From 06856ed973717072aaec63119bb159639e068a8d Mon Sep 17 00:00:00 2001
From: Maxime Morel <maxime@mmorel.eu>
Date: Thu, 22 Oct 2026 18:27:58 +0200
Subject: [PATCH] Water decal improvement 3

---
 src/game/explosion.c | 51 ++++++++++++++++++++++++++++++++++++++++----
 src/game/explosion.h |  5 +++++
 2 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/src/game/explosion.c b/src/game/explosion.c
index eeebd390..fe18dfef 100644
--- a/src/game/explosion.c
+++ b/src/game/explosion.c
@@ -1590,6 +1590,9 @@ void explosionInitFlyingParticles(coord3d *spawnpos, f32 spawn_rand_scale, f32 s
     rand3 = (2.0f * (((f32) randomGetNext()) * (1.0f / (f32)UINT_MAX))) - 1.0f;
 
     g_FlyingParticlesBuffer[g_NumParticleEntries].unk00 = 1;
+#ifdef PORT
+    g_FlyingParticlesBuffer[g_NumParticleEntries].is_splash = FALSE;
+#endif
 
     g_FlyingParticlesBuffer[g_NumParticleEntries].position.f[0] = spawnpos->f[0] + (spawn_rand_scale * rand1);
     g_FlyingParticlesBuffer[g_NumParticleEntries].position.f[1] = spawnpos->f[1] + (spawn_rand_scale * rand2);
@@ -1739,6 +1742,15 @@ void explosionUpdateFlyingParticles(void)
                 g_FlyingParticlesBuffer[i].unk00 = 0;
             }
 
+#ifdef PORT
+            if (g_FlyingParticlesBuffer[i].is_splash
+                && g_FlyingParticlesBuffer[i].position_drift.f[1] < 0.0f
+                && g_FlyingParticlesBuffer[i].position.f[1] < g_FlyingParticlesBuffer[i].splash_y)
+            {
+                g_FlyingParticlesBuffer[i].unk00 = 0;
+            }
+#endif
+
             // position-related. deletes particles that are too low or too high.
             if ((g_FlyingParticlesBuffer[i].position.f[1] < -30000.0f) || (g_FlyingParticlesBuffer[i].position.f[1] > 30000.0f))
             {
@@ -1754,22 +1766,53 @@ void explosionUpdateFlyingParticles(void)
 
 /* Bullet hitting water (PC): the N64 only drew the yellow impact flash there.
  * Use the chr hit puffs instead (chrCreateHitPuffs: the small impact puff and
- * the larger burst), tinted to the water colour. */
+ * the larger burst), tinted to the water colour, plus droplets (the wall-hit
+ * dust particles, recoloured) thrown up and removed when they fall back
+ * through the surface. */
+#define WATER_SPLASH_R 0xA0
+#define WATER_SPLASH_G 0xC8
+#define WATER_SPLASH_B 0xF0
+#define WATER_SPLASH_DROPLETS 12
+
 static void explosionTintSpark(s_bullet_spark *spark)
 {
     if (spark != NULL)
     {
-        spark->unk28 = 0xA0;
-        spark->unk29 = 0xC8;
-        spark->unk2A = 0xF0;
+        spark->unk28 = WATER_SPLASH_R;
+        spark->unk29 = WATER_SPLASH_G;
+        spark->unk2A = WATER_SPLASH_B;
         spark->unk2B = 0xFF;
     }
 }
 
 void explosionCreateWaterSplash(coord3d *pos, s16 room)
 {
+    s32 i;
+    s32 j;
+
     explosionTintSpark(bullet_spark_create(pos, 3, 43.0f, room));
     explosionTintSpark(bullet_spark_create(pos, 1, 21.0f, room));
+
+    for (i = 0; i < WATER_SPLASH_DROPLETS; i++)
+    {
+        struct FlyingParticles *drop = &g_FlyingParticlesBuffer[g_NumParticleEntries];
+
+        explosionInitFlyingParticles(pos, 2.0f, 1.0f, 6.0f, 3.0f);
+
+        drop->is_splash = TRUE;
+        drop->splash_y = pos->f[1];
+
+        for (j = 0; j < 4; j++)
+        {
+            /* vary the brightness per vertex, keep the water hue */
+            s32 shade = 0xC0 + (randomGetNext() & 0x3F);
+
+            drop->vertex_list[j].v.cn[0] = (WATER_SPLASH_R * shade) / 0xFF;
+            drop->vertex_list[j].v.cn[1] = (WATER_SPLASH_G * shade) / 0xFF;
+            drop->vertex_list[j].v.cn[2] = (WATER_SPLASH_B * shade) / 0xFF;
+            drop->vertex_list[j].v.cn[3] = 0xB0;
+        }
+    }
 }
 #endif
 
diff --git a/src/game/explosion.h b/src/game/explosion.h
index 58740f1a..83d55c39 100644
--- a/src/game/explosion.h
+++ b/src/game/explosion.h
@@ -148,6 +148,11 @@ struct FlyingParticles {
     s32 unk34;
 
     Vtx vertex_list[4];
+#ifdef PORT
+    /* water splash droplet: removed once it falls back below splash_y */
+    s32 is_splash;
+    f32 splash_y;
+#endif
 };
 
 extern f32 g_SpExplosionDamageMult;