From aa9d85958e212e9e6d1c5bd27c2e137f572a0e73 Mon Sep 17 00:00:00 2001
From: Martin Gerhardy <martin.gerhardy@gmail.com>
Date: Tue, 14 Jan 2025 17:34:00 +0100
Subject: [PATCH] VOXELGENERATOR: new lua script to flatten errors by certain
 thresholds

---
 src/modules/voxelgenerator/CMakeLists.txt     |  1 +
 .../voxelgenerator/lua/scripts/flatten.lua    | 58 +++++++++++++++++++
 .../voxelgenerator/tests/LUAApiTest.cpp       |  5 ++
 3 files changed, 64 insertions(+)
 create mode 100644 src/modules/voxelgenerator/lua/scripts/flatten.lua

diff --git a/src/modules/voxelgenerator/CMakeLists.txt b/src/modules/voxelgenerator/CMakeLists.txt
index e659e994f..9f6111fed 100644
--- a/src/modules/voxelgenerator/CMakeLists.txt
+++ b/src/modules/voxelgenerator/CMakeLists.txt
@@ -19,6 +19,7 @@ set(LUA_SRCS
 	scripts/delete-rgb.lua
 	scripts/erode.lua
 	scripts/fillhollow.lua
+	scripts/flatten.lua
 	scripts/gameoflife.lua
 	scripts/gradient.lua
 	scripts/grass.lua
diff --git a/src/modules/voxelgenerator/lua/scripts/flatten.lua b/src/modules/voxelgenerator/lua/scripts/flatten.lua
new file mode 100644
index 000000000..8c107071d
--- /dev/null
+++ b/src/modules/voxelgenerator/lua/scripts/flatten.lua
@@ -0,0 +1,58 @@
+--
+-- flatten a model by filling minor gaps between voxels or by removing voxels are not well connected
+--
+
+local vol = require "modules.volume"
+
+function arguments()
+	return {
+		{ name = 'empty', desc = 'The amount of empty voxels that will lead to a removal.', type = 'int', default = '24', min = '1', max = '26' },
+		{ name = 'nonempty', desc = 'The amount of non-empty voxels that will lead to a new voxel.', type = 'int', default = '16', min = '1', max = '25' }
+	}
+end
+
+function main(node, region, color, empty, nonempty)
+	local visitor = function (volume, x, y, z)
+		local emptyVoxels = vol.countEmptyAround(volume, x, y, z, 1)
+		local mins = region:mins()
+		local maxs = region:maxs()
+		local edges = 0
+		if (mins.x == x or maxs.x == x) then
+			edges = edges + 1
+		end
+		if (mins.y == y or maxs.y == y) then
+			edges = edges + 1
+		end
+		if (mins.z == z or maxs.z == z) then
+			edges = edges + 1
+		end
+		if (edges == 3) then
+			emptyVoxels = emptyVoxels - 19
+		end
+		if (edges == 2) then
+			emptyVoxels = emptyVoxels - 15
+		end
+		if (edges == 1) then
+			emptyVoxels = emptyVoxels - 9
+		end
+		local voxel = volume:voxel(x, y, z)
+		if (emptyVoxels >= empty) then
+			if (voxel == -1) then
+				return
+			end
+			g_log.debug("remove voxel at " .. x .. ", " .. y .. ", " .. z .. " because of " .. emptyVoxels .. " empty voxels threshold of: " .. empty)
+			volume:setVoxel(x, y, z, -1)
+		else
+			local occupiedVoxels = 26 - emptyVoxels
+			if (occupiedVoxels >= nonempty) then
+				if (voxel ~= -1) then
+					return
+				end
+				-- TODO: find the best color
+				g_log.debug("add voxel at " .. x .. ", " .. y .. ", " .. z .. " because of " .. occupiedVoxels .. " occupied voxels threshold of: " .. nonempty)
+				volume:setVoxel(x, y, z, color)
+			end
+		end
+	end
+	vol.visitYXZ(node:volume(), region, visitor)
+end
diff --git a/src/modules/voxelgenerator/tests/LUAApiTest.cpp b/src/modules/voxelgenerator/tests/LUAApiTest.cpp
index a3f392e95..dddbe24e1 100644
--- a/src/modules/voxelgenerator/tests/LUAApiTest.cpp
+++ b/src/modules/voxelgenerator/tests/LUAApiTest.cpp
@@ -327,6 +327,11 @@ TEST_F(LUAApiTest, testScriptReplaceColor) {
 	runFile(sceneGraph, "replacecolor.lua");
 }
 
+TEST_F(LUAApiTest, testScriptFlatten) {
+	scenegraph::SceneGraph sceneGraph;
+	runFile(sceneGraph, "flatten.lua");
+}
+
 TEST_F(LUAApiTest, testScriptReplacePalette) {
 	scenegraph::SceneGraph sceneGraph;
 	runFile(sceneGraph, "replacepalette.lua", {"built-in:minecraft"});