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skybox: two different setup for AM/PN

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minjaesong
2023-08-06 15:50:04 +09:00
parent 52ad8f0c46
commit 30fb57eca3
7 changed files with 115 additions and 64 deletions
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67
src/net/torvald/terrarum/clut/GenerateSkyboxTextureAtlas.kt
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@@ -19,7 +19,7 @@ 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 = Skybox.elevCnt * Skybox.albedoCnt
val texw = Skybox.elevCnt * Skybox.albedoCnt * 2
val TGA_HEADER_SIZE = 18
val bytes = ByteArray(TGA_HEADER_SIZE + texw * texh * 4 + 26)
@@ -44,47 +44,50 @@ fun main() {
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=$turbidity")
for (elev0 in 0 until Skybox.elevCnt) {
val elevationDeg = Skybox.elevationsD[elev0]
val elevationRad = Math.toRadians(elevationDeg)
for (gammaPair in 0..1) {
for (albedo0 in 0 until Skybox.albedoCnt) {
val albedo = Skybox.albedos[albedo0]
println("Albedo=$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: $elevationDeg")
val state = ArHosekSkyModel.arhosek_xyz_skymodelstate_alloc_init(turbidity, albedo, elevationRad.abs())
val state =
ArHosekSkyModel.arhosek_xyz_skymodelstate_alloc_init(turbidity, albedo, elevationRad.abs())
for (yp in 0 until Skybox.gradSize) {
val yi = yp - 3
val xf = -elevationDeg / 90.0
var yf = (yi / 58.0).coerceIn(0.0, 1.0).mapCircle().coerceInSmoothly(0.0, 0.95)
for (yp in 0 until Skybox.gradSize) {
val yi = yp - 3
val xf = -elevationDeg / 90.0
var yf = (yi / 58.0).coerceIn(0.0, 1.0).mapCircle().coerceInSmoothly(0.0, 0.95)
// experiments visualisation: https://www.desmos.com/calculator/5crifaekwa
// experiments visualisation: https://www.desmos.com/calculator/5crifaekwa
// if (elevationDeg < 0) yf *= 1.0 - pow(xf, 0.333)
// if (elevationDeg < 0) yf *= -2.0 * asin(xf - 1.0) / PI
if (elevationDeg < 0) yf *= Skybox.superellipsoidDecay(1.0 / 3.0, xf)
val theta = yf * HALF_PI
// vertical angle, where 0 is zenith, ±90 is ground (which is odd)
if (elevationDeg < 0) yf *= Skybox.superellipsoidDecay(1.0 / 3.0, xf)
val theta = yf * HALF_PI
// vertical angle, where 0 is zenith, ±90 is ground (which is odd)
// println("$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 xyz = CIEXYZ(
ArHosekSkyModel.arhosek_tristim_skymodel_radiance(state, theta, (gammaPair * 2f + 1f) * HALF_PI, 0).toFloat(),
ArHosekSkyModel.arhosek_tristim_skymodel_radiance(state, theta, (gammaPair * 2f + 1f) * HALF_PI, 1).toFloat(),
ArHosekSkyModel.arhosek_tristim_skymodel_radiance(state, theta, (gammaPair * 2f + 1f) * HALF_PI, 2).toFloat()
)
val xyz2 = xyz.scaleToFit(elevationDeg)
val rgb = xyz2.toRGB().toColor()
val colour = rgb.toIntBits().toLittle()
val imgOffX = (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..3) {
bytes[fileOffset + i] = colour[bytesLut[i]]
val imgOffX = albedo0 * Skybox.elevCnt + elev0 + Skybox.elevCnt * Skybox.albedoCnt * gammaPair
val imgOffY = texh - 1 - (Skybox.gradSize * turb0 + yp)
val fileOffset = TGA_HEADER_SIZE + 4 * (imgOffY * texw + imgOffX)
for (i in 0..3) {
bytes[fileOffset + i] = colour[bytesLut[i]]
}
}
}
}