diff --git a/polymer/eduke32/build/include/a.h b/polymer/eduke32/build/include/a.h
index 5f0ad9f7b..7730a288c 100644
--- a/polymer/eduke32/build/include/a.h
+++ b/polymer/eduke32/build/include/a.h
@@ -35,7 +35,7 @@ extern int32_t __cdecl fixtransluscence(int32_t);
 extern int32_t __cdecl prevlineasm1(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
 extern int32_t __cdecl vlineasm1(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
 extern int32_t __cdecl vlineasm1nonpow2(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
-extern int32_t __cdecl setuptvlineasm(int32_t);
+extern int32_t __cdecl setuptvlineasm(int32_t,int32_t);
 extern int32_t __cdecl tvlineasm1(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
 extern int32_t __cdecl tvlineasm1nonpow2(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
 extern int32_t __cdecl setuptvlineasm2(int32_t,int32_t,int32_t);
@@ -44,7 +44,7 @@ extern int32_t __cdecl mvlineasm1(int32_t,int32_t,int32_t,int32_t,int32_t,int32_
 extern int32_t __cdecl mvlineasm1nonpow2(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
 extern int32_t __cdecl setupvlineasm(int32_t);
 extern int32_t __cdecl vlineasm4(int32_t,char *);
-extern int32_t __cdecl setupmvlineasm(int32_t);
+extern int32_t __cdecl setupmvlineasm(int32_t,int32_t);
 extern int32_t __cdecl mvlineasm4(int32_t,char *);
 extern int32_t __cdecl setupspritevline(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
 extern int32_t __cdecl spritevline(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
@@ -93,7 +93,7 @@ extern int32_t _cdecl fixtransluscence(int32_t);
 extern int32_t _cdecl prevlineasm1(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
 extern int32_t _cdecl vlineasm1(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
 extern int32_t _cdecl vlineasm1nonpow2(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
-extern int32_t _cdecl setuptvlineasm(int32_t);
+extern int32_t _cdecl setuptvlineasm(int32_t,int32_t);
 extern int32_t _cdecl tvlineasm1(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
 extern int32_t _cdecl tvlineasm1nonpow2(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
 extern int32_t _cdecl setuptvlineasm2(int32_t,int32_t,int32_t);
@@ -102,7 +102,7 @@ extern int32_t _cdecl mvlineasm1(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t
 extern int32_t _cdecl mvlineasm1nonpow2(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
 extern int32_t _cdecl setupvlineasm(int32_t);
 extern int32_t _cdecl vlineasm4(int32_t,char *);
-extern int32_t _cdecl setupmvlineasm(int32_t);
+extern int32_t _cdecl setupmvlineasm(int32_t,int32_t);
 extern int32_t _cdecl mvlineasm4(int32_t,char *);
 extern int32_t _cdecl setupspritevline(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
 extern int32_t _cdecl spritevline(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
@@ -152,11 +152,11 @@ void setupvlineasm(int32_t neglogy);
 int32_t vlineasm1(int32_t vinc, intptr_t paloffs, int32_t cnt, uint32_t vplc, intptr_t bufplc, intptr_t p);
 void vlineasm4(int32_t cnt, char *p);
 
-void setupmvlineasm(int32_t neglogy);
+void setupmvlineasm(int32_t neglogy, int32_t dosaturate);
 int32_t mvlineasm1(int32_t vinc, intptr_t paloffs, int32_t cnt, uint32_t vplc, intptr_t bufplc, intptr_t p);
 void mvlineasm4(int32_t cnt, char *p);
 
-void setuptvlineasm(int32_t neglogy);
+void setuptvlineasm(int32_t neglogy, int32_t dosaturate);
 int32_t tvlineasm1(int32_t vinc, intptr_t paloffs, int32_t cnt, uint32_t vplc, intptr_t bufplc, intptr_t p);
 
 void setuptvlineasm2(int32_t neglogy, intptr_t paloffs1, intptr_t paloffs2);
diff --git a/polymer/eduke32/build/src/a-c.c b/polymer/eduke32/build/src/a-c.c
index 6a434f4c8..e904dfc97 100644
--- a/polymer/eduke32/build/src/a-c.c
+++ b/polymer/eduke32/build/src/a-c.c
@@ -15,6 +15,12 @@ int32_t krecip(int32_t num);	// from engine.c
 #define BITSOFPRECISION 3
 #define BITSOFPRECISIONPOW 8
 
+// Compile code to saturate vplc for sprites to prevent stray lines at the
+// bottom of non-y-flipped ones?
+#define USE_SATURATE_VPLC
+// Also for translucent masks?
+//#define USE_SATURATE_VPLC_TRANS
+
 extern intptr_t asm1, asm2, asm3, asm4;
 extern int32_t fpuasm, globalx3, globaly3;
 extern void *reciptable;
@@ -161,6 +167,21 @@ extern intptr_t bufplce[4];
 typedef uint32_t uint32_vec4 __attribute__ ((vector_size (16)));
 #endif
 
+#ifdef USE_SATURATE_VPLC
+# define saturate_vplc(vplc, vinc) vplc |= g_saturate & -(vplc < (uint32_t)vinc)
+// NOTE: the vector types yield -1 for logical "true":
+# define saturate_vplc_vec(vplc, vinc) vplc |= g_saturate & (vplc < vinc)
+# ifdef USE_SATURATE_VPLC_TRANS
+#  define saturate_vplc_trans(vplc, vinc) saturate_vplc(vplc, vinc)
+# else
+#  define saturate_vplc_trans(vplc, vinc)
+# endif
+#else
+# define saturate_vplc(vplc, vinc)
+# define saturate_vplc_vec(vplc, vinc)
+# define saturate_vplc_trans(vplc, vinc)
+#endif
+
 // cnt >= 1
 void vlineasm4(int32_t cnt, char *p)
 {
@@ -199,7 +220,19 @@ void vlineasm4(int32_t cnt, char *p)
         vplce[i] = vplc[i];
 }
 
-void setupmvlineasm(int32_t neglogy) { glogy = neglogy; }
+#ifdef USE_SATURATE_VPLC
+static int32_t g_saturate;  // -1 if saturating vplc is requested, 0 else
+# define set_saturate(dosaturate) g_saturate = -!!dosaturate
+#else
+# define set_saturate(dosaturate) UNREFERENCED_PARAMETER(dosaturate)
+#endif
+
+void setupmvlineasm(int32_t neglogy, int32_t dosaturate)
+{
+    glogy = neglogy;
+    set_saturate(dosaturate);
+}
+
 // cnt+1 loop iterations!
 int32_t mvlineasm1(int32_t vinc, intptr_t paloffs, int32_t cnt, uint32_t vplc, intptr_t bufplc, intptr_t p)
 {
@@ -218,6 +251,7 @@ int32_t mvlineasm1(int32_t vinc, intptr_t paloffs, int32_t cnt, uint32_t vplc, i
         if (ch != 255) *pp = pal[ch];
         pp += ourbpl;
         vplc += vinc;
+        saturate_vplc(vplc, vinc);
     }
     while (--cnt);
 
@@ -249,10 +283,12 @@ void mvlineasm4(int32_t cnt, char *p)
             if (ch != 255) p[i] = pal[i][ch];
 #if !defined USE_VECTOR_EXT
             vplc[i] += vinc[i];
+            saturate_vplc(vplc[i], vinc[i]);
 #endif
         }
 #ifdef USE_VECTOR_EXT
         vplc += vinc;
+        saturate_vplc_vec(vplc, vinc);
 #endif
         p += ourbpl;
     }
@@ -268,9 +304,10 @@ void mvlineasm4(int32_t cnt, char *p)
 # define GLOGY glogy
 #endif
 
-void setuptvlineasm(int32_t neglogy)
+void setuptvlineasm(int32_t neglogy, int32_t dosaturate)
 {
     GLOGY = neglogy;
+    set_saturate(dosaturate);
 }
 
 #if !defined USE_ASM64
@@ -295,6 +332,7 @@ int32_t tvlineasm1(int32_t vinc, intptr_t paloffs, int32_t cnt, uint32_t vplc, i
             if (ch != 255) *pp = trans[(*pp)|(pal[ch]<<8)];
             pp += ourbpl;
             vplc += vinc;
+            saturate_vplc_trans(vplc, vinc);
         }
         while (--cnt);
     }
@@ -306,6 +344,7 @@ int32_t tvlineasm1(int32_t vinc, intptr_t paloffs, int32_t cnt, uint32_t vplc, i
             if (ch != 255) *pp = trans[((*pp)<<8)|pal[ch]];
             pp += ourbpl;
             vplc += vinc;
+            saturate_vplc_trans(vplc, vinc);
         }
         while (--cnt);
     }
@@ -347,10 +386,12 @@ void tvlineasm2(uint32_t vplc2, int32_t vinc1, intptr_t bufplc1, intptr_t bufplc
             ch = getpix(logy, buf1, vplc1);
             if (ch != 255) pp[0] = gtrans[pp[0]|(gpal[ch]<<8)];
             vplc1 += vinc1;
+            saturate_vplc_trans(vplc1, vinc1);
 
             ch = getpix(logy, buf2, vplc2);
             if (ch != 255) pp[1] = gtrans[pp[1]|(gpal2[ch]<<8)];
             vplc2 += vinc2;
+            saturate_vplc_trans(vplc2, vinc2);
 
             pp += ourbpl;
         }
@@ -363,10 +404,12 @@ void tvlineasm2(uint32_t vplc2, int32_t vinc1, intptr_t bufplc1, intptr_t bufplc
             ch = getpix(logy, buf1, vplc1);
             if (ch != 255) pp[0] = gtrans[(pp[0]<<8)|gpal[ch]];
             vplc1 += vinc1;
+            saturate_vplc_trans(vplc1, vinc1);
 
             ch = getpix(logy, buf2, vplc2);
             if (ch != 255) pp[1] = gtrans[(pp[1]<<8)|gpal2[ch]];
             vplc2 += vinc2;
+            saturate_vplc_trans(vplc2, vinc2);
 
             pp += ourbpl;
         }
diff --git a/polymer/eduke32/build/src/a.nasm b/polymer/eduke32/build/src/a.nasm
index b94b824f7..ef822022d 100644
--- a/polymer/eduke32/build/src/a.nasm
+++ b/polymer/eduke32/build/src/a.nasm
@@ -656,6 +656,8 @@ CDECLENDSET 1
 	
 	ALIGN 16
 setupmvlineasm:
+    ;; NOTE: We actually receive two args (second one: saturate vplc?), but the
+    ;; second one is currently unused here. See the others: UNUSED_DO_SATURATE.
 CDECLBEGINSET 1
 	mov byte [maskmach3a+2], al
 	mov byte [machmv13+2], al
@@ -668,6 +670,7 @@ CDECLENDSET 1
 
 	ALIGN 16
 setuptvlineasm:
+    ;; UNUSED_DO_SATURATE
 CDECLBEGINSET 1
 	mov byte [transmach3a+2], al
 CDECLENDSET 1
diff --git a/polymer/eduke32/build/src/engine.c b/polymer/eduke32/build/src/engine.c
index 3c9fd7ea1..3b72e671e 100644
--- a/polymer/eduke32/build/src/engine.c
+++ b/polymer/eduke32/build/src/engine.c
@@ -2790,7 +2790,7 @@ static WSHELPER_DECL void calc_vplcinc(uint32_t *vplc, int32_t *vinc, const int3
 //
 // maskwallscan (internal)
 //
-static void maskwallscan(int32_t x1, int32_t x2)
+static void maskwallscan(int32_t x1, int32_t x2, int32_t saturatevplc)
 {
     int32_t x;
     intptr_t p, fpalookup;
@@ -2818,7 +2818,7 @@ static void maskwallscan(int32_t x1, int32_t x2)
 
     fpalookup = FP_OFF(palookup[globalpal]);
 
-    setupmvlineasm(globalshiftval);
+    setupmvlineasm(globalshiftval, saturatevplc);
 
 
     x = x1;
@@ -4021,7 +4021,7 @@ static void transmaskvline2(int32_t x)
 //
 // transmaskwallscan (internal)
 //
-static void transmaskwallscan(int32_t x1, int32_t x2)
+static void transmaskwallscan(int32_t x1, int32_t x2, int32_t saturatevplc)
 {
     int32_t x;
 
@@ -4034,7 +4034,7 @@ static void transmaskwallscan(int32_t x1, int32_t x2)
 
     if (waloff[globalpicnum] == 0) loadtile(globalpicnum);
 
-    setuptvlineasm(globalshiftval);
+    setuptvlineasm(globalshiftval, saturatevplc);
 
     x = x1;
     while ((startumost[x+windowx1] > startdmost[x+windowx1]) && (x <= x2)) x++;
@@ -5808,9 +5808,9 @@ draw_as_face_sprite:
         drawing_sprite = 1;
 
         if ((cstat&2) == 0)
-            maskwallscan(lx,rx);
+            maskwallscan(lx,rx, (cstat&8)==0);
         else
-            transmaskwallscan(lx,rx);
+            transmaskwallscan(lx,rx, (cstat&8)==0);
 
         drawing_sprite = 0;
     }
@@ -6070,9 +6070,9 @@ draw_as_face_sprite:
         drawing_sprite = 1;
 
         if ((cstat&2) == 0)
-            maskwallscan(sx1,sx2);
+            maskwallscan(sx1,sx2, (cstat&8)==0);
         else
-            transmaskwallscan(sx1,sx2);
+            transmaskwallscan(sx1,sx2, (cstat&8)==0);
 
         drawing_sprite = 0;
     }
@@ -6653,7 +6653,7 @@ static void drawmaskwall(int16_t damaskwallcnt)
 
     if ((globalorientation&128) == 0)
     {
-        maskwallscan(xb1[z],xb2[z]);
+        maskwallscan(xb1[z],xb2[z], 0);
     }
     else
     {
@@ -6662,7 +6662,7 @@ static void drawmaskwall(int16_t damaskwallcnt)
             if (globalorientation&512) settransreverse(); else settransnormal();
         }
 
-        transmaskwallscan(xb1[z],xb2[z]);
+        transmaskwallscan(xb1[z],xb2[z], 0);
     }
 }
 
@@ -7417,7 +7417,7 @@ static void dorotatesprite(int32_t sx, int32_t sy, int32_t z, int16_t a, int16_t
             if (dastat&64)
                 setupvlineasm(24L);
             else
-                setupmvlineasm(24L);
+                setupmvlineasm(24L, 0);
 
             by <<= 8; yv <<= 8; yv2 <<= 8;