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