Lunatic: show on-screen errors even in passive menu; fix '(display)rand*' for large values.

Also, some minor style cleanup in game.c. DONT_BUILD.

git-svn-id: https://svn.eduke32.com/eduke32@4815 1a8010ca-5511-0410-912e-c29ae57300e0

polymer/eduke32/source/demo.c

@@ -787,6 +787,9 @@ nextdemo_nomenu:
         if (foundemo == 0)
         {
             G_DrawBackground();
+#ifdef LUNATIC
+            El_DisplayErrors();
+#endif
         }
         else
         {

polymer/eduke32/source/game.c

@@ -3963,18 +3963,20 @@ static int32_t G_DoThirdPerson(const DukePlayer_t *pp, vec3_t *vect, int16_t *vs
 void G_DrawBackground(void)
 {
     const int32_t dapicnum = BIGHOLE;
-    int32_t x,y,x1,y1,x2,y2,rx;
+    int32_t x,y,x1,x2;
 
     flushperms();
 
+    // XXX: if dapicnum is not available, this might leave the menu background
+    // not drawn, leading to "HOM".
     if (tilesiz[dapicnum].x == 0 || tilesiz[dapicnum].y == 0)
     {
         pus = pub = NUMPAGES;
         return;
     }
 
-    y1 = 0;
+    int32_t y1=0, y2=ydim;
-    y2 = ydim;
+
     if ((g_player[myconnectindex].ps->gm&MODE_GAME) || ud.recstat == 2)
     {
         if (GametypeFlags[ud.coop] & GAMETYPE_FRAGBAR)
@@ -4007,6 +4009,7 @@ void G_DrawBackground(void)
                         rotatesprite_fs(x<<16,y<<16,65536L,0,bgtile,16,0,8+16+64);
         }
         else rotatesprite_fs(160<<16,100<<16,65536L,0,bgtile,16,0,2+8+64+(ud.bgstretch?1024:0));
+
         return;
     }
 
@@ -4020,7 +4023,7 @@ void G_DrawBackground(void)
                 rotatesprite(x<<16,y<<16,65536L,0,dapicnum,8,0,8+16+64,0,y1,xdim-1,windowy1-1);
 
         // sides
-        rx = windowx2-windowx2%tilesiz[dapicnum].x;
+        const int32_t rx = windowx2-windowx2%tilesiz[dapicnum].x;
         for (y=windowy1-windowy1%tilesiz[dapicnum].y; y<windowy2; y+=tilesiz[dapicnum].y)
             for (x=0; x<windowx1 || x+rx<xdim; x+=tilesiz[dapicnum].x)
             {

polymer/eduke32/source/lunatic/control.lua

@@ -460,11 +460,11 @@ end
 --- Legacy operators ---
 
 function _rand(x)
-    return rshift(ffiC.krand()*(x+1), 16)
+    return tobit((ffiC.krand()*(x+1))/65536)
 end
 
 function _displayrand(x)
-    return rshift(math.random(0, 32767)*(x+1), 15)
+    return tobit((math.random(0, 32767)*(x+1))/32768)
 end
 
 do