Patch based on trunk.
Original shader was not running on various NVidia cards due to old
syntax in shader.
Maybe Wang Rui can test this, as he is the original author.
cheers
Sebastian
/* -*-c++-*- OpenSceneGraph example, osgcomputeshaders.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
// Written by Wang Rui
// This example can work only if GL version is 4.3 or greater
#include <osg/Texture2D>
#include <osg/Geometry>
#include <osg/Geode>
#include <osgDB/ReadFile>
#include <osgGA/StateSetManipulator>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>
static const char* computeSrc = {
"#version 430\n"
"uniform float osg_FrameTime;\n"
"layout (r32f, binding =0) uniform image2D targetTex;\n"
"layout (local_size_x = 16, local_size_y = 16) in;\n"
"void main() {\n"
" ivec2 storePos = ivec2(gl_GlobalInvocationID.xy);\n"
" float coeffcient = 0.5*sin(float(gl_WorkGroupID.x +
gl_WorkGroupID.y)*0.1 + osg_FrameTime);\n"
" coeffcient *= length(vec2(ivec2(gl_LocalInvocationID.xy) - ivec2(8)) /
vec2(8.0));\n"
" imageStore(targetTex, storePos, vec4(1.0-coeffcient, 0.0, 0.0, 0.0));\n"
"}\n"
};
int main( int argc, char** argv )
{
osg::ArgumentParser arguments( &argc, argv );
// Create the texture as both the output of compute shader and the input of
a normal quad
osg::ref_ptr<osg::Texture2D> tex2D = new osg::Texture2D;
tex2D->setTextureSize( 512, 512 );
tex2D->setFilter( osg::Texture2D::MIN_FILTER, osg::Texture2D::LINEAR );
tex2D->setFilter( osg::Texture2D::MAG_FILTER, osg::Texture2D::LINEAR );
tex2D->setInternalFormat( GL_R32F );
tex2D->setSourceFormat( GL_RED );
tex2D->setSourceType( GL_FLOAT );
tex2D->bindToImageUnit( 0, osg::Texture::WRITE_ONLY ); // So we can use
'image2D' in the compute shader
// The compute shader can't work with other kinds of shaders
// It also requires the work group numbers. Setting them to 0 will disable
the compute shader
osg::ref_ptr<osg::Program> computeProg = new osg::Program;
computeProg->setComputeGroups( 512/16, 512/16, 1 );
computeProg->addShader( new osg::Shader(osg::Shader::COMPUTE, computeSrc) );
// Create a node for outputting to the texture.
// It is OK to have just an empty node here, but seems inbuilt uniforms
like osg_FrameTime won't work then.
// TODO: maybe we can have a custom drawable which also will implement
glMemoryBarrier?
osg::Node* sourceNode = osgDB::readNodeFile("axes.osgt");
if ( !sourceNode ) sourceNode = new osg::Node;
sourceNode->setDataVariance( osg::Object::DYNAMIC );
sourceNode->getOrCreateStateSet()->setAttributeAndModes( computeProg.get()
);
sourceNode->getOrCreateStateSet()->addUniform( new
osg::Uniform("targetTex", (int)0) );
sourceNode->getOrCreateStateSet()->setTextureAttributeAndModes( 0,
tex2D.get() );
// Display the texture on a quad. We will also be able to operate on the
data if reading back to CPU side
osg::Geometry* geom = osg::createTexturedQuadGeometry(
osg::Vec3(), osg::Vec3(1.0f,0.0f,0.0f), osg::Vec3(0.0f,0.0f,1.0f) );
osg::ref_ptr<osg::Geode> quad = new osg::Geode;
quad->addDrawable( geom );
quad->getOrCreateStateSet()->setMode( GL_LIGHTING, osg::StateAttribute::OFF
);
quad->getOrCreateStateSet()->setTextureAttributeAndModes( 0, tex2D.get() );
// Create the scene graph and start the viewer
osg::ref_ptr<osg::Group> scene = new osg::Group;
scene->addChild( sourceNode );
scene->addChild( quad.get() );
osgViewer::Viewer viewer;
viewer.addEventHandler( new
osgGA::StateSetManipulator(viewer.getCamera()->getOrCreateStateSet()) );
viewer.addEventHandler( new osgViewer::StatsHandler );
viewer.addEventHandler( new osgViewer::WindowSizeHandler );
viewer.setSceneData( scene.get() );
return viewer.run();
}
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