From 239af5e7ab134c077d9ddb20bbe7870ca3e62b09 Mon Sep 17 00:00:00 2001
From: austin <austin@austinhoover.net>
Date: Sat, 30 Nov 2024 20:22:18 -0500
Subject: [PATCH] multichunk fluidsim

---
 .../fluid/manager/ServerFluidChunk.java       | 40 +++++++++++++++
 .../fluid/manager/ServerFluidManager.java     | 49 ++++++++++++++++++-
 2 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/src/main/java/electrosphere/server/fluid/manager/ServerFluidChunk.java b/src/main/java/electrosphere/server/fluid/manager/ServerFluidChunk.java
index 766b6cbd..3d01b16a 100644
--- a/src/main/java/electrosphere/server/fluid/manager/ServerFluidChunk.java
+++ b/src/main/java/electrosphere/server/fluid/manager/ServerFluidChunk.java
@@ -427,4 +427,44 @@ public class ServerFluidChunk {
         return updated;
     }
 
+    /**
+     * Gets the neighbor index given an offset in each dimension
+     * @param x The x coordinate
+     * @param y The y coordinate
+     * @param z The z coordinate
+     * @return The neighbor index
+     */
+    public static final int getNeighborIndex(int x, int y, int z){
+        return x + y * 3 + z * 3 * 3;
+    }
+
+    /**
+     * Sets the neighbor of this chunk
+     * @param x The x coordinate
+     * @param y The y coordinate
+     * @param z The z coordinate
+     * @param neighbor The neighbor ServerFluidChunk
+     */
+    public void setNeighbor(int x, int y, int z, ServerFluidChunk neighbor){
+        if(neighbor == null){
+            bWeights[getNeighborIndex(x,y,z)] = null;
+            b0Weights[getNeighborIndex(x,y,z)] = null;
+            bVelocityX[getNeighborIndex(x,y,z)] = null;
+            bVelocityY[getNeighborIndex(x,y,z)] = null;
+            bVelocityZ[getNeighborIndex(x,y,z)] = null;
+            b0VelocityX[getNeighborIndex(x,y,z)] = null;
+            b0VelocityY[getNeighborIndex(x,y,z)] = null;
+            b0VelocityZ[getNeighborIndex(x,y,z)] = null;
+        } else {
+            bWeights[getNeighborIndex(x,y,z)] = neighbor.bWeights[CENTER_BUFF];
+            b0Weights[getNeighborIndex(x,y,z)] = neighbor.b0Weights[CENTER_BUFF];
+            bVelocityX[getNeighborIndex(x,y,z)] = neighbor.bVelocityX[CENTER_BUFF];
+            bVelocityY[getNeighborIndex(x,y,z)] = neighbor.bVelocityY[CENTER_BUFF];
+            bVelocityZ[getNeighborIndex(x,y,z)] = neighbor.bVelocityZ[CENTER_BUFF];
+            b0VelocityX[getNeighborIndex(x,y,z)] = neighbor.b0VelocityX[CENTER_BUFF];
+            b0VelocityY[getNeighborIndex(x,y,z)] = neighbor.b0VelocityY[CENTER_BUFF];
+            b0VelocityZ[getNeighborIndex(x,y,z)] = neighbor.b0VelocityZ[CENTER_BUFF];
+        }
+    }
+
 }
diff --git a/src/main/java/electrosphere/server/fluid/manager/ServerFluidManager.java b/src/main/java/electrosphere/server/fluid/manager/ServerFluidManager.java
index 78de3e9c..236a3548 100644
--- a/src/main/java/electrosphere/server/fluid/manager/ServerFluidManager.java
+++ b/src/main/java/electrosphere/server/fluid/manager/ServerFluidManager.java
@@ -222,7 +222,7 @@ public class ServerFluidManager {
             }
             //generate if it does not exist
             if(returnedChunk == null){
-                returnedChunk = chunkGenerator.generateChunk(worldX, worldY, worldZ);
+                returnedChunk = this.generateChunk(worldX, worldY, worldZ);
             }
             chunkCache.put(key, returnedChunk);
             chunkCacheContents.add(key);
@@ -307,6 +307,53 @@ public class ServerFluidManager {
         Globals.profiler.endCpuSample();
     }
 
+    /**
+     * Generates a fluid chunk
+     * @param worldX The world x position
+     * @param worldY The world y position
+     * @param worldZ The world z position
+     * @return The fluid chunk
+     */
+    private ServerFluidChunk generateChunk(int worldX, int worldY, int worldZ){
+        lock.lock();
+        ServerFluidChunk rVal = chunkGenerator.generateChunk(worldX, worldY, worldZ);
+        this.linkNeighbors(rVal, worldX, worldY, worldZ);
+        lock.unlock();
+        return rVal;
+    }
+
+    /**
+     * Links the world position to all its neighboring fluid chunks
+     * @param current The chunk to link
+     * @param worldX The world x position
+     * @param worldY The world y position
+     * @param worldZ The world z position
+     */
+    private void linkNeighbors(ServerFluidChunk current, int worldX, int worldY, int worldZ){
+        String key = this.getKey(worldX,worldY,worldZ);
+        for(int i = -1; i < 2; i++){
+            for(int j = -1; j < 2; j++){
+                for(int k = -1; k < 2; k++){
+                    if(i == j && j == k && k == 0){
+                        continue;
+                    }
+                    if(
+                        0 <= worldX + i && worldX + i < this.parent.getWorldSizeDiscrete() &&
+                        0 <= worldY + j && worldY + j < this.parent.getWorldSizeDiscrete() &&
+                        0 <= worldZ + k && worldZ + k < this.parent.getWorldSizeDiscrete()
+                    ){
+                        key = this.getKey(worldX + i,worldY +j,worldZ + k);
+                        ServerFluidChunk neighbor = this.chunkCache.get(key);
+                        current.setNeighbor(i+1,j+1,k+1,neighbor);
+                        if(neighbor != null){
+                            neighbor.setNeighbor(1-i,1-j,1-k,current);
+                        }
+                    }
+                }
+            }
+        }
+    }
+
     /**
      * Gets the broadcast queue
      * @return The broadcast queue