From 77b05f044a7b35e3699159716428117b3416ee1b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ga=C3=ABl=20C?= <gael-de-sailly@netc.eu>
Date: Mon, 12 Feb 2024 22:22:24 +0100
Subject: [PATCH] Added caves (hardcoded for now)

---
 mapgen.lua | 59 +++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 52 insertions(+), 7 deletions(-)

diff --git a/mapgen.lua b/mapgen.lua
index 952f9fa..101a1b8 100644
--- a/mapgen.lua
+++ b/mapgen.lua
@@ -28,12 +28,13 @@ local floor, min = math.floor, math.min
 
 local data = {}
 
-local noise_x_obj, noise_z_obj, noise_distort_obj, noise_heat_obj, noise_heat_blend_obj
+local noise_x_obj, noise_z_obj, noise_distort_obj, noise_heat_obj, noise_heat_blend_obj, noise_cave_obj
 local noise_x_map = {}
 local noise_z_map = {}
 local noise_distort_map = {}
 local noise_heat_map = {}
 local noise_heat_blend_map = {}
+local noise_cave = {}
 local mapsize
 local init = false
 
@@ -41,6 +42,18 @@ local sumtime = 0
 local sumtime2 = 0
 local ngen = 0
 
+local use_caves = true
+local np_cave = {
+	offset = 0,
+	scale = 8,
+	spread = {x=256, y=128, z=256},
+	seed = -9152,
+	octaves = 4,
+	persist = 0.65,
+	lacunarity = 2,
+	flags = "absvalue",
+}
+
 function mapgen_rivers.make_chunk(minp, maxp, seed)
 	minetest.log("info", ("[mapgen_rivers] Generating from %s to %s"):format(minetest.pos_to_string(minp), minetest.pos_to_string(maxp)))
 
@@ -65,6 +78,9 @@ function mapgen_rivers.make_chunk(minp, maxp, seed)
 			noise_heat_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.heat, chulens)
 			noise_heat_blend_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.heat_blend, chulens)
 		end
+		if use_caves then
+			noise_cave_obj = minetest.get_perlin_map(np_cave, mapsize)
+		end
 		init = true
 	end
 
@@ -79,7 +95,9 @@ function mapgen_rivers.make_chunk(minp, maxp, seed)
 		noise_heat_obj:get_2d_map_flat(minp2d, noise_heat_map)
 		noise_heat_blend_obj:get_2d_map_flat(minp2d, noise_heat_blend_map)
 	end
-
+	if use_caves then
+		noise_cave_obj:get_3d_map_flat(minp, noise_cave)
+	end
 	local terrain_map, lake_map, incr, i_origin
 
 	if use_distort then
@@ -146,6 +164,7 @@ function mapgen_rivers.make_chunk(minp, maxp, seed)
 	local c_stone = minetest.get_content_id("mapgen_stone")
 	local c_water = minetest.get_content_id("mapgen_water_source")
 	local c_rwater = minetest.get_content_id("mapgen_river_water_source")
+	local c_air = minetest.get_content_id("air")
 
 	local c_dirt, c_lawn, c_dirtsnow, c_snow, c_sand, c_ice
 	if use_biomes then
@@ -178,7 +197,7 @@ function mapgen_rivers.make_chunk(minp, maxp, seed)
 			if use_biomes then
 				temperature = noise_heat_map[i2d]+noise_heat_blend_map[i2d]
 			end
-			local terrain, lake
+			local terrain, lake, caveness
 			if not use_distort then
 				terrain = terrain_map[i2d]
 				lake = lake_map[i2d]
@@ -200,6 +219,10 @@ function mapgen_rivers.make_chunk(minp, maxp, seed)
 					lake = min(lake_map[i0], lake_map[i1], lake_map[i2], lake_map[i3])
 				end
 
+				if use_caves then
+					noise_cave[nid] = noise_cave[nid] < math.min(math.max(terrain - y, 0), 100) ^ 0.5 / 10
+				end
+
 				if y <= maxp.y then
 
 					local is_lake = lake > terrain
@@ -249,10 +272,32 @@ function mapgen_rivers.make_chunk(minp, maxp, seed)
 	end
 
 	if use_biomegen_mod then
-		biomegen.generate_all(data, a, vm, minp, maxp, seed)
-	else
-		vm:set_data(data)
-		minetest.generate_ores(vm, minp, maxp)
+		biomegen.generate_biomes(data, a, minp, maxp)
+	end
+	if use_caves then
+		local i = 1
+		for z=minp.z, maxp.z do
+			for y=minp.y, maxp.y do
+				local vi = a:index(minp.x, y, z)
+				for x=minp.x, maxp.x do
+					if noise_cave[i] then
+						data[vi] = c_air
+					end
+					i = i + 1
+					vi = vi + 1
+				end
+			end
+			i = i + chulens.x -- Skip etra row
+		end		
+	end
+	vm:set_data(data)
+	if use_biomegen_mod then
+		biomegen.place_all_decos(data, a, vm, minp, maxp, seed)
+	end
+	minetest.generate_ores(vm, minp, maxp)
+	if use_biomegen_mod then
+		vm:get_data(data)
+		biomegen.dust_top_nodes(data, a, vm, minp, maxp)
 	end
 
 	vm:set_lighting({day = 0, night = 0})