particle_step — GFX2D particle op

• 資料種類:table → table

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

用法

把粒子狀態推進 `dt` 秒。回傳新的 dict。

> 以下的詳細說明為原文 —— 摘要與標題已翻譯。

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.

參考(範例資料・文獻)

• 範例資料目錄(下載 URL / 授權) —— 2-D 用 skimage.data(BSD/公有領域)加合成圖,3-D 給出真實資料源(Stanford/PDS 等)的下載 URL。

• 運算子來歷與參考文獻 —— 該運算子族所依據的研究/方法出處。

• 演算法的正典(作者・年份)與用途見上面的族使用指南。

可執行的範例(實際呼叫該運算子並已驗證的樣例)

• gfx2d_scene — py -3.11 examples/gfx2d_scene.py

型別可銜接的下一個運算子(可接受 table 作為輸入)

layer_stack · particle_render

同類別(particle)

particle_emit · particle_render

*Provenance: gfx2d.py — GFX2D 運算子登記表。本條目由 tools/opdocs.py md 自動產生(請勿手動編輯)。*

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