particle_step — GFX2D particle op

• 数据种类:table → table

• 调用:import gfx2d; gfx2d.particle_step(state, dt, gravity=(0.0, 98.0), drag=0.0)(或 opsgfx2d.get("particle_step"))

用法

把粒子状态推进 `dt` 秒。返回新的 dict。

> 以下的详细说明为原文 —— 摘要与标题已翻译。

Semi-implicit (symplectic) Euler::

v <- v + (g - drag*v) * dt

p <- p + v * dt

age <- age + dt

which makes the closed form exact and checkable: with `gravity=(0,0)` and

`drag=0 the position after k steps is p0 + v0*k*dt`, and with drag

the speed is `v0 * (1 - drag*dt)**k`. Both are compared as equalities in

the test suite.

`gravity is (gx, gy) in px/s^2, positive gy` pulling down the

screen. The input dict is never mutated.

Raises ValueError: `dt <= 0; drag * dt >= 1`, which is the point where

explicit drag stops decaying the speed and starts reversing it — an

instability that otherwise shows up as particles flying backwards rather

than as an error.

参考(示例数据・文献)

• 示例数据目录(下载 URL / 许可证) —— 2-D 用 skimage.data(BSD/公有领域)加合成图,3-D 给出真实数据源(Stanford/PDS 等)的下载 URL。

• 算子来历与参考文献 —— 该算子族所依据的研究/方法出处。

• 算法的正典(作者・年份)与用途见上面的族使用指南。

可运行的示例(实际调用该算子并已验证的样例)

• gfx2d_scene — py -3.11 examples/gfx2d_scene.py

类型可衔接的下一个算子(可接受 table 作为输入)

layer_stack · particle_render

同类别(particle)

particle_emit · particle_render

*Provenance: gfx2d.py — GFX2D 算子登记表。本条目由 tools/opdocs.py md 自动生成(请勿手工编辑)。*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.