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import numpy as np
import moderngl
from _example import Example
def particle():
a = np.random.uniform(0.0, np.pi * 2.0)
r = np.random.uniform(0.0, 0.001)
return np.array([0.0, 0.0, np.cos(a) * r - 0.003, np.sin(a) * r - 0.008]).astype('f4')
class Particles(Example):
title = "Particle System"
gl_version = (3, 3)
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.prog = self.ctx.program(
vertex_shader='''
#version 330
in vec2 in_vert;
void main() {
gl_Position = vec4(in_vert, 0.0, 1.0);
}
''',
fragment_shader='''
#version 330
out vec4 f_color;
void main() {
f_color = vec4(0.30, 0.50, 1.00, 1.0);
}
''',
)
self.transform = self.ctx.program(
vertex_shader='''
#version 330
uniform vec2 Acc;
in vec2 in_pos;
in vec2 in_prev;
out vec2 out_pos;
out vec2 out_prev;
void main() {
vec2 velocity = in_pos - in_prev;
out_pos = in_pos + velocity + Acc;
out_prev = in_pos;
}
''',
varyings=['out_pos', 'out_prev']
)
self.acc = self.transform['Acc']
self.acc.value = (0.0, -0.0001)
self.vbo1 = self.ctx.buffer(b''.join(particle() for i in range(1024)))
self.vbo2 = self.ctx.buffer(reserve=self.vbo1.size)
self.vao1 = self.ctx.simple_vertex_array(self.transform, self.vbo1, 'in_pos', 'in_prev')
self.vao2 = self.ctx.simple_vertex_array(self.transform, self.vbo2, 'in_pos', 'in_prev')
self.render_vao = self.ctx.vertex_array(self.prog, [
(self.vbo1, '2f 2x4', 'in_vert'),
])
self.idx = 0
def render(self, time, frame_time):
self.ctx.clear(1.0, 1.0, 1.0)
self.ctx.point_size = 2.0
for i in range(8):
self.vbo1.write(particle(), offset=self.idx * 16)
self.idx = (self.idx + 1) % 1024
self.render_vao.render(moderngl.POINTS, 1024)
self.vao1.transform(self.vbo2, moderngl.POINTS, 1024)
self.ctx.copy_buffer(self.vbo1, self.vbo2)
if __name__ == '__main__':
Particles.run()
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