some block light fixes

src/integration-test/kotlin/de/bixilon/minosoft/data/world/chunk/light/GeneralHeightmapTest.kt

@@ -43,5 +43,4 @@ class GeneralHeightmapTest {
         chunk[InChunkPosition(2, 255, 3)] = GlassTest0.state
         assertEquals(chunk.light.heightmap[2, 3], Int.MIN_VALUE)
     }
-
 }

src/integration-test/kotlin/de/bixilon/minosoft/data/world/chunk/light/place/BlockLightPlaceIT.kt

@@ -204,9 +204,8 @@ class BlockLightPlaceIT {
         chunk.assertLight(9, 256, 8, 0xFC)
     }
 
-    @Test(enabled = false) // TODO: update heightmap of neighbours on change
     fun bottomHeightmap() {
-        val world = SessionTestUtil.createSession(4).world
+        val world = SessionTestUtil.createSession(4, light = true).world
         world.fill(BlockPosition(-25, 0, -25), BlockPosition(40, 1, 40), IT.BLOCK_1)
 
         world.assertLight(8, -1, 8, 0x00)
@@ -218,9 +217,8 @@ class BlockLightPlaceIT {
         world.assertLight(+8, -1, -4, 0x00)
     }
 
-    @Test(enabled = false) // TODO: update heightmap of neighbours on change
     fun bottomPropagation() {
-        val world = SessionTestUtil.createSession(4).world
+        val world = SessionTestUtil.createSession(4, light = true).world
         world.fill(BlockPosition(-25, 0, -25), BlockPosition(40, 1, 40), IT.BLOCK_1)
         world[BlockPosition(8, 0, 8)] = TorchTest0.state
 
@@ -228,7 +226,7 @@ class BlockLightPlaceIT {
         world.assertLight(9, -1, 8, 0x0C)
 
         world.assertLight(+20, -1, +8, 0x01)
-        world.assertLight(+8, -1, +8, 0x01)
+        world.assertLight(+8, -1, +20, 0x01)
         world.assertLight(-4, -1, +8, 0x01)
         world.assertLight(+8, -1, -4, 0x01)
     }

src/main/java/de/bixilon/minosoft/data/world/chunk/light/section/SectionLight.kt

@@ -153,7 +153,7 @@ class SectionLight(
         }
 
         val height = section.chunk.light.heightmap[position.xz]
-        if (position.y + section.height * SECTION_HEIGHT_Y >= height) { // TODO: > or >=
+        if (section.height * SECTION_HEIGHT_Y + position.y >= height) {
             level = level.with(sky = 0) // level is set with heightmap, no need to trace anything
         }
 
@@ -180,7 +180,7 @@ class SectionLight(
         event = true
     }
 
-    fun calculate() {
+    private fun calculateBlocks() {
         if (section.blocks.isEmpty) return
         val min = section.blocks.minPosition
         val max = section.blocks.maxPosition
@@ -197,11 +197,15 @@ class SectionLight(
                 }
             }
         }
-        // TODO: Start skylight tracing from heightmap start max per xz
+    }
+
+    fun calculate() {
+        calculateBlocks()
+        // TODO: Start skylight tracing from (top of the world (max neighbour heightmap) to heightmap start) per xz
     }
 
     protected fun getNeighbour(direction: Directions): SectionLight? {
-        return section.chunk.neighbours[direction]?.sections?.get(section.height)?.light
+        return section.chunk.neighbours[direction]?.get(section.height)?.light
     }
 
     private fun propagateVertical() {

src/main/java/de/bixilon/minosoft/data/world/chunk/light/section/border/BottomSectionLight.kt

@@ -39,14 +39,14 @@ class BottomSectionLight(
 
 
         val height = chunk.light.heightmap[position.xz]
-        if (position.y + chunk.minSection * SECTION_HEIGHT_Y >= height) { // TODO: > or >=
+        if ((chunk.minSection - 1) * SECTION_HEIGHT_Y + SECTION_MAX_Y >= height) {
             level = level.with(sky = 0) // level is set with heightmap, no need to trace anything
         }
 
         light[position.xz] = level.raw
-        if (level.block <= 1 && level.sky <= 1) return // can not increase further
+        if (level.block <= 1 && level.sky <= 1) return // can not decrease any further
 
-        val next = current.decrease()
+        val next = level.decrease()
 
         chunk.getOrPut(chunk.minSection)?.light?.trace(position.with(y = SECTION_MAX_Y), next, Directions.UP)
         traceVertical(position, next)
@@ -59,7 +59,7 @@ class BottomSectionLight(
     override fun propagate() {
         super.propagateVertical()
 
-        val section = chunk.sections.first()?.light ?: return
+        val section = chunk[chunk.minSection]?.light ?: return
         for (xz in 0 until SECTION_WIDTH_X * SECTION_WIDTH_Z) {
             val position = InSectionPosition(xz).with(y = 0)
             section.traceFrom(position, Directions.DOWN)

src/main/java/de/bixilon/minosoft/data/world/chunk/light/section/border/TopSectionLight.kt

@@ -36,9 +36,9 @@ class TopSectionLight(
         if (current.block >= level.block) return
 
         light[position.xz] = level.raw
-        if (current.block <= 1) return // can not increase further
+        if (level.block <= 1) return // can not decrease any further
 
-        val next = LightLevel(block = current.block - 1, sky = 0) // remove sky light, its always max
+        val next = LightLevel(block = level.block - 1, sky = 0) // remove sky light, its always max
 
         chunk.getOrPut(chunk.maxSection)?.light?.trace(position.with(y = SECTION_MAX_Y), next, Directions.DOWN)
         traceVertical(position, next)
@@ -48,11 +48,10 @@ class TopSectionLight(
         System.arraycopy(array.array, InSectionPosition(0, 0, 0).index, this.light, 0, SECTION_WIDTH_X * SECTION_WIDTH_Z)
     }
 
-
     override fun propagate() {
         super.propagateVertical()
 
-        val section = chunk.sections.last()?.light ?: return
+        val section = chunk[chunk.maxSection]?.light ?: return
         for (xz in 0 until SECTION_WIDTH_X * SECTION_WIDTH_Z) {
             val position = InSectionPosition(xz).with(y = SECTION_MAX_Y)
             section.traceFrom(position, Directions.UP)

src/main/java/de/bixilon/minosoft/gui/rendering/light/RenderLight.kt

@@ -1,6 +1,6 @@
 /*
  * Minosoft
- * Copyright (C) 2020-2024 Moritz Zwerger
+ * Copyright (C) 2020-2025 Moritz Zwerger
  *
  * This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
  *
@@ -40,7 +40,7 @@ class RenderLight(val context: RenderContext) {
         )
         ) {
             DefaultThreadPool += {
-                session.world.recalculateLight()
+                session.world.recalculateLight(heightmap = true)
                 session.util.sendDebugMessage("Light recalculated and chunk cache cleared!")
             }
         }