Disable the GL sprite shadows behind a #define.

Reasoning:
* They're horribly broken (they completely ignore slopes).
* A similar final demo GL-only feature (coronas) has been completely disabled.
* Nobody's going to bugfix them before release because not even the devteam's resident GL users use them.
* They look ugly.

src/hardware/hw_main.c

@@ -4068,6 +4068,7 @@ static gr_vissprite_t *HWR_NewVisSprite(void)
 	return HWR_GetVisSprite(gr_visspritecount++);
 }
 
+#ifdef GLBADSHADOWS
 // Finds a floor through which light does not pass.
 static fixed_t HWR_OpaqueFloorAtPos(fixed_t x, fixed_t y, fixed_t z, fixed_t height)
 {
@@ -4098,6 +4099,7 @@ static fixed_t HWR_OpaqueFloorAtPos(fixed_t x, fixed_t y, fixed_t z, fixed_t hei
 
 	return floorz;
 }
+#endif //#ifdef GLBADSHADOWS
 
 //
 // HWR_DoCulling
@@ -4139,6 +4141,7 @@ static boolean HWR_DoCulling(line_t *cullheight, line_t *viewcullheight, float v
 	return false;
 }
 
+#ifdef GLBADSHADOWS
 static void HWR_DrawSpriteShadow(gr_vissprite_t *spr, GLPatch_t *gpatch, float this_scale)
 {
 	FOutVector swallVerts[4];
@@ -4311,6 +4314,7 @@ static void HWR_DrawSpriteShadow(gr_vissprite_t *spr, GLPatch_t *gpatch, float t
 		HWD.pfnDrawPolygon(&sSurf, swallVerts, 4, PF_Translucent|PF_Modulated|PF_Clip);
 	}
 }
+#endif //#ifdef GLBADSHADOWS
 
 // This is expecting a pointer to an array containing 4 wallVerts for a sprite
 static void HWR_RotateSpritePolyToAim(gr_vissprite_t *spr, FOutVector *wallVerts)
@@ -4386,6 +4390,7 @@ static void HWR_SplitSprite(gr_vissprite_t *spr)
 	//Hurdler: 25/04/2000: now support colormap in hardware mode
 	HWR_GetMappedPatch(gpatch, spr->colormap);
 
+#ifdef GLBADSHADOWS
 	// Draw shadow BEFORE sprite
 	if (cv_shadow.value // Shadows enabled
 		&& (spr->mobj->flags & (MF_SCENERY|MF_SPAWNCEILING|MF_NOGRAVITY)) != (MF_SCENERY|MF_SPAWNCEILING|MF_NOGRAVITY) // Ceiling scenery have no shadow.
@@ -4401,6 +4406,7 @@ static void HWR_SplitSprite(gr_vissprite_t *spr)
 		////////////////////
 		HWR_DrawSpriteShadow(spr, gpatch, this_scale);
 	}
+#endif //#ifdef GLBADSHADOWS
 
 	baseWallVerts[0].x = baseWallVerts[3].x = spr->x1;
 	baseWallVerts[2].x = baseWallVerts[1].x = spr->x2;
@@ -4788,6 +4794,7 @@ static void HWR_DrawSprite(gr_vissprite_t *spr)
 	//Hurdler: 25/04/2000: now support colormap in hardware mode
 	HWR_GetMappedPatch(gpatch, spr->colormap);
 
+#ifdef GLBADSHADOWS
 	// Draw shadow BEFORE sprite
 	if (cv_shadow.value // Shadows enabled
 		&& (spr->mobj->flags & (MF_SCENERY|MF_SPAWNCEILING|MF_NOGRAVITY)) != (MF_SCENERY|MF_SPAWNCEILING|MF_NOGRAVITY) // Ceiling scenery have no shadow.
@@ -4803,6 +4810,7 @@ static void HWR_DrawSprite(gr_vissprite_t *spr)
 		////////////////////
 		HWR_DrawSpriteShadow(spr, gpatch, this_scale);
 	}
+#endif //#ifdef GLBADSHADOWS
 
 	// if it has a dispoffset, push it a little towards the camera
 	if (spr->dispoffset) {

src/r_main.c

@@ -123,8 +123,12 @@ consvar_t cv_chasecam2 = {"chasecam2", "On", CV_CALL, CV_OnOff, ChaseCam2_OnChan
 consvar_t cv_flipcam = {"flipcam", "No", CV_SAVE|CV_CALL|CV_NOINIT, CV_YesNo, FlipCam_OnChange, 0, NULL, NULL, 0, 0, NULL};
 consvar_t cv_flipcam2 = {"flipcam2", "No", CV_SAVE|CV_CALL|CV_NOINIT, CV_YesNo, FlipCam2_OnChange, 0, NULL, NULL, 0, 0, NULL};
 
+#if defined(FLOORSPLATS) || defined(GLBADSHADOWS)
 consvar_t cv_shadow = {"shadow", "Off", CV_SAVE, CV_OnOff, NULL, 0, NULL, NULL, 0, 0, NULL};
+#endif //#if defined(FLOORSPLATS) || defined(GLBADSHADOWS)
+#ifdef GLBADSHADOWS
 consvar_t cv_shadowoffs = {"offsetshadows", "Off", CV_SAVE, CV_OnOff, NULL, 0, NULL, NULL, 0, 0, NULL};
+#endif //#ifdef GLBADSHADOWS
 consvar_t cv_skybox = {"skybox", "On", CV_SAVE, CV_OnOff, NULL, 0, NULL, NULL, 0, 0, NULL};
 consvar_t cv_allowmlook = {"allowmlook", "Yes", CV_NETVAR, CV_YesNo, NULL, 0, NULL, NULL, 0, 0, NULL};
 consvar_t cv_showhud = {"showhud", "Yes", CV_CALL,  CV_YesNo, R_SetViewSize, 0, NULL, NULL, 0, 0, NULL};
@@ -1172,8 +1176,12 @@ void R_RegisterEngineStuff(void)
 
 	CV_RegisterVar(&cv_chasecam);
 	CV_RegisterVar(&cv_chasecam2);
+#if defined(FLOORSPLATS) || defined(GLBADSHADOWS)
 	CV_RegisterVar(&cv_shadow);
+#endif //#if defined(FLOORSPLATS) || defined(GLBADSHADOWS)
+#ifdef GLBADSHADOWS
 	CV_RegisterVar(&cv_shadowoffs);
+#endif //#ifdef GLBADSHADOWS
 	CV_RegisterVar(&cv_skybox);
 
 	CV_RegisterVar(&cv_cam_dist);

src/r_main.h

@@ -76,7 +76,12 @@ extern consvar_t cv_showhud, cv_translucenthud;
 extern consvar_t cv_homremoval;
 extern consvar_t cv_chasecam, cv_chasecam2;
 extern consvar_t cv_flipcam, cv_flipcam2;
-extern consvar_t cv_shadow, cv_shadowoffs;
+#if defined(FLOORSPLATS) || defined(GLBADSHADOWS)
+extern consvar_t cv_shadow;
+#endif
+#ifdef GLBADSHADOWS
+extern conscar_t cv_shadowoffs;
+#endif //#ifdef GLBADSHADOWS
 extern consvar_t cv_translucency;
 extern consvar_t cv_drawdist, cv_drawdist_nights, cv_drawdist_precip;
 extern consvar_t cv_skybox;