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39
40#include "qquickwander_p.h"
41#include "qquickparticlesystem_p.h"//for ParticlesVertices
42#include <QRandomGenerator>
43QT_BEGIN_NAMESPACE
44/*!
45 \qmltype Wander
46 \instantiates QQuickWanderAffector
47 \inqmlmodule QtQuick.Particles
48 \ingroup qtquick-particles
49 \inherits Affector
50 \brief For applying random particle trajectory.
51
52*/
53/*!
54 \qmlproperty real QtQuick.Particles::Wander::pace
55
56 Maximum attribute change per second.
57*/
58/*!
59 \qmlproperty real QtQuick.Particles::Wander::xVariance
60
61 Maximum attribute x value (as a result of Wander).
62
63 If unset, Wander will not affect x values.
64*/
65/*!
66 \qmlproperty real QtQuick.Particles::Wander::yVariance
67
68 Maximum attribute y value (as a result of Wander).
69
70 If unset, Wander will not affect y values.
71*/
72/*!
73 \qmlproperty AffectableParameter QtQuick.Particles::Wander::affectedParameter
74
75 What attribute of particles is directly affected.
76 \list
77 \li PointAttractor.Position
78 \li PointAttractor.Velocity
79 \li PointAttractor.Acceleration
80 \endlist
81*/
82
83QQuickWanderAffector::QQuickWanderAffector(QQuickItem *parent) :
84 QQuickParticleAffector(parent), m_xVariance(0), m_yVariance(0), m_pace(0)
85 , m_affectedParameter(Velocity)
86{
87 m_needsReset = true;
88}
89
90QQuickWanderAffector::~QQuickWanderAffector()
91{
92 for (QHash<int, WanderData*>::const_iterator iter=m_wanderData.constBegin();
93 iter != m_wanderData.constEnd(); ++iter)
94 delete (*iter);
95}
96
97WanderData* QQuickWanderAffector::getData(int idx)
98{
99 if (m_wanderData.contains(akey: idx))
100 return m_wanderData[idx];
101 WanderData* d = new WanderData;
102 d->x_vel = 0;
103 d->y_vel = 0;
104 d->x_peak = m_xVariance;
105 d->y_peak = m_yVariance;
106 d->x_var = m_pace * QRandomGenerator::global()->generateDouble();
107 d->y_var = m_pace * QRandomGenerator::global()->generateDouble();
108
109 m_wanderData.insert(akey: idx, avalue: d);
110 return d;
111}
112
113// TODO: see below
114//void QQuickWanderAffector::reset(int systemIdx)
115//{
116// if (m_wanderData.contains(systemIdx))
117// delete m_wanderData[systemIdx];
118// m_wanderData.remove(systemIdx);
119//}
120
121bool QQuickWanderAffector::affectParticle(QQuickParticleData* data, qreal dt)
122{
123 /*TODO: Add a mode which does basically this - picking a direction, going in it (random velocity) and then going back
124 WanderData* d = getData(data->systemIndex);
125 if (m_xVariance != 0.) {
126 if ((d->x_vel > d->x_peak && d->x_var > 0.0) || (d->x_vel < -d->x_peak && d->x_var < 0.0)) {
127 d->x_var = -d->x_var;
128 d->x_peak = m_xVariance + m_xVariance * QRandomGenerator::global()->generateDouble();
129 }
130 d->x_vel += d->x_var * dt;
131 }
132 qreal dx = dt * d->x_vel;
133
134 if (m_yVariance != 0.) {
135 if ((d->y_vel > d->y_peak && d->y_var > 0.0) || (d->y_vel < -d->y_peak && d->y_var < 0.0)) {
136 d->y_var = -d->y_var;
137 d->y_peak = m_yVariance + m_yVariance * QRandomGenerator::global()->generateDouble();
138 }
139 d->y_vel += d->y_var * dt;
140 }
141 qreal dy = dt * d->x_vel;
142
143 //### Should we be amending vel instead?
144 ParticleVertex* p = &(data->pv);
145 p->x += dx;
146
147 p->y += dy;
148 return true;
149 */
150 qreal dx = dt * m_pace * (2 * QRandomGenerator::global()->generateDouble() - 1);
151 qreal dy = dt * m_pace * (2 * QRandomGenerator::global()->generateDouble() - 1);
152 qreal newX, newY;
153 switch (m_affectedParameter){
154 case Position:
155 newX = data->curX(particleSystem: m_system) + dx;
156 if (m_xVariance > qAbs(t: newX) )
157 data->x += dx;
158 newY = data->curY(particleSystem: m_system) + dy;
159 if (m_yVariance > qAbs(t: newY) )
160 data->y += dy;
161 break;
162 default:
163 case Velocity:
164 newX = data->curVX(particleSystem: m_system) + dx;
165 if (m_xVariance > qAbs(t: newX))
166 data->setInstantaneousVX(vx: newX, particleSystem: m_system);
167 newY = data->curVY(particleSystem: m_system) + dy;
168 if (m_yVariance > qAbs(t: newY))
169 data->setInstantaneousVY(vy: newY, particleSystem: m_system);
170 break;
171 case Acceleration:
172 newX = data->ax + dx;
173 if (m_xVariance > qAbs(t: newX))
174 data->setInstantaneousAX(ax: newX, particleSystem: m_system);
175 newY = data->ay + dy;
176 if (m_yVariance > qAbs(t: newY))
177 data->setInstantaneousAY(ay: newY, particleSystem: m_system);
178 break;
179 }
180 return true;
181}
182QT_END_NAMESPACE
183
184#include "moc_qquickwander_p.cpp"
185

source code of qtdeclarative/src/particles/qquickwander.cpp