From eb942371cdcdab401ccc7a203d12ba17faf07219 Mon Sep 17 00:00:00 2001
From: Alexander Nutz <alexandernutz68@gmail.com>
Date: Sat, 27 Sep 2025 18:11:12 +0200
Subject: [PATCH] proper fluid flow

---
 include/globals.h |  4 ++--
 src/procedures.c  | 41 ++++++++++++++++++++++++++++-------------
 2 files changed, 30 insertions(+), 15 deletions(-)

diff --git a/include/globals.h b/include/globals.h
index 32910a7..085b2f9 100644
--- a/include/globals.h
+++ b/include/globals.h
@@ -34,8 +34,8 @@
 // Max render distance, determines how many chunks to send
 #define VIEW_DISTANCE 2
 
-// Time between server ticks in microseconds (default = 1s)
-#define TIME_BETWEEN_TICKS 1000000
+// Time between server ticks in microseconds (default = 0.05s)
+#define TIME_BETWEEN_TICKS 50000
 
 // Calculated from TIME_BETWEEN_TICKS
 #define TICKS_PER_SECOND ((float)1000000 / TIME_BETWEEN_TICKS)
diff --git a/src/procedures.c b/src/procedures.c
index 75f7c07..a0ac832 100644
--- a/src/procedures.c
+++ b/src/procedures.c
@@ -1037,6 +1037,20 @@ void handleFluidMovement (short x, uint8_t y, short z, uint8_t fluid, uint8_t bl
   // a higher fluid "level" means the fluid has traveled farther
   uint8_t level = block - fluid;
 
+  uint8_t flow_speed;
+  uint8_t max_level;
+  switch (fluid) {
+    case B_lava:
+      flow_speed = 30;
+      max_level = 3;
+      break;
+
+    case B_water:
+      flow_speed = 5;
+      max_level = 7;
+      break;
+  }
+
   // Query blocks adjacent to this fluid stream
   uint8_t adjacent[4] = {
     getBlockAt(x + 1, y, z),
@@ -1058,10 +1072,10 @@ void handleFluidMovement (short x, uint8_t y, short z, uint8_t fluid, uint8_t bl
     // If not connected, clear this block and recalculate surrounding flow
     if (!connected) {
       makeBlockChange(x, y, z, B_air);
-      checkFluidUpdate(x + 1, y, z, adjacent[0]);
-      checkFluidUpdate(x - 1, y, z, adjacent[1]);
-      checkFluidUpdate(x, y, z + 1, adjacent[2]);
-      checkFluidUpdate(x, y, z - 1, adjacent[3]);
+      deferBlockUpdate(x + 1, y, z, flow_speed);
+      deferBlockUpdate(x - 1, y, z, flow_speed);
+      deferBlockUpdate(x, y, z + 1, flow_speed);
+      deferBlockUpdate(x, y, z - 1, flow_speed);
       return;
     }
   }
@@ -1070,29 +1084,29 @@ void handleFluidMovement (short x, uint8_t y, short z, uint8_t fluid, uint8_t bl
   uint8_t block_below = getBlockAt(x, y - 1, z);
   if (isReplaceableBlock(block_below)) {
     makeBlockChange(x, y - 1, z, fluid);
-    return handleFluidMovement(x, y - 1, z, fluid, fluid);
+    deferBlockUpdate(x, y - 1, z, flow_speed);
+    return;
   }
 
   // Stop flowing laterally at the maximum level
-  if (level == 3 && fluid == B_lava) return;
-  if (level == 7) return;
+  if (level == max_level) return;
 
   // Handle lateral water flow, increasing level by 1
   if (isReplaceableFluid(adjacent[0], level, fluid)) {
     makeBlockChange(x + 1, y, z, block + 1);
-    handleFluidMovement(x + 1, y, z, fluid, block + 1);
+    deferBlockUpdate(x + 1, y, z, flow_speed);
   }
   if (isReplaceableFluid(adjacent[1], level, fluid)) {
     makeBlockChange(x - 1, y, z, block + 1);
-    handleFluidMovement(x - 1, y, z, fluid, block + 1);
+    deferBlockUpdate(x - 1, y, z, flow_speed);
   }
   if (isReplaceableFluid(adjacent[2], level, fluid)) {
     makeBlockChange(x, y, z + 1, block + 1);
-    handleFluidMovement(x, y, z + 1, fluid, block + 1);
+    deferBlockUpdate(x, y, z + 1, flow_speed);
   }
   if (isReplaceableFluid(adjacent[3], level, fluid)) {
     makeBlockChange(x, y, z - 1, block + 1);
-    handleFluidMovement(x, y, z - 1, fluid, block + 1);
+    deferBlockUpdate(x, y, z - 1, flow_speed);
   }
 
 }
@@ -1156,8 +1170,9 @@ void processBlockUpdate (short x, uint8_t y, short z, uint8_t block) {
       makeBlockChange(x, y, z, 0);
       makeBlockChange(x, y - 1, z, 0);
       makeBlockChange(x, y - 1, z, block);
-      // update this (now moved) block and the block above next tick
-      deferBlockUpdate(x, y - 1, z, 0);
+      // update this now moved block at the sand fall speed
+      deferBlockUpdate(x, y - 1, z, 15);
+      // update the block above next tick
       deferBlockUpdate(x, y + 1, z, 0);
     }
   }