skybox atlas texture generation

src/net/torvald/parametricsky/datasets/DatasetCIEXYZ.kt

@@ -107,13 +107,13 @@ import kotlin.test.assertEquals
 
 object DatasetCIEXYZ {
 
-    val datasetXYZ1 = DatasetOp.readDatasetFromFile("./assets/clut/hosek/datasetXYZ1.bin")
+    val datasetXYZ1 = DatasetOp.readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetXYZ1.bin")
-    val datasetXYZ2 = DatasetOp.readDatasetFromFile("./assets/clut/hosek/datasetXYZ2.bin")
+    val datasetXYZ2 = DatasetOp.readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetXYZ2.bin")
-    val datasetXYZ3 = DatasetOp.readDatasetFromFile("./assets/clut/hosek/datasetXYZ3.bin")
+    val datasetXYZ3 = DatasetOp.readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetXYZ3.bin")
 
-    val datasetXYZRad1 = DatasetOp.readDatasetFromFile("./assets/clut/hosek/datasetXYZRad1.bin")
+    val datasetXYZRad1 = DatasetOp.readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetXYZRad1.bin")
-    val datasetXYZRad2 = DatasetOp.readDatasetFromFile("./assets/clut/hosek/datasetXYZRad2.bin")
+    val datasetXYZRad2 = DatasetOp.readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetXYZRad2.bin")
-    val datasetXYZRad3 = DatasetOp.readDatasetFromFile("./assets/clut/hosek/datasetXYZRad3.bin")
+    val datasetXYZRad3 = DatasetOp.readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetXYZRad3.bin")
 
     init {
         assertEquals(1080, datasetXYZ2.size, "Dataset size mismatch: expected 1080, got ${datasetXYZ2.size}")

src/net/torvald/parametricsky/datasets/DatasetRGB.kt

@@ -107,13 +107,13 @@ import kotlin.test.assertEquals
 
 object DatasetRGB {
 
-    val datasetRGB1 = DatasetOp.readDatasetFromFile("./assets/clut/hosek/datasetRGB1.bin")
+    val datasetRGB1 = DatasetOp.readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRGB1.bin")
-    val datasetRGB2 = DatasetOp.readDatasetFromFile("./assets/clut/hosek/datasetRGB2.bin")
+    val datasetRGB2 = DatasetOp.readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRGB2.bin")
-    val datasetRGB3 = DatasetOp.readDatasetFromFile("./assets/clut/hosek/datasetRGB3.bin")
+    val datasetRGB3 = DatasetOp.readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRGB3.bin")
 
-    val datasetRGBRad1 = DatasetOp.readDatasetFromFile("./assets/clut/hosek/datasetRGBRad1.bin")
+    val datasetRGBRad1 = DatasetOp.readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRGBRad1.bin")
-    val datasetRGBRad2 = DatasetOp.readDatasetFromFile("./assets/clut/hosek/datasetRGBRad2.bin")
+    val datasetRGBRad2 = DatasetOp.readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRGBRad2.bin")
-    val datasetRGBRad3 = DatasetOp.readDatasetFromFile("./assets/clut/hosek/datasetRGBRad3.bin")
+    val datasetRGBRad3 = DatasetOp.readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRGBRad3.bin")
 
     init {
         assertEquals(1080, datasetRGB2.size, "Dataset size mismatch: expected 1080, got ${datasetRGB2.size}")

src/net/torvald/parametricsky/datasets/DatasetSpectral.kt

@@ -108,41 +108,41 @@ import kotlin.test.assertEquals
 
 object DatasetSpectral {
 
-    val dataset320 = readDatasetFromFile("./assets/clut/hosek/dataset320.bin")
+    val dataset320 = readDatasetFromFile("./work_files/skylight/hosek_model_source/dataset320.bin")
-    val dataset360 = readDatasetFromFile("./assets/clut/hosek/dataset360.bin")
+    val dataset360 = readDatasetFromFile("./work_files/skylight/hosek_model_source/dataset360.bin")
-    val dataset400 = readDatasetFromFile("./assets/clut/hosek/dataset400.bin")
+    val dataset400 = readDatasetFromFile("./work_files/skylight/hosek_model_source/dataset400.bin")
-    val dataset440 = readDatasetFromFile("./assets/clut/hosek/dataset440.bin")
+    val dataset440 = readDatasetFromFile("./work_files/skylight/hosek_model_source/dataset440.bin")
-    val dataset480 = readDatasetFromFile("./assets/clut/hosek/dataset480.bin")
+    val dataset480 = readDatasetFromFile("./work_files/skylight/hosek_model_source/dataset480.bin")
-    val dataset520 = readDatasetFromFile("./assets/clut/hosek/dataset520.bin")
+    val dataset520 = readDatasetFromFile("./work_files/skylight/hosek_model_source/dataset520.bin")
-    val dataset560 = readDatasetFromFile("./assets/clut/hosek/dataset560.bin")
+    val dataset560 = readDatasetFromFile("./work_files/skylight/hosek_model_source/dataset560.bin")
-    val dataset600 = readDatasetFromFile("./assets/clut/hosek/dataset600.bin")
+    val dataset600 = readDatasetFromFile("./work_files/skylight/hosek_model_source/dataset600.bin")
-    val dataset640 = readDatasetFromFile("./assets/clut/hosek/dataset640.bin")
+    val dataset640 = readDatasetFromFile("./work_files/skylight/hosek_model_source/dataset640.bin")
-    val dataset680 = readDatasetFromFile("./assets/clut/hosek/dataset680.bin")
+    val dataset680 = readDatasetFromFile("./work_files/skylight/hosek_model_source/dataset680.bin")
-    val dataset720 = readDatasetFromFile("./assets/clut/hosek/dataset720.bin")
+    val dataset720 = readDatasetFromFile("./work_files/skylight/hosek_model_source/dataset720.bin")
 
-    val datasetRad320 = readDatasetFromFile("./assets/clut/hosek/datasetRad320.bin")
+    val datasetRad320 = readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRad320.bin")
-    val datasetRad360 = readDatasetFromFile("./assets/clut/hosek/datasetRad360.bin")
+    val datasetRad360 = readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRad360.bin")
-    val datasetRad400 = readDatasetFromFile("./assets/clut/hosek/datasetRad400.bin")
+    val datasetRad400 = readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRad400.bin")
-    val datasetRad440 = readDatasetFromFile("./assets/clut/hosek/datasetRad440.bin")
+    val datasetRad440 = readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRad440.bin")
-    val datasetRad480 = readDatasetFromFile("./assets/clut/hosek/datasetRad480.bin")
+    val datasetRad480 = readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRad480.bin")
-    val datasetRad520 = readDatasetFromFile("./assets/clut/hosek/datasetRad520.bin")
+    val datasetRad520 = readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRad520.bin")
-    val datasetRad560 = readDatasetFromFile("./assets/clut/hosek/datasetRad560.bin")
+    val datasetRad560 = readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRad560.bin")
-    val datasetRad600 = readDatasetFromFile("./assets/clut/hosek/datasetRad600.bin")
+    val datasetRad600 = readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRad600.bin")
-    val datasetRad640 = readDatasetFromFile("./assets/clut/hosek/datasetRad640.bin")
+    val datasetRad640 = readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRad640.bin")
-    val datasetRad680 = readDatasetFromFile("./assets/clut/hosek/datasetRad680.bin")
+    val datasetRad680 = readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRad680.bin")
-    val datasetRad720 = readDatasetFromFile("./assets/clut/hosek/datasetRad720.bin")
+    val datasetRad720 = readDatasetFromFile("./work_files/skylight/hosek_model_source/datasetRad720.bin")
 
-    val solarDataset320 = readDatasetFromFile("./assets/clut/hosek/solarDataset320.bin")
+    val solarDataset320 = readDatasetFromFile("./work_files/skylight/hosek_model_source/solarDataset320.bin")
-    val solarDataset360 = readDatasetFromFile("./assets/clut/hosek/solarDataset360.bin")
+    val solarDataset360 = readDatasetFromFile("./work_files/skylight/hosek_model_source/solarDataset360.bin")
-    val solarDataset400 = readDatasetFromFile("./assets/clut/hosek/solarDataset400.bin")
+    val solarDataset400 = readDatasetFromFile("./work_files/skylight/hosek_model_source/solarDataset400.bin")
-    val solarDataset440 = readDatasetFromFile("./assets/clut/hosek/solarDataset440.bin")
+    val solarDataset440 = readDatasetFromFile("./work_files/skylight/hosek_model_source/solarDataset440.bin")
-    val solarDataset480 = readDatasetFromFile("./assets/clut/hosek/solarDataset480.bin")
+    val solarDataset480 = readDatasetFromFile("./work_files/skylight/hosek_model_source/solarDataset480.bin")
-    val solarDataset520 = readDatasetFromFile("./assets/clut/hosek/solarDataset520.bin")
+    val solarDataset520 = readDatasetFromFile("./work_files/skylight/hosek_model_source/solarDataset520.bin")
-    val solarDataset560 = readDatasetFromFile("./assets/clut/hosek/solarDataset560.bin")
+    val solarDataset560 = readDatasetFromFile("./work_files/skylight/hosek_model_source/solarDataset560.bin")
-    val solarDataset600 = readDatasetFromFile("./assets/clut/hosek/solarDataset600.bin")
+    val solarDataset600 = readDatasetFromFile("./work_files/skylight/hosek_model_source/solarDataset600.bin")
-    val solarDataset640 = readDatasetFromFile("./assets/clut/hosek/solarDataset640.bin")
+    val solarDataset640 = readDatasetFromFile("./work_files/skylight/hosek_model_source/solarDataset640.bin")
-    val solarDataset680 = readDatasetFromFile("./assets/clut/hosek/solarDataset680.bin")
+    val solarDataset680 = readDatasetFromFile("./work_files/skylight/hosek_model_source/solarDataset680.bin")
-    val solarDataset720 = readDatasetFromFile("./assets/clut/hosek/solarDataset720.bin")
+    val solarDataset720 = readDatasetFromFile("./work_files/skylight/hosek_model_source/solarDataset720.bin")
 
     init {
         assertEquals(1080, dataset600.size, "Dataset size mismatch - expected 1080, got ${dataset600.size}")

src/net/torvald/terrarum/modulebasegame/TitleScreen.kt

@@ -241,7 +241,8 @@ class TitleScreen(batch: FlippingSpriteBatch) : IngameInstance(batch) {
         uiContainer.add(uiRemoCon)
 
         CommandDict // invoke
-        Skybox // invoke
+        Skybox.loadlut() // invoke
+//        Skybox.initiate() // invoke the lengthy calculation
         // TODO add console here
 
 

src/net/torvald/terrarum/modulebasegame/clut/GenerateSkyboxTextureAtlas.kt

@@ -0,0 +1,102 @@
+package net.torvald.terrarum.modulebasegame.clut
+
+import net.torvald.colourutil.CIEXYZ
+import net.torvald.colourutil.toColor
+import net.torvald.colourutil.toRGB
+import net.torvald.parametricsky.ArHosekSkyModel
+import net.torvald.terrarum.abs
+import net.torvald.terrarum.modulebasegame.clut.Skybox.coerceInSmoothly
+import net.torvald.terrarum.modulebasegame.clut.Skybox.mapCircle
+import net.torvald.terrarum.modulebasegame.clut.Skybox.scaleToFit
+import net.torvald.terrarum.modulebasegame.worldgenerator.HALF_PI
+import net.torvald.terrarum.serialise.toLittle
+import java.io.File
+import kotlin.math.PI
+import kotlin.math.pow
+import kotlin.math.roundToInt
+
+/**
+ * Created by minjaesong on 2023-08-01.
+ */
+fun main() {
+    // y: increasing turbidity (1.0 .. 10.0, in steps of 0.333)
+    // x: elevations (-75 .. 75 in steps of 1, then albedo of [0.1, 0.3, 0.5, 0.7, 0.9])
+    val texh = Skybox.gradSize * Skybox.turbCnt
+    val texw = 2 * Skybox.elevCnt * 5
+    val TGA_HEADER_SIZE = 18
+
+    val bytes = ByteArray(TGA_HEADER_SIZE + texw * texh * 4 + 26)
+    // write header
+    byteArrayOf(
+        0, // ID field
+        0, // colour map (none)
+        2, // colour type (unmapped RGB)
+        0,0,0,0,0, // colour map spec (empty)
+        0,0, // x origin (0)
+        0,0, // y origin (0)
+        (texw and 255).toByte(),(texw.ushr(8) and 255).toByte(), // width
+        (texh and 255).toByte(),(texh.ushr(8) and 255).toByte(), // height
+        32, // bits-per-pixel (8bpp RGBA)
+        8 // image descriptor
+    ).forEachIndexed { i,b -> bytes[i] = b }
+    // write footer
+    "\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000TRUEVISION-XFILE\u002E\u0000".forEachIndexed { i, c -> bytes[18 + texw * texh * 4 + i] =
+        c.code.toByte()
+    }
+
+    println("Generating texture atlas ($texw x $texh)...")
+
+    // write pixels
+    for (albedo0 in 0 until Skybox.albedoCnt) {
+        val albedo = Skybox.albedos[albedo0]
+        println("Albedo=$albedo")
+        for (turb0 in 0 until Skybox.turbCnt) {
+            val turbidity = Skybox.turbiditiesD[turb0]
+            println("....... Turbidity=$turbidity")
+            for (elev0 in 0 until Skybox.elevCnt) {
+                val elevationDeg = Skybox.elevationsD[elev0]
+                val elevationRad = Math.toRadians(elevationDeg)
+//                println("... Elevation: $elevationDeg")
+
+                val state = ArHosekSkyModel.arhosek_xyz_skymodelstate_alloc_init(turbidity, albedo, elevationRad.abs())
+
+                for (yp in 0 until Skybox.gradSize) {
+                    val yi = yp - 3
+                    val xf = -elevationDeg / 90.0
+                    var yf = (yi / 58.0).coerceIn(0.0, 1.0).mapCircle().coerceInSmoothly(0.0, 0.95)
+
+                    // experiments visualisation: https://www.desmos.com/calculator/5crifaekwa
+//                    if (elevationDeg < 0) yf *= 1.0 - pow(xf, 0.333)
+//                    if (elevationDeg < 0) yf *= -2.0 * asin(xf - 1.0) / PI
+                    if (elevationDeg < 0) yf *= Skybox.superellipsoidDecay(1.0 / 3.0, xf)
+                    val theta = yf * HALF_PI
+                    // vertical angle, where 0 is zenith, ±90 is ground (which is odd)
+
+//                    println("$yp\t$theta")
+
+                    val xyz = CIEXYZ(
+                        ArHosekSkyModel.arhosek_tristim_skymodel_radiance(state, theta, HALF_PI, 0).toFloat(),
+                        ArHosekSkyModel.arhosek_tristim_skymodel_radiance(state, theta, HALF_PI, 1).toFloat(),
+                        ArHosekSkyModel.arhosek_tristim_skymodel_radiance(state, theta, HALF_PI, 2).toFloat()
+                    )
+                    val xyz2 = xyz.scaleToFit(elevationDeg)
+                    val rgb = xyz2.toRGB().toColor()
+                    val colour = rgb.toIntBits().toLittle()
+
+                    val imgOffX = 2 * (albedo0 * Skybox.elevCnt + elev0)
+                    val imgOffY = texh - 1 - (Skybox.gradSize * turb0 + yp)
+                    val fileOffset = TGA_HEADER_SIZE + 4 * (imgOffY * texw + imgOffX)
+                    for (i in 0..7) {
+                        bytes[fileOffset + i] = colour[bytesLut[i]]
+                    }
+                }
+            }
+        }
+    }
+
+    println("Atlas generation done!")
+
+    File("./assets/mods/basegame/weathers/main_skybox.tga").writeBytes(bytes)
+}
+
+private val bytesLut = arrayOf(2,1,0,3,2,1,0,3) // For some reason BGRA order is what makes it work

src/net/torvald/terrarum/modulebasegame/clut/Skybox.kt

@@ -2,6 +2,7 @@ package net.torvald.terrarum.modulebasegame.clut
 
 import com.badlogic.gdx.graphics.Pixmap
 import com.badlogic.gdx.graphics.Texture
+import com.badlogic.gdx.graphics.g2d.TextureRegion
 import com.badlogic.gdx.utils.Disposable
 import com.jme3.math.FastMath
 import net.torvald.colourutil.CIEXYZ
@@ -10,8 +11,10 @@ import net.torvald.colourutil.toRGB
 import net.torvald.parametricsky.ArHosekSkyModel
 import net.torvald.terrarum.App
 import net.torvald.terrarum.App.printdbg
+import net.torvald.terrarum.ModMgr
 import net.torvald.terrarum.abs
 import net.torvald.terrarum.modulebasegame.worldgenerator.HALF_PI
+import net.torvald.terrarumsansbitmap.gdx.TextureRegionPack
 import kotlin.math.*
 
 /**
@@ -21,29 +24,39 @@ object Skybox : Disposable {
 
     const val gradSize = 64
 
-    private val gradTexBinLowAlbedo: Array<Texture>
+    private lateinit var gradTexBinLowAlbedo: Array<TextureRegion>
-    private val gradTexBinHighAlbedo: Array<Texture>
+    private lateinit var gradTexBinHighAlbedo: Array<TextureRegion>
 
-    operator fun get(elevationDeg: Double, turbidity: Double, highAlbedo: Boolean = false): Texture {
+    private lateinit var tex: Texture
-//        if (elevationDeg !in elevationsD) {
+    private lateinit var texRegions: TextureRegionPack
-//            throw IllegalArgumentException("Elevation not in ±75° (got $elevationDeg)")
-//        }
-//        if (turbidity !in turbiditiesD) {
-//            throw IllegalArgumentException("Turbidity not in 1..10 (got $turbidity)")
-//        }
 
-        val elev = elevationDeg.coerceIn(elevationsD).toInt() - elevations.first
+    fun loadlut() {
-        val turb = ((turbidity.coerceIn(turbiditiesD) - turbiditiesD.start) / (turbidities.step / 10.0)).toInt()
+        tex = Texture(ModMgr.getGdxFile("basegame", "weathers/main_skybox.png"))
+        tex.setFilter(Texture.TextureFilter.Linear, Texture.TextureFilter.Linear)
+        texRegions = TextureRegionPack(tex, 2, gradSize - 2, 0, 2, 0, 1)
+    }
 
-//        printdbg(this, "$elevationDeg $turbidity ; $elev $turb")
+    // use internal LUT
+    /*operator fun get(elevationDeg: Double, turbidity: Double, albedo: Double): TextureRegion {
+        val elev = elevationDeg.coerceIn(-75.0, 75.0).times(2.0).roundToInt().plus(150)
+        val turb = turbidity.coerceIn(1.0, 10.0).minus(1.0).times(3.0).roundToInt()
+        val alb = albedo.coerceIn(0.1, 0.9).minus(0.1).times(5.0).roundToInt()
+        return gradTexBinLowAlbedo[elev * turbCnt + turb]
+    }*/
 
-        return (if (highAlbedo) gradTexBinHighAlbedo else gradTexBinLowAlbedo)[elev * turbCnt + turb]
+    // use external LUT
+    operator fun get(elevationDeg: Double, turbidity: Double, albedo: Double): TextureRegion {
+        val elev = elevationDeg.coerceIn(-75.0, 75.0).roundToInt().plus(75)
+        val turb = turbidity.coerceIn(1.0, 10.0).minus(1.0).times(3.0).roundToInt()
+        val alb = albedo.coerceIn(0.1, 0.9).minus(0.1).times(5.0).roundToInt()
+        //printdbg(this, "elev $elevationDeg->$elev; turb $turbidity->$turb; alb $albedo->$alb")
+        return texRegions.get(alb * elevCnt + elev, turb)
     }
 
     private fun Float.scaleFun() =
         (1f - 1f / 2f.pow(this/6f)) * 0.97f
 
-    private fun CIEXYZ.scaleToFit(elevationDeg: Double): CIEXYZ {
+    internal fun CIEXYZ.scaleToFit(elevationDeg: Double): CIEXYZ {
         return if (elevationDeg >= 0) {
             CIEXYZ(
                 this.X.scaleFun(),
@@ -67,20 +80,21 @@ object Skybox : Disposable {
         }
     }
 
-    private val elevations = (-75..75) //zw 151
+    val elevations = (0..150) //
-    private val elevationsD = (elevations.first.toDouble() .. elevations.last.toDouble())
+    val elevationsD = elevations.map { -75.0 + it } // -75, -74, -73, ..., 74, 75 // (specifically using whole number of angles because angle units any finer than 1.0 would make "hack" sunsut happen too fast)
-    private val turbidityStep = 5
+    val turbidities = (0..27) // 1, 1.333, 1.666, 2, 2,333, ... , 10.0
-    private val turbidities = (1_0..10_0 step turbidityStep) // (100 / turbidityStep) - 1
+    val turbiditiesD = turbidities.map { 1.0 + it / 3.0 }
-    private val turbiditiesD = (turbidities.first / 10.0..turbidities.last / 10.0)
+    val albedos = arrayOf(0.1, 0.3, 0.5, 0.7, 0.9)
-    private val elevCnt = elevations.count()
+    val elevCnt = elevations.count()
-    private val turbCnt = turbidities.count()
+    val turbCnt = turbidities.count()
-    private val albedoLow = 0.1
+    val albedoCnt = albedos.size
-    private val albedoHight = 0.8 // for theoretical "winter wonderland"?
+    val albedoLow = 0.1
-    private val gamma = HALF_PI
+    val albedoHight = 0.8 // for theoretical "winter wonderland"?
+    val gamma = HALF_PI
 
-    private fun Double.mapCircle() = sin(HALF_PI * this)
+    internal fun Double.mapCircle() = sin(HALF_PI * this)
 
-    init {
+    internal fun initiate() {
         printdbg(this, "Initialising skybox model")
 
         gradTexBinLowAlbedo = getTexturmaps(albedoLow)
@@ -97,7 +111,7 @@ object Skybox : Disposable {
      * @param q polynomial degree. 2+. Larger value means sharper transition around the point p
      * @param x the 'x' value of the function, as in `y=f(x)`. 0.0..1.0
      */
-    private fun polynomialDecay(p: Double, q: Int, x: Double): Double {
+    internal fun polynomialDecay(p: Double, q: Int, x: Double): Double {
         val sign = if (q % 2 == 1) -1 else 1
         val a1 = -1.0 / p
         val a2 = 1.0 / (1.0 - p)
@@ -108,7 +122,7 @@ object Skybox : Disposable {
             sign * a2.pow(q - 1.0) * (x - 1.0).pow(q)
     }
 
-    private fun polynomialDecay2(p: Double, q: Int, x: Double): Double {
+    internal fun polynomialDecay2(p: Double, q: Int, x: Double): Double {
         val sign = if (q % 2 == 1) 1 else -1
         val a1 = -1.0 / p
         val a2 = 1.0 / (1.0 - p)
@@ -119,11 +133,11 @@ object Skybox : Disposable {
             sign * a2.pow(q - 1.0) * (x - 1.0).pow(q) + 1.0
     }
 
-    private fun superellipsoidDecay(p: Double, x: Double): Double {
+    internal fun superellipsoidDecay(p: Double, x: Double): Double {
         return 1.0 - (1.0 - (1.0 - x).pow(1.0 / p)).pow(p)
     }
 
-    private fun Double.coerceInSmoothly(low: Double, high: Double): Double {
+    internal fun Double.coerceInSmoothly(low: Double, high: Double): Double {
         val x = this.coerceIn(low, high)
         val x2 = ((x - low) * (high - low).pow(-1.0))
 //        return FastMath.interpolateLinear(polynomialDecay2(0.5, 2, x2), low, high)
@@ -133,25 +147,26 @@ object Skybox : Disposable {
     /**
      * To get the idea what the fuck is going on here, please refer to https://www.desmos.com/calculator/snqglcu2wl
      */
-    private fun smoothLinear(p: Double, x0: Double): Double {
+    internal fun smoothLinear(p: Double, x0: Double): Double {
         val x = x0 - 0.5
-        val t = 0.5 * sqrt(1.0 - 2.0 * p)
+        val p1 = sqrt(1.0 - 2.0 * p)
+        val t = 0.5 * p1
         val y0 = if (x < -t)
             (1.0 / p) * (x + 0.5).pow(2) - 0.5
         else if (x > t)
             -(1.0 / p) * (x - 0.5).pow(2) + 0.5
         else
-            x * 2.0 / (1.0 + sqrt(1.0 - 2.0 * p))
+            x * 2.0 / (1.0 + p1)
 
         return y0 + 0.5
     }
 
-    private fun getTexturmaps(albedo: Double): Array<Texture> {
+    private fun getTexturmaps(albedo: Double): Array<TextureRegion> {
         return Array(elevCnt * turbCnt) {
 
-            val elevationDeg = (it / turbCnt).plus(elevations.first).toDouble()
+            val elevationDeg = elevationsD[it / turbCnt]
             val elevationRad = Math.toRadians(elevationDeg)
-            val turbidity = 1.0 + (it % turbCnt) / (10.0 / turbidityStep)
+            val turbidity = turbiditiesD[it % turbCnt]
 
             val state = ArHosekSkyModel.arhosek_xyz_skymodelstate_alloc_init(turbidity, albedo, elevationRad.abs())
             val pixmap = Pixmap(1, gradSize, Pixmap.Format.RGBA8888)
@@ -161,15 +176,17 @@ object Skybox : Disposable {
             for (yp in 0 until gradSize) {
                 val yi = yp - 3
                 val xf = -elevationDeg / 90.0
-                var yf = (yi / 58.0).coerceInSmoothly(0.0, 0.95)
+                var yf = (yi / 58.0).coerceIn(0.0, 1.0).mapCircle().coerceInSmoothly(0.0, 0.95)
 
                 // experiments visualisation: https://www.desmos.com/calculator/5crifaekwa
 //                if (elevationDeg < 0) yf *= 1.0 - pow(xf, 0.333)
 //                if (elevationDeg < 0) yf *= -2.0 * asin(xf - 1.0) / PI
                 if (elevationDeg < 0) yf *= superellipsoidDecay(1.0 / 3.0, xf)
-                val theta = (yf.mapCircle() * HALF_PI)
+                val theta = yf * HALF_PI
                 // vertical angle, where 0 is zenith, ±90 is ground (which is odd)
 
+//                println("$yp\t$theta")
+
                 val xyz = CIEXYZ(
                     ArHosekSkyModel.arhosek_tristim_skymodel_radiance(state, theta, gamma, 0).toFloat(),
                     ArHosekSkyModel.arhosek_tristim_skymodel_radiance(state, theta, gamma, 1).toFloat(),
@@ -187,12 +204,13 @@ object Skybox : Disposable {
                 it.setFilter(Texture.TextureFilter.Linear, Texture.TextureFilter.Linear)
             }
             pixmap.dispose()
-            texture
+            TextureRegion(texture)
         }
     }
 
     override fun dispose() {
-        gradTexBinLowAlbedo.forEach { it.dispose() }
+        if (::gradTexBinLowAlbedo.isInitialized) gradTexBinLowAlbedo.forEach { it.texture.dispose() }
-        gradTexBinHighAlbedo.forEach { it.dispose() }
+        if (::gradTexBinHighAlbedo.isInitialized) gradTexBinHighAlbedo.forEach { it.texture.dispose() }
+        if (::tex.isInitialized) tex.dispose()
     }
 }

src/net/torvald/terrarum/weather/WeatherMixer.kt

@@ -152,7 +152,7 @@ internal object WeatherMixer : RNGConsumer {
     }
 
     var turbidity = 4.0; private set
-    private var gH = (4f/3f) * App.scr.height
+    private var gH = 1.4f * App.scr.height
 //    private var gH = 0.8f * App.scr.height
 
     internal var parallaxPos = 0f; private set
@@ -195,13 +195,17 @@ internal object WeatherMixer : RNGConsumer {
 
         gdxBlendNormalStraightAlpha()
 
-        val degThis = if (timeNow < HALF_DAY) solarElev.floorToDouble() else solarElev.ceilToDouble()
+        val degThis = if (timeNow < HALF_DAY)
+            solarElev.floorToDouble()
+        else
+            solarElev.ceilToDouble()
         val degNext = degThis + if (timeNow < HALF_DAY) 1 else -1 // Skybox.get has internal coerceIn
 
         val thisTurbidity = forceTurbidity ?: turbidity
 
-        val texture1 = Skybox[degThis, thisTurbidity]
+        // TODO trilinear with (deg, turb, alb)
-        val texture2 = Skybox[degNext, thisTurbidity]
+        val texture1 = Skybox[degThis, thisTurbidity, 0.1]
+        val texture2 = Skybox[degNext, thisTurbidity, 0.1]
         val lerpScale = (if (timeNow < HALF_DAY) solarElev - degThis else -(solarElev - degThis)).toFloat()
 
 //        println("degThis=$degThis, degNext=$degNext, lerp=$lerpScale")
@@ -210,10 +214,10 @@ internal object WeatherMixer : RNGConsumer {
         batch.inUse {
             batch.shader = null
             batch.color = Color.WHITE
-            batch.draw(texture1, 0f, gradY, App.scr.wf, gH)
+            batch.draw(texture1, -App.scr.halfwf, gradY, 2f * App.scr.wf, gH)
 
             batch.color = Color(1f, 1f, 1f, lerpScale)
-            batch.draw(texture2, 0f, gradY, App.scr.wf, gH)
+            batch.draw(texture2, -App.scr.halfwf, gradY, 2f * App.scr.wf, gH)
 
             batch.color = Color.WHITE
         }