Files
Terrarum/src/net/torvald/terrarum/clut/GenerateSkyboxTextureAtlas.kt
2025-03-22 19:39:35 +09:00

245 lines
10 KiB
Kotlin

package net.torvald.terrarum.clut
import com.badlogic.gdx.graphics.Color
import net.torvald.colourutil.CIEXYZ
import net.torvald.colourutil.HUSLColorConverter
import net.torvald.colourutil.toColor
import net.torvald.colourutil.toRGB
import net.torvald.gdx.graphics.Cvec
import net.torvald.parametricsky.ArHosekSkyModel
import net.torvald.terrarum.abs
import net.torvald.terrarum.modulebasegame.worldgenerator.HALF_PI
import net.torvald.terrarum.serialise.toLittle
import net.torvald.terrarum.serialise.toUint
import net.torvald.terrarum.weather.SkyboxModelHosek
import net.torvald.terrarum.weather.SkyboxModelHosek.coerceInSmoothly
import net.torvald.terrarum.weather.SkyboxModelHosek.mapCircle
import net.torvald.terrarum.weather.SkyboxModelHosek.scaleToFit
import java.io.File
import kotlin.math.PI
import kotlin.math.cos
import kotlin.math.pow
import kotlin.math.roundToInt
/**
* Created by minjaesong on 2023-08-01.
*/
class GenerateSkyboxTextureAtlas {
fun generateStrip(
gammaPair: Int,
albedo: Double,
turbidity: Double,
elevationDeg: Double,
writefun: (Int, Int, Byte) -> Unit
) {
val elevationRad = Math.toRadians(elevationDeg)
/*val gamma = if (gammaPair == 0) HALF_PI else {
Math.toRadians(180 + 114 + 24 * cos(PI * elevationDeg / 40))
}*/
val gamma = Math.toRadians(115 + 25 * cos(PI * elevationDeg / 40)) + (gammaPair * PI)
// println("... Elevation: $elevationDeg")
val state =
ArHosekSkyModel.arhosek_xyz_skymodelstate_alloc_init(turbidity, albedo, elevationRad.abs())
for (yp in 0 until SkyboxModelHosek.gradSize) {
val yi = yp - 10
val xf = -elevationDeg / 90.0
var yf = (yi / 58.0).coerceIn(0.0, 1.0).mapCircle().coerceInSmoothly(0.0, 0.95)
// experiments visualisation: https://www.desmos.com/calculator/5crifaekwa
// if (elevationDeg < 0) yf *= 1.0 - pow(xf, 0.333)
// if (elevationDeg < 0) yf *= -2.0 * asin(xf - 1.0) / PI
// if (elevationDeg < 0) yf *= Skybox.superellipsoidDecay(1.0 / 3.0, xf)
val theta = yf * HALF_PI
// vertical angle, where 0 is zenith, ±90 is ground (which is odd)
// println("$yp\t$theta")
val xyz = CIEXYZ(
ArHosekSkyModel.arhosek_tristim_skymodel_radiance(state, theta, gamma, 0).toFloat(),
ArHosekSkyModel.arhosek_tristim_skymodel_radiance(state, theta, gamma, 1).toFloat(),
ArHosekSkyModel.arhosek_tristim_skymodel_radiance(state, theta, gamma, 2).toFloat()
)
val xyz2 = xyz.scaleToFit(elevationDeg)
val rgb = xyz2.toRGB().toColor().gamma(1.2f)
val colour = rgb.toIntBits().toLittle()
for (i in 0..3) {
writefun(yp, i, colour[bytesLut[i]])
}
}
}
private fun Color.gamma(gam: Float): Color {
this.r = this.r.pow(gam)
this.g = this.g.pow(gam)
this.b = this.b.pow(gam)
return this
}
// y: increasing turbidity (1.0 .. 10.0, in steps of 0.333)
// x: elevations (-75 .. 75 in steps of 1, then albedo of [0.1, 0.3, 0.5, 0.7, 0.9])
val TGA_HEADER_SIZE = 18
val texh = SkyboxModelHosek.gradSize * SkyboxModelHosek.turbCnt
val texh2 = SkyboxModelHosek.turbCnt
val texw = SkyboxModelHosek.elevCnt * SkyboxModelHosek.albedoCnt * 2
val bytesSize = texw * texh
val bytes2Size = texw * texh2
val bytes = ByteArray(TGA_HEADER_SIZE + bytesSize * 4 + 26)
val bytes2 = ByteArray(TGA_HEADER_SIZE + texw * bytes2Size * 4 + 26)
fun generateMainFile() {
// write header
byteArrayOf(
0, // ID field
0, // colour map (none)
2, // colour type (unmapped RGB)
0, 0, 0, 0, 0, // colour map spec (empty)
0, 0, 0, 0, // unused for modern purposes
(texw and 255).toByte(), (texw.ushr(8) and 255).toByte(), // width
(texh and 255).toByte(), (texh.ushr(8) and 255).toByte(), // height
32, // bits-per-pixel (8bpp RGBA)
8 // image descriptor (32bpp, bottom-left origin)
).forEachIndexed { i, b -> bytes[i] = b }
// write footer
"\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000TRUEVISION-XFILE\u002E\u0000".forEachIndexed { i, c ->
bytes[TGA_HEADER_SIZE + bytesSize * 4 + i] =
c.code.toByte()
}
println("Generating texture atlas ($texw x $texh)...")
// write pixels
for (gammaPair in 0..1) {
for (albedo0 in 0 until SkyboxModelHosek.albedoCnt) {
val albedo = SkyboxModelHosek.albedos[albedo0]
println("Albedo=$albedo")
for (turb0 in 0 until SkyboxModelHosek.turbCnt) {
val turbidity = SkyboxModelHosek.turbiditiesD[turb0]
println("....... Turbidity=$turbidity")
for (elev0 in 0 until SkyboxModelHosek.elevCnt) {
var elevationDeg = SkyboxModelHosek.elevationsD[elev0]
if (elevationDeg == 0.0) elevationDeg = 0.5 // dealing with the edge case
generateStrip(gammaPair, albedo, turbidity, elevationDeg) { yp, i, colour ->
val imgOffX = albedo0 * SkyboxModelHosek.elevCnt + elev0 + SkyboxModelHosek.elevCnt * SkyboxModelHosek.albedoCnt * gammaPair
val imgOffY = texh - 1 - (SkyboxModelHosek.gradSize * turb0 + yp)
val fileOffset = TGA_HEADER_SIZE + 4 * (imgOffY * texw + imgOffX)
bytes[fileOffset + i] = colour
}
}
}
}
}
println("Atlas generation done!")
File("./assets/clut/skybox.tga").writeBytes(bytes)
}
private val gradSizes = listOf(50)
private fun getByte(gammaPair: Int, albedo0: Int, turb0: Int, elev0: Int, yp: Int, channel: Int): Byte {
val imgOffX = albedo0 * SkyboxModelHosek.elevCnt + elev0 + SkyboxModelHosek.elevCnt * SkyboxModelHosek.albedoCnt * gammaPair
val imgOffY = texh - 1 - (SkyboxModelHosek.gradSize * turb0 + yp)
val fileOffset = TGA_HEADER_SIZE + 4 * (imgOffY * texw + imgOffX)
return bytes[fileOffset + channel]
}
fun generateCloudColourmap() {
if (bytes[TGA_HEADER_SIZE].toInt() == 0) throw IllegalStateException("Atlas not generated")
// write header
byteArrayOf(
0, // ID field
0, // colour map (none)
2, // colour type (unmapped RGB)
0, 0, 0, 0, 0, // colour map spec (empty)
0, 0, 0, 0, // unused for modern purposes
(texw and 255).toByte(), (texw.ushr(8) and 255).toByte(), // width
(texh2 and 255).toByte(), (texh2.ushr(8) and 255).toByte(), // height
32, // bits-per-pixel (8bpp RGBA)
8 // image descriptor (32bpp, bottom-left origin)
).forEachIndexed { i, b -> bytes2[i] = b }
// write footer
"\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000TRUEVISION-XFILE\u002E\u0000".forEachIndexed { i, c ->
bytes2[TGA_HEADER_SIZE + bytes2Size * 4 + i] =
c.code.toByte()
}
println("Generating cloud colour atlas ($texw x $texh2)...")
for (gammaPair in 0..1) {
for (albedo0 in 0 until SkyboxModelHosek.albedoCnt) {
val albedo = SkyboxModelHosek.albedos[albedo0]
println("Albedo=$albedo")
for (turb0 in 0 until SkyboxModelHosek.turbCnt) {
val turbidity = SkyboxModelHosek.turbiditiesD[turb0]
println("....... Turbidity=$turbidity")
for (elev0 in 0 until SkyboxModelHosek.elevCnt) {
val avrB = (gradSizes.sumOf { getByte(gammaPair, albedo0, turb0, elev0, it, 0).toUint() }.toDouble() / gradSizes.size).div(255.0).toFloat()
val avrG = (gradSizes.sumOf { getByte(gammaPair, albedo0, turb0, elev0, it, 1).toUint() }.toDouble() / gradSizes.size).div(255.0).toFloat()
val avrR = (gradSizes.sumOf { getByte(gammaPair, albedo0, turb0, elev0, it, 2).toUint() }.toDouble() / gradSizes.size).div(255.0).toFloat()
val avrA = (gradSizes.sumOf { getByte(gammaPair, albedo0, turb0, elev0, it, 3).toUint() }.toDouble() / gradSizes.size).div(255.0).toFloat()
val colour = Cvec(avrR, avrG, avrB, avrA).mul(1.02f).vibrancy(1.1f)
val colourBytes = arrayOf(
colour.b.times(255f).roundToInt().coerceIn(0..255).toByte(),
colour.g.times(255f).roundToInt().coerceIn(0..255).toByte(),
colour.r.times(255f).roundToInt().coerceIn(0..255).toByte(),
colour.a.times(255f).roundToInt().coerceIn(0..255).toByte()
)
val imgOffX = albedo0 * SkyboxModelHosek.elevCnt + elev0 + SkyboxModelHosek.elevCnt * SkyboxModelHosek.albedoCnt * gammaPair
val imgOffY = texh2 - 1 - turb0
val fileOffset = TGA_HEADER_SIZE + 4 * (imgOffY * texw + imgOffX)
for (i in 0..3) {
bytes2[fileOffset + i] = colourBytes[i]
}
}
}
}
}
println("Colourmap generation done!")
File("./assets/clut/skyboxavr.tga").writeBytes(bytes2)
}
fun invoke() {
generateMainFile()
generateCloudColourmap()
}
private fun Double.srgbLinearise(): Double {
return if (this > 0.0031308)
1.055 * this.pow(1 / 2.4) - 0.055
else
this * 12.92
}
private fun Cvec.vibrancy(intensity: Float): Cvec {
val luv = HUSLColorConverter.rgbToHsluv(floatArrayOf(this.r, this.g, this.b))
val sat = luv[1] // 0..100
luv[1] = (sat / 100f).pow(1f / intensity) * 100f
val rgb = HUSLColorConverter.hsluvToRgb(luv)
this.r = rgb[0]
this.g = rgb[1]
this.b = rgb[2]
return this
}
private val bytesLut = arrayOf(2, 1, 0, 3, 2, 1, 0, 3) // For some reason BGRA order is what makes it work
}
fun main() {
GenerateSkyboxTextureAtlas().invoke()
}