diff --git a/panda/src/bullet/bulletHeightfieldShape.cxx b/panda/src/bullet/bulletHeightfieldShape.cxx
index 08f91bd036..55ed86d16e 100644
--- a/panda/src/bullet/bulletHeightfieldShape.cxx
+++ b/panda/src/bullet/bulletHeightfieldShape.cxx
@@ -200,7 +200,7 @@ fillin(DatagramIterator &scan, BamReader *manager) {
 
   size_t size = (size_t)_num_rows * (size_t)_num_cols;
   delete [] _data;
-  _data = new float[size];
+  _data = new btScalar[size];
 
   for (size_t i = 0; i < size; ++i) {
     _data[i]  = scan.get_stdfloat();
diff --git a/panda/src/glstuff/glShaderContext_src.cxx b/panda/src/glstuff/glShaderContext_src.cxx
index df510abf69..eb9c534b44 100644
--- a/panda/src/glstuff/glShaderContext_src.cxx
+++ b/panda/src/glstuff/glShaderContext_src.cxx
@@ -888,7 +888,17 @@ reflect_uniform(int i, char *name_buffer, GLsizei name_buflen) {
 
         // Add it once for each index.
         for (bind._index = 0; bind._index < param_size; ++bind._index) {
+          // It was discovered in #846, that GLSL 4.10 and lower don't seem to
+          // guarantee that matrices occupy successive locations, and on macOS
+          // they indeed occupy four locations per element.
+          // As a big fat hack, we multiply by four on macOS, because this is
+          // hard to fix on the 1.10 branch.  We'll have a proper fix on the
+          // master branch.
+#ifdef __APPLE__
+          bind._id._seqno = p + bind._index * 4;
+#else
           bind._id._seqno = p + bind._index;
+#endif
           _shader->cp_add_mat_spec(bind);
         }
         return;
diff --git a/panda/src/gobj/shader.cxx b/panda/src/gobj/shader.cxx
index a4b6881518..a1067e9c9e 100644
--- a/panda/src/gobj/shader.cxx
+++ b/panda/src/gobj/shader.cxx
@@ -2514,9 +2514,10 @@ read(const ShaderFile &sfile, BamCacheRecord *record) {
     // Determine which language the shader is written in.
     if (_language == SL_Cg) {
 #ifdef HAVE_CG
-      cg_get_profile_from_header(_default_caps);
+      ShaderCaps caps = _default_caps;
+      cg_get_profile_from_header(caps);
 
-      if (!cg_analyze_shader(_default_caps)) {
+      if (!cg_analyze_shader(caps)) {
         shader_cat.error()
           << "Shader encountered an error.\n";
         return false;
@@ -2606,9 +2607,10 @@ load(const ShaderFile &sbody, BamCacheRecord *record) {
     // Determine which language the shader is written in.
     if (_language == SL_Cg) {
 #ifdef HAVE_CG
-      cg_get_profile_from_header(_default_caps);
+      ShaderCaps caps = _default_caps;
+      cg_get_profile_from_header(caps);
 
-      if (!cg_analyze_shader(_default_caps)) {
+      if (!cg_analyze_shader(caps)) {
         shader_cat.error()
           << "Shader encountered an error.\n";
         return false;