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#include <private/qsgcontext_p.h>
#include <private/qsgadaptationlayer_p.h>
#include <qsgnode.h>
#include <qsgtexturematerial.h>
#include <qsgtexture.h>
#include <QFile>
#include "coloredparticle.h"
#include "particleemitter.h"
#include <QGLFunctions>
#include <qsgengine.h>

QT_BEGIN_NAMESPACE

class ParticleTrailsMaterial : public QSGMaterial
{
public:
    ParticleTrailsMaterial()
        : timestamp(0)
    {
        setFlag(Blending, true);
    }

    ~ParticleTrailsMaterial()
    {
        delete texture;
    }

    virtual QSGMaterialType *type() const { static QSGMaterialType type; return &type; }
    virtual QSGMaterialShader *createShader() const;
    virtual int compare(const QSGMaterial *other) const
    {
        return this - static_cast<const ParticleTrailsMaterial *>(other);
    }

    QSGTexture *texture;

    qreal timestamp;
};


class ParticleTrailsMaterialData : public QSGMaterialShader
{
public:
    ParticleTrailsMaterialData(const char *vertexFile = 0, const char *fragmentFile = 0)
    {
        QFile vf(vertexFile ? vertexFile : ":resources/trailsvertex.shader");
        vf.open(QFile::ReadOnly);
        m_vertex_code = vf.readAll();

        QFile ff(fragmentFile ? fragmentFile : ":resources/trailsfragment.shader");
        ff.open(QFile::ReadOnly);
        m_fragment_code = ff.readAll();

        Q_ASSERT(!m_vertex_code.isNull());
        Q_ASSERT(!m_fragment_code.isNull());
    }

    void deactivate() {
        QSGMaterialShader::deactivate();

        for (int i=0; i<8; ++i) {
            m_program.setAttributeArray(i, GL_FLOAT, chunkOfBytes, 1, 0);
        }
    }

    virtual void updateState(const RenderState &state, QSGMaterial *newEffect, QSGMaterial *)
    {
        ParticleTrailsMaterial *m = static_cast<ParticleTrailsMaterial *>(newEffect);
        state.context()->functions()->glActiveTexture(GL_TEXTURE0);
        m->texture->bind();

        m_program.setUniformValue(m_opacity_id, state.opacity());
        m_program.setUniformValue(m_timestamp_id, (float) m->timestamp);

        if (state.isMatrixDirty())
            m_program.setUniformValue(m_matrix_id, state.combinedMatrix());
    }

    virtual void initialize() {
        m_matrix_id = m_program.uniformLocation("matrix");
        m_opacity_id = m_program.uniformLocation("opacity");
        m_timestamp_id = m_program.uniformLocation("timestamp");
    }

    virtual const char *vertexShader() const { return m_vertex_code.constData(); }
    virtual const char *fragmentShader() const { return m_fragment_code.constData(); }

    virtual char const *const *attributeNames() const {
        static const char *attr[] = {
            "vPos",
            "vTex",
            "vData",
            "vVec",
            "vColor",
            0
        };
        return attr;
    }

    virtual bool isColorTable() const { return false; }

    int m_matrix_id;
    int m_opacity_id;
    int m_timestamp_id;

    QByteArray m_vertex_code;
    QByteArray m_fragment_code;

    static float chunkOfBytes[1024];
};
float ParticleTrailsMaterialData::chunkOfBytes[1024];


QSGMaterialShader *ParticleTrailsMaterial::createShader() const
{
    return new ParticleTrailsMaterialData;
}


class ParticleTrailsMaterialCT : public ParticleTrailsMaterial
{
public:
    ParticleTrailsMaterialCT()
    {
    }

    ~ParticleTrailsMaterialCT()
    {
        delete colortable;
        delete sizetable;
        delete opacitytable;
    }

    virtual QSGMaterialType *type() const { static QSGMaterialType type; return &type; }
    virtual QSGMaterialShader *createShader() const;

    QSGTexture *colortable;
    QSGTexture *sizetable;
    QSGTexture *opacitytable;
};


class ParticleTrailsMaterialDataCT : public ParticleTrailsMaterialData
{
public:
    ParticleTrailsMaterialDataCT()
        : ParticleTrailsMaterialData(":resources/ctvertex.shader", ":resources/ctfragment.shader")
    {
    }

    bool isColorTable() const { return true; }

    virtual void initialize() {
        ParticleTrailsMaterialData::initialize();
        m_colortable_id = m_program.uniformLocation("colortable");
        m_sizetable_id = m_program.uniformLocation("sizetable");
        m_opacitytable_id = m_program.uniformLocation("opacitytable");
    }

    virtual void updateState(const RenderState &state, QSGMaterial *current, QSGMaterial *old)
    {
        // Bind the texture to unit 1 before calling the base class, so that the
        // base class can set active texture back to 0.
        ParticleTrailsMaterialCT *m = static_cast<ParticleTrailsMaterialCT *>(current);
        state.context()->functions()->glActiveTexture(GL_TEXTURE1);
        m->colortable->bind();
        m_program.setUniformValue(m_colortable_id, 1);

        state.context()->functions()->glActiveTexture(GL_TEXTURE2);
        m->sizetable->bind();
        m_program.setUniformValue(m_sizetable_id, 2);

        state.context()->functions()->glActiveTexture(GL_TEXTURE3);
        m->opacitytable->bind();
        m_program.setUniformValue(m_opacitytable_id, 3);

        ParticleTrailsMaterialData::updateState(state, current, old);
    }

    int m_colortable_id;
    int m_sizetable_id;
    int m_opacitytable_id;
};


QSGMaterialShader *ParticleTrailsMaterialCT::createShader() const
{
    return new ParticleTrailsMaterialDataCT;
}

ColoredParticle::ColoredParticle(QSGItem* parent)
    : ParticleType(parent)
    , m_do_reset(false)
    , m_color(Qt::white)
    , m_color_variation(0.5)
    , m_node(0)
    , m_material(0)
    , m_alphaVariation(0.0)
    , m_alpha(1.0)
    , m_redVariation(0.0)
    , m_greenVariation(0.0)
    , m_blueVariation(0.0)
{
    setFlag(ItemHasContents);
}

void ColoredParticle::setImage(const QUrl &image)
{
    if (image == m_image_name)
        return;
    m_image_name = image;
    emit imageChanged();
    reset();
}


void ColoredParticle::setColortable(const QUrl &table)
{
    if (table == m_colortable_name)
        return;
    m_colortable_name = table;
    emit colortableChanged();
    reset();
}

void ColoredParticle::setSizetable(const QUrl &table)
{
    if (table == m_sizetable_name)
        return;
    m_sizetable_name = table;
    emit sizetableChanged();
    reset();
}

void ColoredParticle::setOpacitytable(const QUrl &table)
{
    if (table == m_opacitytable_name)
        return;
    m_opacitytable_name = table;
    emit opacitytableChanged();
    reset();
}

void ColoredParticle::setColor(const QColor &color)
{
    if (color == m_color)
        return;
    m_color = color;
    emit colorChanged();
    //m_system->pleaseReset();//XXX
}

void ColoredParticle::setColorVariation(qreal var)
{
    if (var == m_color_variation)
        return;
    m_color_variation = var;
    emit colorVariationChanged();
    //m_system->pleaseReset();//XXX
}

void ColoredParticle::setCount(int c)
{
    ParticleType::setCount(c);
    m_pleaseReset = true;
}

void ColoredParticle::reset()
{
    ParticleType::reset();
     m_pleaseReset = true;
}

static QSGGeometry::Attribute ColoredParticle_Attributes[] = {
    { 0, 2, GL_FLOAT },             // Position
    { 1, 2, GL_FLOAT },             // TexCoord
    { 2, 4, GL_FLOAT },             // Data
    { 3, 4, GL_FLOAT },             // Vectors
    { 4, 4, GL_UNSIGNED_BYTE }   // Colors
};

static QSGGeometry::AttributeSet ColoredParticle_AttributeSet =
{
    5, // Attribute Count
    (2 + 2 + 4 + 4) * sizeof(float) + 4 * sizeof(uchar),
    ColoredParticle_Attributes
};

QSGGeometryNode* ColoredParticle::buildParticleNode()
{
    if (m_count * 4 > 0xffff) {
        printf("ColoredParticle: Too many particles... \n");
        return 0;
    }

    if(m_count <= 0) {
        printf("ColoredParticle: Too few particles... \n");
        return 0;
    }

    QImage image(m_image_name.toLocalFile());
    if (image.isNull()) {
        printf("ParticleTrails: loading image failed... '%s'\n", qPrintable(m_image_name.toLocalFile()));
        return 0;
    }

    int vCount = m_count * 4;
    int iCount = m_count * 6;

    QSGGeometry *g = new QSGGeometry(ColoredParticle_AttributeSet, vCount, iCount);
    g->setDrawingMode(GL_TRIANGLES);

    ColoredParticleVertex *vertices = (ColoredParticleVertex *) g->vertexData();
    for (int p=0; p<m_count; ++p) {

        for (int i=0; i<4; ++i) {
            vertices[i].x = 0;
            vertices[i].y = 0;
            vertices[i].t = -1;
            vertices[i].lifeSpan = 0;
            vertices[i].size = 0;
            vertices[i].endSize = 0;
            vertices[i].sx = 0;
            vertices[i].sy = 0;
            vertices[i].ax = 0;
            vertices[i].ay = 0;
        }

        vertices[0].tx = 0;
        vertices[0].ty = 0;

        vertices[1].tx = 1;
        vertices[1].ty = 0;

        vertices[2].tx = 0;
        vertices[2].ty = 1;

        vertices[3].tx = 1;
        vertices[3].ty = 1;

        vertices += 4;
    }

    quint16 *indices = g->indexDataAsUShort();
    for (int i=0; i<m_count; ++i) {
        int o = i * 4;
        indices[0] = o;
        indices[1] = o + 1;
        indices[2] = o + 2;
        indices[3] = o + 1;
        indices[4] = o + 3;
        indices[5] = o + 2;
        indices += 6;
    }

    if (m_material) {
        delete m_material;
        m_material = 0;
    }

    QImage colortable(m_colortable_name.toLocalFile());
    QImage sizetable(m_sizetable_name.toLocalFile());
    QImage opacitytable(m_opacitytable_name.toLocalFile());
    if(!colortable.isNull() || !sizetable.isNull() || !opacitytable.isNull()){
        //using tabled shaders
        m_material = new ParticleTrailsMaterialCT();
        if(colortable.isNull())
            colortable = QImage(":resources/identitytable.png");
        if(sizetable.isNull())
            sizetable = QImage(":resources/identitytable.png");
        if(opacitytable.isNull())
            opacitytable = QImage(":resources/defaultFadeInOut.png");
        Q_ASSERT(!colortable.isNull());
        Q_ASSERT(!sizetable.isNull());
        Q_ASSERT(!opacitytable.isNull());
        ParticleTrailsMaterialCT* ct_material = static_cast<ParticleTrailsMaterialCT *>(m_material);
        ct_material->colortable = sceneGraphEngine()->createTextureFromImage(colortable);
        ct_material->sizetable = sceneGraphEngine()->createTextureFromImage(sizetable);
        ct_material->opacitytable = sceneGraphEngine()->createTextureFromImage(opacitytable);
    }

    if (!m_material)
        m_material = new ParticleTrailsMaterial();


    m_material->texture = sceneGraphEngine()->createTextureFromImage(image);
    m_material->texture->setFiltering(QSGTexture::Linear);

    m_node = new QSGGeometryNode();
    m_node->setGeometry(g);
    m_node->setMaterial(m_material);

    m_last_particle = 0;

    return m_node;
}

QSGNode *ColoredParticle::updatePaintNode(QSGNode *, UpdatePaintNodeData *)
{
    if(m_pleaseReset){
        if(m_node)
            delete m_node;
        if(m_material)
            delete m_material;

        m_node = 0;
        m_material = 0;
        m_pleaseReset = false;
    }

    if(m_system && m_system->isRunning())
        prepareNextFrame();
    if (m_node){
        update();
        m_node->markDirty(QSGNode::DirtyMaterial);
    }

    return m_node;
}

void ColoredParticle::prepareNextFrame()
{
    if (m_node == 0){    //TODO: Staggered loading (as emitted)
        m_node = buildParticleNode();
        if(m_node == 0)
            return;
    }
    qint64 timeStamp = m_system->systemSync(this);

    qreal time = timeStamp / 1000.;
    m_material->timestamp = time;
}

void ColoredParticle::reloadColor(const Color4ub &c, ParticleData* d)
{
    ColoredParticleVertices *particles = (ColoredParticleVertices *) m_node->geometry()->vertexData();
    int pos = particleTypeIndex(d);
    ColoredParticleVertices &p = particles[pos];
    p.v1.color = p.v2.color = p.v3.color = p.v4.color = c;
}

void ColoredParticle::vertexCopy(ColoredParticleVertex &b,const ParticleVertex& a)
{
    b.x = a.x - m_systemOffset.x();
    b.y = a.y - m_systemOffset.y();
    b.t = a.t;
    b.lifeSpan = a.lifeSpan;
    b.size = a.size;
    b.endSize = a.endSize;
    b.sx = a.sx;
    b.sy = a.sy;
    b.ax = a.ax;
    b.ay = a.ay;
}

void ColoredParticle::reload(ParticleData *d)
{
    if (m_node == 0)
        return;

    ColoredParticleVertices *particles = (ColoredParticleVertices *) m_node->geometry()->vertexData();

    int pos = particleTypeIndex(d);

    ColoredParticleVertices &p = particles[pos];

    //Perhaps we could be more efficient?
    vertexCopy(p.v1, d->pv);
    vertexCopy(p.v2, d->pv);
    vertexCopy(p.v3, d->pv);
    vertexCopy(p.v4, d->pv);
}

void ColoredParticle::load(ParticleData *d)
{
    if (m_node == 0)
        return;

    //Color initialization
    // Particle color
    Color4ub color;
    qreal redVariation = m_color_variation + m_redVariation;
    qreal greenVariation = m_color_variation + m_greenVariation;
    qreal blueVariation = m_color_variation + m_blueVariation;
    color.r = m_color.red() * (1 - redVariation) + rand() % 256 * redVariation;
    color.g = m_color.green() * (1 - greenVariation) + rand() % 256 * greenVariation;
    color.b = m_color.blue() * (1 - blueVariation) + rand() % 256 * blueVariation;
    color.a = m_alpha * m_color.alpha() * (1 - m_alphaVariation) + rand() % 256 * m_alphaVariation;
    ColoredParticleVertices *particles = (ColoredParticleVertices *) m_node->geometry()->vertexData();
    ColoredParticleVertices &p = particles[particleTypeIndex(d)];
    p.v1.color = p.v2.color = p.v3.color = p.v4.color = color;

    vertexCopy(p.v1, d->pv);
    vertexCopy(p.v2, d->pv);
    vertexCopy(p.v3, d->pv);
    vertexCopy(p.v4, d->pv);
}

QT_END_NAMESPACE