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-rw-r--r--gfx/gl/instanceVertices.h23
-rw-r--r--test/test-instancing.cpp30
2 files changed, 53 insertions, 0 deletions
diff --git a/gfx/gl/instanceVertices.h b/gfx/gl/instanceVertices.h
index d9d9123..ad1716d 100644
--- a/gfx/gl/instanceVertices.h
+++ b/gfx/gl/instanceVertices.h
@@ -124,6 +124,13 @@ public:
return base::size();
}
+ template<typename Pred>
+ glContainer<T>::iterator
+ partition(Pred pred)
+ {
+ return partition(base::begin(), base::end(), pred);
+ }
+
protected:
friend InstanceProxy;
@@ -152,6 +159,22 @@ protected:
return base::data()[index[pindex]];
}
+ template<typename Pred>
+ glContainer<T>::iterator
+ partition(glContainer<T>::iterator first, glContainer<T>::iterator last, Pred pred)
+ {
+ while (first < last) {
+ first = std::find_if_not(first, last, pred);
+ last = --std::find_if(std::make_reverse_iterator(last), std::make_reverse_iterator(first), pred).base();
+ if (first < last) {
+ std::iter_swap(first, last);
+ std::iter_swap(std::find(index.begin(), index.end(), first - base::begin()),
+ std::find(index.begin(), index.end(), last - base::begin()));
+ }
+ }
+ return first;
+ }
+
// Index into buffer given to nth proxy
std::vector<size_t> index;
// List of free spaces in index
diff --git a/test/test-instancing.cpp b/test/test-instancing.cpp
index c1860a4..37f32c8 100644
--- a/test/test-instancing.cpp
+++ b/test/test-instancing.cpp
@@ -174,4 +174,34 @@ BOOST_DATA_TEST_CASE(shuffle_random, boost::unit_test::data::xrange(0, 10), x)
}
}
+BOOST_AUTO_TEST_CASE(partition_by, *boost::unit_test::timeout(1))
+{
+ std::mt19937 gen(std::random_device {}());
+ std::uniform_int_distribution<int> dist(0, 100000);
+ static constexpr auto N = 1000;
+ reserve(N);
+ std::vector<decltype(acquire(0))> instances;
+ instances.reserve(N);
+ // At least one of each
+ instances.push_back(acquire(1));
+ instances.push_back(acquire(3));
+ while (instances.size() < N) {
+ instances.push_back(acquire(dist(gen)));
+ }
+ const std::vector<int> values(instances.begin(), instances.end());
+ BOOST_REQUIRE_EQUAL(size(), N);
+
+ const auto pred = [](auto x) {
+ return (x % 3) == 0;
+ };
+ auto matchedEnd = partition(pred);
+ // The underlying data is partitioned...
+ BOOST_REQUIRE(std::is_partitioned(mkcspan().cbegin(), mkcspan().cend(), pred));
+ // The external view of the data is unchanged...
+ BOOST_CHECK_EQUAL_COLLECTIONS(values.cbegin(), values.cend(), instances.cbegin(), instances.cend());
+ // The partition point is right...
+ BOOST_CHECK(!pred(*matchedEnd));
+ BOOST_CHECK(pred(*--matchedEnd));
+}
+
BOOST_AUTO_TEST_SUITE_END()