera is moved, and reappears when it is
moved back. Expanding the the bounding box fixed the clipping bug."
Tweaked by Robert Osfield to expand it to a -1 to 1 unit box.
Actual clipping bug is not due to rounding errors but the shaders creating vertices outside the bounding box of the original input vertices
git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14747 16af8721-9629-0410-8352-f15c8da7e697
and outer tessellation. The minus key decrease both the inner and
outer tessellation. You can still use the arrow keys to control inner
and outer tessellation separately."
From Robert Osfield, clean up the code to fix warnings and make the coding style more consistent with the rest of the OSG.
git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14716 16af8721-9629-0410-8352-f15c8da7e697
Introduced a new shader composition example based on the new #pragama and #define based GLSL shader/osg::StateSet::setDefine() functionality now built into the core OSG.
git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14692 16af8721-9629-0410-8352-f15c8da7e697
algorithm consisting of two consequent phases :
- first phase is a GLSL shader performing object culling and LOD picking ( a culling shader ).
Every culled object is represented as GL_POINT in the input osg::Geometry.
The output of the culling shader is a set of object LODs that need to be rendered.
The output is stored in texture buffer objects. No pixel is drawn to the screen
because GL_RASTERIZER_DISCARD mode is used.
- second phase draws osg::Geometry containing merged LODs using glDrawArraysIndirect()
function. Information about quantity of instances to render, its positions and other
parameters is sourced from texture buffer objects filled in the first phase.
The example uses various OpenGL 4.2 features such as texture buffer objects,
atomic counters, image units and functions defined in GL_ARB_shader_image_load_store
extension to achieve its goal and thus will not work on graphic cards with older OpenGL
versions.
The example was tested on Linux and Windows with NVidia 570 and 580 cards.
The tests on AMD cards were not conducted ( due to lack of it ).
The tests were performed using OSG revision 14088.
The main advantages of this rendering method :
- instanced rendering capable of drawing thousands of different objects with
almost no CPU intervention ( cull and draw times are close to 0 ms ).
- input objects may be sourced from any OSG graph ( for example - information about
object points may be stored in a PagedLOD graph. This way we may cover the whole
countries with trees, buildings and other objects ).
Furthermore if we create osgDB plugins that generate data on the fly, we may
generate information for every grass blade for that country.
- every object may have its own parameters and thus may be distinct from other objects
of the same type.
- relatively low memory footprint ( single object information is stored in a few
vertex attributes ).
- no GPU->CPU roundtrip typical for such methods ( method uses atomic counters
and glDrawArraysIndirect() function instead of OpenGL queries. This way
information about quantity of rendered objects never goes back to CPU.
The typical GPU->CPU roundtrip cost is about 2 ms ).
- this example also shows how to render dynamic objects ( objects that may change
its position ) with moving parts ( like car wheels or airplane propellers ) .
The obvious extension to that dynamic method would be the animated crowd rendering.
- rendered objects may be easily replaced ( there is no need to process the whole
OSG graphs, because these graphs store only positional information ).
The main disadvantages of a method :
- the maximum quantity of objects to render must be known beforehand
( because texture buffer objects holding data between phases have constant size ).
- OSG statistics are flawed ( they don't know anymore how many objects are drawn ).
- osgUtil::Intersection does not work
Example application may be used to make some performance tests, so below you
will find some extended parameter description :
--skip-dynamic - skip rendering of dynamic objects if you only want to
observe static object statistics
--skip-static - the same for static objects
--dynamic-area-size - size of the area for dynamic rendering. Default = 1000 meters
( square 1000m x 1000m ). Along with density defines
how many dynamic objects is there in the example.
--static-area-size - the same for static objects. Default = 2000 meters
( square 2000m x 2000m ).
Example application defines some parameters (density, LOD ranges, object's triangle count).
You may manipulate its values using below described modifiers:
--density-modifier - density modifier in percent. Default = 100%.
Density ( along with LOD ranges ) defines maximum
quantity of rendered objects. registerType() function
accepts maximum density ( in objects per square kilometer )
as its parameter.
--lod-modifier - defines the LOD ranges. Default = 100%.
--triangle-modifier - defines the number of triangles in finally rendered objects.
Default = 100 %.
--instances-per-cell - for static rendering the application builds OSG graph using
InstanceCell class ( this class is a modified version of Cell class
from osgforest example - it builds simple quadtree from a list
of static instances ). This parameter defines maximum number
of instances in a single osg::Group in quadtree.
If, for example, you modify it to value=100, you will see
really big cull time in OSG statistics ( because resulting
tree generated by InstanceCell will be very deep ).
Default value = 4096 .
--export-objects - write object geometries and quadtree of instances to osgt files
for later analysis.
--use-multi-draw - use glMultiDrawArraysIndirect() instead of glDrawArraysIndirect() in a
draw shader. Thanks to this we may render all ( different ) objects
using only one draw call. Requires OpenGL version 4.3 and some more
work from me, because now it does not work ( probably I implemented
it wrong, or Windows NVidia driver has errors, because it hangs
the apllication at the moment ).
This application is inspired by Daniel Rákos work : "GPU based dynamic geometry LOD" that
may be found under this address : http://rastergrid.com/blog/2010/10/gpu-based-dynamic-geometry-lod/
There are however some differences :
- Daniel Rákos uses GL queries to count objects to render, while this example
uses atomic counters ( no GPU->CPU roundtrip )
- this example does not use transform feedback buffers to store intermediate data
( it uses texture buffer objects instead ).
- I use only the vertex shader to cull objects, whereas Daniel Rákos uses vertex shader
and geometry shader ( because only geometry shader can send more than one primitive
to transform feedback buffers ).
- objects in the example are drawn using glDrawArraysIndirect() function,
instead of glDrawElementsInstanced().
Finally there are some things to consider/discuss :
- the whole algorithm exploits nice OpenGL feature that any GL buffer
may be bound as any type of buffer ( in our example a buffer is once bound
as a texture buffer object, and later is bound as GL_DRAW_INDIRECT_BUFFER ).
osg::TextureBuffer class has one handy method to do that trick ( bindBufferAs() ),
and new primitive sets use osg::TextureBuffer as input.
For now I added new primitive sets to example ( DrawArraysIndirect and
MultiDrawArraysIndirect defined in examples/osggpucull/DrawIndirectPrimitiveSet.h ),
but if Robert will accept its current implementations ( I mean - primitive
sets that have osg::TextureBuffer in constructor ), I may add it to
osg/include/PrimitiveSet header.
- I used BufferTemplate class writen and published by Aurelien in submission forum
some time ago. For some reason this class never got into osg/include, but is
really needed during creation of UBOs, TBOs, and possibly SSBOs in the future.
I added std::vector specialization to that template class.
- I needed to create similar osg::Geometries with variable number of vertices
( to create different LODs in my example ). For this reason I've written
some code allowing me to create osg::Geometries from osg::Shape descendants.
This code may be found in ShapeToGeometry.* files. Examples of use are in
osggpucull.cpp . The question is : should this code stay in example, or should
it be moved to osgUtil ?
- this remark is important for NVidia cards on Linux and Windows : if
you have "Sync to VBlank" turned ON in nvidia-settings and you want to see
real GPU times in OSG statistics window, you must set the power management
settings to "Prefer maximum performance", because when "Adaptive mode" is used,
the graphic card's clock may be slowed down by the driver during program execution
( On Linux when OpenGL application starts in adaptive mode, clock should work
as fast as possible, but after one minute of program execution, the clock slows down ).
This happens when GPU time in OSG statistics window is shorter than 3 ms.
"
git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14531 16af8721-9629-0410-8352-f15c8da7e697
Requires shader files place in OpenSceneGraph-Data/shaders from OpenSceneGraph-Data's svn/trunk to function.
Run osgterrain example with --shader command line option to select displacement mapping shader approach.
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