From 36531006da83a7b82f008eb0df8227c492f68049 Mon Sep 17 00:00:00 2001
From: Campbell Barton <campbell@blender.org>
Date: Sun, 2 Feb 2025 13:56:46 +1100
Subject: [PATCH] Cleanup: use const pointer for the gravity vector

---
 source/blender/blenkernel/BKE_particle.h            | 5 ++++-
 source/blender/blenkernel/intern/particle_system.cc | 4 ++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/source/blender/blenkernel/BKE_particle.h b/source/blender/blenkernel/BKE_particle.h
index 9184c3228c8..7915c9704ab 100644
--- a/source/blender/blenkernel/BKE_particle.h
+++ b/source/blender/blenkernel/BKE_particle.h
@@ -89,7 +89,10 @@ typedef struct SPHData {
   ParticleData *pa;
   float mass;
   std::optional<blender::Map<blender::OrderedEdge, int>> eh;
-  float *gravity;
+
+  /** The gravity as a `float[3]`, may also be null when the simulation doesn't use gravity. */
+  const float *gravity;
+
   float hfac;
   /* Average distance to neighbors (other particles in the support domain),
    * for calculating the Courant number (adaptive time step). */
diff --git a/source/blender/blenkernel/intern/particle_system.cc b/source/blender/blenkernel/intern/particle_system.cc
index dd65ef00ad6..3dfe805070f 100644
--- a/source/blender/blenkernel/intern/particle_system.cc
+++ b/source/blender/blenkernel/intern/particle_system.cc
@@ -1795,7 +1795,7 @@ static void sph_force_cb(void *sphdata_v, ParticleKey *state, float *force, floa
   ParticleSpring *spring = nullptr;
   SPHRangeData pfr;
   SPHNeighbor *pfn;
-  float *gravity = sphdata->gravity;
+  const float *gravity = sphdata->gravity;
   const std::optional<blender::Map<blender::OrderedEdge, int>> &springhash = sphdata->eh;
 
   float q, u, rij, dv[3];
@@ -1996,7 +1996,7 @@ static void sphclassical_force_cb(void *sphdata_v,
   SPHFluidSettings *fluid = psys[0]->part->fluid;
   SPHRangeData pfr;
   SPHNeighbor *pfn;
-  float *gravity = sphdata->gravity;
+  const float *gravity = sphdata->gravity;
 
   float dq, u, rij, dv[3];
   float pressure, npressure;