public void getSamples(ShadingState state)
{
if (lightBounds.contains(state.getPoint()) && state.getPoint().z < maxZ)
{
int n = state.getDiffuseDepth() > 0 ? 1 : samples;
float a = area / n;
for (int i = 0; i < n; i++)
{
// random offset on unit square, we use the infinite version of
// getRandom
// because the light sampling is adaptive
double randX = state.getRandom(i, 0);
double randY = state.getRandom(i, 1);
Point3 p = new Point3();
p.x = (float)(lxmin * (1 - randX) + lxmax * randX);
p.y = (float)(lymin * (1 - randY) + lymax * randY);
p.z = maxZ - 0.001f;
LightSample dest = new LightSample();
// prepare shadow ray to sampled point
dest.setShadowRay(new Ray(state.getPoint(), p));
// check that the direction of the sample is the same as the
// normal
float cosNx = dest.dot(state.getNormal());
if (cosNx <= 0)
{
return;
}
// light source facing point ?
// (need to check with light source's normal)
float cosNy = dest.getShadowRay().dz;
if (cosNy > 0)
{
// compute geometric attenuation and probability scale
// factor
float r = dest.getShadowRay().getMax();
float g = cosNy / (r * r);
float scale = g * a;
// set sample radiance
dest.setRadiance(radiance, radiance);
dest.getDiffuseRadiance().mul(scale);
dest.getSpecularRadiance().mul(scale);
dest.traceShadow(state);
state.addSample(dest);
}
}
}
}