Examples with ConstantSpectralCurve org.sunflow.image.ConstantSpectralCurve used on opensource projects

Example 1 with ConstantSpectralCurve

use of org.sunflow.image.ConstantSpectralCurve in project joons-renderer by joonhyublee.

the class SunSkyLight method initSunSky.

private void initSunSky() {
    // perform all the required initialization of constants
    sunDirWorld.normalize();
    sunDir = basis.untransform(sunDirWorld, new Vector3());
    sunDir.normalize();
    sunTheta = (float) Math.acos(MathUtils.clamp(sunDir.z, -1, 1));
    if (sunDir.z > 0) {
        sunSpectralRadiance = computeAttenuatedSunlight(sunTheta, turbidity);
        // produce color suitable for rendering
        sunColor = RGBSpace.SRGB.convertXYZtoRGB(sunSpectralRadiance.toXYZ().mul(1e-4f)).constrainRGB();
    } else {
        sunSpectralRadiance = new ConstantSpectralCurve(0);
    }
    // sunSolidAngle = (float) (0.25 * Math.PI * 1.39 * 1.39 / (150 * 150));
    float theta2 = sunTheta * sunTheta;
    float theta3 = sunTheta * theta2;
    float T = turbidity;
    float T2 = turbidity * turbidity;
    double chi = (4.0 / 9.0 - T / 120.0) * (Math.PI - 2.0 * sunTheta);
    zenithY = (4.0453 * T - 4.9710) * Math.tan(chi) - 0.2155 * T + 2.4192;
    zenithY *= 1000;
    /* conversion from kcd/m^2 to cd/m^2 */
    zenithx = (0.00165 * theta3 - 0.00374 * theta2 + 0.00208 * sunTheta + 0) * T2 + (-0.02902 * theta3 + 0.06377 * theta2 - 0.03202 * sunTheta + 0.00394) * T + (0.11693 * theta3 - 0.21196 * theta2 + 0.06052 * sunTheta + 0.25885);
    zenithy = (0.00275 * theta3 - 0.00610 * theta2 + 0.00316 * sunTheta + 0) * T2 + (-0.04212 * theta3 + 0.08970 * theta2 - 0.04153 * sunTheta + 0.00515) * T + (0.15346 * theta3 - 0.26756 * theta2 + 0.06669 * sunTheta + 0.26688);
    perezY[0] = 0.17872 * T - 1.46303;
    perezY[1] = -0.35540 * T + 0.42749;
    perezY[2] = -0.02266 * T + 5.32505;
    perezY[3] = 0.12064 * T - 2.57705;
    perezY[4] = -0.06696 * T + 0.37027;
    perezx[0] = -0.01925 * T - 0.25922;
    perezx[1] = -0.06651 * T + 0.00081;
    perezx[2] = -0.00041 * T + 0.21247;
    perezx[3] = -0.06409 * T - 0.89887;
    perezx[4] = -0.00325 * T + 0.04517;
    perezy[0] = -0.01669 * T - 0.26078;
    perezy[1] = -0.09495 * T + 0.00921;
    perezy[2] = -0.00792 * T + 0.21023;
    perezy[3] = -0.04405 * T - 1.65369;
    perezy[4] = -0.01092 * T + 0.05291;
    final int w = 32, h = 32;
    imageHistogram = new float[w][h];
    colHistogram = new float[w];
    float du = 1.0f / w;
    float dv = 1.0f / h;
    for (int x = 0; x < w; x++) {
        for (int y = 0; y < h; y++) {
            float u = (x + 0.5f) * du;
            float v = (y + 0.5f) * dv;
            Color c = getSkyRGB(getDirection(u, v));
            imageHistogram[x][y] = c.getLuminance() * (float) Math.sin(Math.PI * v);
            if (y > 0) {
                imageHistogram[x][y] += imageHistogram[x][y - 1];
            }
        }
        colHistogram[x] = imageHistogram[x][h - 1];
        if (x > 0) {
            colHistogram[x] += colHistogram[x - 1];
        }
        for (int y = 0; y < h; y++) {
            imageHistogram[x][y] /= imageHistogram[x][h - 1];
        }
    }
    for (int x = 0; x < w; x++) {
        colHistogram[x] /= colHistogram[w - 1];
    }
    jacobian = (float) (2 * Math.PI * Math.PI) / (w * h);
}