luboslenco
123 lines
6.1 KiB
Haxe
123 lines
6.1 KiB
Haxe
// An Analytic Model for Full Spectral Sky-Dome Radiance
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// Lukas Hosek and Alexander Wilkie
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// Based on https://github.com/ddiakopoulos/sandbox
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package arm.data;
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import kha.math.FastVector3;
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import iron.data.WorldData;
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class HosekWilkieRadianceData {
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public var hosekA = new FastVector3();
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public var hosekB = new FastVector3();
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public var hosekC = new FastVector3();
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public var hosekD = new FastVector3();
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public var hosekE = new FastVector3();
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public var hosekF = new FastVector3();
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public var hosekG = new FastVector3();
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public var hosekH = new FastVector3();
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public var hosekI = new FastVector3();
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public var hosekZ = new FastVector3();
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function evaluateSpline(spline: Array<Float>, index: Int, stride: Int, value: Float): Float {
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return
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1 * Math.pow(1 - value, 5) * spline[index ] +
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5 * Math.pow(1 - value, 4) * Math.pow(value, 1) * spline[index + 1 * stride] +
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10 * Math.pow(1 - value, 3) * Math.pow(value, 2) * spline[index + 2 * stride] +
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10 * Math.pow(1 - value, 2) * Math.pow(value, 3) * spline[index + 3 * stride] +
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5 * Math.pow(1 - value, 1) * Math.pow(value, 4) * spline[index + 4 * stride] +
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1 * Math.pow(value, 5) * spline[index + 5 * stride];
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}
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function clamp(n: Int, lower: Int, upper: Int): Int {
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return n <= lower ? lower : n >= upper ? upper : n;
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}
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function clampF(n: Float, lower: Float, upper: Float): Float {
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return n <= lower ? lower : n >= upper ? upper : n;
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}
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function evaluate(dataset: Array<Float>, index: Int, stride: Int, turbidity: Float, albedo: Float, sunTheta: Float): Float {
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// Splines are functions of elevation^1/3
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var elevationK = Math.pow(Math.max(0.0, 1.0 - sunTheta / (Math.PI / 2.0)), 1.0 / 3.0);
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// Table has values for turbidity 1..10
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var turbidity0 = clamp(Std.int(turbidity), 1, 10);
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var turbidity1 = Std.int(Math.min(turbidity0 + 1, 10));
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var turbidityK = clampF(turbidity - turbidity0, 0.0, 1.0);
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var datasetA0Index = index;
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var datasetA1Index = index + stride * 6 * 10;
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var a0t0 = evaluateSpline(dataset, datasetA0Index + stride * 6 * (turbidity0 - 1), stride, elevationK);
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var a1t0 = evaluateSpline(dataset, datasetA1Index + stride * 6 * (turbidity0 - 1), stride, elevationK);
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var a0t1 = evaluateSpline(dataset, datasetA0Index + stride * 6 * (turbidity1 - 1), stride, elevationK);
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var a1t1 = evaluateSpline(dataset, datasetA1Index + stride * 6 * (turbidity1 - 1), stride, elevationK);
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return a0t0 * (1 - albedo) * (1 - turbidityK) + a1t0 * albedo * (1 - turbidityK) + a0t1 * (1 - albedo) * turbidityK + a1t1 * albedo * turbidityK;
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}
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function hosekWilkie(cosTheta: Float, gamma: Float, cosGamma: Float, hosekA: FastVector3, hosekB: FastVector3, hosekC: FastVector3, hosekD: FastVector3, hosekE: FastVector3, hosekF: FastVector3, hosekG: FastVector3, hosekH: FastVector3, hosekI: FastVector3): FastVector3 {
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var val = (1.0 + cosGamma * cosGamma);
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var chix = val / Math.pow(1.0 + hosekH.x * hosekH.x - 2.0 * cosGamma * hosekH.x, 1.5);
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var chiy = val / Math.pow(1.0 + hosekH.y * hosekH.y - 2.0 * cosGamma * hosekH.y, 1.5);
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var chiz = val / Math.pow(1.0 + hosekH.z * hosekH.z - 2.0 * cosGamma * hosekH.z, 1.5);
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var chi = new FastVector3(chix, chiy, chiz);
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var vx = (1.0 + hosekA.x * Math.exp(hosekB.x / (cosTheta + 0.01))) * (hosekC.x + hosekD.x * Math.exp(hosekE.x * gamma) + hosekF.x * (cosGamma * cosGamma) + hosekG.x * chi.x + hosekI.x * Math.sqrt(Math.max(0.0, cosTheta)));
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var vy = (1.0 + hosekA.y * Math.exp(hosekB.y / (cosTheta + 0.01))) * (hosekC.y + hosekD.y * Math.exp(hosekE.y * gamma) + hosekF.y * (cosGamma * cosGamma) + hosekG.y * chi.y + hosekI.y * Math.sqrt(Math.max(0.0, cosTheta)));
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var vz = (1.0 + hosekA.z * Math.exp(hosekB.z / (cosTheta + 0.01))) * (hosekC.z + hosekD.z * Math.exp(hosekE.z * gamma) + hosekF.z * (cosGamma * cosGamma) + hosekG.z * chi.z + hosekI.z * Math.sqrt(Math.max(0.0, cosTheta)));
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return new FastVector3(vx, vy, vz);
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}
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function setVector(v: FastVector3, index: Int, f: Float) {
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index == 0 ? v.x = f : index == 1 ? v.y = f : v.z = f;
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}
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public function new() {}
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public function recompute(sunTheta: Float, turbidity: kha.FastFloat, albedo: kha.FastFloat, normalizedSunY: Float) {
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for (i in 0...3) {
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setVector(hosekA, i, evaluate(HosekWilkieData.datasetsRGB[i], 0, 9, turbidity, albedo, sunTheta));
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setVector(hosekB, i, evaluate(HosekWilkieData.datasetsRGB[i], 1, 9, turbidity, albedo, sunTheta));
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setVector(hosekC, i, evaluate(HosekWilkieData.datasetsRGB[i], 2, 9, turbidity, albedo, sunTheta));
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setVector(hosekD, i, evaluate(HosekWilkieData.datasetsRGB[i], 3, 9, turbidity, albedo, sunTheta));
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setVector(hosekE, i, evaluate(HosekWilkieData.datasetsRGB[i], 4, 9, turbidity, albedo, sunTheta));
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setVector(hosekF, i, evaluate(HosekWilkieData.datasetsRGB[i], 5, 9, turbidity, albedo, sunTheta));
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setVector(hosekG, i, evaluate(HosekWilkieData.datasetsRGB[i], 6, 9, turbidity, albedo, sunTheta));
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// Swapped in the dataset
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setVector(hosekH, i, evaluate(HosekWilkieData.datasetsRGB[i], 8, 9, turbidity, albedo, sunTheta));
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setVector(hosekI, i, evaluate(HosekWilkieData.datasetsRGB[i], 7, 9, turbidity, albedo, sunTheta));
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setVector(hosekZ, i, evaluate(HosekWilkieData.datasetsRGBRad[i], 0, 1, turbidity, albedo, sunTheta));
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}
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if (normalizedSunY != 0.0) {
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var hosekS: FastVector3 = hosekWilkie(Math.cos(sunTheta), 0, 1.0, hosekA, hosekB, hosekC, hosekD, hosekE, hosekF, hosekG, hosekH, hosekI);
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hosekS.x *= hosekZ.x;
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hosekS.y *= hosekZ.y;
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hosekS.z *= hosekZ.z;
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var dotS = hosekS.dot(new FastVector3(0.2126, 0.7152, 0.0722));
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hosekZ.x /= dotS;
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hosekZ.y /= dotS;
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hosekZ.z /= dotS;
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hosekZ = hosekZ.mult(normalizedSunY);
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}
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}
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}
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class HosekWilkie {
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public static var data: HosekWilkieRadianceData = null;
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public static function recompute(world: WorldData) {
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if (world == null || world.raw.sun_direction == null) return;
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if (data == null) data = new HosekWilkieRadianceData();
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// Clamp Z for night cycle
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var sunZ = world.raw.sun_direction[2] > 0 ? world.raw.sun_direction[2] : 0;
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var sunPositionX = Math.acos(sunZ);
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var normalizedSunY: kha.FastFloat = 1.15;
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data.recompute(sunPositionX, world.raw.turbidity, world.raw.ground_albedo, normalizedSunY);
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}
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}
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