Lights Tutorial#

../../_images/lights.png

(To be done.)

light_demo.py#
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
"""
Show how to use lights.

.. note:: This uses features from the upcoming version 2.4. The API for these
          functions may still change. To use, you will need to install one of the
          pre-release packages, or install via GitHub.

Artwork from http://kenney.nl

"""
import arcade
from arcade.experimental.lights import Light, LightLayer

SCREEN_WIDTH = 1024
SCREEN_HEIGHT = 768
SCREEN_TITLE = "Lighting Demo"
VIEWPORT_MARGIN = 200
MOVEMENT_SPEED = 5

# This is the color used for 'ambient light'. If you don't want any
# ambient light, set it to black.
AMBIENT_COLOR = (10, 10, 10)

class MyGame(arcade.Window):
    """ Main Game Window """

    def __init__(self, width, height, title):
        """ Set up the class. """
        super().__init__(width, height, title, resizable=True)

        # Sprite lists
        self.background_sprite_list = None
        self.player_list = None
        self.wall_list = None
        self.player_sprite = None

        # Physics engine
        self.physics_engine = None

        # Used for scrolling
        self.view_left = 0
        self.view_bottom = 0

        # --- Light related ---
        # List of all the lights
        self.light_layer = None
        # Individual light we move with player, and turn on/off
        self.player_light = None

    def setup(self):
        """ Create everything """

        # Create sprite lists
        self.background_sprite_list = arcade.SpriteList()
        self.player_list = arcade.SpriteList()
        self.wall_list = arcade.SpriteList()

        # Create player sprite
        self.player_sprite = arcade.Sprite(":resources:images/animated_characters/female_person/femalePerson_idle.png", 0.4)
        self.player_sprite.center_x = 64
        self.player_sprite.center_y = 270
        self.player_list.append(self.player_sprite)

        # --- Light related ---
        # Lights must shine on something. If there is no background sprite or color,
        # you will just see black. Therefore, we use a loop to create a whole bunch of brick tiles to go in the
        # background.
        for x in range(-128, 2000, 128):
            for y in range(-128, 1000, 128):
                sprite = arcade.Sprite(":resources:images/tiles/brickTextureWhite.png")
                sprite.position = x, y
                self.background_sprite_list.append(sprite)

        # Create a light layer, used to render things to, then post-process and
        # add lights. This must match the screen size.
        self.light_layer = LightLayer(SCREEN_WIDTH, SCREEN_HEIGHT)
        # We can also set the background color that will be lit by lights,
        # but in this instance we just want a black background
        self.light_layer.set_background_color(arcade.color.BLACK)

        # Here we create a bunch of lights.

        # Create a small white light
        x = 100
        y = 200
        radius = 100
        mode = 'soft'
        color = arcade.csscolor.WHITE
        light = Light(x, y, radius, color, mode)
        self.light_layer.add(light)

        # Create an overlapping, large white light
        x = 300
        y = 150
        radius = 200
        color = arcade.csscolor.WHITE
        mode = 'soft'
        light = Light(x, y, radius, color, mode)
        self.light_layer.add(light)

        # Create three, non-overlapping RGB lights
        x = 50
        y = 450
        radius = 100
        mode = 'soft'
        color = arcade.csscolor.RED
        light = Light(x, y, radius, color, mode)
        self.light_layer.add(light)

        x = 250
        y = 450
        radius = 100
        mode = 'soft'
        color = arcade.csscolor.GREEN
        light = Light(x, y, radius, color, mode)
        self.light_layer.add(light)

        x = 450
        y = 450
        radius = 100
        mode = 'soft'
        color = arcade.csscolor.BLUE
        light = Light(x, y, radius, color, mode)
        self.light_layer.add(light)

        # Create three, overlapping RGB lights
        x = 650
        y = 450
        radius = 100
        mode = 'soft'
        color = arcade.csscolor.RED
        light = Light(x, y, radius, color, mode)
        self.light_layer.add(light)

        x = 750
        y = 450
        radius = 100
        mode = 'soft'
        color = arcade.csscolor.GREEN
        light = Light(x, y, radius, color, mode)
        self.light_layer.add(light)

        x = 850
        y = 450
        radius = 100
        mode = 'soft'
        color = arcade.csscolor.BLUE
        light = Light(x, y, radius, color, mode)
        self.light_layer.add(light)

        # Create three, overlapping RGB lights
        # But 'hard' lights that don't fade out.
        x = 650
        y = 150
        radius = 100
        mode = 'hard'
        color = arcade.csscolor.RED
        light = Light(x, y, radius, color, mode)
        self.light_layer.add(light)

        x = 750
        y = 150
        radius = 100
        mode = 'hard'
        color = arcade.csscolor.GREEN
        light = Light(x, y, radius, color, mode)
        self.light_layer.add(light)

        x = 850
        y = 150
        radius = 100
        mode = 'hard'
        color = arcade.csscolor.BLUE
        light = Light(x, y, radius, color, mode)
        self.light_layer.add(light)

        # Create a light to follow the player around.
        # We'll position it later, when the player moves.
        # We'll only add it to the light layer when the player turns the light
        # on. We start with the light off.
        radius = 150
        mode = 'soft'
        color = arcade.csscolor.WHITE
        self.player_light = Light(0, 0, radius, color, mode)

        # Create the physics engine
        self.physics_engine = arcade.PhysicsEngineSimple(self.player_sprite, self.wall_list)

        # Set the viewport boundaries
        # These numbers set where we have 'scrolled' to.
        self.view_left = 0
        self.view_bottom = 0

    def on_draw(self):
        """ Draw everything. """
        self.clear()

        # --- Light related ---
        # Everything that should be affected by lights gets rendered inside this
        # 'with' statement. Nothing is rendered to the screen yet, just the light
        # layer.
        with self.light_layer:
            self.background_sprite_list.draw()
            self.player_list.draw()

        # Draw the light layer to the screen.
        # This fills the entire screen with the lit version
        # of what we drew into the light layer above.
        self.light_layer.draw(ambient_color=AMBIENT_COLOR)

        # Now draw anything that should NOT be affected by lighting.
        arcade.draw_text("Press SPACE to turn character light on/off.",
                         10 + self.view_left, 10 + self.view_bottom,
                         arcade.color.WHITE, 20)

    def on_resize(self, width, height):
        """ User resizes the screen. """

        # --- Light related ---
        # We need to resize the light layer to
        self.light_layer.resize(width, height)

        # Scroll the screen so the user is visible
        self.scroll_screen()

    def on_key_press(self, key, _):
        """Called whenever a key is pressed. """

        if key == arcade.key.UP:
            self.player_sprite.change_y = MOVEMENT_SPEED
        elif key == arcade.key.DOWN:
            self.player_sprite.change_y = -MOVEMENT_SPEED
        elif key == arcade.key.LEFT:
            self.player_sprite.change_x = -MOVEMENT_SPEED
        elif key == arcade.key.RIGHT:
            self.player_sprite.change_x = MOVEMENT_SPEED
        elif key == arcade.key.SPACE:
            # --- Light related ---
            # We can add/remove lights from the light layer. If they aren't
            # in the light layer, the light is off.
            if self.player_light in self.light_layer:
                self.light_layer.remove(self.player_light)
            else:
                self.light_layer.add(self.player_light)

    def on_key_release(self, key, _):
        """Called when the user releases a key. """

        if key == arcade.key.UP or key == arcade.key.DOWN:
            self.player_sprite.change_y = 0
        elif key == arcade.key.LEFT or key == arcade.key.RIGHT:
            self.player_sprite.change_x = 0

    def scroll_screen(self):
        """ Manage Scrolling """

        # Scroll left
        left_boundary = self.view_left + VIEWPORT_MARGIN
        if self.player_sprite.left < left_boundary:
            self.view_left -= left_boundary - self.player_sprite.left

        # Scroll right
        right_boundary = self.view_left + self.width - VIEWPORT_MARGIN
        if self.player_sprite.right > right_boundary:
            self.view_left += self.player_sprite.right - right_boundary

        # Scroll up
        top_boundary = self.view_bottom + self.height - VIEWPORT_MARGIN
        if self.player_sprite.top > top_boundary:
            self.view_bottom += self.player_sprite.top - top_boundary

        # Scroll down
        bottom_boundary = self.view_bottom + VIEWPORT_MARGIN
        if self.player_sprite.bottom < bottom_boundary:
            self.view_bottom -= bottom_boundary - self.player_sprite.bottom

        # Make sure our boundaries are integer values. While the viewport does
        # support floating point numbers, for this application we want every pixel
        # in the view port to map directly onto a pixel on the screen. We don't want
        # any rounding errors.
        self.view_left = int(self.view_left)
        self.view_bottom = int(self.view_bottom)

        arcade.set_viewport(self.view_left,
                            self.width + self.view_left,
                            self.view_bottom,
                            self.height + self.view_bottom)

    def on_update(self, delta_time):
        """ Movement and game logic """

        # Call update on all sprites (The sprites don't do much in this
        # example though.)
        self.physics_engine.update()

        # --- Light related ---
        # We can easily move the light by setting the position,
        # or by center_x, center_y.
        self.player_light.position = self.player_sprite.position

        # Scroll the screen so we can see the player
        self.scroll_screen()


if __name__ == "__main__":
    window = MyGame(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
    window.setup()
    arcade.run()