diff --git a/polymer/eduke32/build/include/compat.h b/polymer/eduke32/build/include/compat.h
index 2bc7c0a72..c679007db 100644
--- a/polymer/eduke32/build/include/compat.h
+++ b/polymer/eduke32/build/include/compat.h
@@ -588,5 +588,10 @@ char *Bstrupr(char *);
 #define EDUKE32_TMRTIC t[ti++]=getticks()
 #define EDUKE32_TMRPRN do { int ii=0; fprintf(stderr,"%s: ",tmrstr); for (ii=1; ii<ti; ii++) fprintf(stderr,"%d ", t[ii]-t[ii-1]); fprintf(stderr,"\n"); } while (0)
 
+#if defined USE_OPENGL && defined DEBUGGINGAIDS && defined DEBUG_TEXTURE_NAMES
+# define bglGenTextures(numtexs, texnamear) texdbg_bglGenTextures(numtexs, texnamear, __FILE__)
+# define bglDeleteTextures(numtexs, texnamear) texdbg_bglDeleteTextures(numtexs, texnamear, __FILE__)
+#endif
+
 #endif // __compat_h__
 
diff --git a/polymer/eduke32/build/include/glbuild.h b/polymer/eduke32/build/include/glbuild.h
index 7582d78d3..e65ed6957 100644
--- a/polymer/eduke32/build/include/glbuild.h
+++ b/polymer/eduke32/build/include/glbuild.h
@@ -317,6 +317,9 @@ extern BOOL (WINAPI * bwglSetPixelFormat)(HDC,int32_t,const PIXELFORMATDESCRIPTO
 extern BOOL (WINAPI * bwglSwapIntervalEXT)(int32_t);
 #endif
 
+//////// glGenTextures/glDeleteTextures debugging ////////
+void texdbg_bglGenTextures(GLsizei n, GLuint *textures, const char *srcfn);
+void texdbg_bglDeleteTextures(GLsizei n, const GLuint *textures, const char *srcfn);
 #endif //USE_OPENGL
 
 extern char *gldriver;
diff --git a/polymer/eduke32/build/include/polymost.h b/polymer/eduke32/build/include/polymost.h
index ddf6a0deb..39e4e69d3 100644
--- a/polymer/eduke32/build/include/polymost.h
+++ b/polymer/eduke32/build/include/polymost.h
@@ -87,6 +87,8 @@ extern float shadescale;
 extern int32_t shadescale_unbounded;
 extern float alphahackarray[MAXTILES];
 
+extern int32_t r_usenewshading;
+
 typedef struct pthtyp_t
 {
     struct pthtyp_t *next;
@@ -119,22 +121,33 @@ extern double gyxscale, gxyaspect, gviewxrange, ghalfx, grhalfxdown10, grhalfxdo
 extern double gcosang, gsinang, gcosang2, gsinang2;
 extern double gchang, gshang, gctang, gstang, gvisibility;
 
-#define FOGSCALE 0.0000768
+//#define FOGSCALE 0.0000768
+#define FOGSCALE ((0.0000768+0.0000128)/(1 + 0.5f*(getrendermode()==4)))
 
 extern float fogresult, fogcol[4], fogtable[4*MAXPALOOKUPS];
 
 static inline void fogcalc(const int32_t shade, const int32_t vis, const int32_t pal)
 {
-    float f = (shade < 0) ? shade * 3.5f :
-        shade * .66f;
+    float f;
 
-    f = (vis > 239) ? (float)(gvisibility*((vis-240+f)/(klabs(vis-256)))) :
-        (float)(gvisibility*(vis+16+f));
+    if (r_usenewshading)
+    {
+        f = 0.9f * shade;
+        f = (vis > 239) ? (float)(gvisibility*((vis-240+f))) :
+            (float)(gvisibility*(vis+16+f));
+    }
+    else
+    {
+        f = (shade < 0) ? shade * 3.5f : shade * .66f;
+        f = (vis > 239) ? (float)(gvisibility*((vis-240+f)/(klabs(vis-256)))) :
+            (float)(gvisibility*(vis+16+f));
+    }
 
     if (f < 0.001f)
         f = 0.001f;
     else if (f > 100.0f)
         f = 100.0f;
+
     fogresult = f;
 
     Bmemcpy(fogcol, &fogtable[pal<<2], sizeof(fogcol));
diff --git a/polymer/eduke32/build/src/build.c b/polymer/eduke32/build/src/build.c
index f1b368b53..516c903f2 100644
--- a/polymer/eduke32/build/src/build.c
+++ b/polymer/eduke32/build/src/build.c
@@ -2883,8 +2883,16 @@ void overheadeditor(void)
                     if (keystatus[0x28])
                         drawline16base(searchx+16, searchy-16, 0,-4, 0,+4, col);
                 }
-                else if (keystatus[0x36] && eitherCTRL)
-                    printext16(searchx+6,searchy-6-8,editorcolors[12],-1,"S",0);
+
+                if (keystatus[0x36])
+                {
+                    if (eitherCTRL)
+                        printext16(searchx+6,searchy-6-8,editorcolors[12],-1,"S",0);
+#ifdef YAX_ENABLE
+                    if (keystatus[0xcf])
+                        printext16(searchx+6,searchy-6+8,editorcolors[12],-1,"A",0);
+#endif
+                }
             }
 
             drawline16base(searchx,searchy, +0,-8, +0,-1, col);
@@ -3734,7 +3742,8 @@ end_yax: ;
                             if (sprite[i].statnum == MAXSTATUS)
                                 continue;
 
-                            if ((unsigned)sprite[i].sectnum < MAXSECTORS)
+                            //  v v v: if END pressed, also permit sprites from grayed out sectors
+                            if (!keystatus[0xcf] && (unsigned)sprite[i].sectnum < MAXSECTORS)
                                 YAX_SKIPSECTOR(sprite[i].sectnum);
 
                             if (!m32_sideview)
diff --git a/polymer/eduke32/build/src/engine.c b/polymer/eduke32/build/src/engine.c
index 14f7bf6b7..3b081646c 100644
--- a/polymer/eduke32/build/src/engine.c
+++ b/polymer/eduke32/build/src/engine.c
@@ -15637,6 +15637,8 @@ int32_t setrendermode(int32_t renderer)
         if (!polymer_init())
             renderer = 3;
     }
+    else if (rendmode==4)  // going from Polymer to another renderer
+        polymer_uninit();
 # else
     else renderer = 3;
 # endif
diff --git a/polymer/eduke32/build/src/glbuild.c b/polymer/eduke32/build/src/glbuild.c
index 438d4697b..62948a583 100644
--- a/polymer/eduke32/build/src/glbuild.c
+++ b/polymer/eduke32/build/src/glbuild.c
@@ -999,5 +999,100 @@ int32_t unloadglulibrary(void)
 
     return 0;
 }
-#endif
 
+
+//////// glGenTextures/glDeleteTextures debugging ////////
+# if defined DEBUGGINGAIDS && defined DEBUG_TEXTURE_NAMES
+static uint8_t *texnameused;  // bitmap
+static uint32_t *texnamefromwhere;  // hash of __FILE__
+static uint32_t texnameallocsize;
+
+// djb3 algorithm
+static inline uint32_t texdbg_getcode(const char *s)
+{
+    uint32_t h = 5381;
+    int32_t ch;
+
+    while ((ch = *s++) != '\0')
+        h = ((h << 5) + h) ^ ch;
+
+    return h;
+}
+
+static void texdbg_realloc(uint32_t maxtexname)
+{
+    uint32_t newsize = texnameallocsize ? texnameallocsize : 64;
+
+    if (texnameallocsize >= maxtexname)
+        return;
+
+    while (newsize < maxtexname)
+        newsize <<= 1;
+//    initprintf("texdebug: new size %u\n", newsize);
+
+    texnameused = Brealloc(texnameused, newsize>>3);
+    texnamefromwhere = Brealloc(texnamefromwhere, newsize*sizeof(uint32_t));
+
+    Bmemset(texnameused + (texnameallocsize>>3), 0, (newsize-texnameallocsize)>>3);
+    Bmemset(texnamefromwhere + texnameallocsize, 0, (newsize-texnameallocsize)*sizeof(uint32_t));
+
+    texnameallocsize = newsize;
+}
+
+#undef bglGenTextures
+void texdbg_bglGenTextures(GLsizei n, GLuint *textures, const char *srcfn)
+{
+    int32_t i;
+    uint32_t hash = srcfn ? texdbg_getcode(srcfn) : 0;
+
+    for (i=0; i<n; i++)
+        if (textures[i] < texnameallocsize && (texnameused[textures[i]>>3]&(1<<(textures[i]&7))))
+            initprintf("texdebug %x Gen: overwriting used tex name %u from %x\n", hash, textures[i], texnamefromwhere[textures[i]]);
+
+    bglGenTextures(n, textures);
+
+    {
+        GLuint maxtexname = 0;
+
+        for (i=0; i<n; i++)
+            maxtexname = max(maxtexname, textures[i]);
+
+        texdbg_realloc(maxtexname);
+
+        for (i=0; i<n; i++)
+        {
+            texnameused[textures[i]>>3] |= (1<<(textures[i]&7));
+            texnamefromwhere[textures[i]] = hash;
+        }
+    }
+}
+
+#undef bglDeleteTextures
+void texdbg_bglDeleteTextures(GLsizei n, const GLuint *textures, const char *srcfn)
+{
+    int32_t i;
+    uint32_t hash = srcfn ? texdbg_getcode(srcfn) : 0;
+
+    for (i=0; i<n; i++)
+        if (textures[i] < texnameallocsize)
+        {
+            if ((texnameused[textures[i]>>3]&(1<<(textures[i]&7)))==0)
+                initprintf("texdebug %x Del: deleting unused tex name %u\n", hash, textures[i]);
+            else if ((texnameused[textures[i]>>3]&(1<<(textures[i]&7))) &&
+                         texnamefromwhere[textures[i]] != hash)
+                initprintf("texdebug %x Del: deleting foreign tex name %u from %x\n", hash,
+                           textures[i], texnamefromwhere[textures[i]]);
+        }
+
+    bglDeleteTextures(n, textures);
+
+    if (texnameallocsize)
+        for (i=0; i<n; i++)
+        {
+            texnameused[textures[i]>>3] &= ~(1<<(textures[i]&7));
+            texnamefromwhere[textures[i]] = 0;
+        }
+}
+# endif  // defined DEBUGGINGAIDS
+
+#endif
diff --git a/polymer/eduke32/build/src/mdsprite.c b/polymer/eduke32/build/src/mdsprite.c
index 7197eb62e..fea8c58e6 100644
--- a/polymer/eduke32/build/src/mdsprite.c
+++ b/polymer/eduke32/build/src/mdsprite.c
@@ -2486,8 +2486,8 @@ static void md3free(md3model_t *m)
                 if (s->xyzn) Bfree(s->xyzn);
                 if (s->geometry) Bfree(s->geometry);
             }
-            else
-                if (s->geometry) Bfree(s->geometry);  // ?
+//            else
+//                if (s->geometry) Bfree(s->geometry);  // this is wrong!
         }
         Bfree(m->head.surfs);
     }
diff --git a/polymer/eduke32/build/src/polymer.c b/polymer/eduke32/build/src/polymer.c
index 1ec67b47a..ec8c804fe 100644
--- a/polymer/eduke32/build/src/polymer.c
+++ b/polymer/eduke32/build/src/polymer.c
@@ -648,14 +648,12 @@ int32_t             polymer_init(void)
         return (0);
     }
 
-    polymer_freeboard();
+    // clean up existing stuff since it will be initialized again if we're re-entering here
+    polymer_uninit();
 
     Bmemset(&prsectors[0], 0, sizeof(prsectors[0]) * MAXSECTORS);
     Bmemset(&prwalls[0], 0, sizeof(prwalls[0]) * MAXWALLS);
 
-    if (prtess)
-        bgluDeleteTess(prtess);
-
     prtess = bgluNewTess();
     if (prtess == 0)
     {
@@ -693,7 +691,7 @@ int32_t             polymer_init(void)
     polymersearching = FALSE;
 
     polymer_initrendertargets(pr_shadowcount + 1);
-    
+
     // Prime highpalookup maps
     i = 0;
     while (i < MAXBASEPALS)
@@ -703,9 +701,6 @@ int32_t             polymer_init(void)
         {
             if (prhighpalookups[i][j].data)
             {
-                if (prhighpalookups[i][j].map)
-                    bglDeleteTextures(1, &prhighpalookups[i][j].map);
-
                 bglGenTextures(1, &prhighpalookups[i][j].map);
                 bglBindTexture(GL_TEXTURE_3D, prhighpalookups[i][j].map);
                 bglTexImage3D(GL_TEXTURE_3D,                // target
@@ -739,8 +734,16 @@ void                polymer_uninit(void)
 {
     int32_t         i, j;
 
+    if (prtess)
+    {
+        bgluDeleteTess(prtess);
+        prtess = NULL;
+    }
+
     polymer_freeboard();
-    
+
+    polymer_initrendertargets(0);
+
     i = 0;
     while (i < MAXBASEPALS)
     {
@@ -5341,19 +5344,34 @@ static void         polymer_initrendertargets(int32_t count)
     int32_t         i;
 
     static int32_t ocount;
-    if (prrts)
+
+    if (count == 0)  // uninit
     {
-        for (i=0; i<ocount; i++)
+        if (prrts)
         {
-            if (!i)
-                bglDeleteTextures(1, &prrts[i].color);
-            bglDeleteTextures(1, &prrts[i].z);
-            bglDeleteFramebuffersEXT(1, &prrts[i].fbo);
+            for (i=0; i<ocount; i++)
+            {
+                if (prrts[i].color)
+                {
+                    bglDeleteTextures(1, &prrts[i].color);
+                    prrts[i].color = 0;
+                }
+                bglDeleteTextures(1, &prrts[i].z);
+                prrts[i].z = 0;
+
+                bglDeleteFramebuffersEXT(1, &prrts[i].fbo);
+                prrts[i].fbo = 0;
+            }
+            Bfree(prrts);
+            prrts = NULL;
         }
 
-        Bfree(prrts);
+        ocount = 0;
+        return;
     }
+
     ocount = count;
+    //////////
 
     prrts = Bcalloc(count, sizeof(_prrt));
 
diff --git a/polymer/eduke32/build/src/polymost.c b/polymer/eduke32/build/src/polymost.c
index 31216b1a9..8eaa3243e 100644
--- a/polymer/eduke32/build/src/polymost.c
+++ b/polymer/eduke32/build/src/polymost.c
@@ -112,6 +112,8 @@ static double dxb1[MAXWALLSB], dxb2[MAXWALLSB];
 float shadescale = 1.3f;
 int32_t shadescale_unbounded = 0;
 
+int32_t r_usenewshading = 1;
+
 double gyxscale, gxyaspect, gviewxrange, ghalfx, grhalfxdown10, grhalfxdown10x, ghoriz;
 double gcosang, gsinang, gcosang2, gsinang2;
 double gchang, gshang, gctang, gstang, gvisibility;
@@ -6303,6 +6305,7 @@ void polymost_initosdfuncs(void)
         { "r_texturemaxsize","r_texturemaxsize: changes the maximum OpenGL texture size limit",(void *) &gltexmaxsize, CVAR_INT | CVAR_NOSAVE, 0, 4096 },
         { "r_texturemiplevel","r_texturemiplevel: changes the highest OpenGL mipmap level used",(void *) &gltexmiplevel, CVAR_INT, 0, 6 },
         { "r_texturemode", "r_texturemode: changes the texture filtering settings", (void *) &gltexfiltermode, CVAR_INT|CVAR_FUNCPTR, 0, 5 },
+        { "r_usenewshading", "r_usenewshading: enable/disable new shading/visibility code", (void *) &r_usenewshading, CVAR_BOOL, 0, 1 },
         { "r_vbocount","r_vbocount: sets the number of Vertex Buffer Objects to use when drawing models",(void *) &r_vbocount, CVAR_INT, 1, 256 },
         { "r_vbos","r_vbos: enable/disable using Vertex Buffer Objects when drawing models",(void *) &r_vbos, CVAR_BOOL, 0, 1 },
         { "r_vertexarrays","r_vertexarrays: enable/disable using vertex arrays when drawing models",(void *) &r_vertexarrays, CVAR_BOOL, 0, 1 },
diff --git a/polymer/eduke32/source/animvpx.c b/polymer/eduke32/source/animvpx.c
index ba26a1394..db38077f4 100644
--- a/polymer/eduke32/source/animvpx.c
+++ b/polymer/eduke32/source/animvpx.c
@@ -292,7 +292,7 @@ read_ivf_frame:
 
 
 /////////////// DRAWING! ///////////////
-static GLuint texname = -1;
+static GLuint texname = 0;
 static int32_t texuploaded;
 
 // YUV->RGB conversion fragment shader adapted from
@@ -409,7 +409,7 @@ void animvpx_restore_glstate(void)
     bglPopAttrib();
 
     bglDeleteTextures(1, &texname);
-    texname = -1;
+    texname = 0;
     texuploaded = 0;
 }
 
diff --git a/polymer/eduke32/source/astub.c b/polymer/eduke32/source/astub.c
index 3856b0688..50feedbf8 100644
--- a/polymer/eduke32/source/astub.c
+++ b/polymer/eduke32/source/astub.c
@@ -5621,9 +5621,20 @@ static void Keys3d(void)
                 {
                     if (ASSERT_AIMING)
                     {
-                        clamped = addtobyte(&AIMED_CF_SEL(shade), tsign);
-                        message("%s %d shade %d%s", Typestr[searchstat], i, AIMED_CF_SEL(shade),
-                                clamped ? " (clamped)":"");
+                        if (AIMING_AT_SPRITE && (show2dsprite[searchwall>>3]&(1<<(searchwall&7))))
+                        {
+                            for (i=0; i<highlightcnt; i++)
+                                if (highlight[i]&16384)
+                                    clamped = addtobyte(&sprite[highlight[i]&16383].shade, tsign);
+                            message("Highlighted sprite shade changed by %d%s", tsign,
+                                    clamped?" (some sprites' shade clamped)":"");
+                        }
+                        else
+                        {
+                            clamped = addtobyte(&AIMED_CF_SEL(shade), tsign);
+                            message("%s %d shade %d%s", Typestr[searchstat], i, AIMED_CF_SEL(shade),
+                                    clamped ? " (clamped)":"");
+                        }
                     }
                 }
                 else