Somewhat more dangerous neoplasm

core/src/mindustry/content/Liquids.java

@@ -48,9 +48,10 @@ public class Liquids{
             heatCapacity = 0.4f;
             temperature = 0.54f;
             viscosity = 0.85f;
-            flammability = 0.1f;
+            flammability = 0f;
             capPuddles = false;
             hidden = true;
+            spreadTarget = Liquids.water;
 
             colorFrom = Color.valueOf("f98f4a");
             colorTo = Color.valueOf("9e172c");

core/src/mindustry/entities/Puddles.java

@@ -124,7 +124,7 @@ public class Puddles{
             }
             return -0.4f * amount;
         }
-        return 0f;
+        return dest.react(liquid, amount, tile, x, y);
     }
 
     /**

core/src/mindustry/logic/LExecutor.java

@@ -1289,14 +1289,16 @@ public class LExecutor{
                         if(b instanceof OverlayFloor o && tile.overlay() != o) tile.setOverlayNet(o);
                     }
                     case floor -> {
-                        if(b instanceof Floor f && tile.floor() != f) tile.setFloorNet(f);
+                        if(b instanceof Floor f && tile.floor() != f && !f.isOverlay()) tile.setFloorNet(f);
                     }
                     case block -> {
-                        Team t = exec.team(team);
-                        if(t == null) t = Team.derelict;
+                        if(!b.isFloor()){
+                            Team t = exec.team(team);
+                            if(t == null) t = Team.derelict;
 
-                        if(tile.block() != b || tile.team() != t){
-                            tile.setNet(b, t, Mathf.clamp(exec.numi(rotation), 0, 3));
+                            if(tile.block() != b || tile.team() != t){
+                                tile.setNet(b, t, Mathf.clamp(exec.numi(rotation), 0, 3));
+                            }
                         }
                     }
                     //building case not allowed

core/src/mindustry/type/CellLiquid.java

@@ -3,16 +3,23 @@ package mindustry.type;
 import arc.graphics.*;
 import arc.graphics.g2d.*;
 import arc.math.*;
+import arc.math.geom.*;
 import arc.util.*;
+import mindustry.entities.*;
 import mindustry.gen.*;
 import mindustry.graphics.*;
+import mindustry.world.*;
 
 import static mindustry.entities.Puddles.*;
 
+/** Liquid that draws cells in its puddle. */
 public class CellLiquid extends Liquid{
     public Color colorFrom = Color.white.cpy(), colorTo = Color.white.cpy();
     public int cells = 8;
 
+    public @Nullable Liquid spreadTarget;
+    public float maxSpread = 0.5f, spreadConversion = 0.5f, spreadDamage = 0.1f;
+
     public CellLiquid(String name, Color color){
         super(name, color);
     }
@@ -21,11 +28,58 @@ public class CellLiquid extends Liquid{
         super(name);
     }
 
+    @Override
+    public void update(Puddle puddle){
+        if(spreadTarget != null){
+            float scaling = Mathf.pow(Mathf.clamp(puddle.amount / maxLiquid), 2f);
+
+            for(var point : Geometry.d4c){
+                Tile tile = puddle.tile.nearby(point);
+                if(tile != null && tile.build != null && tile.build.liquids != null && tile.build.liquids.get(spreadTarget) > 0){
+                    float amount = Math.min(tile.build.liquids.get(spreadTarget), maxSpread * Time.delta * scaling);
+                    tile.build.liquids.remove(spreadTarget, amount);
+                    Puddles.deposit(tile, this, amount * spreadConversion);
+                }
+            }
+
+            //damage thing it is on
+            if(spreadDamage > 0 && puddle.tile.build != null && puddle.tile.build.liquids != null && puddle.tile.build.liquids.get(spreadTarget) > 0){
+                puddle.tile.build.damage(spreadDamage * Time.delta * scaling);
+            }
+
+            //spread to nearby puddles
+            for(var point : Geometry.d4){
+                Tile tile = puddle.tile.nearby(point);
+                if(tile != null){
+                    var other = Puddles.get(tile);
+                    if(other != null && other.liquid == spreadTarget){
+                        //TODO looks somewhat buggy when outputs are occurring
+                        float amount = Math.min(other.amount, Math.max(maxSpread * Time.delta * scaling, other.amount * 0.25f * scaling));
+                        other.amount -= amount;
+                        puddle.amount += amount;
+                        if(other.amount <= maxLiquid / 3f){
+                            other.remove();
+                            Puddles.deposit(tile, puddle.tile, this, Math.max(amount, maxLiquid / 3f));
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    @Override
+    public float react(Liquid other, float amount, Tile tile, float x, float y){
+        if(other == spreadTarget){
+            return amount;
+        }
+        return 0f;
+    }
+
     @Override
     public void drawPuddle(Puddle puddle){
         super.drawPuddle(puddle);
 
-        Draw.z(Layer.debris - 0.5f);
+        float baseLayer = puddle.tile != null && puddle.tile.build != null ? Layer.blockOver : Layer.debris - 0.5f;
 
         int id = puddle.id;
         float amount = puddle.amount, x = puddle.x, y = puddle.y;
@@ -35,7 +89,7 @@ public class CellLiquid extends Liquid{
 
         rand.setSeed(id);
         for(int i = 0; i < cells; i++){
-            Draw.z(Layer.debris - 0.5f + i/1000f + (id % 100) / 10000f);
+            Draw.z(baseLayer + i/1000f + (id % 100) / 10000f);
             Tmp.v1.trns(rand.random(360f), rand.random(length));
             float vx = x + Tmp.v1.x, vy = y + Tmp.v1.y;
 

core/src/mindustry/type/Liquid.java

@@ -10,6 +10,7 @@ import mindustry.entities.*;
 import mindustry.gen.*;
 import mindustry.graphics.*;
 import mindustry.logic.*;
+import mindustry.world.*;
 import mindustry.world.meta.*;
 
 import static mindustry.entities.Puddles.*;
@@ -145,6 +146,11 @@ public class Liquid extends UnlockableContent implements Senseable{
 
     }
 
+    //TODO proper API for this (do not use yet!)
+    public float react(Liquid other, float amount, Tile tile, float x, float y){
+        return 0f;
+    }
+
     @Override
     public void setStats(){
         stats.addPercent(Stat.explosiveness, explosiveness);