ShapeElementList说明#

如果您在屏幕上绘制了很多项，则 arcade.ShapeElementList 可以加快您的绘图速度。它怎麽工作?

假设我们有一个大约有9,600个矩形的屏幕：

使用形状列表制作矩形的屏幕截图

这些矩形由38,400个点+9,600种颜色+9,600个角度创建。它们需要以每秒60次的速度发送到显卡。这会迅速膨胀为每秒发送到显卡的350万个数字，以显示一堆甚至不动的矩形。

相反，我们想要做的是将所有这些矩形打包，将它们发送到显卡，然后在一个命令中绘制它们。这使我们从每秒350万件降到了大约60件。

这里有三个例子：

  • 首先，没有形状列表。只是画长方形而已。

  • 其次，每个矩形被单独缓冲到GPU。

  • 第三，所有的矩形都被缓冲到GPU中，并作为一个组绘制。

使用形状列表制作矩形的屏幕截图

示例一-无形状列表#

shape_list_demo_1.py#
 1"""
 2This demo shows the speed of drawing a full grid of squares using no buffering.
 3
 4For me this takes about 0.16 seconds per frame.
 5
 6It is slow because we load all the points and all the colors to the card every
 7time.
 8
 9If Python and Arcade are installed, this example can be run from the command line with:
10python -m arcade.examples.shape_list_demo_1
11"""
12
13import arcade
14import timeit
15
16SCREEN_WIDTH = 1200
17SCREEN_HEIGHT = 800
18SCREEN_TITLE = "Shape List Demo 1"
19
20SQUARE_WIDTH = 5
21SQUARE_HEIGHT = 5
22SQUARE_SPACING = 10
23
24
25class MyGame(arcade.Window):
26    """ Main application class. """
27
28    def __init__(self, width, height, title):
29        super().__init__(width, height, title)
30
31        self.background_color = arcade.color.DARK_SLATE_GRAY
32
33        self.draw_time = 0
34
35    def on_draw(self):
36        """
37        Render the screen.
38        """
39
40        # This command has to happen before we start drawing
41        self.clear()
42
43        # Start timing how long this takes
44        draw_start_time = timeit.default_timer()
45
46        # --- Draw all the rectangles
47        for x in range(0, SCREEN_WIDTH, SQUARE_SPACING):
48            for y in range(0, SCREEN_HEIGHT, SQUARE_SPACING):
49                arcade.draw_rectangle_filled(x, y,
50                                             SQUARE_WIDTH, SQUARE_HEIGHT,
51                                             arcade.color.DARK_BLUE)
52
53        # Print the timing
54        output = f"Drawing time: {self.draw_time:.3f} seconds per frame."
55        arcade.draw_text(output, 20, SCREEN_HEIGHT - 40, arcade.color.WHITE, 18)
56
57        self.draw_time = timeit.default_timer() - draw_start_time
58
59
60def main():
61    MyGame(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
62
63    arcade.run()
64
65
66if __name__ == "__main__":
67    main()

示例2-简单的形状列表#

shape_list_demo_2.py#
 1"""
 2This demo shows using buffered rectangles to draw a grid of squares on the
 3screen.
 4
 5For me this runs about 0.002 seconds per frame.
 6
 7It is faster than demo 1 because we aren't loading the vertices and color
 8to the card again and again. It could be faster though, if we group all
 9rectangles together.
10
11If Python and Arcade are installed, this example can be run from the command line with:
12python -m arcade.examples.shape_list_demo_2
13"""
14
15import arcade
16import timeit
17
18SCREEN_WIDTH = 1200
19SCREEN_HEIGHT = 800
20SCREEN_TITLE = "Shape List Demo 2"
21
22SQUARE_WIDTH = 5
23SQUARE_HEIGHT = 5
24SQUARE_SPACING = 10
25
26
27class MyGame(arcade.Window):
28    """ Main application class. """
29
30    def __init__(self, width, height, title):
31        super().__init__(width, height, title)
32
33        self.background_color = arcade.color.DARK_SLATE_GRAY
34
35        self.draw_time = 0
36        self.shape_list = None
37
38    def setup(self):
39        # --- Create the vertex buffers objects for each square before we do
40        # any drawing.
41        self.shape_list = arcade.shape_list.ShapeElementList()
42        for x in range(0, SCREEN_WIDTH, SQUARE_SPACING):
43            for y in range(0, SCREEN_HEIGHT, SQUARE_SPACING):
44                shape = arcade.shape_list.create_rectangle_filled(
45                    center_x=x,
46                    center_y=y,
47                    width=SQUARE_WIDTH,
48                    height=SQUARE_HEIGHT,
49                    color=arcade.color.DARK_BLUE,
50                )
51                self.shape_list.append(shape)
52
53    def on_draw(self):
54        """
55        Render the screen.
56        """
57
58        # This command has to happen before we start drawing
59        self.clear()
60
61        # Start timing how long this takes
62        draw_start_time = timeit.default_timer()
63
64        # --- Draw all the rectangles
65        self.shape_list.draw()
66
67        output = f"Drawing time: {self.draw_time:.3f} seconds per frame."
68        arcade.draw_text(output, 20, SCREEN_HEIGHT - 40, arcade.color.WHITE, 18)
69
70        self.draw_time = timeit.default_timer() - draw_start_time
71
72
73def main():
74    window = MyGame(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
75    window.setup()
76    arcade.run()
77
78
79if __name__ == "__main__":
80    main()

示例三-复杂的形状列表#

shape_list_demo_3.py#
  1"""
  2This demo shows drawing a grid of squares using a single buffer.
  3
  4We calculate the points of each rectangle and add them to a point list.
  5We create a list of colors for each point.
  6We then draw all the squares with one drawing command.
  7
  8This runs in about 0.000 seconds for me. It is much more complex in code
  9than the prior two examples, but the pay-off in speed is huge.
 10
 11If Python and Arcade are installed, this example can be run from the command line with:
 12python -m arcade.examples.shape_list_demo_3
 13"""
 14
 15import arcade
 16import timeit
 17
 18SCREEN_WIDTH = 1200
 19SCREEN_HEIGHT = 800
 20SCREEN_TITLE = "Shape List Demo 3"
 21
 22HALF_SQUARE_WIDTH = 2.5
 23HALF_SQUARE_HEIGHT = 2.5
 24SQUARE_SPACING = 10
 25
 26
 27class MyGame(arcade.Window):
 28    """ Main application class. """
 29
 30    def __init__(self, width, height, title):
 31        super().__init__(width, height, title)
 32
 33        self.background_color = arcade.color.DARK_SLATE_GRAY
 34
 35        self.draw_time = 0
 36        self.shape_list = None
 37
 38    def setup(self):
 39        self.shape_list = arcade.shape_list.ShapeElementList()
 40
 41        # --- Create all the rectangles
 42
 43        # We need a list of all the points and colors
 44        point_list = []
 45        color_list = []
 46
 47        # Now calculate all the points
 48        for x in range(0, SCREEN_WIDTH, SQUARE_SPACING):
 49            for y in range(0, SCREEN_HEIGHT, SQUARE_SPACING):
 50
 51                # Calculate where the four points of the rectangle will be if
 52                # x and y are the center
 53                top_left = (x - HALF_SQUARE_WIDTH, y + HALF_SQUARE_HEIGHT)
 54                top_right = (x + HALF_SQUARE_WIDTH, y + HALF_SQUARE_HEIGHT)
 55                bottom_right = (x + HALF_SQUARE_WIDTH, y - HALF_SQUARE_HEIGHT)
 56                bottom_left = (x - HALF_SQUARE_WIDTH, y - HALF_SQUARE_HEIGHT)
 57
 58                # Add the points to the points list.
 59                # ORDER MATTERS!
 60                # Rotate around the rectangle, don't append points caty-corner
 61                point_list.append(top_left)
 62                point_list.append(top_right)
 63                point_list.append(bottom_right)
 64                point_list.append(bottom_left)
 65
 66                # Add a color for each point. Can be different colors if you want
 67                # gradients.
 68                for i in range(4):
 69                    color_list.append(arcade.color.DARK_BLUE)
 70
 71        shape = arcade.shape_list.create_rectangles_filled_with_colors(point_list, color_list)
 72        self.shape_list.append(shape)
 73
 74    def on_draw(self):
 75        """
 76        Render the screen.
 77        """
 78
 79        # This command has to happen before we start drawing
 80        self.clear()
 81
 82        # Start timing how long this takes
 83        draw_start_time = timeit.default_timer()
 84
 85        # --- Draw all the rectangles
 86        self.shape_list.draw()
 87
 88        output = f"Drawing time: {self.draw_time:.3f} seconds per frame."
 89        arcade.draw_text(output, 20, SCREEN_HEIGHT - 40, arcade.color.WHITE, 18)
 90
 91        self.draw_time = timeit.default_timer() - draw_start_time
 92
 93
 94def main():
 95    window = MyGame(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
 96    window.setup()
 97    arcade.run()
 98
 99
100if __name__ == "__main__":
101    main()