"""
Example showing how to create particle explosions via the GPU.
"""
from array import array
from dataclasses import dataclass
import arcade
import arcade.gl
SCREEN_WIDTH = 1024
SCREEN_HEIGHT = 768
SCREEN_TITLE = "GPU Particle Explosion"
@dataclass
class Burst:
""" Track for each burst. """
buffer: arcade.gl.Buffer
vao: arcade.gl.Geometry
class MyWindow(arcade.Window):
""" Main window"""
def __init__(self):
super().__init__(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_TITLE)
self.burst_list = []
# Program to visualize the points
self.program = self.ctx.load_program(
vertex_shader="vertex_shader_v1.glsl",
fragment_shader="fragment_shader.glsl",
)
self.ctx.enable_only()
def on_draw(self):
""" Draw everything """
self.clear()
# Set the particle size
self.ctx.point_size = 2 * self.get_pixel_ratio()
# Loop through each burst
for burst in self.burst_list:
# Render the burst
burst.vao.render(self.program, mode=self.ctx.POINTS)
def on_update(self, dt):
""" Update everything """
pass
def on_mouse_press(self, x: float, y: float, button: int, modifiers: int):
""" User clicks mouse """
def _gen_initial_data(initial_x, initial_y):
""" Generate data for each particle """
yield initial_x
yield initial_y
# Recalculate the coordinates from pixels to the OpenGL system with
# 0, 0 at the center.
x2 = x / self.width * 2. - 1.
y2 = y / self.height * 2. - 1.
# Get initial particle data
initial_data = _gen_initial_data(x2, y2)
# Create a buffer with that data
buffer = self.ctx.buffer(data=array('f', initial_data))
# Create a buffer description that says how the buffer data is formatted.
buffer_description = arcade.gl.BufferDescription(buffer,
'2f',
['in_pos'])
# Create our Vertex Attribute Object
vao = self.ctx.geometry([buffer_description])
# Create the Burst object and add it to the list of bursts
burst = Burst(buffer=buffer, vao=vao)
self.burst_list.append(burst)
if __name__ == "__main__":
window = MyWindow()
window.center_window()
arcade.run()