# Sprite Explosions Particles¶

sprite_explosion_particles.py
```  1"""
2Sprite Explosion
3
4Simple program to show creating explosions with particles
5
6Artwork from https://kenney.nl
7
8If Python and Arcade are installed, this example can be run from the command line with:
10"""
11import random
12import math
14
15SPRITE_SCALING_PLAYER = 0.5
16SPRITE_SCALING_COIN = 0.3
17SPRITE_SCALING_LASER = 0.8
18COIN_COUNT = 50
19
20SCREEN_WIDTH = 800
21SCREEN_HEIGHT = 600
22SCREEN_TITLE = "Sprite Explosion Example"
23
24BULLET_SPEED = 5
25
26# --- Explosion Particles Related
27
28# How fast the particle will accelerate down. Make 0 if not desired
29PARTICLE_GRAVITY = 0.05
30
31# How fast to fade the particle
33
34# How fast the particle moves. Range is from 2.5 <--> 5 with 2.5 and 2.5 set.
35PARTICLE_MIN_SPEED = 2.5
36PARTICLE_SPEED_RANGE = 2.5
37
38# How many particles per explosion
39PARTICLE_COUNT = 20
40
41# How big the particle
43
44# Possible particle colors
50
51# Chance we'll flip the texture to white and make it 'sparkle'
52PARTICLE_SPARKLE_CHANCE = 0.02
53
54# --- Smoke
55# Note: Adding smoke trails makes for a lot of sprites and can slow things
56# down. If you want a lot, it will be necessary to move processing to GPU
57# using transform feedback. If to slow, just get rid of smoke.
58
59# Start scale of smoke, and how fast is scales up
60SMOKE_START_SCALE = 0.25
61SMOKE_EXPANSION_RATE = 0.03
62
63# Rate smoke fades, and rises
65SMOKE_RISE_RATE = 0.5
66
67# Chance we leave smoke trail
68SMOKE_CHANCE = 0.25
69
70
72    """ This represents a puff of smoke """
73    def __init__(self, size):
75        self.change_y = SMOKE_RISE_RATE
76        self.scale = SMOKE_START_SCALE
77
78    def update(self):
79        """ Update this particle """
81            # Remove faded out particles
82            self.remove_from_sprite_lists()
83        else:
84            # Update values
86            self.center_x += self.change_x
87            self.center_y += self.change_y
88            self.scale += SMOKE_EXPANSION_RATE
89
90
92    """ Explosion particle """
93    def __init__(self, my_list):
94        # Choose a random color
95        color = random.choice(PARTICLE_COLORS)
96
97        # Make the particle
99
100        # Track normal particle texture, so we can 'flip' when we sparkle.
101        self.normal_texture = self.texture
102
103        # Keep track of the list we are in, so we can add a smoke trail
104        self.my_list = my_list
105
106        # Set direction/speed
107        speed = random.random() * PARTICLE_SPEED_RANGE + PARTICLE_MIN_SPEED
108        direction = random.randrange(360)
109        self.change_x = math.sin(math.radians(direction)) * speed
110        self.change_y = math.cos(math.radians(direction)) * speed
111
112        # Track original alpha. Used as part of 'sparkle' where we temp set the
113        # alpha back to 255
114        self.my_alpha = 255
115
116        # What list do we add smoke particles to?
117        self.my_list = my_list
118
119    def update(self):
120        """ Update the particle """
123            self.remove_from_sprite_lists()
124        else:
125            # Update
127            self.alpha = self.my_alpha
128            self.center_x += self.change_x
129            self.center_y += self.change_y
130            self.change_y -= PARTICLE_GRAVITY
131
132            # Should we sparkle this?
133            if random.random() <= PARTICLE_SPARKLE_CHANCE:
134                self.alpha = 255
137            else:
138                self.texture = self.normal_texture
139
140            # Leave a smoke particle?
141            if random.random() <= SMOKE_CHANCE:
142                smoke = Smoke(5)
143                smoke.position = self.position
144                self.my_list.append(smoke)
145
146
148    """ Main application class. """
149
150    def __init__(self):
151        """ Initializer """
152        # Call the parent class initializer
153        super().__init__(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
154
155        # Variables that will hold sprite lists
156        self.player_list = None
157        self.coin_list = None
158        self.bullet_list = None
159        self.explosions_list = None
160
161        # Set up the player info
162        self.player_sprite = None
163        self.score = 0
164
165        # Don't show the mouse cursor
166        self.set_mouse_visible(False)
167
168        # Load sounds. Sounds from kenney.nl
171
173
174    def setup(self):
175
176        """ Set up the game and initialize the variables. """
177
178        # Sprite lists
183
184        # Set up the player
185        self.score = 0
186
187        # Image from kenney.nl
189                                           scale=SPRITE_SCALING_PLAYER)
190        self.player_sprite.center_x = 50
191        self.player_sprite.center_y = 70
192        self.player_list.append(self.player_sprite)
193
194        # Create the coins
195        for coin_index in range(COIN_COUNT):
196
197            # Create the coin instance
198            # Coin image from kenney.nl
200                                 scale=SPRITE_SCALING_COIN)
201            coin.angle = 180
202
203            # Position the coin
204            coin.center_x = random.randrange(SCREEN_WIDTH)
205            coin.center_y = random.randrange(150, SCREEN_HEIGHT)
206
207            # Add the coin to the lists
208            self.coin_list.append(coin)
209
210    def on_draw(self):
211        """
212        Render the screen.
213        """
214
215        # This command has to happen before we start drawing
216        self.clear()
217
218        # Draw all the sprites.
219        self.coin_list.draw()
220        self.bullet_list.draw()
221        self.player_list.draw()
222        self.explosions_list.draw()
223
224        # Render the text
226
227    def on_mouse_motion(self, x, y, dx, dy):
228        """
229        Called whenever the mouse moves.
230        """
231        self.player_sprite.center_x = x
232
233    def on_mouse_press(self, x, y, button, modifiers):
234        """
235        Called whenever the mouse button is clicked.
236        """
237
238        # Gunshot sound
240
241        # Create a bullet
243
244        # The image points to the right, and we want it to point up. So
245        # rotate it.
246        bullet.angle = 270
247
248        # Give it a speed
249        bullet.change_y = BULLET_SPEED
250
251        # Position the bullet
252        bullet.center_x = self.player_sprite.center_x
253        bullet.bottom = self.player_sprite.top
254
255        # Add the bullet to the appropriate lists
256        self.bullet_list.append(bullet)
257
258    def on_update(self, delta_time):
259        """ Movement and game logic """
260
261        # Call update on bullet sprites
262        self.bullet_list.update()
263        self.explosions_list.update()
264
265        # Loop through each bullet
266        for bullet in self.bullet_list:
267
268            # Check this bullet to see if it hit a coin
270
271            # If it did...
272            if len(hit_list) > 0:
273
274                # Get rid of the bullet
275                bullet.remove_from_sprite_lists()
276
277            # For every coin we hit, add to the score and remove the coin
278            for coin in hit_list:
279                # Make an explosion
280                for i in range(PARTICLE_COUNT):
281                    particle = Particle(self.explosions_list)
282                    particle.position = coin.position
283                    self.explosions_list.append(particle)
284
285                smoke = Smoke(50)
286                smoke.position = coin.position
287                self.explosions_list.append(smoke)
288
289                coin.remove_from_sprite_lists()
290                self.score += 1
291
292                # Hit Sound
294
295            # If the bullet flies off-screen, remove it.
296            if bullet.bottom > SCREEN_HEIGHT:
297                bullet.remove_from_sprite_lists()
298
299
300def main():
301    window = MyGame()
302    window.center_window()
303    window.setup()