give sky its own simple mapgen

src/CMakeLists.txt

@@ -202,6 +202,7 @@ set(common_SRCS
 	mapgen/mapgen_dungeon.cpp
 	mapgen/mapgen_util.cpp
 	mapgen/mapgen_space.cpp
+	mapgen/mapgen_sky.cpp
 	mapgen/mapgen_thedeep.cpp
 	nodemeta/content_nodemeta_circuits.cpp
 	nodemeta/content_nodemeta_sign.cpp

src/mapgen.h

@@ -126,6 +126,9 @@ namespace mapgen
 	/* defined in mapgen_space.cpp */
 	void make_space(BlockMakeData *data);
 
+	/* defined in mapgen_sky.cpp */
+	void make_sky(BlockMakeData *data);
+
 	/* defined in mapgen_thedeep.cpp */
 	void make_thedeep(BlockMakeData *data);
 

src/mapgen/mapgen.cpp

@@ -51,6 +51,11 @@ void make_block(BlockMakeData *data)
 		return;
 	}
 
+	if (data->biome == BIOME_SKY) {
+		make_sky(data);
+		return;
+	}
+
 	v3s16 blockpos = data->blockpos;
 
 	ManualMapVoxelManipulator &vmanip = *(data->vmanip);

src/mapgen/mapgen_sky.cpp

@@ -0,0 +1,64 @@
+/************************************************************************
+* Minetest-c55
+* Copyright (C) 2010-2011 celeron55, Perttu Ahola <celeron55@gmail.com>
+*
+* mapgen.cpp
+* voxelands - 3d voxel world sandbox game
+* Copyright (C) Lisa 'darkrose' Milne 2014-2017 <lisa@ltmnet.com>
+*
+* This program is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+*
+* This program is distributed in the hope that it will be useful, but
+* WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+* See the GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program.  If not, see <http://www.gnu.org/licenses/>
+*
+* License updated from GPLv2 or later to GPLv3 or later by Lisa Milne
+* for Voxelands.
+************************************************************************/
+
+#include "mapgen.h"
+#include "voxel.h"
+#include "content_mapnode.h"
+#include "noise.h"
+#include "mapblock.h"
+#include "map.h"
+#include "mineral.h"
+
+namespace mapgen
+{
+
+void make_sky(BlockMakeData *data)
+{
+	v3s16 blockpos = data->blockpos;
+
+	ManualMapVoxelManipulator &vmanip = *(data->vmanip);
+	// Area of center block
+	v3s16 node_min = blockpos*MAP_BLOCKSIZE;
+	v3s16 node_max = (blockpos+v3s16(1,1,1))*MAP_BLOCKSIZE-v3s16(1,1,1);
+
+	v2s16 p2d_center(node_min.X+MAP_BLOCKSIZE/2, node_min.Z+MAP_BLOCKSIZE/2);
+
+	for (s16 x=node_min.X; x<=node_max.X; x++)
+	for (s16 z=node_min.Z; z<=node_max.Z; z++) {
+		// Node position
+		v2s16 p2d(x,z);
+		{
+			// Use fast index incrementing
+			v3s16 em = vmanip.m_area.getExtent();
+			u32 i = vmanip.m_area.index(v3s16(p2d.X, node_min.Y, p2d.Y));
+			for (s16 y=node_min.Y; y<=node_max.Y; y++) {
+				vmanip.m_data[i] = MapNode(CONTENT_AIR);
+				data->vmanip->m_area.add_y(em, i, 1);
+			}
+		}
+	}
+}
+
+}