diff --git a/.idea/libraries/lib.xml b/.idea/libraries/lib.xml
index 8759a8be1..65eddedc5 100644
--- a/.idea/libraries/lib.xml
+++ b/.idea/libraries/lib.xml
@@ -19,6 +19,7 @@
       <root url="jar://$PROJECT_DIR$/lib/Terrarum_Joise.jar!/" />
       <root url="jar://$PROJECT_DIR$/lib/source/gdx-backend-lwjgl-sources.jar!/" />
       <root url="jar://$PROJECT_DIR$/lib/TerrarumSansBitmap.jar!/" />
+      <root url="jar://$PROJECT_DIR$/lib/kotlin-stdlib-sources.jar!/" />
     </SOURCES>
     <jarDirectory url="file://$PROJECT_DIR$/lib" recursive="false" />
     <jarDirectory url="file://$PROJECT_DIR$/lib/source" recursive="false" type="SOURCES" />
diff --git a/src/net/torvald/terrarum/DefaultConfig.kt b/src/net/torvald/terrarum/DefaultConfig.kt
index c94fb8451..5f3b367b3 100644
--- a/src/net/torvald/terrarum/DefaultConfig.kt
+++ b/src/net/torvald/terrarum/DefaultConfig.kt
@@ -20,7 +20,8 @@ object DefaultConfig {
         jsonObject.addProperty("imtooyoungtodie", false) // no perma-death
         jsonObject.addProperty("language", AppLoader.getSysLang())
         jsonObject.addProperty("notificationshowuptime", 6500)
-        jsonObject.addProperty("multithread", false) // experimental!
+        jsonObject.addProperty("multithread", true) // experimental!
+        jsonObject.addProperty("multithreadedlight", false) // experimental!
 
 
 
diff --git a/src/net/torvald/terrarum/concurrent/ThreadParallel.kt b/src/net/torvald/terrarum/concurrent/ThreadParallel.kt
index 951e407cd..c6bc08c6a 100644
--- a/src/net/torvald/terrarum/concurrent/ThreadParallel.kt
+++ b/src/net/torvald/terrarum/concurrent/ThreadParallel.kt
@@ -6,7 +6,9 @@ import net.torvald.terrarum.Terrarum
  * Created by minjaesong on 2016-05-25.
  */
 object ThreadParallel {
-    private val pool: Array<Thread?> = Array(Terrarum.THREADS, { null })
+    val threads = Terrarum.THREADS // modify this to your taste
+
+    private val pool: Array<Thread?> = Array(threads, { null })
 
     /**
      * Map Runnable object to certain index of the thread pool.
@@ -14,18 +16,21 @@ object ThreadParallel {
      * @param runnable
      * @param prefix Will name each thread like "Foo-1", "Foo-2", etc.
      */
-    fun map(index: Int, runnable: Runnable, prefix: String) {
+    fun map(index: Int, prefix: String, runnable: Runnable) {
         pool[index] = Thread(runnable, "$prefix-$index")
     }
 
-    fun map(index: Int, runFunc: (Int) -> Unit, prefix: String) {
+    /**
+     * @param runFunc A function that takes an int input (the index), and returns nothing
+     */
+    fun map(index: Int, prefix: String, runFunc: (Int) -> Unit) {
         val runnable = object : Runnable {
             override fun run() {
                 runFunc(index)
             }
         }
 
-        map(index, runnable, prefix)
+        map(index, prefix, runnable)
     }
 
     /**
@@ -50,4 +55,81 @@ object ThreadParallel {
         pool.forEach { if (it?.state != Thread.State.TERMINATED) return false }
         return true
     }
+}
+
+object ParallelUtils {
+    fun <T, R> Iterable<T>.parallelMap(transform: (T) -> R): List<R> {
+        val tasks = this.sliceEvenly(ThreadParallel.threads)
+        val destination = Array(ThreadParallel.threads) { ArrayList<R>() }
+        tasks.forEachIndexed { index, list ->
+            ThreadParallel.map(index, "ParallelUtils.parallelMap@${this.javaClass.canonicalName}") {
+                for (item in list)
+                    destination[index].add(transform(item as T))
+            }
+        }
+
+        ThreadParallel.startAllWaitForDie()
+
+        return destination.flatten()
+    }
+
+    /**
+     * Shallow flat of the array
+     */
+    fun <T> Array<out Iterable<T>>.flatten(): List<T> {
+        val al = ArrayList<T>()
+        this.forEach { it.forEach { al.add(it) } }
+        return al
+    }
+
+    /**
+     * Shallow flat of the iterable
+     */
+    fun <T> Iterable<out Iterable<T>>.flatten(): List<T> {
+        val al = ArrayList<T>()
+        this.forEach { it.forEach { al.add(it) } }
+        return al
+    }
+
+    /**
+     * Shallow flat of the array
+     */
+    fun <T> Array<out Array<T>>.flatten(): List<T> {
+        val al = ArrayList<T>()
+        this.forEach { it.forEach { al.add(it) } }
+        return al
+    }
+
+    fun Iterable<*>.sliceEvenly(slices: Int): List<List<*>> = this.toList().sliceEvenly(slices)
+
+    fun List<*>.sliceEvenly(slices: Int): List<List<*>> {
+        return (0 until slices).map {
+            this.subList(
+                    this.size.toFloat().div(slices).times(it).roundInt(),
+                    this.size.toFloat().div(slices).times(it + 1).roundInt()
+            )
+        }
+    }
+
+    fun Array<*>.sliceEvenly(slices: Int): List<Array<*>> {
+        return (0 until slices).map {
+            this.sliceArray(
+                    this.size.toFloat().div(slices).times(it).roundInt() until
+                            this.size.toFloat().div(slices).times(it + 1).roundInt()
+            )
+        }
+    }
+
+    fun IntRange.sliceEvenly(slices: Int): List<IntRange> {
+        if (this.step != 1) throw UnsupportedOperationException("Sorry, step != 1")
+        val size = this.last - this.first + 1f
+
+        return (0 until slices).map {
+            size.div(slices).times(it).roundInt() until
+                    size.div(slices).times(it + 1).roundInt()
+        }
+    }
+
+
+    private inline fun Float.roundInt(): Int = Math.round(this)
 }
\ No newline at end of file
diff --git a/src/net/torvald/terrarum/modulebasegame/Ingame.kt b/src/net/torvald/terrarum/modulebasegame/Ingame.kt
index 40afc4392..9f47a0e27 100644
--- a/src/net/torvald/terrarum/modulebasegame/Ingame.kt
+++ b/src/net/torvald/terrarum/modulebasegame/Ingame.kt
@@ -671,12 +671,11 @@ open class Ingame(batch: SpriteBatch) : IngameInstance(batch) {
             // set up indices
             for (i in 0..Terrarum.THREADS - 1) {
                 ThreadParallel.map(
-                        i,
+                        i, "ActorUpdate",
                         ThreadActorUpdate(
                                 actors.div(Terrarum.THREADS).times(i).roundInt(),
-                                actors.div(Terrarum.THREADS).times(i.plus(1)).roundInt() - 1
-                        ),
-                        "ActorUpdate"
+                                actors.div(Terrarum.THREADS).times(i + 1).roundInt() - 1
+                        )
                 )
             }
 
diff --git a/src/net/torvald/terrarum/modulebasegame/worldgenerator/WorldGenerator.kt b/src/net/torvald/terrarum/modulebasegame/worldgenerator/WorldGenerator.kt
index eea11114c..1b29992ce 100644
--- a/src/net/torvald/terrarum/modulebasegame/worldgenerator/WorldGenerator.kt
+++ b/src/net/torvald/terrarum/modulebasegame/worldgenerator/WorldGenerator.kt
@@ -781,13 +781,12 @@ object WorldGenerator {
             // set up indices
             for (i in 0 until Terrarum.THREADS) {
                 ThreadParallel.map(
-                        i,
+                        i, "SampleJoiseMap",
                         ThreadProcessNoiseLayers(
                                 HEIGHT.toFloat().div(Terrarum.THREADS).times(i).roundInt(),
                                 HEIGHT.toFloat().div(Terrarum.THREADS).times(i.plus(1)).roundInt() - 1,
                                 noiseRecords
-                        ),
-                        "SampleJoiseMap"
+                        )
                 )
             }
 
diff --git a/src/net/torvald/terrarum/worlddrawer/LightmapRendererNew.kt b/src/net/torvald/terrarum/worlddrawer/LightmapRendererNew.kt
index 98ab85190..1b827c47d 100644
--- a/src/net/torvald/terrarum/worlddrawer/LightmapRendererNew.kt
+++ b/src/net/torvald/terrarum/worlddrawer/LightmapRendererNew.kt
@@ -10,14 +10,17 @@ import net.torvald.terrarum.blockproperties.BlockCodex
 import com.jme3.math.FastMath
 import net.torvald.terrarum.AppLoader.printdbg
 import net.torvald.terrarum.Terrarum
+import net.torvald.terrarum.blendNormal
 import net.torvald.terrarum.gameworld.GameWorld
 import net.torvald.terrarum.blockproperties.Block
 import net.torvald.terrarum.gameactors.*
 import net.torvald.terrarum.gameactors.ActorWBMovable
 import net.torvald.terrarum.ceilInt
+import net.torvald.terrarum.concurrent.ThreadParallel
 import net.torvald.terrarum.floorInt
 import net.torvald.terrarum.modulebasegame.IngameRenderer
-import java.util.*
+import net.torvald.terrarum.concurrent.ParallelUtils.sliceEvenly
+import kotlin.collections.ArrayList
 import kotlin.system.measureNanoTime
 
 /**
@@ -148,6 +151,10 @@ object LightmapRenderer {
 
     // TODO in regard of "colour math against integers", take Int
     private fun setLight(x: Int, y: Int, colour: Color) {
+        setLightOf(lightmap, x, y, colour)
+    }
+
+    private fun setLightOf(list: Array<Color>, x: Int, y: Int, colour: Color) {
         if (y - for_y_start + overscan_open in 0 until LIGHTMAP_HEIGHT &&
             x - for_x_start + overscan_open in 0 until LIGHTMAP_WIDTH) {
 
@@ -155,7 +162,7 @@ object LightmapRenderer {
             val xpos = x - for_x_start + overscan_open
 
             //lightmap[ypos][xpos] = colour
-            lightmap[ypos * LIGHTMAP_WIDTH + xpos] = colour
+            list[ypos * LIGHTMAP_WIDTH + xpos] = colour
         }
     }
 
@@ -195,9 +202,9 @@ object LightmapRenderer {
         // Because of inevitable overlaps on the area, it only works with ADDITIVE blend (aka maxblend)
 
 
-        // each usually takes 1-3 miliseconds when not threaded
+        // each usually takes 8 000 000..12 000 000 miliseconds total when not threaded
 
-        if (!Terrarum.getConfigBoolean("multithread")) {
+        if (!Terrarum.getConfigBoolean("multithreadedlight")) {
             // Round 1
             Terrarum.debugTimers["Renderer.Light1"] = measureNanoTime {
                 for (y in for_y_start - overscan_open..for_y_end) {
@@ -233,13 +240,103 @@ object LightmapRenderer {
                     }
                 }
             }
+
+            Terrarum.debugTimers["Renderer.LightSequential"] =
+                    Terrarum.debugTimers["Renderer.Light1"]!! +
+                    Terrarum.debugTimers["Renderer.Light2"]!! +
+                    Terrarum.debugTimers["Renderer.Light3"]!! +
+                    Terrarum.debugTimers["Renderer.Light4"]!!
         }
         else {
-            TODO()
-            //val bufferForPasses = arrayOf(lightmap.)
+            Terrarum.debugTimers["Renderer.LightPre"] = measureNanoTime {
+
+                val bufferForPasses = arrayOf(
+                        lightmap.copyOf(), lightmap.copyOf(), lightmap.copyOf(), lightmap.copyOf()
+                )
+                //val combiningBuffer = Array(lightmap.size) { Color(0) }
+
+                // this is kind of inefficient...
+                val calcTask = ArrayList<ThreadedLightmapUpdateMessage>()
+
+                // Round 1 preload
+                for (y in for_y_start - overscan_open..for_y_end) {
+                    for (x in for_x_start - overscan_open..for_x_end) {
+                        calcTask.add(ThreadedLightmapUpdateMessage(x, y, 1))
+                    }
+                }
+
+                // Round 2 preload
+                for (y in for_y_end + overscan_open downTo for_y_start) {
+                    for (x in for_x_start - overscan_open..for_x_end) {
+                        calcTask.add(ThreadedLightmapUpdateMessage(x, y, 2))
+                    }
+                }
+
+                // Round 3 preload
+                for (y in for_y_end + overscan_open downTo for_y_start) {
+                    for (x in for_x_end + overscan_open downTo for_x_start) {
+                        calcTask.add(ThreadedLightmapUpdateMessage(x, y, 3))
+                    }
+                }
+
+                // Round 4 preload
+                for (y in for_y_start - overscan_open..for_y_end) {
+                    for (x in for_x_end + overscan_open downTo for_x_start) {
+                        calcTask.add(ThreadedLightmapUpdateMessage(x, y, 4))
+                    }
+                }
+
+                val calcTasks = calcTask.sliceEvenly(Terrarum.THREADS)
+                val combineTasks = (0 until lightmap.size).sliceEvenly(Terrarum.THREADS)
+
+
+                // couldn't help but do this nested timer
+
+                Terrarum.debugTimers["Renderer.LightParallel${Terrarum.THREADS}x"] = measureNanoTime {
+                    calcTasks.forEachIndexed { index, list ->
+                        ThreadParallel.map(index, "LightCalculate") { index -> // this index is that index
+                            list.forEach {
+                                val msg = it as ThreadedLightmapUpdateMessage
+
+                                setLightOf(bufferForPasses[it.pass - 1], it.x, it.y, calculate(it.x, it.y, it.pass))
+                                //setLightOf(bufferForPasses[it.pass - 1], it.x, it.y, calculate(it.x, it.y, 1))
+                            }
+                        }
+                    }
+
+                    ThreadParallel.startAllWaitForDie()
+                }
+
+                Terrarum.debugTimers["Runderer.LightPost"] = measureNanoTime {
+                    combineTasks.forEachIndexed { index, intRange ->
+                        ThreadParallel.map(index, "LightCombine") { index -> // this index is that index
+                            for (i in intRange) {
+                                val max1 = bufferForPasses[0][i] maxBlend bufferForPasses[1][i]
+                                val max2 = bufferForPasses[2][i] maxBlend bufferForPasses[3][i]
+                                val max = max1 maxBlend max2
+
+                                lightmap[i] = max
+                            }
+                        }
+                    }
+
+                    ThreadParallel.startAllWaitForDie()
+                }
+            }
+
+
+            // get correct Renderer.LightPre by subtracting some shits
+            Terrarum.debugTimers["Renderer.LightParaTotal"] = Terrarum.debugTimers["Renderer.LightPre"]!!
+            Terrarum.debugTimers["Renderer.LightPre"] =
+                    Terrarum.debugTimers["Renderer.LightPre"]!! -
+                    Terrarum.debugTimers["Renderer.LightParallel${Terrarum.THREADS}x"]!! -
+                    Terrarum.debugTimers["Runderer.LightPost"]!!
+
+            // accuracy may suffer (overheads maybe?) but it doesn't matter (i think...)
         }
     }
 
+    internal data class ThreadedLightmapUpdateMessage(val x: Int, val y: Int, val pass: Int)
 
 
     private fun buildLanternmap() {
@@ -282,9 +379,14 @@ object LightmapRenderer {
     private var thisTileOpacity = Color(0f,0f,0f,0f)
     private var sunLight = Color(0f,0f,0f,0f)
 
-
+    /**
+     * @param pass one-based
+     */
     private fun calculate(x: Int, y: Int, pass: Int): Color = calculate(x, y, pass, false)
 
+    /**
+     * @param pass one-based
+     */
     private fun calculate(x: Int, y: Int, pass: Int, doNotCalculateAmbient: Boolean): Color {
         // O(9n) == O(n) where n is a size of the map
         // TODO devise multithreading on this
@@ -392,9 +494,9 @@ object LightmapRenderer {
         val this_y_end = for_y_end// + overscan_open
 
         // wipe out beforehand. You DO need this
-        lightBuffer.blending = Pixmap.Blending.None // gonna overwrite
+        lightBuffer.blending = Pixmap.Blending.None // gonna overwrite (remove this line causes the world to go bit darker)
         lightBuffer.setColor(colourNull)
-        lightBuffer.fillRectangle(0, 0, lightBuffer.width, lightBuffer.height)
+        lightBuffer.fill()
 
 
         // write to colour buffer
@@ -443,8 +545,6 @@ object LightmapRenderer {
         batch.draw(_lightBufferAsTex, 0f, 0f, _lightBufferAsTex.width * DRAW_TILE_SIZE, _lightBufferAsTex.height * DRAW_TILE_SIZE)
 
 
-
-
     }
 
     fun dispose() {