commit 4ffab163030d92ddc00751e9e3bd2251a30d600b
Author: Perttu Ahola <celeron55@gmail.com>
Date:   Sat Apr 1 18:17:00 2023 +0300

    Initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..151e299
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+.*
+!.gitignore
+*~
diff --git a/init.lua b/init.lua
new file mode 100644
index 0000000..f412f3d
--- /dev/null
+++ b/init.lua
@@ -0,0 +1,443 @@
+-- Function to calculate the positions of nodes inside the box
+-- box: A table containing yaw angle (in radians), dimensions, and the origin position
+function get_nodes_in_box(box)
+	local yaw, dimensions, origin = box.yaw, box.dimensions, box.origin
+	local longitudinal, transverse, height = dimensions[1], dimensions[2], dimensions[3]
+	local nodes = {}
+
+	local sin_yaw = math.sin(yaw)
+	local cos_yaw = math.cos(yaw)
+
+	for x = -math.floor(longitudinal / 2), math.floor(longitudinal / 2) do
+		for y = 0, height - 1 do
+			for z = -math.floor(transverse / 2), math.floor(transverse / 2) do
+				local rotated_x = origin.x + (x * cos_yaw - z * sin_yaw)
+				local rotated_y = origin.y + y
+				local rotated_z = origin.z + (x * sin_yaw + z * cos_yaw)
+
+				local node_pos = {x = math.floor(rotated_x), y = math.floor(rotated_y), z = math.floor(rotated_z)}
+				table.insert(nodes, node_pos)
+			end
+		end
+	end
+
+	return nodes
+end
+
+-- Function to get non-walkable nodes in the box
+-- box: A table containing yaw angle (in radians), dimensions, and the origin position
+function get_non_walkable_nodes_in_box(box)
+	local all_nodes = get_nodes_in_box(box)
+	local non_walkable_nodes = {}
+
+	for _, node_pos in ipairs(all_nodes) do
+		local node = minetest.get_node(node_pos)
+		local node_def = minetest.registered_nodes[node.name]
+		if node_def and not node_def.walkable or node_def.drawtype ~= "normal" then
+			table.insert(non_walkable_nodes, node_pos)
+		end
+	end
+
+	return non_walkable_nodes
+end
+
+function get_walkable_nodes_in_box(box)
+	local all_nodes = get_nodes_in_box(box)
+	local walkable_nodes = {}
+
+	for _, node_pos in ipairs(all_nodes) do
+		local node = minetest.get_node(node_pos)
+		local node_def = minetest.registered_nodes[node.name]
+		if node_def and node_def.walkable then
+			table.insert(walkable_nodes, node_pos)
+		end
+	end
+
+	return walkable_nodes
+end
+
+-- Function to create a virtual wall in front of the player and move nodes in front of the wall
+function create_virtual_wall(player_pos_float, player_yaw, wall_dimensions, move_distance,
+		placement_height, placement_depth)
+	local player_pos = {
+		x = player_pos_float.x + 0.5,
+		y = player_pos_float.y + 0.5,
+		z = player_pos_float.z + 0.5,
+	}
+
+	local wall_pos = {
+		x = player_pos.x + math.cos(player_yaw) * 0,
+		y = player_pos.y,
+		z = player_pos.z + math.sin(player_yaw) * 0,
+	}
+
+	local wall_box = {
+		yaw = player_yaw,
+		dimensions = wall_dimensions,
+		origin = {
+			x = wall_pos.x + math.cos(player_yaw),
+			y = wall_pos.y + 1.5 - 1,
+			z = wall_pos.z + math.sin(player_yaw),
+		},
+	}
+
+	local nodes_in_wall = get_nodes_in_box(wall_box)
+
+	-- Main placement box in front
+
+	local placement_box = {
+		yaw = player_yaw,
+		dimensions = {move_distance, wall_dimensions[2], placement_height - placement_depth},
+		origin = {
+			x = player_pos.x + math.cos(player_yaw) * 5,
+			y = player_pos.y + 1.5 + placement_depth,
+			z = player_pos.z + math.sin(player_yaw) * 5,
+		},
+	}
+
+	local non_walkable_nodes_in_placement_box = get_non_walkable_nodes_in_box(placement_box)
+
+	table.sort(non_walkable_nodes_in_placement_box, function(a, b) return a.y < b.y end)
+
+	-- Side placement boxes
+
+	local side_box_width = wall_dimensions[2]
+
+	local left_box = {
+		yaw = player_yaw,
+		dimensions = {move_distance, side_box_width, wall_dimensions[3] + 2},
+		origin = {
+			x = player_pos.x + math.cos(player_yaw+math.pi/2) * side_box_width,
+			y = player_pos.y + 0.5 * wall_dimensions[3] - 3,
+			z = player_pos.z + math.sin(player_yaw+math.pi/2) * side_box_width,
+		},
+	}
+
+	local nwn_in_left_box = get_non_walkable_nodes_in_box(left_box)
+
+	local right_box = {
+		yaw = player_yaw,
+		dimensions = {move_distance, side_box_width, wall_dimensions[3] + 2},
+		origin = {
+			x = player_pos.x + math.cos(player_yaw-math.pi/2) * side_box_width,
+			y = player_pos.y + 0.5 * wall_dimensions[3] - 3,
+			z = player_pos.z + math.sin(player_yaw-math.pi/2) * side_box_width,
+		},
+	}
+
+	local nwn_in_right_box = get_non_walkable_nodes_in_box(right_box)
+
+	local nwn_left_right_combined = {}
+
+	for i, node_pos in ipairs(nwn_in_left_box) do
+		table.insert(nwn_left_right_combined, node_pos)
+	end
+	for i, node_pos in ipairs(nwn_in_right_box) do
+		table.insert(nwn_left_right_combined, node_pos)
+	end
+
+	table.sort(nwn_left_right_combined, function(a, b) return a.y < b.y end)
+
+	for i, node_pos in ipairs(nwn_left_right_combined) do
+		table.insert(non_walkable_nodes_in_placement_box, node_pos)
+	end
+
+	local num_sounds_played = 0
+
+	for i, node_pos in ipairs(nodes_in_wall) do
+		local node = minetest.get_node(node_pos)
+		if node.name ~= "air" then
+			if #non_walkable_nodes_in_placement_box > 0 then
+				minetest.set_node(non_walkable_nodes_in_placement_box[1], node)
+				minetest.remove_node(node_pos)
+				table.remove(non_walkable_nodes_in_placement_box, 1)
+
+				if num_sounds_played < 1 then
+					local node_def = minetest.registered_nodes[node.name]
+					if node_def then
+						local sounds = node_def.sounds
+						if sounds and sounds.dig then
+							num_sounds_played = num_sounds_played + 1
+							minetest.sound_play(sounds.dig, {pos = pos, gain = 0.5})
+						end
+					end
+				end
+			end
+		end
+	end
+end
+
+function target_value(current, target, rate)
+	if current < target - rate then
+		return current + rate
+	elseif current > target + rate then
+		return current - rate
+	else
+		return target
+	end
+end
+
+local BULLDOZER_SIZE = 3
+local BULLDOZER_HEIGHT = 1
+local CLEAR_HEIGHT = 10
+local PLACEMENT_HEIGHT = 3
+local PLACEMENT_DEPTH = -5
+
+-- Register the bulldozer entity
+minetest.register_entity("bulldozer:bulldozer", {
+    initial_properties = {
+        physical = true,
+        collisionbox = {-1.4, -0.5, -1.4, 1.4, 0.8, 1.4},
+        visual = "mesh",
+        mesh = "bulldozer_bulldozer.obj",
+		textures = {
+			"bulldozer_bulldozer_blade.png",
+			"bulldozer_bulldozer_track.png",
+			"bulldozer_bulldozer_track.png",
+			"bulldozer_bulldozer_body.png",
+			"bulldozer_bulldozer_body.png",
+			"bulldozer_bulldozer_body.png",
+		},
+    },
+    driver = nil,
+	wanted_sound_pitch = 0.7,
+	played_sound_pitch = 0.0,
+	wanted_sound_gain = 0.2,
+	played_sound_gain = 0.0,
+
+    on_rightclick = function(self, clicker)
+        if not clicker or not clicker:is_player() then
+            return
+        end
+
+        local player_name = clicker:get_player_name()
+
+        if self.driver and player_name == self.driver:get_player_name() then
+            -- Detach the player
+            self.driver:set_detach()
+            self.driver:set_eye_offset()
+            self.driver = nil
+            self.object:set_properties({
+				physical = true,
+			})
+			if self.sound_handle then minetest.sound_stop(self.sound_handle) end
+        elseif not self.driver then
+            -- Attach the player
+            self.driver = clicker
+            self.driver:set_attach(self.object, "", {x = 0, y = 0, z = 0}, {x = 0, y = -90, z = 0})
+            self.driver:set_eye_offset({x = 0, y = 2, z = 0})
+            self.object:set_properties({
+				physical = false, -- We want to go through nodes
+			})
+			self.wanted_sound_pitch = 0.7
+			self.wanted_sound_gain = 0.2
+        end
+    end,
+
+    on_step = function(self, dtime)
+        if not self.driver then
+			self:update_sound()
+            return
+        end
+
+        -- Get player control inputs
+        local ctrl = self.driver:get_player_control()
+        --local yaw = self.driver:get_look_horizontal()
+        local yaw = self.object:get_yaw()
+
+		local object_pos = self.object:get_pos()
+
+		local y_off = -0.5
+
+		local box = {
+			yaw = yaw,
+			dimensions = {(BULLDOZER_SIZE+1), (BULLDOZER_SIZE+1), 1},
+			origin = {
+				x = object_pos.x,
+				y = object_pos.y - y_off + 0.9,
+				z = object_pos.z,
+			},
+		}
+		local nwn_tracks = get_walkable_nodes_in_box(box)
+
+		local box = {
+			yaw = yaw,
+			dimensions = {(BULLDOZER_SIZE+1), (BULLDOZER_SIZE+1), 1},
+			origin = {
+				x = object_pos.x,
+				y = object_pos.y - y_off - 0.5,
+				z = object_pos.z,
+			},
+		}
+		local nwn_support = get_walkable_nodes_in_box(box)
+
+		local box = {
+			yaw = yaw,
+			dimensions = {(BULLDOZER_SIZE+1), (BULLDOZER_SIZE+1), 1},
+			origin = {
+				x = object_pos.x,
+				y = object_pos.y - y_off - 0.15,
+				z = object_pos.z,
+			},
+		}
+		local nwn_close_support = get_walkable_nodes_in_box(box)
+
+		local box = {
+			yaw = yaw,
+			dimensions = {(BULLDOZER_SIZE+1), (BULLDOZER_SIZE+1), 1},
+			origin = {
+				x = object_pos.x,
+				y = object_pos.y - y_off - 0.05,
+				z = object_pos.z,
+			},
+		}
+		local nwn_very_close_support = get_walkable_nodes_in_box(box)
+
+        if ctrl.up then
+			local speed = 2.0
+
+            -- Move the bulldozer forward
+            self.object:set_velocity(vector.new(
+				math.cos(yaw+math.pi) * speed,
+				0,
+				math.sin(yaw+math.pi) * speed
+			))
+
+			local object_pos2 = self.object:get_pos()
+			if ctrl.jump then
+				object_pos2.y = object_pos2.y - y_off + 1.1
+			elseif ctrl.sneak then
+				object_pos2.y = object_pos2.y - y_off - 0.9
+			else
+				object_pos2.y = object_pos2.y - y_off - 0.5
+			end
+			local object_yaw = self.object:get_yaw()+math.pi
+
+			local wall_dimensions = {2, (BULLDOZER_SIZE+1), CLEAR_HEIGHT}
+			local move_distance = 5
+			create_virtual_wall(object_pos2, object_yaw, wall_dimensions, move_distance, PLACEMENT_HEIGHT, PLACEMENT_DEPTH)
+        elseif ctrl.down then
+			local speed = 1.5
+            -- Move the bulldozer backward
+            self.object:set_velocity(vector.new(
+				math.cos(yaw) * speed,
+				0,
+				math.sin(yaw) * speed
+			))
+        else
+            self.object:set_velocity({x = 0, y = 0, z = 0})
+        end
+
+		if ctrl.left then
+			self.object:set_yaw(self.object:get_yaw() + 0.020)
+		elseif ctrl.right then
+			self.object:set_yaw(self.object:get_yaw() - 0.020)
+		end
+
+        if (ctrl.jump and ctrl.up and (#nwn_tracks >= 1 or #nwn_very_close_support >= (BULLDOZER_SIZE*BULLDOZER_SIZE/2))) or
+				(ctrl.down and #nwn_tracks >= 1 and not ctrl.sneak) then
+			local rate = 0.01
+			if #nwn_very_close_support >= 9 then
+				rate = 0.03
+			elseif #nwn_very_close_support >= 5 then
+				rate = 0.02
+			end
+            self.object:set_pos({
+				x = self.object:get_pos().x,
+				y = self.object:get_pos().y + rate,
+				z = self.object:get_pos().z
+			})
+        elseif (ctrl.sneak and ctrl.up) then
+			local rate = 0.01
+			if #nwn_support <= 7 then
+				rate = 0.02
+			end
+            self.object:set_pos({
+				x = self.object:get_pos().x,
+				y = self.object:get_pos().y - rate,
+				z = self.object:get_pos().z
+			})
+		else
+			if #nwn_close_support >= (BULLDOZER_SIZE*BULLDOZER_SIZE*0.8) and not ctrl.sneak then
+				local off = -y_off
+				local new_y = math.floor(self.object:get_pos().y + off + 0.5) - off
+				if math.abs(new_y - self.object:get_pos().y) >= 0.2 then
+					self.object:set_pos({
+						x = self.object:get_pos().x,
+						y = new_y,
+						z = self.object:get_pos().z
+					})
+				end
+			end
+		end
+
+		if not ctrl.sneak then
+			if #nwn_support <= (BULLDOZER_SIZE*BULLDOZER_SIZE/3) then
+				self.object:set_pos({
+					x = self.object:get_pos().x,
+					--y = math.floor(self.object:get_pos().y + 0.5 - 1.0),
+					y = self.object:get_pos().y - 0.1,
+					z = self.object:get_pos().z
+				})
+			elseif #nwn_close_support <= (BULLDOZER_SIZE*BULLDOZER_SIZE/3) then
+				self.object:set_pos({
+					x = self.object:get_pos().x,
+					--y = math.floor(self.object:get_pos().y + 0.5 - 1.0),
+					y = self.object:get_pos().y - 0.02,
+					z = self.object:get_pos().z
+				})
+			end
+		end
+
+		if ctrl.up then
+			self.wanted_sound_pitch = target_value(self.wanted_sound_pitch, 1.3, 0.02)
+			self.wanted_sound_gain = target_value(self.wanted_sound_gain, 0.30, 0.02)
+		elseif ctrl.down or ctrl.left or ctrl.right then
+			self.wanted_sound_pitch = target_value(self.wanted_sound_pitch, 1.1, 0.02)
+			self.wanted_sound_gain = target_value(self.wanted_sound_gain, 0.25, 0.02)
+		else
+			self.wanted_sound_pitch = target_value(self.wanted_sound_pitch, 0.9, 0.02)
+			self.wanted_sound_gain = target_value(self.wanted_sound_gain, 0.20, 0.02)
+		end
+		self:update_sound()
+	end,
+
+	update_sound = function(self)
+        if not self.driver then
+			if self.sound_handle then minetest.sound_stop(self.sound_handle) end
+            return
+        end
+		if math.abs(self.wanted_sound_pitch - self.played_sound_pitch) < 0.06 and
+				math.abs(self.wanted_sound_gain - self.played_sound_gain) < 0.03 then
+			return
+		end
+		if self.sound_handle then minetest.sound_stop(self.sound_handle) end
+		if self.object then
+			self.played_sound_pitch = self.wanted_sound_pitch
+			self.played_sound_gain = self.wanted_sound_gain
+			self.sound_handle = minetest.sound_play({name = "bulldozer_engine"}, {
+				object = self.object, gain = self.wanted_sound_gain,
+				pitch = self.wanted_sound_pitch,
+				max_hear_distance = 45,
+				loop = true,
+			})
+		end
+	end,
+})
+
+-- Register the bulldozer item for spawning the entity
+minetest.register_craftitem("bulldozer:bulldozer_item", {
+description = "Bulldozer",
+inventory_image = "bulldozer_bulldozer_item.png",
+on_place = function(itemstack, placer, pointed_thing)
+if pointed_thing.type ~= "node" then
+return
+end
+    local ent = minetest.add_entity(pointed_thing.above, "bulldozer:bulldozer")
+    ent:set_yaw(placer:get_look_horizontal())
+
+    itemstack:take_item()
+    return itemstack
+end,
+})
+
diff --git a/media/bulldozer_bulldozer.obj b/media/bulldozer_bulldozer.obj
new file mode 100644
index 0000000..ec761e7
--- /dev/null
+++ b/media/bulldozer_bulldozer.obj
@@ -0,0 +1,141 @@
+# Axis-aligned boxes for Minetest
+
+mtllib boxes.mtl
+
+# Blade
+o Box1
+g Group1
+usemtl Texture1
+v 18.5 0 -15.0
+v 20.5 0 -15.0
+v 20.5 0  15.0
+v 18.5 0  15.0
+v 18.5 8 -15.0
+v 20.5 8 -15.0
+v 20.5 8  15.0
+v 18.5 8  15.0
+vt 0 0
+vt 1 0
+vt 1 1
+vt 0 1
+f 1/1 5/4 6/3 2/2
+f 2/1 6/4 7/3 3/2
+f 3/1 7/4 8/3 4/2
+f 4/1 8/4 5/3 1/2
+f 1/1 2/2 3/3 4/4
+f 5/1 8/2 7/3 6/4
+
+# Left track
+o Box2
+g Group2
+usemtl Texture2
+v -10.0 0 -14
+v  17.0 0 -14
+v  17.0 0 -8
+v -10.0 0 -8
+v -10.0 6 -14
+v  17.0 6 -14
+v  17.0 6 -8
+v -10.0 6 -8
+vt 0 0
+vt 1 0
+vt 1 1
+vt 0 1
+f 9/1 13/4 14/3 10/2
+f 10/1 14/4 15/3 11/2
+f 11/1 15/4 16/3 12/2
+f 12/1 16/4 13/3 9/2
+f 9/1 10/2 11/3 12/4
+f 13/1 16/2 15/3 14/4
+
+# Right track
+o Box3
+g Group3
+usemtl Texture3
+v -10.0 0 8
+v  17.0 0 8
+v  17.0 0 14
+v -10.0 0 14
+v -10.0 6 8
+v  17.0 6 8
+v  17.0 6 14
+v -10.0 6 14
+vt 0 0
+vt 1 0
+vt 1 1
+vt 0 1
+f 17/1 21/4 22/3 18/2
+f 18/1 22/4 23/3 19/2
+f 19/1 23/4 24/3 20/2
+f 20/1 24/4 21/3 17/2
+f 17/1 18/2 19/3 20/4
+f 21/1 24/2 23/3 22/4
+
+# Body
+o Box4
+g Group4
+usemtl Texture4
+v -10.0  1 -7.0
+v  17.0  1 -7.0
+v  17.0  1  7.0
+v -10.0  1  7.0
+v -10.0 10 -7.0
+v  17.0 10 -7.0
+v  17.0 10  7.0
+v -10.0 10  7.0
+vt 0 0
+vt 1 0
+vt 1 1
+vt 0 1
+f 25/1 29/4 30/3 26/2
+f 26/1 30/4 31/3 27/2
+f 27/1 31/4 32/3 28/2
+f 28/1 32/4 29/3 25/2
+f 25/1 26/2 27/3 28/4
+f 29/1 32/2 31/3 30/4
+
+# Left track cover
+o Box5
+g Group5
+usemtl Texture5
+v  -9.0 1 -15
+v  16.0 1 -15
+v  16.0 1 -7
+v  -9.0 1 -7
+v  -9.0 5 -15
+v  16.0 5 -15
+v  16.0 5 -7
+v  -9.0 5 -7
+vt 0 0
+vt 1 0
+vt 1 1
+vt 0 1
+f 33/1 37/4 38/3 34/2
+f 34/1 38/4 39/3 35/2
+f 35/1 39/4 40/3 36/2
+f 36/1 40/4 37/3 33/2
+f 33/1 34/2 35/3 36/4
+f 37/1 40/2 39/3 38/4
+
+# Right track cover
+o Box6
+g Group6
+usemtl Texture6
+v  -9.0 1 7
+v  16.0 1 7
+v  16.0 1 15
+v  -9.0 1 15
+v  -9.0 5 7
+v  16.0 5 7
+v  16.0 5 15
+v  -9.0 5 15
+vt 0 0
+vt 1 0
+vt 1 1
+vt 0 1
+f 41/1 45/4 46/3 42/2
+f 42/1 46/4 47/3 43/2
+f 43/1 47/4 48/3 44/2
+f 44/1 48/4 45/3 41/2
+f 41/1 42/2 43/3 44/4
+f 45/1 48/2 47/3 46/4
diff --git a/media/bulldozer_bulldozer_blade.png b/media/bulldozer_bulldozer_blade.png
new file mode 100644
index 0000000..50d3cce
Binary files /dev/null and b/media/bulldozer_bulldozer_blade.png differ
diff --git a/media/bulldozer_bulldozer_body.png b/media/bulldozer_bulldozer_body.png
new file mode 100644
index 0000000..fa8d0a1
Binary files /dev/null and b/media/bulldozer_bulldozer_body.png differ
diff --git a/media/bulldozer_bulldozer_track.png b/media/bulldozer_bulldozer_track.png
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