gpu_particle_burst_02.py Full Listing

gpu_particle_burst_02.py
 1"""
 2Example showing how to create particle explosions via the GPU.
 3"""
 4from array import array
 5from dataclasses import dataclass
 6
 7import arcade
 8import arcade.gl
 9
10SCREEN_WIDTH = 1024
11SCREEN_HEIGHT = 768
12SCREEN_TITLE = "GPU Particle Explosion"
13
14
15@dataclass
16class Burst:
17    """ Track for each burst. """
18    buffer: arcade.gl.Buffer
19    vao: arcade.gl.Geometry
20
21
22class MyWindow(arcade.Window):
23    """ Main window"""
24    def __init__(self):
25        super().__init__(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
26        self.burst_list = []
27
28        # Program to visualize the points
29        self.program = self.ctx.load_program(
30            vertex_shader="vertex_shader_v1.glsl",
31            fragment_shader="fragment_shader.glsl",
32        )
33
34        self.ctx.enable_only()
35
36    def on_draw(self):
37        """ Draw everything """
38        self.clear()
39
40        # Set the particle size
41        self.ctx.point_size = 2 * self.get_pixel_ratio()
42
43        # Loop through each burst
44        for burst in self.burst_list:
45
46            # Render the burst
47            burst.vao.render(self.program, mode=self.ctx.POINTS)
48
49    def on_update(self, dt):
50        """ Update everything """
51        pass
52
53    def on_mouse_press(self, x: float, y: float, button: int, modifiers: int):
54        """ User clicks mouse """
55
56        def _gen_initial_data(initial_x, initial_y):
57            """ Generate data for each particle """
58            yield initial_x
59            yield initial_y
60
61        # Recalculate the coordinates from pixels to the OpenGL system with
62        # 0, 0 at the center.
63        x2 = x / self.width * 2. - 1.
64        y2 = y / self.height * 2. - 1.
65
66        # Get initial particle data
67        initial_data = _gen_initial_data(x2, y2)
68
69        # Create a buffer with that data
70        buffer = self.ctx.buffer(data=array('f', initial_data))
71
72        # Create a buffer description specifying the buffer's data format
73        buffer_description = arcade.gl.BufferDescription(
74            buffer,
75            '2f',
76            ['in_pos'])
77
78        # Create our Vertex Attribute Object
79        vao = self.ctx.geometry([buffer_description])
80
81        # Create the Burst object and add it to the list of bursts
82        burst = Burst(buffer=buffer, vao=vao)
83        self.burst_list.append(burst)
84
85
86if __name__ == "__main__":
87    window = MyWindow()
88    window.center_window()
89    arcade.run()