fixed attribute views

polymesh @ 2ee20575

-Subproject commit 85dc7a4197ffeca4f4602fbfe735cd83a04d9819
+Subproject commit 2ee20575b944d16d44528653aa4ae158099493c8

tests/attributes/attribute-view-test.cc

+#include <doctest.hh>
+
+#include <polymesh/Mesh.hh>
+
+#include <typed-geometry/tg-lean.hh>
+
+TEST_CASE("attribute views")
+{
+    pm::Mesh m;
+    auto pos = m.vertices().make_attribute<tg::pos3>();
+
+    auto v = m.vertices().add();
+    pos[v] = {1, 2, 3};
+
+    auto pos_v = pos.view([](tg::pos3& p) -> tg::vec3& { return reinterpret_cast<tg::vec3&>(p); });
+
+    static_assert(std::is_same_v<decltype(pos_v[v]), tg::vec3&>);
+
+    CHECK(pos.size() == pos_v.size());
+    CHECK(pos[v] == tg::pos3(1, 2, 3));
+    CHECK(pos_v[v] == tg::vec3(1, 2, 3));
+
+    pos[v] = {2, 3, 4};
+    CHECK(pos[v] == tg::pos3(2, 3, 4));
+    CHECK(pos_v[v] == tg::vec3(2, 3, 4));
+
+    pos_v[v] = {1, 5, 3};
+
+    CHECK(pos[v] == tg::pos3(1, 5, 3));
+    CHECK(pos_v[v] == tg::vec3(1, 5, 3));
+
+    pos_v[v].y = 7;
+
+    CHECK(pos[v] == tg::pos3(1, 7, 3));
+    CHECK(pos_v[v] == tg::vec3(1, 7, 3));
+
+    auto pos_vz = pos_v.map([](tg::vec3& v) -> float& { return v.z; });
+    static_assert(std::is_same_v<decltype(pos_vz[v]), float&>);
+
+    CHECK(pos_vz[v] == 3);
+
+    pos_vz[v] = 9;
+
+    CHECK(pos[v] == tg::pos3(1, 7, 9));
+    CHECK(pos_v[v] == tg::vec3(1, 7, 9));
+}