From cc5edb452b41989ebcd5392a77798ce202e21919 Mon Sep 17 00:00:00 2001
From: unknown <>
Date: Mon, 24 Jul 2023 18:57:30 -0400
Subject: [PATCH] DENSITY TRANSITIONS!

---
 src/main/c/velocitystep.c                 | 32 +++++++++++------------
 src/main/java/electrosphere/FluidSim.java | 16 +++++++++---
 2 files changed, 29 insertions(+), 19 deletions(-)

diff --git a/src/main/c/velocitystep.c b/src/main/c/velocitystep.c
index 0275a69..17e8183 100644
--- a/src/main/c/velocitystep.c
+++ b/src/main/c/velocitystep.c
@@ -612,21 +612,21 @@ JNIEXPORT void JNICALL Java_electrosphere_FluidSim_copyNeighbors
     int DIM = N;
     float * target = GET_ARR(env,neighborArray,CENTER_LOC);
     float * source;
-    // if(ARR_EXISTS(chunk_mask,0,1,1)){
-    //     source = GET_ARR(env,neighborArray,CK(0,1,1));
-    //     for(int x=1; x < DIM-1; x++){
-    //         for(int y = 1; y < DIM-1; y++){
-    //             target[IX(0,x,y)] = source[IX(DIM-2,x,y)];
-    //         }
-    //     }
-    // }
+    if(ARR_EXISTS(chunk_mask,0,1,1)){
+        source = GET_ARR(env,neighborArray,CK(0,1,1));
+        for(int x=1; x < DIM-1; x++){
+            for(int y = 1; y < DIM-1; y++){
+                target[IX(0,x,y)] = source[IX(DIM-2,x,y)];
+            }
+        }
+    }
 
-    // if(ARR_EXISTS(chunk_mask,2,1,1)){
-    //     source = GET_ARR(env,neighborArray,CK(2,1,1));
-    //     for(int x=1; x < DIM-1; x++){
-    //         for(int y = 1; y < DIM-1; y++){
-    //             target[IX(DIM-1,x,y)] = source[IX(1,x,y)];
-    //         }
-    //     }
-    // }
+    if(ARR_EXISTS(chunk_mask,2,1,1)){
+        source = GET_ARR(env,neighborArray,CK(2,1,1));
+        for(int x=1; x < DIM-1; x++){
+            for(int y = 1; y < DIM-1; y++){
+                target[IX(DIM-1,x,y)] = source[IX(1,x,y)];
+            }
+        }
+    }
   }
\ No newline at end of file
diff --git a/src/main/java/electrosphere/FluidSim.java b/src/main/java/electrosphere/FluidSim.java
index af1903b..7925ab0 100644
--- a/src/main/java/electrosphere/FluidSim.java
+++ b/src/main/java/electrosphere/FluidSim.java
@@ -186,7 +186,9 @@ public class FluidSim {
         //
         //Density stage
         addDensity(simArray, timestep);
+        swapAllDensityArrays(simArray, timestep);
         diffuseDensity(simArray, timestep);
+        swapAllDensityArrays(simArray, timestep);
         advectDensity(simArray, timestep);
         // mirrorNeighborDensities(simArray, timestep);
         
@@ -351,6 +353,9 @@ public class FluidSim {
                     simArray[x][y][z].setBoundsToNeighborsWrapper(1, simArray[x][y][z].uVector);
                     simArray[x][y][z].setBoundsToNeighborsWrapper(2, simArray[x][y][z].vVector);
                     simArray[x][y][z].setBoundsToNeighborsWrapper(3, simArray[x][y][z].wVector);
+                    simArray[x][y][z].copyNeighborsWrapper(2, simArray[x][y][z].uAdditionVector);
+                    simArray[x][y][z].copyNeighborsWrapper(2, simArray[x][y][z].vAdditionVector);
+                    simArray[x][y][z].copyNeighborsWrapper(2, simArray[x][y][z].wAdditionVector);
                 }
             }
         }
@@ -442,13 +447,13 @@ public class FluidSim {
                     simArray[x][y][z].addDensityWrapper(timestep);
                     //swap x <=> x0
                     //swap arrays in java side...
-                    simArray[x][y][z].swapDensityArrays();
+                    // simArray[x][y][z].swapDensityArrays();
                 }
             }
         }
     }
 
-    private void swapAllDensityArrays(FluidSim[][][] simArray, float timestep){
+    private static void swapAllDensityArrays(FluidSim[][][] simArray, float timestep){
         for(int x = 0; x < simArray.length; x++){
             for(int y = 0; y < simArray[0].length; y++){
                 for(int z = 0; z < simArray[0][0].length; z++){
@@ -499,7 +504,7 @@ public class FluidSim {
             for(int y = 0; y < simArray[0].length; y++){
                 for(int z = 0; z < simArray[0][0].length; z++){
                     //swap x <=> x0 again
-                    simArray[x][y][z].swapDensityArrays();
+                    // simArray[x][y][z].swapDensityArrays();
                     //advect density
                     simArray[x][y][z].advectDensityWrapper(timestep);
                 }
@@ -874,6 +879,10 @@ public class FluidSim {
         return density[getNeighborIndex(1,1,1)];
     }
 
+    public ByteBuffer getDensityAdditionBuffer(){
+        return densityAddition[getNeighborIndex(1,1,1)];
+    }
+
     public ByteBuffer getUBuffer(){
         return uVector[getNeighborIndex(1,1,1)];
     }
@@ -900,6 +909,7 @@ public class FluidSim {
 
     public void setNeighbor(int x, int y, int z, FluidSim neighbor){
         density[getNeighborIndex(x,y,z)] = neighbor.getDensityBuffer();
+        densityAddition[getNeighborIndex(x,y,z)] = neighbor.getDensityAdditionBuffer();
         uVector[getNeighborIndex(x,y,z)] = neighbor.getUBuffer();
         vVector[getNeighborIndex(x,y,z)] = neighbor.getVBuffer();
         wVector[getNeighborIndex(x,y,z)] = neighbor.getWBuffer();