Subject: Enable shading support as a command line option "--shading".
Author: Fabian Greffrath <fabian+debian@greffrath.com>

--- a/Makefile
+++ b/Makefile
@@ -65,6 +65,7 @@ SRCS += wl_agent.cpp
 SRCS += wl_atmos.cpp
 SRCS += wl_cloudsky.cpp
 SRCS += wl_debug.cpp
+SRCS += wl_shade.cpp
 SRCS += wl_draw.cpp
 SRCS += wl_floorceiling.cpp
 SRCS += wl_game.cpp
--- a/version.h
+++ b/version.h
@@ -32,7 +32,7 @@
 #endif
 
 //#define USE_FEATUREFLAGS    // Enables the level feature flags (see bottom of wl_def.h)
-//#define USE_SHADING         // Enables shading support (see wl_shade.cpp)
+#define USE_SHADING         // Enables shading support (see wl_shade.cpp)
 //#define USE_DIR3DSPR        // Enables directional 3d sprites (see wl_dir3dspr.cpp)
 //#define USE_FLOORCEILINGTEX // Enables floor and ceiling textures stored in the third mapplane (see wl_floorceiling.cpp)
 //#define USE_HIRES           // Enables high resolution textures/sprites (128x128)
--- a/wl_def.h
+++ b/wl_def.h
@@ -933,6 +933,7 @@ extern  int      param_audiobuffer;
 extern  int      param_mission;
 extern  boolean  param_goodtimes;
 extern  boolean  param_ignorenumchunks;
+extern  boolean  param_shading;
 
 
 void            NewGame (int difficulty,int episode);
--- a/wl_dir3dspr.cpp
+++ b/wl_dir3dspr.cpp
@@ -101,10 +101,11 @@ void Scale3DShaper(int x1, int x2, int s
                         if(scrstarty!=screndy && screndy>0)
                         {
 #ifdef USE_SHADING
+                            if (param_shading)
                             col=curshades[((byte *)shape)[newstart+j]];
-#else
-                            col=((byte *)shape)[newstart+j];
+                            else
 #endif
+                            col=((byte *)shape)[newstart+j];
                             if(scrstarty<0) scrstarty=0;
                             if(screndy>viewheight) screndy=viewheight,j=endy;
 
--- a/wl_draw.cpp
+++ b/wl_draw.cpp
@@ -307,10 +307,11 @@ void ScalePost()
     if(yw < 0) return;
 
 #ifdef USE_SHADING
+    if (param_shading)
     col = curshades[postsource[yw]];
-#else
-    col = postsource[yw];
+    else
 #endif
+    col = postsource[yw];
     yendoffs = yendoffs * vbufPitch + postx;
     while(yoffs <= yendoffs)
     {
@@ -326,10 +327,11 @@ void ScalePost()
             while(ywcount <= 0);
             if(yw < 0) break;
 #ifdef USE_SHADING
+            if (param_shading)
             col = curshades[postsource[yw]];
-#else
-            col = postsource[yw];
+            else
 #endif
+            col = postsource[yw];
         }
         yendoffs -= vbufPitch;
     }
@@ -640,16 +642,21 @@ void VGAClearScreen (void)
     int y;
     byte *ptr = vbuf;
 #ifdef USE_SHADING
+    if (param_shading)
+    {
     for(y = 0; y < viewheight / 2; y++, ptr += vbufPitch)
         memset(ptr, shadetable[GetShade((viewheight / 2 - y) << 3)][ceiling], viewwidth);
     for(; y < viewheight; y++, ptr += vbufPitch)
         memset(ptr, shadetable[GetShade((y - viewheight / 2) << 3)][0x19], viewwidth);
-#else
+    }
+    else
+#endif
+    {
     for(y = 0; y < viewheight / 2; y++, ptr += vbufPitch)
         memset(ptr, ceiling, viewwidth);
     for(; y < viewheight; y++, ptr += vbufPitch)
         memset(ptr, 0x19, viewwidth);
-#endif
+    }
 }
 
 //==========================================================================
@@ -756,10 +763,11 @@ void ScaleShape (int xcenter, int shapen
                             if(scrstarty!=screndy && screndy>0)
                             {
 #ifdef USE_SHADING
+                                if (param_shading)
                                 col=curshades[((byte *)shape)[newstart+j]];
-#else
-                                col=((byte *)shape)[newstart+j];
+                                else
 #endif
+                                col=((byte *)shape)[newstart+j];
                                 if(scrstarty<0) scrstarty=0;
                                 if(screndy>viewheight) screndy=viewheight,j=endy;
 
--- a/wl_floorceiling.cpp
+++ b/wl_floorceiling.cpp
@@ -66,16 +66,21 @@ void DrawFloorAndCeiling(byte *vbuf, uns
                     v = (gv >> (TILESHIFT - TEXTURESHIFT)) & (TEXTURESIZE - 1);
                     unsigned texoffs = (u << TEXTURESHIFT) + (TEXTURESIZE - 1) - v;
 #ifdef USE_SHADING
+                    if (param_shading)
+                    {
                     if(curtoptex)
                         vbuf[top_add] = curshades[toptex[texoffs]];
                     if(curbottex)
                         vbuf[bot_add] = curshades[bottex[texoffs]];
-#else
+                    }
+                    else
+#endif
+                    {
                     if(curtoptex)
                         vbuf[top_add] = toptex[texoffs];
                     if(curbottex)
                         vbuf[bot_add] = bottex[texoffs];
-#endif
+                    }
                 }
             }
             gu += du;
--- a/wl_main.cpp
+++ b/wl_main.cpp
@@ -102,6 +102,7 @@ int     param_audiobuffer = 2048 / (4410
 int     param_mission = 0;
 boolean param_goodtimes = false;
 boolean param_ignorenumchunks = false;
+boolean param_shading = false;
 
 /*
 =============================================================================
@@ -1717,6 +1718,10 @@ void CheckParameters(int argc, char *arg
             fullscreen = false;
             forcegrabmouse = true;
         }
+#ifdef USE_SHADING
+        else IFARG("--shading")
+            param_shading = true;
+#endif
         else IFARG("--res")
         {
             if(i + 2 >= argc)
@@ -1897,6 +1902,9 @@ void CheckParameters(int argc, char *arg
             " --hard                 Sets the difficulty to hard for tedlevel\n"
             " --nowait               Skips intro screens\n"
             " --windowed[-mouse]     Starts the game in a window [and grabs mouse]\n"
+#ifdef USE_SHADING
+            " --shading              Enables shading support\n"
+#endif
             " --res <width> <height> Sets the screen resolution\n"
             "                        (must be multiple of 320x200 or 320x240)\n"
             " --resf <w> <h>         Sets any screen resolution >= 320x200\n"