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/* OpenSceneGraph example, osgdrawinstanced.
*
* 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.
*/
//
// This code is copyright (c) 2008 Skew Matrix Software LLC. You may use
// the code under the licensing terms described above.
//
#include <osgDB/ReadFile>
#include <osgViewer/Viewer>
#include <osg/Geometry>
#include <osg/Texture2D>
#include <osgDB/WriteFile>
#include <iostream>
void
createDAIGeometry( osg::Geometry& geom, int nInstances=1 )
{
const float halfDimX( .5 );
const float halfDimZ( .5 );
osg::Vec3Array* v = new osg::Vec3Array;
v->resize( 4 );
geom.setVertexArray( v );
// Geometry for a single quad.
(*v)[ 0 ] = osg::Vec3( -halfDimX, 0., -halfDimZ );
(*v)[ 1 ] = osg::Vec3( halfDimX, 0., -halfDimZ );
(*v)[ 2 ] = osg::Vec3( halfDimX, 0., halfDimZ );
(*v)[ 3 ] = osg::Vec3( -halfDimX, 0., halfDimZ );
// Use the DrawArraysInstanced PrimitiveSet and tell it to draw 1024 instances.
geom.addPrimitiveSet( new osg::DrawArrays( GL_QUADS, 0, 4, nInstances ) );
}
osg::StateSet*
createStateSet()
{
osg::ref_ptr< osg::StateSet > ss = new osg::StateSet;
// Create a vertex program that references the gl_InstanceID to
// render each instance uniquely. gl_InstanceID will be in the range
// 0 to numInstances-1 (1023 in our case).
std::string vertexSource =
"uniform sampler2D osgLogo; \n"
"uniform float osg_SimulationTime; \n"
"void main() \n"
"{ \n"
// Using the instance ID, generate "texture coords" for this instance.
"vec2 tC; \n"
"float r = float(gl_InstanceID) / 32.; \n"
"tC.s = fract( r ); tC.t = floor( r ) / 32.; \n"
// Get the color from the OSG logo.
"gl_FrontColor = texture2D( osgLogo, tC ); \n"
// Use the (scaled) tex coord to translate the position of the vertices.
"vec4 pos = vec4( tC.s * 48., 0., tC.t * 48., 1. ); \n"
// Compute a rotation angle from the instanceID and elapsed time.
"float timeOffset = gl_InstanceID / (32. * 32.); \n"
"float angle = ( osg_SimulationTime - timeOffset ) * 6.283; \n"
"float sa = sin( angle ); \n"
"float ca = cos( angle ); \n"
// New orientation, rotate around z axis.
"vec4 newX = vec4( ca, sa, 0., 0. ); \n"
"vec4 newY = vec4( sa, ca, 0., 0. ); \n"
"vec4 newZ = vec4( 0., 0., 1., 0. ); \n"
"mat4 mV = mat4( newX, newY, newZ, pos ); \n"
"gl_Position = ( gl_ModelViewProjectionMatrix * mV * gl_Vertex ); \n"
"} \n";
osg::ref_ptr< osg::Shader > vertexShader = new osg::Shader();
vertexShader->setType( osg::Shader::VERTEX );
vertexShader->setShaderSource( vertexSource );
osg::ref_ptr< osg::Program > program = new osg::Program();
program->addShader( vertexShader.get() );
ss->setAttribute( program.get(),
osg::StateAttribute::ON | osg::StateAttribute::PROTECTED );
osg::ref_ptr< osg::Image> iLogo = osgDB::readImageFile( "Images/osg128.png" );
if( !iLogo.valid() )
{
osg::notify( osg::ALWAYS ) << "Can't open image file osg128.png" << std::endl;
return( NULL );
}
osg::Texture2D* texLogo = new osg::Texture2D( iLogo.get() );
texLogo->setFilter( osg::Texture2D::MIN_FILTER, osg::Texture2D::LINEAR );
texLogo->setFilter( osg::Texture2D::MAG_FILTER, osg::Texture2D::LINEAR );
ss->setTextureAttribute( 0, texLogo );
osg::ref_ptr< osg::Uniform > texLogoUniform =
new osg::Uniform( "osgLogo", 0 );
ss->addUniform( texLogoUniform.get() );
return( ss.release() );
}
int main( int argc, char **argv )
{
osg::ArgumentParser arguments(&argc, argv);
// Make a scene graph consisting of a single Geode, containing
// a single Geometry, and a single PrimitiveSet.
osg::ref_ptr< osg::Geode > geode = new osg::Geode;
osg::ref_ptr< osg::Geometry > geom = new osg::Geometry;
// Configure the Geometry for use with EXT_draw_arrays:
// DL off and buffer objects on.
geom->setUseDisplayList( false );
geom->setUseVertexBufferObjects( true );
// OSG has no clue where out vertex shader will place the geometric data,
// so specify an initial bound to allow proper culling and near/far computation.
osg::BoundingBox bb( -1., -.1, -1., 49., 1., 49. );
geom->setInitialBound( bb );
// Add geometric data and the PrimitiveSet. Specify numInstances as 32*32 or 1024.
createDAIGeometry( *geom, 32*32 );
geode->addDrawable( geom.get() );
// Create a StateSet to render the instanced Geometry.
osg::ref_ptr< osg::StateSet > ss = createStateSet();
geode->setStateSet( ss.get() );
// osgDB::writeNodeFile(*geode, "instanced.osgt");
osgViewer::Viewer viewer(arguments);
viewer.setSceneData( geode.get() );
return viewer.run();
}
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