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| 1 | +import 'dart:math'; |
| 2 | + |
| 3 | +import 'package:flutter/material.dart'; |
| 4 | +import 'rnd.dart'; |
| 5 | + |
| 6 | +import 'particle.dart'; |
| 7 | + |
| 8 | + |
| 9 | +final easingDelayDuration = Duration(seconds: 10); |
| 10 | + |
| 11 | +/// Probabilities of Hour, Minute, Noise. |
| 12 | +// final particleDistributions = [2, 4, 100]; |
| 13 | + |
| 14 | +/// Number of "arms" to emit noise particles from center. |
| 15 | +final int noiseAngles = 2000; |
| 16 | + |
| 17 | +/// Threshold for particles to go rouge. Lower = more particles. |
| 18 | +final rougeDistributionLmt = 85; |
| 19 | + |
| 20 | +/// Threshold for particles to go jelly. Lower = more particles. |
| 21 | +final jellyDistributionLmt = 97; |
| 22 | + |
| 23 | + |
| 24 | +class ClockFx with ChangeNotifier { |
| 25 | + |
| 26 | + double width; //宽 |
| 27 | + double height;//高 |
| 28 | + double sizeMin; // 宽高最小值 |
| 29 | + Offset center; //画布中心 |
| 30 | + Rect spawnArea; // 粒子活动区域 |
| 31 | + |
| 32 | + List<Particle> particles; // 所有粒子 |
| 33 | + |
| 34 | + int numParticles;// 最大粒子数 |
| 35 | + |
| 36 | + DateTime time; //时间 |
| 37 | + |
| 38 | + ClockFx({ |
| 39 | + @required Size size, |
| 40 | + @required DateTime time, |
| 41 | + this.numParticles = 5000, |
| 42 | + }) { |
| 43 | + this.time = time; |
| 44 | + particles = List<Particle>.filled(numParticles, null); |
| 45 | + setSize(size); |
| 46 | + } |
| 47 | + |
| 48 | + void init() { |
| 49 | + for (int i = 0; i < numParticles; i++) { |
| 50 | + particles[i] = Particle(color:Colors.black ); |
| 51 | + resetParticle(i); |
| 52 | + } |
| 53 | + } |
| 54 | + |
| 55 | + void setTime(DateTime time) { |
| 56 | + this.time = time; |
| 57 | + } |
| 58 | + |
| 59 | + void setSize(Size size) { |
| 60 | + width = size.width; |
| 61 | + height = size.height; |
| 62 | + sizeMin = min(width, height); |
| 63 | + center = Offset(width / 2, height / 2); |
| 64 | + spawnArea = Rect.fromLTRB( |
| 65 | + center.dx - sizeMin / 100, |
| 66 | + center.dy - sizeMin / 100, |
| 67 | + center.dx + sizeMin / 100, |
| 68 | + center.dy + sizeMin / 100, |
| 69 | + ); |
| 70 | + init(); |
| 71 | + } |
| 72 | + |
| 73 | + /// Resets a particle's values. |
| 74 | + Particle resetParticle(int i) { |
| 75 | + Particle p = particles[i]; |
| 76 | + p.size = p.a = p.vx = p.vy = p.life = p.lifeLeft = 0; |
| 77 | + p.x = center.dx; |
| 78 | + p.y = center.dy; |
| 79 | + return p; |
| 80 | + } |
| 81 | + |
| 82 | + void tick(Duration duration) { |
| 83 | + updateParticles(duration); // 更新粒子 |
| 84 | + notifyListeners();// 通知监听者(画板)更新 |
| 85 | + } |
| 86 | + |
| 87 | + void updateParticles(Duration duration){ |
| 88 | + var secFrac = DateTime.now().millisecond / 1000; |
| 89 | + |
| 90 | + var vecSpeed = duration.compareTo(easingDelayDuration) > 0 |
| 91 | + ? max(.2, Curves.easeInOutSine.transform(1 - secFrac)) |
| 92 | + : 1; |
| 93 | + |
| 94 | + var vecSpeedInv = Curves.easeInSine.transform(secFrac); |
| 95 | + |
| 96 | + var maxSpawnPerTick = 10; |
| 97 | + |
| 98 | + particles.asMap().forEach((i, p) { |
| 99 | + p.x -= p.vx * vecSpeed; |
| 100 | + p.y -= p.vy * vecSpeed; |
| 101 | + |
| 102 | + p.dist = _getDistanceFromCenter(p); |
| 103 | + p.distFrac = p.dist / (sizeMin / 2); |
| 104 | + |
| 105 | + p.lifeLeft = p.life - p.distFrac; |
| 106 | + |
| 107 | + p.vx -= p.lifeLeft * p.vx * .001; |
| 108 | + p.vy -= p.lifeLeft * p.vy * .001; |
| 109 | + |
| 110 | + if (p.lifeLeft < .3) { |
| 111 | + p.size -= p.size * .0015; |
| 112 | + } |
| 113 | + |
| 114 | + if (p.distribution > rougeDistributionLmt && p.distribution < jellyDistributionLmt) { |
| 115 | + var r = Rnd.getDouble(.2, 2.5) * vecSpeedInv * p.distFrac; |
| 116 | + p.x -= p.vx * r + (p.distFrac * Rnd.getDouble(-.4, .4)); |
| 117 | + p.y -= p.vy * r + (p.distFrac * Rnd.getDouble(-.4, .4)); |
| 118 | + } |
| 119 | + |
| 120 | + if (p.distribution >= jellyDistributionLmt) { |
| 121 | + var r = Rnd.getDouble(.1, .9) * vecSpeedInv * (1 - p.lifeLeft); |
| 122 | + p.x += p.vx * r; |
| 123 | + p.y += p.vy * r; |
| 124 | + } |
| 125 | + |
| 126 | + if (p.lifeLeft <= 0 || p.size <= .5) { |
| 127 | + resetParticle(i); |
| 128 | + if (maxSpawnPerTick > 0) { |
| 129 | + _activateParticle(p); |
| 130 | + maxSpawnPerTick--; |
| 131 | + } |
| 132 | + } |
| 133 | + |
| 134 | + }); |
| 135 | + } |
| 136 | + |
| 137 | + void _activateParticle(Particle p) { |
| 138 | + p.x = Rnd.getDouble(spawnArea.left, spawnArea.right); |
| 139 | + p.y = Rnd.getDouble(spawnArea.top, spawnArea.bottom); |
| 140 | + p.isFilled = Rnd.getBool(); |
| 141 | + p.size = Rnd.getDouble(3, 8); |
| 142 | + p.distFrac = 0; |
| 143 | + p.distribution = Rnd.getInt(1, 2); |
| 144 | + |
| 145 | + double angle = Rnd.ratio * pi * 2; |
| 146 | + |
| 147 | + |
| 148 | + var am = _getMinuteRadians(); |
| 149 | + var ah = _getHourRadians() % (pi * 2); |
| 150 | + var d = pi / 18; |
| 151 | + // |
| 152 | + // Probably not the most efficient solution right here. |
| 153 | + do { |
| 154 | + angle = Rnd.ratio * pi * 2; |
| 155 | + } while (_isBetween(angle, am - d, am + d) || |
| 156 | + _isBetween(angle, ah - d, ah + d) ); |
| 157 | + |
| 158 | + p.life = Rnd.getDouble(0.75, .8); |
| 159 | + |
| 160 | + p.size = sizeMin * |
| 161 | + (Rnd.ratio > .8 |
| 162 | + ? Rnd.getDouble(.0015, .003) |
| 163 | + : Rnd.getDouble(.002, .006)); |
| 164 | + |
| 165 | + p.vx = sin(-angle); |
| 166 | + p.vy = cos(-angle); |
| 167 | + |
| 168 | + p.a = atan2(p.vy, p.vx) + pi; |
| 169 | + |
| 170 | + double v = Rnd.getDouble(.5, 1); |
| 171 | + |
| 172 | + p.vx *= v; |
| 173 | + p.vy *= v; |
| 174 | + } |
| 175 | + |
| 176 | + double _getDistanceFromCenter(Particle p) { |
| 177 | + var a = pow(center.dx - p.x, 2); |
| 178 | + var b = pow(center.dy - p.y, 2); |
| 179 | + return sqrt(a + b); |
| 180 | + } |
| 181 | + |
| 182 | + /// Gets the radians of the hour hand. |
| 183 | + double _getHourRadians() => |
| 184 | + (time.hour * pi / 6) + |
| 185 | + (time.minute * pi / (6 * 60)) + |
| 186 | + (time.second * pi / (360 * 60)); |
| 187 | + |
| 188 | + /// Gets the radians of the minute hand. |
| 189 | + double _getMinuteRadians() => |
| 190 | + (time.minute * (2 * pi) / 60) + (time.second * pi / (30 * 60)); |
| 191 | + |
| 192 | + /// Checks if a value is between two other values. |
| 193 | + bool _isBetween(double value, double min, double max) { |
| 194 | + return value >= min && value <= max; |
| 195 | + } |
| 196 | + |
| 197 | +} |
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