Document the deprecation of hardcoded cave liquids (#8692)

builtin/settingtypes.txt

@@ -1375,6 +1375,7 @@ mgv5_cave_width (Cave width) float 0.09
 #    Y of upper limit of large caves.
 mgv5_large_cave_depth (Large cave depth) int -256
 
+#    Deprecated, define and locate cave liquids using biome definitions instead.
 #    Y of upper limit of lava in large caves.
 mgv5_lava_depth (Lava depth) int -256
 
@@ -1491,6 +1492,7 @@ mgv7_cave_width (Cave width) float 0.09
 #    Y of upper limit of large caves.
 mgv7_large_cave_depth (Large cave depth) int -33
 
+#    Deprecated, define and locate cave liquids using biome definitions instead.
 #    Y of upper limit of lava in large caves.
 mgv7_lava_depth (Lava depth) int -256
 
@@ -1598,6 +1600,7 @@ mgcarpathian_cave_width (Cave width) float 0.09
 #    Y of upper limit of large caves.
 mgcarpathian_large_cave_depth (Large cave depth) int -33
 
+#    Deprecated, define and locate cave liquids using biome definitions instead.
 #    Y of upper limit of lava in large caves.
 mgcarpathian_lava_depth (Lava depth) int -256
 
@@ -1681,6 +1684,7 @@ mgflat_ground_level (Ground level) int 8
 #    Y of upper limit of large caves.
 mgflat_large_cave_depth (Large cave depth) int -33
 
+#    Deprecated, define and locate cave liquids using biome definitions instead.
 #    Y of upper limit of lava in large caves.
 mgflat_lava_depth (Lava depth) int -256
 
@@ -1734,6 +1738,7 @@ mgfractal_cave_width (Cave width) float 0.09
 #    Y of upper limit of large caves.
 mgfractal_large_cave_depth (Large cave depth) int -33
 
+#    Deprecated, define and locate cave liquids using biome definitions instead.
 #    Y of upper limit of lava in large caves.
 mgfractal_lava_depth (Lava depth) int -256
 
@@ -1856,6 +1861,7 @@ mgvalleys_altitude_chill (Altitude chill) int 90
 #    Depth below which you'll find large caves.
 mgvalleys_large_cave_depth (Large cave depth) int -33
 
+#    Deprecated, define and locate cave liquids using biome definitions instead.
 #    Y of upper limit of lava in large caves.
 mgvalleys_lava_depth (Lava depth) int 1
 

src/mapgen/cavegen.cpp

@@ -29,6 +29,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "mg_biome.h"
 #include "cavegen.h"
 
+// TODO Remove this. Cave liquids are now defined and located using biome definitions
 static NoiseParams nparams_caveliquids(0, 1, v3f(150.0, 150.0, 150.0), 776, 3, 0.6, 2.0);
 
 
@@ -526,7 +527,9 @@ void CavesRandomWalk::carveRoute(v3f vec, float f, bool randomize_xz)
 		if (use_biome_liquid) {
 			liquidnode = c_biome_liquid;
 		} else {
-			// If cave liquid not defined by biome, fallback to old hardcoded behaviour
+			// TODO remove this. Cave liquids are now defined and located using biome
+			// definitions.
+			// If cave liquid not defined by biome, fallback to old hardcoded behaviour.
 			float nval = NoisePerlin3D(np_caveliquids, startp.X,
 				startp.Y, startp.Z, seed);
 			liquidnode = (nval < 0.40f && node_max.Y < lava_depth) ?

src/mapgen/cavegen.h

@@ -119,6 +119,8 @@ public:
 	// configurable parameters
 	s32 seed;
 	int water_level;
+	// TODO 'lava_depth' and 'np_caveliquids' are deprecated and should be removed.
+	// Cave liquids are now defined and located using biome definitions.
 	int lava_depth;
 	NoiseParams *np_caveliquids;
 

src/mapgen/mapgen.h

@@ -278,5 +278,7 @@ protected:
 	float cavern_limit;
 	float cavern_taper;
 	float cavern_threshold;
+	// TODO 'lava_depth' is deprecated and should be removed. Cave liquids are
+	// now defined and located using biome definitions.
 	int lava_depth;
 };