bool CustomImplicitSurface2::intersectsLocal(const Ray2D& ray) const {
BoundingBoxRayIntersection2D intersection =
_domain.closestIntersection(ray);
if (intersection.isIntersecting) {
double tStart, tEnd;
if (intersection.tFar == kMaxD) {
tStart = 0.0;
tEnd = intersection.tNear;
} else {
tStart = intersection.tNear;
tEnd = intersection.tFar;
}
double t = tStart;
Vector2D pt = ray.pointAt(t);
double prevPhi = _func(pt);
while (t <= tEnd) {
pt = ray.pointAt(t);
const double newPhi = _func(pt);
const double newPhiAbs = std::fabs(newPhi);
if (newPhi * prevPhi < 0.0) {
return true;
}
t += std::max(newPhiAbs, _rayMarchingResolution);
prevPhi = newPhi;
}
}
return false;
}
SurfaceRayIntersection2 CustomImplicitSurface2::closestIntersectionLocal(
const Ray2D& ray) const {
SurfaceRayIntersection2 result;
BoundingBoxRayIntersection2D intersection =
_domain.closestIntersection(ray);
if (intersection.isIntersecting) {
double tStart, tEnd;
if (intersection.tFar == kMaxD) {
tStart = 0.0;
tEnd = intersection.tNear;
} else {
tStart = intersection.tNear;
tEnd = intersection.tFar;
}
double t = tStart;
Vector2D pt = ray.pointAt(t);
double prevPhi = _func(pt);
while (t <= tEnd) {
pt = ray.pointAt(t);
const double newPhi = _func(pt);
const double newPhiAbs = std::fabs(newPhi);
if (newPhi * prevPhi < 0.0) {
const double frac = prevPhi / (prevPhi - newPhi);
const double tSub = t + _rayMarchingResolution * frac;
result.isIntersecting = true;
result.distance = tSub;
result.point = ray.pointAt(tSub);
result.normal = gradientLocal(result.point);
if (result.normal.length() > 0.0) {
result.normal.normalize();
}
return result;
}
t += std::max(newPhiAbs, _rayMarchingResolution);
prevPhi = newPhi;
}
}
return result;
}
TEST(Ray2, PointAt) {
Ray2D ray;
EXPECT_EQ(Vector2D(4.5, 0.0), ray.pointAt(4.5));
}