diff --git a/dtool/src/dtoolbase/patomic.cxx b/dtool/src/dtoolbase/patomic.cxx
index 47da5a01768..15fef9a1e2e 100644
--- a/dtool/src/dtoolbase/patomic.cxx
+++ b/dtool/src/dtoolbase/patomic.cxx
@@ -128,7 +128,13 @@ initialize_wait(volatile VOID *addr, PVOID cmp, SIZE_T size, DWORD timeout) {
 #elif !defined(CPPPARSER) && !defined(__linux__) && !defined(__APPLE__) && !defined(__FreeBSD__) && defined(HAVE_POSIX_THREADS)
 
 // Same as above, but using pthreads.
-struct alignas(64) WaitTableEntry {
+struct
+#ifdef __APPLE__ && defined(__arm64__)
+alignas(128)
+#else
+alignas(64)
+#endif
+WaitTableEntry {
   pthread_mutex_t _lock = PTHREAD_MUTEX_INITIALIZER;
   pthread_cond_t _cvar = PTHREAD_COND_INITIALIZER;
   unsigned int _waiters = 0;
diff --git a/panda/src/grutil/cardMaker.I b/panda/src/grutil/cardMaker.I
index bc329f8291a..270eaa0f071 100644
--- a/panda/src/grutil/cardMaker.I
+++ b/panda/src/grutil/cardMaker.I
@@ -19,20 +19,17 @@ CardMaker(std::string name) : Namable(std::move(name)) {
   reset();
 }
 
-/**
- *
- */
-INLINE CardMaker::
-~CardMaker() {
-}
-
 /**
  * Sets the flag indicating whether vertices will be generated with UV's or
  * not.
  */
 INLINE void CardMaker::
 set_has_uvs(bool flag) {
-  _has_uvs = flag;
+  if (flag) {
+    _flags |= F_has_uvs;
+  } else {
+    _flags &= ~F_has_uvs;
+  }
 }
 
 /**
@@ -42,7 +39,11 @@ set_has_uvs(bool flag) {
  */
 INLINE void CardMaker::
 set_has_3d_uvs(bool flag) {
-  _has_3d_uvs = flag;
+  if (flag) {
+    _flags |= F_has_3d_uvs;
+  } else {
+    _flags &= ~F_has_3d_uvs;
+  }
 }
 
 /**
@@ -50,10 +51,10 @@ set_has_3d_uvs(bool flag) {
  */
 INLINE void CardMaker::
 set_frame(PN_stdfloat left, PN_stdfloat right, PN_stdfloat bottom, PN_stdfloat top) {
-  _ll_pos = LVector3::rfu(left,  0.0f, bottom);
-  _lr_pos = LVector3::rfu(right, 0.0f, bottom);
-  _ur_pos = LVector3::rfu(right, 0.0f, top);
-  _ul_pos = LVector3::rfu(left,  0.0f, top);
+  _ll_pos = LVertex::rfu(left,  0.0f, bottom);
+  _lr_pos = LVertex::rfu(right, 0.0f, bottom);
+  _ur_pos = LVertex::rfu(right, 0.0f, top);
+  _ul_pos = LVertex::rfu(left,  0.0f, top);
 }
 
 /**
@@ -98,7 +99,7 @@ set_color(PN_stdfloat r, PN_stdfloat g, PN_stdfloat b, PN_stdfloat a) {
 INLINE void CardMaker::
 set_color(const LVecBase4 &color) {
   _color = color;
-  _has_color = true;
+  _flags |= F_has_color;
 }
 
 /**
@@ -106,7 +107,7 @@ set_color(const LVecBase4 &color) {
  */
 INLINE void CardMaker::
 clear_color() {
-  _has_color = false;
+  _flags &= ~F_has_color;
   _color.set(1.0f, 1.0f, 1.0f, 1.0f);
 }
 
@@ -119,7 +120,11 @@ clear_color() {
  */
 INLINE void CardMaker::
 set_has_normals(bool flag) {
-  _has_normals = flag;
+  if (flag) {
+    _flags |= F_has_normals;
+  } else {
+    _flags &= ~F_has_normals;
+  }
 }
 
 /**
diff --git a/panda/src/grutil/cardMaker.cxx b/panda/src/grutil/cardMaker.cxx
index 33f6fc88ad1..bbab02cc739 100644
--- a/panda/src/grutil/cardMaker.cxx
+++ b/panda/src/grutil/cardMaker.cxx
@@ -26,13 +26,13 @@
  */
 void CardMaker::
 reset() {
+  _flags = F_has_normals;
+
   set_frame(0.0f, 1.0f, 0.0f, 1.0f);
   set_uv_range(LTexCoord(0.0f, 0.0f), LTexCoord(1.0f, 1.0f));
 
-  _has_color = false;
   _color.set(1.0f, 1.0f, 1.0f, 1.0f);
 
-  _has_normals = true;
   _source_geometry = nullptr;
   _source_frame.set(0.0f, 0.0f, 0.0f, 0.0f);
 }
@@ -50,9 +50,9 @@ generate() {
   PT(GeomNode) gnode = new GeomNode(get_name());
 
   CPT(GeomVertexFormat) format;
-  if (_has_normals) {
-    if (_has_uvs) {
-      if (_has_3d_uvs) {
+  if (_flags & F_has_normals) {
+    if (_flags & F_has_uvs) {
+      if (_flags & F_has_3d_uvs) {
         format = GeomVertexFormat::register_format
           (new GeomVertexArrayFormat
            (InternalName::get_vertex(), 3,
@@ -68,8 +68,8 @@ generate() {
       format = GeomVertexFormat::get_v3n3();
     }
   } else {
-    if (_has_uvs) {
-      if (_has_3d_uvs) {
+    if (_flags & F_has_uvs) {
+      if (_flags & F_has_3d_uvs) {
         format = GeomVertexFormat::register_format
           (new GeomVertexArrayFormat
            (InternalName::get_vertex(), 3,
@@ -86,36 +86,37 @@ generate() {
 
   PT(GeomVertexData) vdata = new GeomVertexData
     ("card", format, Geom::UH_static);
+  vdata->unclean_set_num_rows(4);
   GeomVertexWriter vertex(vdata, InternalName::get_vertex());
 
-  vertex.add_data3(_ul_pos);
-  vertex.add_data3(_ll_pos);
-  vertex.add_data3(_ur_pos);
-  vertex.add_data3(_lr_pos);
+  vertex.set_data3(_ul_pos);
+  vertex.set_data3(_ll_pos);
+  vertex.set_data3(_ur_pos);
+  vertex.set_data3(_lr_pos);
 
-  if (_has_uvs) {
+  if (_flags & F_has_uvs) {
     GeomVertexWriter texcoord(vdata, InternalName::get_texcoord());
-    texcoord.add_data3(_ul_tex);
-    texcoord.add_data3(_ll_tex);
-    texcoord.add_data3(_ur_tex);
-    texcoord.add_data3(_lr_tex);
+    texcoord.set_data3(_ul_tex);
+    texcoord.set_data3(_ll_tex);
+    texcoord.set_data3(_ur_tex);
+    texcoord.set_data3(_lr_tex);
   }
 
-  if (_has_normals) {
+  if (_flags & F_has_normals) {
     GeomVertexWriter normal(vdata, InternalName::get_normal());
     LVector3 n;
     n = (_ll_pos - _ul_pos).cross(_ur_pos - _ul_pos);
     n.normalize();
-    normal.add_data3(n);
+    normal.set_data3(n);
     n = (_lr_pos - _ll_pos).cross(_ul_pos - _ll_pos);
     n.normalize();
-    normal.add_data3(n);
+    normal.set_data3(n);
     n = (_ul_pos - _ur_pos).cross(_lr_pos - _ur_pos);
     n.normalize();
-    normal.add_data3(n);
+    normal.set_data3(n);
     n = (_ur_pos - _lr_pos).cross(_ll_pos - _lr_pos);
     n.normalize();
-    normal.add_data3(n);
+    normal.set_data3(n);
   }
 
   PT(GeomTristrips) strip = new GeomTristrips(Geom::UH_static);
@@ -127,7 +128,7 @@ generate() {
   geom->add_primitive(strip);
 
   CPT(RenderState) state = RenderState::make_empty();
-  if (_has_color) {
+  if (_flags & F_has_color) {
     state = RenderState::make(ColorAttrib::make_flat(_color));
   }
 
@@ -148,8 +149,7 @@ set_uv_range(const LTexCoord3 &ll, const LTexCoord3 &lr, const LTexCoord3 &ur, c
   _lr_tex = lr;
   _ur_tex = ur;
   _ul_tex = ul;
-  _has_uvs = true;
-  _has_3d_uvs = true;
+  _flags |= F_has_uvs | F_has_3d_uvs;
 }
 
 /**
@@ -164,8 +164,7 @@ set_uv_range(const LTexCoord &ll, const LTexCoord &lr, const LTexCoord &ur, cons
   _lr_tex.set(lr[0], lr[1], 0.0f);
   _ur_tex.set(ur[0], ur[1], 0.0f);
   _ul_tex.set(ul[0], ul[1], 0.0f);
-  _has_uvs = true;
-  _has_3d_uvs = false;
+  _flags = (_flags | F_has_uvs) & ~F_has_3d_uvs;
 }
 
 /**
@@ -180,8 +179,7 @@ set_uv_range(const LTexCoord &ll, const LTexCoord &ur) {
   _lr_tex.set(ur[0], ll[1], 0.0f);
   _ur_tex.set(ur[0], ur[1], 0.0f);
   _ul_tex.set(ll[0], ur[1], 0.0f);
-  _has_uvs = true;
-  _has_3d_uvs = false;
+  _flags = (_flags | F_has_uvs) & ~F_has_3d_uvs;
 }
 
 /**
@@ -196,8 +194,7 @@ set_uv_range(const LVector4 &x, const LVector4 &y, const LVector4 &z) {
   _lr_tex.set(x[1], y[1], z[1]);
   _ur_tex.set(x[2], y[2], z[2]);
   _ul_tex.set(x[3], y[3], z[3]);
-  _has_uvs = true;
-  _has_3d_uvs = true;
+  _flags |= F_has_uvs | F_has_3d_uvs;
 }
 
 /**
@@ -259,7 +256,7 @@ rescale_source_geometry() {
     TransformState::make_pos_hpr_scale(trans, LPoint3(0.0f, 0.0f, 0.0f), scale);
   root->set_transform(transform);
 
-  if (_has_color) {
+  if (_flags & F_has_color) {
     root->set_attrib(ColorAttrib::make_flat(_color));
   }
 
diff --git a/panda/src/grutil/cardMaker.h b/panda/src/grutil/cardMaker.h
index d930ac70392..435f0803b6d 100644
--- a/panda/src/grutil/cardMaker.h
+++ b/panda/src/grutil/cardMaker.h
@@ -29,7 +29,7 @@
 class EXPCL_PANDA_GRUTIL CardMaker : public Namable {
 PUBLISHED:
   INLINE explicit CardMaker(std::string name);
-  INLINE ~CardMaker();
+  ~CardMaker() = default;
 
   void reset();
   void set_uv_range(const LTexCoord &ll, const LTexCoord &ur);
@@ -61,14 +61,19 @@ class EXPCL_PANDA_GRUTIL CardMaker : public Namable {
 private:
   PT(PandaNode) rescale_source_geometry();
 
-  bool _has_uvs, _has_3d_uvs;
-  LVertex _ul_tex, _ll_tex, _lr_tex, _ur_tex;
-  LTexCoord3 _ul_pos, _ll_pos, _lr_pos, _ur_pos;
+  enum Flags {
+    F_has_uvs = 1,
+    F_has_3d_uvs = 2,
+    F_has_color = 4,
+    F_has_normals = 8,
+  };
 
-  bool _has_color;
-  LColor _color;
+  int _flags;
+
+  LVertex _ul_pos, _ll_pos, _lr_pos, _ur_pos;
+  LTexCoord3 _ul_tex, _ll_tex, _lr_tex, _ur_tex;
 
-  bool _has_normals;
+  LColor _color;
 
   PT(PandaNode) _source_geometry;
   LVecBase4 _source_frame;
diff --git a/tests/prc/test_assert_guard.cxx b/tests/prc/test_assert_guard.cxx
new file mode 100644
index 00000000000..1bf85d29d3c
--- /dev/null
+++ b/tests/prc/test_assert_guard.cxx
@@ -0,0 +1,51 @@
+/**
+ * PANDA 3D SOFTWARE
+ * Copyright (c) Carnegie Mellon University.  All rights reserved.
+ *
+ * All use of this software is subject to the terms of the revised BSD
+ * license.  You should have received a copy of this license along
+ * with this source code in a file named "LICENSE."
+ *
+ * @file test_assert_guard.cxx
+ * @author rdb
+ * @date 2026-07-19
+ */
+
+#include "pnotify.h"
+
+#include "catch_amalgamated.hpp"
+
+/**
+ * Routes a Panda assertion failure (nassertr and friends) into Catch2 as a
+ * test failure at the point where it fired, rather than letting the test
+ * pass with only a line on the notify output.  Returning true preserves the
+ * normal no-abort behavior: the asserting function bails out with its
+ * default return value.
+ */
+static bool
+catch2_assert_handler(const char *expression, int line, const char *source_file) {
+  FAIL_CHECK("Assertion failed: " << expression << " at line " << line << " of " << source_file);
+  return true;
+}
+
+/**
+ * Installs the assert handler for the duration of each test case, so that a
+ * test that trips an assertion fails even if all of its CHECKs pass.  A test
+ * that intentionally provokes an assertion can temporarily install its own
+ * handler; this listener reinstates the guard for the next test case.
+ */
+class PandaAssertListener final : public Catch::EventListenerBase {
+public:
+  using Catch::EventListenerBase::EventListenerBase;
+
+  void testCaseStarting(const Catch::TestCaseInfo &) override {
+    Notify::ptr()->set_assert_handler(&catch2_assert_handler);
+  }
+
+  void testCaseEnded(const Catch::TestCaseStats &) override {
+    Notify::ptr()->clear_assert_handler();
+    Notify::ptr()->clear_assert_failed();
+  }
+};
+
+CATCH_REGISTER_LISTENER(PandaAssertListener)