/* OpenSceneGraph example, osgshaders.
*
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*  of this software and associated documentation files (the "Software"), to deal
*  in the Software without restriction, including without limitation the rights
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*
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*  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
*  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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*/

/* file:        examples/osgshaders/GL2Scene.cpp
 * author:        Mike Weiblen 2005-05-01
 *
 * Compose a scene of several instances of a model, with a different
 * OpenGL Shading Language shader applied to each.
 *
 * See http://www.3dlabs.com/opengl2/ for more information regarding
 * the OpenGL Shading Language.
*/

#include <osg/ShapeDrawable>
#include <osg/PositionAttitudeTransform>
#include <osg/Geode>
#include <osg/Node>
#include <osg/Material>
#include <osg/Notify>
#include <osg/Vec3>
#include <osg/Texture1D>
#include <osg/Texture2D>
#include <osg/Texture3D>
#include <osgDB/ReadFile>
#include <osgUtil/Optimizer>

#include <osg/Program>
#include <osg/Shader>
#include <osg/Uniform>
#include <osgUtil/PerlinNoise>

#include <iostream>

#include "GL2Scene.h"

///////////////////////////////////////////////////////////////////////////

static osg::Image*
make1DSineImage( int texSize )
{
    const float PI = 3.1415927;

    osg::Image* image = new osg::Image;
    image->setImage(texSize, 1, 1,
            4, GL_RGBA, GL_UNSIGNED_BYTE,
            new unsigned char[4 * texSize],
            osg::Image::USE_NEW_DELETE);

    GLubyte* ptr = image->data();
    float inc = 2. * PI / (float)texSize;
    for(int i = 0; i < texSize; i++)
    {
        *ptr++ = (GLubyte)((sinf(i * inc) * 0.5 + 0.5) * 255.);
        *ptr++ = 0;
        *ptr++ = 0;
        *ptr++ = 1;
    }
    return image;        
}

static osg::Texture1D*
make1DSineTexture( int texSize )
{
    osg::Texture1D* sineTexture = new osg::Texture1D;
    sineTexture->setWrap(osg::Texture1D::WRAP_S, osg::Texture1D::REPEAT);
    sineTexture->setFilter(osg::Texture1D::MIN_FILTER, osg::Texture1D::LINEAR);
    sineTexture->setFilter(osg::Texture1D::MAG_FILTER, osg::Texture1D::LINEAR);
    sineTexture->setImage( make1DSineImage(texSize) );
    return sineTexture;
}

///////////////////////////////////////////////////////////////////////////
// in-line GLSL source code for the "microshader" example

static const char *microshaderVertSource = {
    "// microshader - colors a fragment based on its position\n"
    "varying vec4 color;\n"
    "void main(void)\n"
    "{\n"
    "    color = gl_Vertex;\n"
    "    gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;\n"
    "}\n"
};

static const char *microshaderFragSource = {
    "varying vec4 color;\n"
    "void main(void)\n"
    "{\n"
    "    gl_FragColor = clamp( color, 0.0, 1.0 );\n"
    "}\n"
};

///////////////////////////////////////////////////////////////////////////

static osg::ref_ptr<osg::Group> rootNode;

// Create some geometry upon which to render GLSL shaders.
static osg::Geode*
CreateModel()
{
    osg::Geode* geode = new osg::Geode();
    geode->addDrawable(new osg::ShapeDrawable(new osg::Sphere(osg::Vec3(0.0f,0.0f,0.0f),1.0f)));
    geode->addDrawable(new osg::ShapeDrawable(new osg::Cone(osg::Vec3(2.2f,0.0f,-0.4f),0.9f,1.8f)));
    geode->addDrawable(new osg::ShapeDrawable(new osg::Cylinder(osg::Vec3(4.4f,0.0f,0.0f),1.0f,1.4f)));
    return geode;
}

// Add a reference to the masterModel at the specified translation, and
// return its StateSet so we can easily attach StateAttributes.
static osg::StateSet*
ModelInstance()
{
    static float zvalue = 0.0f;
    static osg::Node* masterModel = CreateModel();

    osg::PositionAttitudeTransform* xform = new osg::PositionAttitudeTransform();
    xform->setPosition(osg::Vec3( 0.0f, -1.0f, zvalue ));
    zvalue = zvalue + 2.2f;
    xform->addChild(masterModel);
    rootNode->addChild(xform);
    return xform->getOrCreateStateSet();
}

// load source from a file.
static void
LoadShaderSource( osg::Shader* shader, const std::string& fileName )
{
    osg::ref_ptr<osg::Shader> loaded_shader = osgDB::readRefShaderFile(fileName);
    if (loaded_shader)
    {
        shader->setShaderSource( loaded_shader->getShaderSource() );
    }
    else
    {
        osg::notify(osg::WARN) << "File \"" << fileName << "\" not found." << std::endl;
    }
}


///////////////////////////////////////////////////////////////////////////
// rude but convenient globals

static osg::Program* BlockyProgram;
static osg::Shader*  BlockyVertObj;
static osg::Shader*  BlockyFragObj;

static osg::Program* ErodedProgram;
static osg::Shader*  ErodedVertObj;
static osg::Shader*  ErodedFragObj;

static osg::Program* MarbleProgram;
static osg::Shader*  MarbleVertObj;
static osg::Shader*  MarbleFragObj;


///////////////////////////////////////////////////////////////////////////
// for demo simplicity, this one callback animates all the shaders, instancing
// for each uniform but with a specific operation each time.

class AnimateCallback: public osg::UniformCallback
{
    public:
    
        enum Operation
        {
            OFFSET,
            SIN,
            COLOR1,
            COLOR2            
        };
    
        AnimateCallback(Operation op) : _enabled(true),_operation(op) {}

        virtual void operator() ( osg::Uniform* uniform, osg::NodeVisitor* nv )
        {
            if( _enabled )
            {
                float angle = 2.0 * nv->getFrameStamp()->getSimulationTime();
                float sine = sinf( angle );        // -1 -> 1
                float v01 = 0.5f * sine + 0.5f;        //  0 -> 1
                float v10 = 1.0f - v01;                //  1 -> 0
                switch(_operation)
                {
                    case OFFSET : uniform->set( osg::Vec3(0.505f, 0.8f*v01, 0.0f) ); break;
                    case SIN : uniform->set( sine ); break;
                    case COLOR1 : uniform->set( osg::Vec3(v10, 0.0f, 0.0f) ); break;
                    case COLOR2 : uniform->set( osg::Vec3(v01, v01, v10) ); break;
                }
            }
        }

    private:
        bool _enabled;
        Operation _operation;
};

///////////////////////////////////////////////////////////////////////////
// Compose a scenegraph with examples of GLSL shaders

#define TEXUNIT_SINE        1
#define TEXUNIT_NOISE        2

osg::ref_ptr<osg::Group>
GL2Scene::buildScene()
{
    osg::Texture3D* noiseTexture = osgUtil::create3DNoiseTexture( 32 /*128*/ );
    osg::Texture1D* sineTexture = make1DSineTexture( 32 /*1024*/ );

    // the root of our scenegraph.
    rootNode = new osg::Group;

    // attach some Uniforms to the root, to be inherited by Programs.
    {
        osg::Uniform* OffsetUniform = new osg::Uniform( "Offset", osg::Vec3(0.0f, 0.0f, 0.0f) );
        osg::Uniform* SineUniform   = new osg::Uniform( "Sine", 0.0f );
        osg::Uniform* Color1Uniform = new osg::Uniform( "Color1", osg::Vec3(0.0f, 0.0f, 0.0f) );
        osg::Uniform* Color2Uniform = new osg::Uniform( "Color2", osg::Vec3(0.0f, 0.0f, 0.0f) );

        OffsetUniform->setUpdateCallback(new AnimateCallback(AnimateCallback::OFFSET));
        SineUniform->setUpdateCallback(new AnimateCallback(AnimateCallback::SIN));
        Color1Uniform->setUpdateCallback(new AnimateCallback(AnimateCallback::COLOR1));
        Color2Uniform->setUpdateCallback(new AnimateCallback(AnimateCallback::COLOR2));

        osg::StateSet* ss = rootNode->getOrCreateStateSet();
        ss->addUniform( OffsetUniform );
        ss->addUniform( SineUniform );
        ss->addUniform( Color1Uniform );
        ss->addUniform( Color2Uniform );
    }

    // the simple Microshader (its source appears earlier in this file)
    {
        osg::StateSet* ss = ModelInstance();
        osg::Program* program = new osg::Program;
        program->setName( "microshader" );
        _programList.push_back( program );
        program->addShader( new osg::Shader( osg::Shader::VERTEX, microshaderVertSource ) );
        program->addShader( new osg::Shader( osg::Shader::FRAGMENT, microshaderFragSource ) );
        ss->setAttributeAndModes( program, osg::StateAttribute::ON );
    }

    // the "blocky" shader, a simple animation test
    {
        osg::StateSet* ss = ModelInstance();
        BlockyProgram = new osg::Program;
        BlockyProgram->setName( "blocky" );
        _programList.push_back( BlockyProgram );
        BlockyVertObj = new osg::Shader( osg::Shader::VERTEX );
        BlockyFragObj = new osg::Shader( osg::Shader::FRAGMENT );
        BlockyProgram->addShader( BlockyFragObj );
        BlockyProgram->addShader( BlockyVertObj );
        ss->setAttributeAndModes(BlockyProgram, osg::StateAttribute::ON);
    }

    // the "eroded" shader, uses a noise texture to discard fragments
    {
        osg::StateSet* ss = ModelInstance();
        ss->setTextureAttribute(TEXUNIT_NOISE, noiseTexture);
        ErodedProgram = new osg::Program;
        ErodedProgram->setName( "eroded" );
        _programList.push_back( ErodedProgram );
        ErodedVertObj = new osg::Shader( osg::Shader::VERTEX );
        ErodedFragObj = new osg::Shader( osg::Shader::FRAGMENT );
        ErodedProgram->addShader( ErodedFragObj );
        ErodedProgram->addShader( ErodedVertObj );
        ss->setAttributeAndModes(ErodedProgram, osg::StateAttribute::ON);

        ss->addUniform( new osg::Uniform("LightPosition", osg::Vec3(0.0f, 0.0f, 4.0f)) );
        ss->addUniform( new osg::Uniform("Scale", 1.0f) );
        ss->addUniform( new osg::Uniform("sampler3d", TEXUNIT_NOISE) );
    }

    // the "marble" shader, uses two textures
    {
        osg::StateSet* ss = ModelInstance();
        ss->setTextureAttribute(TEXUNIT_NOISE, noiseTexture);
        ss->setTextureAttribute(TEXUNIT_SINE, sineTexture);
        MarbleProgram = new osg::Program;
        MarbleProgram->setName( "marble" );
        _programList.push_back( MarbleProgram );
        MarbleVertObj = new osg::Shader( osg::Shader::VERTEX );
        MarbleFragObj = new osg::Shader( osg::Shader::FRAGMENT );
        MarbleProgram->addShader( MarbleFragObj );
        MarbleProgram->addShader( MarbleVertObj );
        ss->setAttributeAndModes(MarbleProgram, osg::StateAttribute::ON);

        ss->addUniform( new osg::Uniform("NoiseTex", TEXUNIT_NOISE) );
        ss->addUniform( new osg::Uniform("SineTex", TEXUNIT_SINE) );
    }

#ifdef INTERNAL_3DLABS //[
    // regular GL 1.x texturing for comparison.
    osg::StateSet* ss = ModelInstance();
    osg::Texture2D* tex0 = new osg::Texture2D;
    tex0->setImage( osgDB::readImageFile( "images/3dl-ge100.png" ) );
    ss->setTextureAttributeAndModes(0, tex0, osg::StateAttribute::ON);
#endif //]

    reloadShaderSource();

#ifdef INTERNAL_3DLABS //[
    // add logo overlays
    rootNode->addChild( osgDB::readNodeFile( "3dl_ogl.logo" ) );
#endif //]

    return rootNode;
}

///////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////

GL2Scene::GL2Scene()
{
    _rootNode = buildScene();
    _shadersEnabled = true;
}

GL2Scene::~GL2Scene()
{
}

void
GL2Scene::reloadShaderSource()
{
    osg::notify(osg::INFO) << "reloadShaderSource()" << std::endl;

    LoadShaderSource( BlockyVertObj, "shaders/blocky.vert" );
    LoadShaderSource( BlockyFragObj, "shaders/blocky.frag" );

    LoadShaderSource( ErodedVertObj, "shaders/eroded.vert" );
    LoadShaderSource( ErodedFragObj, "shaders/eroded.frag" );

    LoadShaderSource( MarbleVertObj, "shaders/marble.vert" );
    LoadShaderSource( MarbleFragObj, "shaders/marble.frag" );
}


// mew 2003-09-19 : TODO Need to revisit how to better control
// osg::Program enable state in OSG core.  glProgram are
// different enough from other GL state that StateSet::setAttributeAndModes()
// doesn't fit well, so came up with a local implementation.
void
GL2Scene::toggleShaderEnable()
{
    _shadersEnabled = ! _shadersEnabled;
    osg::notify(osg::WARN) << "shader enable = " <<
            ((_shadersEnabled) ? "ON" : "OFF") << std::endl;
    for( unsigned int i = 0; i < _programList.size(); i++ )
    {
        //_programList[i]->enable( _shadersEnabled );
    }
}

/*EOF*/