\qmlclass Turbulence QSGTurbulenceAffector
\inqmlmodule QtQuick.Particles 2
\inherits Affector
- \brief The TurbulenceAffector is a bit of a hack and probably shouldn't be used yet.
+ \brief Turbulence provides fluid like forces based on a noise image.
+ The Turbulence Element scales the noise source over the area it affects,
+ and uses the curl of that source to generate force vectors.
+
+ Turbulence requires a fixed size. Unlike other affectors, a 0x0 Turbulence element
+ will affect no particles.
+
+ The source should be relatively smooth black and white noise, such as perlin noise.
*/
/*!
- \qmlproperty int QtQuick.Particles2::Turbulence::strength
- Maximum magnitude of a point in the vector field.
-*/
-/*!
- \qmlproperty int QtQuick.Particles2::Turbulence::frequency
- Times per second vector field is perturbed.
+ \qmlproperty real QtQuick.Particles2::Turbulence::strength
+
+ The magnitude of the velocity vector at any point varies between zero and
+ the square root of two. It will then be multiplied by strength to get the
+ velocity per second for the particles affected by the turbulence.
*/
/*!
- \qmlproperty int QtQuick.Particles2::Turbulence::gridSize
- Square root of the number of points in the vector field simulcrum.
+ \qmlproperty url QtQuick.Particles2::Turbulence::noiseSource
+
+ The source image to generate the turbulence from. It will be scaled to the size of the element,
+ so equal or larger sizes will give better results. Tweaking this image is the only way to tweak
+ behavior such as where vortices are or how many exist.
+
+ The source should be a relatively smooth black and white noise image, such as perlin noise.
+ A default image will be used if none is provided.
*/
QSGTurbulenceAffector::QSGTurbulenceAffector(QSGItem *parent) :
QSGParticleAffector(parent),
- m_strength(10), m_lastT(0), m_frequency(64), m_gridSize(10), m_field(0), m_inited(false)
+ m_strength(10), m_lastT(0), m_gridSize(0), m_field(0), m_vectorField(0), m_inited(false)
+{
+}
+
+void QSGTurbulenceAffector::geometryChanged(const QRectF &, const QRectF &)
{
- //TODO: Update grid on size change
+ initializeGrid();
}
QSGTurbulenceAffector::~QSGTurbulenceAffector()
free(m_field[i]);
free(m_field);
}
+ if (m_vectorField) {
+ for (int i=0; i<m_gridSize; i++)
+ free(m_vectorField[i]);
+ free(m_vectorField);
+ }
}
static qreal magnitude(qreal x, qreal y)
return sqrt(x*x + y*y);
}
-void QSGTurbulenceAffector::setSize(int arg)
+void QSGTurbulenceAffector::initializeGrid()
{
+ if (!m_inited)
+ return;
+
+ int arg = qMax(width(), height());
if (m_gridSize != arg) {
if (m_field){ //deallocate and then reallocate grid
for (int i=0; i<m_gridSize; i++)
free(m_field);
m_system = 0;
}
+ if (m_vectorField) {
+ for (int i=0; i<m_gridSize; i++)
+ free(m_vectorField[i]);
+ free(m_vectorField);
+ }
m_gridSize = arg;
- emit sizeChanged(arg);
}
-}
-void QSGTurbulenceAffector::ensureInit()
-{
- if (m_inited)
- return;
- m_inited = true;
- m_field = (QPointF**)malloc(m_gridSize * sizeof(QPointF*));
+ m_field = (qreal**)malloc(m_gridSize * sizeof(qreal*));
for (int i=0; i<m_gridSize; i++)
- m_field[i] = (QPointF*)malloc(m_gridSize * sizeof(QPointF));
+ m_field[i] = (qreal*)malloc(m_gridSize * sizeof(qreal));
+ m_vectorField = (QPointF**)malloc(m_gridSize * sizeof(QPointF*));
+ for (int i=0; i<m_gridSize; i++)
+ m_vectorField[i] = (QPointF*)malloc(m_gridSize * sizeof(QPointF));
+
+ QImage image = QImage(m_noiseSource.toLocalFile()).scaled(QSize(m_gridSize, m_gridSize));
+ if (image.isNull())
+ image = QImage(":defaultshaders/noise.png").scaled(QSize(m_gridSize, m_gridSize));
+
for (int i=0; i<m_gridSize; i++)
for (int j=0; j<m_gridSize; j++)
- m_field[i][j] = QPointF();
- m_spacing = QPointF(width()/m_gridSize, height()/m_gridSize);
- m_magSum = magnitude(m_spacing.x(), m_spacing.y())*2;
+ m_field[i][j] = qRed(image.pixel(QPoint(i,j)));//Red as proxy for Value
+ for (int i=0; i<m_gridSize; i++){
+ for (int j=0; j<m_gridSize; j++){
+ m_vectorField[i][j].setX(boundsRespectingField(i,j) - boundsRespectingField(i,j-1));
+ m_vectorField[i][j].setY(boundsRespectingField(i-1,j) - boundsRespectingField(i,j));
+ }
+ }
}
-void QSGTurbulenceAffector::mapUpdate()
+qreal QSGTurbulenceAffector::boundsRespectingField(int x, int y)
{
- QPoint pos(rand() % m_gridSize, rand() % m_gridSize);
- QPointF vector(m_strength - (((qreal)rand() / RAND_MAX) * m_strength*2),
- m_strength - (((qreal)rand() / RAND_MAX) * m_strength*2));
- for (int i = 0; i < m_gridSize; i++){
- for (int j = 0; j < m_gridSize; j++){
- qreal dist = magnitude(i-pos.x(), j-pos.y());
- m_field[i][j] += vector/(dist + 1);
- if (magnitude(m_field[i][j].x(), m_field[i][j].y()) > m_strength){
- //Speed limit
- qreal theta = atan2(m_field[i][j].y(), m_field[i][j].x());
- m_field[i][j].setX(m_strength * cos(theta));
- m_field[i][j].setY(m_strength * sin(theta));
- }
- }
- }
+ if (x < 0)
+ x = 0;
+ if (x >= m_gridSize)
+ x = m_gridSize - 1;
+ if (y < 0)
+ y = 0;
+ if (y >= m_gridSize)
+ y = m_gridSize - 1;
+ return m_field[x][y];
}
+void QSGTurbulenceAffector::ensureInit()
+{
+ if (m_inited)
+ return;
+ m_inited = true;
+ initializeGrid();
+}
void QSGTurbulenceAffector::affectSystem(qreal dt)
{
if (!m_system || !m_enabled)
return;
ensureInit();
- qreal period = 1.0/m_frequency;
- qreal time = m_system->m_timeInt / 1000.0;
- while ( m_lastT < time ){
- mapUpdate();
- m_lastT += period;
- }
+ QRectF boundsRect(0, 0, width()-1, height()-1);
foreach (QSGParticleGroupData *gd, m_system->m_groupData){
if (!activeGroup(m_system->m_groupData.key(gd)))//TODO: Surely this can be done better
- return;
+ continue;
foreach (QSGParticleData *d, gd->data){
- if (!d || !activeGroup(d->group))
- return;
+ if (!d || !activeGroup(d->group) || !d->stillAlive())
+ continue;
+ QPoint pos = (QPointF(d->curX(), d->curY()) - m_offset).toPoint();
+ if (!boundsRect.contains(pos))
+ continue;
qreal fx = 0.0;
qreal fy = 0.0;
- QPointF pos = QPointF(d->curX() - x(), d->curY() - y());//TODO: Offset
- QPointF nodePos = QPointF(pos.x() / m_spacing.x(), pos.y() / m_spacing.y());
- QSet<QPair<int, int> > nodes;
- nodes << qMakePair((int)ceil(nodePos.x()), (int)ceil(nodePos.y()));
- nodes << qMakePair((int)ceil(nodePos.x()), (int)floor(nodePos.y()));
- nodes << qMakePair((int)floor(nodePos.x()), (int)ceil(nodePos.y()));
- nodes << qMakePair((int)floor(nodePos.x()), (int)floor(nodePos.y()));
- typedef QPair<int, int> intPair;
- foreach (const intPair &p, nodes){
- if (!QRect(0,0,m_gridSize-1,m_gridSize-1).contains(QPoint(p.first, p.second)))
- continue;
- qreal dist = magnitude(pos.x() - p.first*m_spacing.x(), pos.y() - p.second*m_spacing.y());//TODO: Mathematically valid
- fx += m_field[p.first][p.second].x() * ((m_magSum - dist)/m_magSum);//Proportionally weight nodes
- fy += m_field[p.first][p.second].y() * ((m_magSum - dist)/m_magSum);
- }
+ fx += m_vectorField[pos.x()][pos.y()].x() * m_strength;
+ fy += m_vectorField[pos.x()][pos.y()].y() * m_strength;
if (fx || fy){
d->setInstantaneousVX(d->curVX()+ fx * dt);
d->setInstantaneousVY(d->curVY()+ fy * dt);
class QSGTurbulenceAffector : public QSGParticleAffector
{
Q_OBJECT
- Q_PROPERTY(int strength READ strength WRITE setStrength NOTIFY strengthChanged)
- Q_PROPERTY(int frequency READ frequency WRITE setFrequency NOTIFY frequencyChanged)
- Q_PROPERTY(int gridSize READ size WRITE setSize NOTIFY sizeChanged)
-public:
+ Q_PROPERTY(qreal strength READ strength WRITE setStrength NOTIFY strengthChanged)
+ Q_PROPERTY(QUrl noiseSource READ noiseSource WRITE setNoiseSource NOTIFY noiseSourceChanged)
+ public:
explicit QSGTurbulenceAffector(QSGItem *parent = 0);
~QSGTurbulenceAffector();
virtual void affectSystem(qreal dt);
- int strength() const
+ qreal strength() const
{
return m_strength;
}
- int frequency() const
+ QUrl noiseSource() const
{
- return m_frequency;
+ return m_noiseSource;
}
-
- int size() const
- {
- return m_gridSize;
- }
-
signals:
- void strengthChanged(int arg);
-
- void frequencyChanged(int arg);
+ void strengthChanged(qreal arg);
- void sizeChanged(int arg);
+ void noiseSourceChanged(QUrl arg);
public slots:
+ void initializeGrid();
-void setStrength(int arg)
-{
- if (m_strength != arg) {
- m_strength = arg;
- emit strengthChanged(arg);
+ void setStrength(qreal arg)
+ {
+ if (m_strength != arg) {
+ m_strength = arg;
+ emit strengthChanged(arg);
+ }
}
-}
-void setFrequency(int arg)
-{
- if (m_frequency != arg) {
- m_frequency = arg;
- emit frequencyChanged(arg);
+ void setNoiseSource(QUrl arg)
+ {
+ if (m_noiseSource != arg) {
+ m_noiseSource = arg;
+ emit noiseSourceChanged(arg);
+ }
}
-}
-
-void setSize(int arg);
+protected:
+ virtual void geometryChanged(const QRectF &newGeometry,
+ const QRectF &oldGeometry);
private:
void ensureInit();
void mapUpdate();
- int m_strength;
+ qreal boundsRespectingField(int x, int y);
+ qreal m_strength;
qreal m_lastT;
- int m_frequency;
int m_gridSize;
- QPointF** m_field;
- QPointF m_spacing;
- qreal m_magSum;
+ qreal** m_field;
+ QPointF** m_vectorField;
bool m_inited;
+ QUrl m_noiseSource;
};
QT_END_NAMESPACE
projects / konrad/qtdeclarative.git / commitdiff
