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geom/aabb: change contract/expand semantics to mirror region

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This commit is contained in:
Danny Robson 2017-08-24 16:54:48 +10:00
parent f77cdabaee
commit 1cea1600d3
2 changed files with 11 additions and 25 deletions
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32
geom/aabb.cpp
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@ -89,27 +89,19 @@ aabb<S,T>
aabb<S,T>::expand (vector<S,T> mag) const noexcept aabb<S,T>::expand (vector<S,T> mag) const noexcept
{ {
CHECK (all (mag >= T{0})); CHECK (all (mag >= T{0}));
CHECK (all (mag < p1 - p0));
return { return { p0 - mag, p1 + mag };
p0 - mag / T{2},
p1 + mag / T{2}
};
} }
//----------------------------------------------------------------------------- //-----------------------------------------------------------------------------
template <size_t S, typename T> template <size_t S, typename T>
aabb<S,T> aabb<S,T>
aabb<S,T>::expand (T t) const noexcept aabb<S,T>::expand (T mag) const noexcept
{ {
CHECK_GE (t, T{0}); CHECK_GE (mag, T{0});
CHECK (all (t < p1 - p0));
return { return { p0 - mag, p1 + mag };
p0 - t / T{2},
p1 + t / T{2}
};
} }
@ -118,13 +110,10 @@ template <size_t S, typename T>
aabb<S,T> aabb<S,T>
aabb<S,T>::contract (util::vector<S,T> mag) const noexcept aabb<S,T>::contract (util::vector<S,T> mag) const noexcept
{ {
CHECK (all (mag > T{0})); CHECK (all (mag >= T{0}));
CHECK (all (mag <= p1 - p0)); CHECK (all (2 * mag <= p1 - p0));
return { return { p0 + mag, p1 - mag };
p0 + mag / T{2},
p1 - mag / T{2}
};
} }
@ -134,12 +123,9 @@ aabb<S,T>
aabb<S,T>::contract (T mag) const noexcept aabb<S,T>::contract (T mag) const noexcept
{ {
CHECK_GE (mag, T{0}); CHECK_GE (mag, T{0});
CHECK (all (mag <= p1 - p0)); CHECK (all (2 * mag <= p1 - p0));
return { return { p0 + mag, p1 - mag };
p0 + mag / T{2},
p1 - mag / T{2}
};
} }

4
test/geom/aabb.cpp
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@ -17,7 +17,7 @@ main (int, char**)
const aabb2f val { { 2, 2 }, { 8, 8 } }; const aabb2f val { { 2, 2 }, { 8, 8 } };
const aabb2f res { { 3, 3 }, { 7, 7 } }; const aabb2f res { { 3, 3 }, { 7, 7 } };
tap.expect_eq (val.contract (2.f), res, "over contraction"); tap.expect_eq (val.contract (1.f), res, "over contraction");
} }
{ {
@ -25,7 +25,7 @@ main (int, char**)
const aabb2f val { { 2, 2 }, { 8, 8 } }; const aabb2f val { { 2, 2 }, { 8, 8 } };
const aabb2f res { { 1, 1 }, { 9, 9 } }; const aabb2f res { { 1, 1 }, { 9, 9 } };
tap.expect_eq (val.expand (2.f), res, "expansion"); tap.expect_eq (val.expand (1.f), res, "expansion");
} }
return tap.status (); return tap.status ();