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Commit 9207c7f

Browse files
update particle samples
1 parent 8a64f10 commit 9207c7f

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1 file changed

+141
-54
lines changed
  • Tutorial1-1Basics/src/main/java/com/smarttoolfactory/tutorial1_1basics/chapter6_graphics

1 file changed

+141
-54
lines changed

‎Tutorial1-1Basics/src/main/java/com/smarttoolfactory/tutorial1_1basics/chapter6_graphics/ParticlePhysics.kt‎

Lines changed: 141 additions & 54 deletions
Original file line numberDiff line numberDiff line change
@@ -3,22 +3,22 @@ package com.smarttoolfactory.tutorial1_1basics.chapter6_graphics
33
import android.content.res.Resources
44
import androidx.compose.foundation.Canvas
55
import androidx.compose.foundation.border
6-
import androidx.compose.foundation.layout.BoxWithConstraints
76
import androidx.compose.foundation.layout.Column
87
import androidx.compose.foundation.layout.Spacer
98
import androidx.compose.foundation.layout.fillMaxSize
109
import androidx.compose.foundation.layout.fillMaxWidth
1110
import androidx.compose.foundation.layout.height
1211
import androidx.compose.foundation.layout.padding
1312
import androidx.compose.foundation.layout.size
13+
import androidx.compose.foundation.rememberScrollState
14+
import androidx.compose.foundation.verticalScroll
1415
import androidx.compose.material.Slider
1516
import androidx.compose.material.Text
1617
import androidx.compose.runtime.Composable
1718
import androidx.compose.runtime.getValue
1819
import androidx.compose.runtime.mutableFloatStateOf
1920
import androidx.compose.runtime.remember
2021
import androidx.compose.runtime.setValue
21-
import androidx.compose.ui.Alignment
2222
import androidx.compose.ui.Modifier
2323
import androidx.compose.ui.geometry.Offset
2424
import androidx.compose.ui.graphics.Color
@@ -32,77 +32,137 @@ import java.util.Random
3232
@Preview
3333
@Composable
3434
fun ControlledExplosion() {
35+
36+
var progress by remember { mutableFloatStateOf(0f) }
37+
38+
var visibilityThresholdLow by remember {
39+
mutableFloatStateOf(0f)
40+
}
41+
42+
var visibilityThresholdHigh by remember {
43+
mutableFloatStateOf(1f)
44+
}
45+
46+
val particleCount = 1
47+
48+
val density = LocalDensity.current
49+
50+
val sizeDp = with(density) {
51+
1000f.toDp()
52+
}
53+
val sizePx = with(density) {
54+
sizeDp.toPx()
55+
}
56+
val sizePxHalf = sizePx / 2
57+
58+
val particles = remember(
59+
visibilityThresholdLow,
60+
visibilityThresholdHigh
61+
) {
62+
List(particleCount) {
63+
ExplodingParticle(
64+
color = Color(listOf(0xffea4335, 0xff4285f4, 0xfffbbc05, 0xff34a853).random()),
65+
startXPosition = sizePxHalf.toInt(),
66+
startYPosition = sizePxHalf.toInt(),
67+
maxHorizontalDisplacement = sizePxHalf,
68+
maxVerticalDisplacement = sizePxHalf,
69+
visibilityThresholdLow = visibilityThresholdLow,
70+
visibilityThresholdHigh = visibilityThresholdHigh
71+
)
72+
}
73+
}
74+
3575
Column(
36-
modifier = Modifier.fillMaxSize().padding(16.dp),
37-
horizontalAlignment = Alignment.CenterHorizontally
76+
modifier = Modifier.fillMaxSize()
77+
.verticalScroll(rememberScrollState())
78+
.padding(vertical = 16.dp, horizontal = 8.dp),
3879
) {
39-
var progress by remember { mutableFloatStateOf(0f) }
4080

41-
Explosion(progress)
81+
Explosion(
82+
progress = progress,
83+
particles = particles,
84+
sizeDp = sizeDp
85+
)
4286

4387
Spacer(Modifier.height(16.dp))
44-
Text(text = "Progress: $progress", fontSize = 18.sp)
88+
89+
val particle = particles.first()
90+
Text(
91+
text = "Progress: ${(progress * 100).toInt() / 100f}\n" +
92+
"trajectory: ${(particle.trajectoryProgress * 100).toInt() / 100f}\n" +
93+
"currentTime: ${(particle.currentTime * 100f).toInt() / 100f}\n",
94+
fontSize = 18.sp
95+
)
4596
Slider(
4697
modifier = Modifier.fillMaxWidth(),
4798
value = progress,
4899
onValueChange = {
49100
progress = it
50101
}
51102
)
103+
104+
Text("visibilityThresholdLow: $visibilityThresholdLow")
105+
Slider(
106+
modifier = Modifier.fillMaxWidth(),
107+
value = visibilityThresholdLow,
108+
onValueChange = {
109+
visibilityThresholdLow = it
110+
},
111+
valueRange = 0f..visibilityThresholdHigh
112+
)
113+
114+
Text("visibilityThresholdHigh: $visibilityThresholdHigh")
115+
Slider(
116+
modifier = Modifier.fillMaxWidth(),
117+
value = visibilityThresholdHigh,
118+
onValueChange = {
119+
visibilityThresholdHigh = it
120+
},
121+
valueRange = visibilityThresholdLow..1f
122+
)
52123
Spacer(Modifier.height(16.dp))
53124
}
54125
}
55126

56127
@Composable
57128
fun Explosion(
129+
sizeDp: Dp,
130+
particles: List<ExplodingParticle>,
58131
progress: Float
59132
) {
60-
BoxWithConstraints {
133+
val density = LocalDensity.current
134+
val sizePx = with(density) {
135+
sizeDp.toPx()
136+
}
61137

62-
val sizeDp = maxWidth
63-
val density = LocalDensity.current
64-
val sizePx = with(density) {
65-
sizeDp.toPx()
66-
}
67-
val sizePxHalf = sizePx / 2
68-
val particles = remember {
69-
List(150) {
70-
ExplodingParticle(
71-
color = Color(listOf(0xffea4335, 0xff4285f4, 0xfffbbc05, 0xff34a853).random()),
72-
startXPosition = sizePxHalf.toInt(),
73-
startYPosition = sizePxHalf.toInt(),
74-
maxHorizontalDisplacement = sizePxHalf,
75-
maxVerticalDisplacement = sizePxHalf
76-
)
77-
}
78-
}
79-
particles.forEach { it.updateProgress(progress) }
80-
81-
Canvas(
82-
modifier = Modifier
83-
.border(width = 1.dp, color = Color(0x26000000))
84-
.size(sizeDp)
85-
) {
86-
drawLine(
87-
color = Color.Black,
88-
start = Offset(sizePxHalf, 0f),
89-
end = Offset(sizePxHalf, sizePx),
90-
strokeWidth = 2.dp.toPx()
91-
)
92-
drawLine(
93-
color = Color.Black,
94-
start = Offset(0f, sizePxHalf),
95-
end = Offset(sizePx, sizePxHalf),
96-
strokeWidth = 2.dp.toPx()
138+
val sizePxHalf = sizePx / 2
139+
140+
particles.forEach { it.updateProgress(progress) }
141+
142+
Canvas(
143+
modifier = Modifier
144+
.border(width = 1.dp, color = Color(0x26000000))
145+
.size(sizeDp)
146+
) {
147+
drawLine(
148+
color = Color.Black,
149+
start = Offset(sizePxHalf, 0f),
150+
end = Offset(sizePxHalf, sizePx),
151+
strokeWidth = 2.dp.toPx()
152+
)
153+
drawLine(
154+
color = Color.Black,
155+
start = Offset(0f, sizePxHalf),
156+
end = Offset(sizePx, sizePxHalf),
157+
strokeWidth = 2.dp.toPx()
158+
)
159+
particles.forEach { particle ->
160+
drawCircle(
161+
alpha = particle.alpha,
162+
color = particle.color,
163+
radius = 5.dp.toPx(),
164+
center = Offset(particle.currentXPosition, particle.currentYPosition),
97165
)
98-
particles.forEach { particle ->
99-
drawCircle(
100-
alpha = particle.alpha,
101-
color = particle.color,
102-
radius = 5.dp.toPx(),
103-
center = Offset(particle.currentXPosition, particle.currentYPosition),
104-
)
105-
}
106166
}
107167
}
108168
}
@@ -112,7 +172,9 @@ class ExplodingParticle(
112172
val startXPosition: Int,
113173
val startYPosition: Int,
114174
val maxHorizontalDisplacement: Float,
115-
val maxVerticalDisplacement: Float
175+
val maxVerticalDisplacement: Float,
176+
val visibilityThresholdLow: Float,
177+
val visibilityThresholdHigh: Float
116178
) {
117179
private val velocity = 4 * maxVerticalDisplacement
118180
private val acceleration = -2 * velocity
@@ -121,13 +183,38 @@ class ExplodingParticle(
121183

122184
var alpha = 1f
123185

186+
var currentTime: Float = 0f
187+
private set
188+
var trajectoryProgress: Float = 0f
189+
private set
190+
124191
fun updateProgress(explosionProgress: Float) {
125-
val currentTime = explosionProgress * 1f
192+
193+
// Trajectory progress translates progress from 0f-1f to
194+
// visibilityThresholdLow-visibilityThresholdHigh
195+
// range. For instance, 0.1-0.6f range movement starts when
196+
// explosionProgress is at 0.1f and reaches 1f
197+
// when explosionProgress reaches 0.6f and trajectoryProgress .
198+
199+
// Each 0.1f change in trajectoryProgress 0.5f total range
200+
// corresponds to 0.2f change of current time
201+
trajectoryProgress =
202+
if (explosionProgress < visibilityThresholdLow ||
203+
(explosionProgress > visibilityThresholdHigh)
204+
) {
205+
return
206+
} else {
207+
explosionProgress
208+
.mapInRange(visibilityThresholdLow, visibilityThresholdHigh, 0f, 1f)
209+
}
210+
211+
currentTime = trajectoryProgress
212+
// .mapInRange(0f, 1f, 0f, 1.4f)
126213

127214
val verticalDisplacement =
128215
currentTime * velocity + 0.5 * acceleration * currentTime * currentTime
129216

130-
currentXPosition = startXPosition + maxHorizontalDisplacement * explosionProgress
217+
currentXPosition = startXPosition + maxHorizontalDisplacement * trajectoryProgress
131218
currentYPosition = (startYPosition - verticalDisplacement).toFloat()
132219

133220
}

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