Re: [osg-users] Creating a glowing sun in scene

Wed, 22 Feb 2017 03:41:57 -0800 

Hi Suraj,



Hi All,

As i had posted previously, I could obtain the following results attached in 
the screen short in my attempt to create a glowing sun in the scene.

I am also attaching the source code.

As I am taking the baby-steps in doing shaders programming in OSG, i am having 
a really bad time. My problem is :

1)
I am not able to display the scene with both the glowing sun and cessna.osg in 
it. In the present form of the code it only displays me the blurred sphere( 
suppose to be the glowing sun).  How to get bnoth the blurred sphere and cessna 
displayed together?

2) After referring to online resources as previously suggested replies i could 
not implement a Bloom pass using shader? Any code snippet to do this?
Basically i am not able to understand how to use the output of one fragment shader 
"combineFragSource"into another fragment shader that would make the HDR 
effect...
Basically you want postprocessing on rendered scene. Since you already have a RTT-Pass: You need another pass that binds the RTT-pass input texture and use it inside your second pass. It sounds as like to have the blur on the sun only, so I guess you have to do the blur first and the rest of the scene on-top of that. Take a look at osgPPU, it is great for learning how to do multipass rendering with shaders and FBO. In general it boils down to have RTT-passes that either draw from the main-camera's perspective (like multiple scene passes) or to have a fullscreen-pass that renders on FBO-attached textures from other passes. 

Cheers
Sebastian




I know, its a novice question to ask but after putting efforts from my end  i 
am really stalled! Please help, community.



...

Thank you!

Cheers,
Suraj

/* -*-c++-*- OpenSceneGraph Cookbook
  * Chapter 6 Recipe 6
  *
*/

#include <osg/Texture2D>
#include <osg/Group>
#include <osgDB/ReadFile>
#include <osgViewer/Viewer>
#include <osg/ShapeDrawable>
#include "CommonFunctions"
#include <osg/MatrixTransform>
#include <iostream>
#include <osg/Node>
#define texsize 512
//uniform float weight[5] = float[] (0.227027, 0.1945946, 0.1216216, 0.054054, 
0.016216);


static const char* vertSource = {
     "void main(void)\n"
     "{\n"
     "   gl_Position = ftransform();\n"
     "   gl_TexCoord[0] = gl_MultiTexCoord0;\n"
     "}\n"
};

static const char* blurFragSource = {
     "uniform sampler2D inputTex;\n"
     "uniform vec2 blurDir;\n"
     "void main(void)\n"
     "{\n"
     "   vec2 uv = gl_TexCoord[0].st;\n"
     "   vec2 offset = vec2(0.02*blurDir.x, 0.02*blurDir.y);\n"
     "   vec4 color = texture2D(inputTex, uv) * 0.3;\n"
     "   color += texture2D(inputTex, uv - offset*3.0) * 0.15;\n"
     "   color += texture2D(inputTex, uv - offset*2.0) * 0.15;\n"
     "   color += texture2D(inputTex, uv - offset) * 0.25;\n"
     "   color += texture2D(inputTex, uv + offset) * 0.25;\n"
     "   color += texture2D(inputTex, uv + offset*2.0) * 0.1;\n"
     "   color += texture2D(inputTex, uv + offset*3.0) * 0.15;\n"
     "   gl_FragColor = color;\n"
     "}\n"
};


static const char* combineFragSource = {
     "uniform sampler2D sceneTex;\n"
     "uniform sampler2D blurTex;\n"
"void main(void)\n" 
     "{\n"
     "   vec2 uv = gl_TexCoord[0].st;\n"
     "   vec4 fullColor = texture2D(sceneTex, uv);\n"
     "   vec4 blurColor = texture2D(blurTex, uv);\n"
     "   float mod_color = fullColor + 1.5* (blurColor + fullColor);\n"
     "   gl_FragColor = mod_color;\n"
     "}\n"
};


typedef std::pair<osg::Camera*, osg::Texture*> RTTPair;

RTTPair createColorInput( osg::Node* scene )
{
     osg::ref_ptr<osg::Texture2D> tex2D = new osg::Texture2D;
     tex2D->setTextureSize( texsize, texsize );
     tex2D->setInternalFormat( GL_RGBA );
osg::ref_ptr<osg::Camera> camera = osgCookBook::createRTTCamera(osg::Camera::COLOR_BUFFER, tex2D.get()); 
     camera->addChild( scene );
     return RTTPair(camera.release(), tex2D.get());
}

RTTPair createDepthInput( osg::Node* scene )
{
     osg::ref_ptr<osg::Texture2D> tex2D = new osg::Texture2D;
     tex2D->setTextureSize( texsize, texsize );
     tex2D->setInternalFormat( GL_DEPTH_COMPONENT24 );
     tex2D->setSourceFormat( GL_DEPTH_COMPONENT );
     tex2D->setSourceType( GL_FLOAT );
osg::ref_ptr<osg::Camera> camera = osgCookBook::createRTTCamera(osg::Camera::DEPTH_BUFFER, tex2D.get()); 
     camera->addChild( scene );
     return RTTPair(camera.release(), tex2D.get());
}

RTTPair createBlurPass( osg::Texture* inputTex, const osg::Vec2& dir )
{
     osg::ref_ptr<osg::Texture2D> tex2D = new osg::Texture2D;
     tex2D->setTextureSize( texsize, texsize );
     tex2D->setInternalFormat( GL_RGBA );
     osg::ref_ptr<osg::Camera> camera = osgCookBook::createRTTCamera( 
osg::Camera::COLOR_BUFFER, tex2D.get(), true);
osg::ref_ptr<osg::Program> blurProg = new osg::Program; 
     blurProg->addShader( new osg::Shader(osg::Shader::VERTEX, vertSource) );
     blurProg->addShader( new osg::Shader(osg::Shader::FRAGMENT, 
blurFragSource) );
osg::StateSet* ss = camera->getOrCreateStateSet(); 
     ss->setTextureAttributeAndModes( 0, inputTex );
     ss->setAttributeAndModes( blurProg.get(), 
osg::StateAttribute::ON|osg::StateAttribute::OVERRIDE );
     ss->addUniform( new osg::Uniform("sceneTex", 0) );
     ss->addUniform( new osg::Uniform("blurDir", dir) );
     return RTTPair(camera.release(), tex2D.get());
}


int main( int argc, char** argv )
{
     osg::ArgumentParser arguments( &argc, argv );
     //osg::ref_ptr<osg::Node> scene = osgDB::readNodeFiles( arguments );
     osg::Node* scene = osgDB::readNodeFiles( arguments );
     osg::Group* mygroup = new osg::Group;
        osg::Node* cessna = 
osgDB::readNodeFile("/home/suraj/osgex/ex_cam/cessna.osg");
     osg::MatrixTransform * mt_cessna = new osg::MatrixTransform;
     mt_cessna->setMatrix(osg::Matrix::translate(0,0, 2));
     mt_cessna->addChild(cessna);
if ( !scene ) 
      {//scene = osgDB::readNodeFile("lz.osg");

//Model drawing
osg::ref_ptr<osg::Geode> geode = new osg::Geode();
osg::ref_ptr<osg::ShapeDrawable> sh1 = new osg::ShapeDrawable;
sh1->setShape(new osg::Sphere(osg::Vec3(0.0f,0.0f,0.0f),10.0f ) );
sh1->setColor(osg::Vec4(1.0,1.0,1.0,0.5));
geode->addDrawable(sh1.get() );
mygroup->addChild(geode);
scene=dynamic_cast <osg::Node*>(mygroup);
     }
     // The first pass: color
     RTTPair pass0_color = createColorInput( scene );
// The first pass: depth 
     RTTPair pass0_depth = createDepthInput( scene );
// The horizonal blur pass 
     RTTPair pass1 = createBlurPass( pass0_color.second, osg::Vec2(1, 0) );
// The vertical blur pass 
     RTTPair pass2 = createBlurPass( pass1.second, osg::Vec2(0, 1) );

     // The final pass
     osg::ref_ptr<osg::Camera> hudCamera = osgCookBook::createHUDCamera(0.0, 
1.0, 0.0, 1.0);
      hudCamera->addChild( osgCookBook::createScreenQuad(1.0f, 1.0f, 1.) );
     // hudCamera->addChild( mt_cessna );
osg::ref_ptr<osg::Program> finalProg = new osg::Program; 
     finalProg->addShader( new osg::Shader(osg::Shader::VERTEX, vertSource) );
     finalProg->addShader( new osg::Shader(osg::Shader::FRAGMENT, 
combineFragSource) );
osg::StateSet* stateset = hudCamera->getOrCreateStateSet(); 
     stateset->setTextureAttributeAndModes( 0, pass0_color.second );
     stateset->setTextureAttributeAndModes( 1, pass2.second );
     stateset->setTextureAttributeAndModes( 2, pass0_depth.second );
     //stateset->setTextureAttributeAndModes( 3, pass3.second );
     stateset->setAttributeAndModes( finalProg.get() );
     stateset->addUniform( new osg::Uniform("sceneTex", 0) );
     stateset->addUniform( new osg::Uniform("blurTex", 1) );
        // Build the scene graph
     osg::ref_ptr<osg::Group> root = new osg::Group;
     root->addChild(mt_cessna);
     root->addChild( pass0_color.first );
     //root->addChild( pass0_depth.first );
     root->addChild( pass1.first );
     root->addChild( pass2.first );
     root->addChild( hudCamera.get() );
osgViewer::Viewer viewer; 
     viewer.getCamera()->setComputeNearFarMode( 
osg::CullSettings::DO_NOT_COMPUTE_NEAR_FAR );
     viewer.setSceneData( root.get() );
     return viewer.run();
}
...

Thank you!

Cheers,
Suraj

------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=70310#70310




Attachments:
http://forum.openscenegraph.org//files/screenshot_1_514.png


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