pch migration to modules [wip]

utilities/glm_module.cppm

@@ -0,0 +1,71 @@
+/*
+This Source Code Form is subject to the
+terms of the Mozilla Public License, v.
+2.0. If a copy of the MPL was not
+distributed with this file, You can
+obtain one at
+http://mozilla.org/MPL/2.0/.
+*/
+
+module;
+
+// Everything glm reaches for from the standard library and the intrinsics headers
+// is included here, in the global module fragment. Their include guards then turn
+// glm's own #includes into no-ops, so only glm's declarations land in the purview
+// below -- otherwise the export block would try to export system functions that
+// have internal linkage, which is ill-formed.
+#include <cmath>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <cfloat>
+#include <climits>
+#include <limits>
+#include <type_traits>
+#include <iterator>
+#include <algorithm>
+#include <cassert>
+#include <memory>
+#include <string>
+#include <sstream>
+#include <iostream>
+#include <immintrin.h>
+
+export module eu07.glm;
+
+// glm is header-only. Including it inside the module purview attaches its
+// declarations to this module, which is what lets them be exported. Every other
+// module imports this one instead of including glm directly: GCC 16 rejects the
+// merge when the same glm declarations arrive from several different modules
+// ("conflicting imported declaration" on glm::detail::storage), so glm has to be
+// compiled into exactly one module.
+export {
+#include <glm/glm.hpp>
+#include <glm/fwd.hpp>
+#include <glm/mat4x4.hpp>
+#include <glm/gtc/constants.hpp>
+#include <glm/gtc/epsilon.hpp>
+#include <glm/gtc/matrix_access.hpp>
+#include <glm/gtc/matrix_transform.hpp>
+#include <glm/gtc/packing.hpp>
+#include <glm/gtc/quaternion.hpp>
+#include <glm/gtc/type_ptr.hpp>
+#include <glm/gtx/compatibility.hpp>
+#include <glm/gtx/euler_angles.hpp>
+#include <glm/gtx/matrix_transform_2d.hpp>
+#include <glm/gtx/norm.hpp>
+#include <glm/gtx/quaternion.hpp>
+#include <glm/gtx/rotate_vector.hpp>
+// gtx/string_cast is deliberately absent: it defines static label constants,
+// and an export block may not export entities with internal linkage. The two
+// call sites of glm::to_string include it in their own module fragment.
+#include <glm/gtx/transform.hpp>
+}
+
+export {
+// 12-byte vec3 that stays packed regardless of GLM_FORCE_DEFAULT_ALIGNED_GENTYPES.
+// Use in structs that must match an exact binary layout (UBOs, vertex data,
+// serialized formats).
+using packed_vec3 = glm::vec<3, float, glm::packed_highp>;
+}