From e3333882e9e0ec088716c8fe19baeef7cfd744c9 Mon Sep 17 00:00:00 2001
From: ouyu <1986834078@qq.com>
Date: Mon, 20 Apr 2026 21:05:32 +0800
Subject: [PATCH] =?UTF-8?q?feat(=E6=A8=A1=E6=8B=9F):=20=E6=B7=BB=E5=8A=A0?=
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实现风场效果功能，允许在特定区域内施加风力。新增add_wind_field方法，通过指定区域边界和风力向量来创建风场效果，并在网格后处理阶段应用风力影响。
---
 demo/demo_3d.py      |  6 ++++++
 engine/mpm_solver.py | 20 ++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/demo/demo_3d.py b/demo/demo_3d.py
index 50b7954..3e89b9a 100644
--- a/demo/demo_3d.py
+++ b/demo/demo_3d.py
@@ -25,6 +25,12 @@
 
 mpm.set_gravity((0, -50, 0))
 
+mpm.add_wind_field(
+    lower_bound=[0, 0, 0],
+    upper_bound=[3, 10, 10],
+    force=[200, 0, 0]
+)
+
 for frame in range(1500):
     mpm.step(4e-3)
     colors = np.array([0x068587, 0xED553B, 0xEEEEF0, 0xFFFF00],
diff --git a/engine/mpm_solver.py b/engine/mpm_solver.py
index b898c37..3098ec4 100644
--- a/engine/mpm_solver.py
+++ b/engine/mpm_solver.py
@@ -318,6 +318,26 @@ def set_gravity(self, g):
         assert len(g) == self.dim
         self.gravity[None] = g
 
+    def add_wind_field(self, lower_bound, upper_bound, force):
+        lower_bound = list(lower_bound)
+        upper_bound = list(upper_bound)
+        force = list(force)
+        assert len(lower_bound) == self.dim
+        assert len(upper_bound) == self.dim
+        assert len(force) == self.dim
+
+        @ti.kernel
+        def apply_wind(t: ti.f32, dt: ti.f32, grid_v: ti.template()):
+            for I in ti.grouped(grid_v):
+                grid_pos = I * self.dx
+                inside = True
+                for d in ti.static(range(self.dim)):
+                    inside = inside and (lower_bound[d] <= grid_pos[d] < upper_bound[d])
+                if inside:
+                    grid_v[I] += dt * ti.Vector(force)
+
+        self.grid_postprocess.append(apply_wind)
+
     @ti.func
     def sand_projection(self, sigma, p):
         sigma_out = ti.Matrix.zero(ti.f32, self.dim, self.dim)