From 42d0081367060ace2dd21c50b5914cf2ad5615da Mon Sep 17 00:00:00 2001
From: ShadowNinja <shadowninja@minetest.net>
Date: Wed, 24 Sep 2014 20:32:36 -0400
Subject: [PATCH] Replace mining laser ray tracer with a simpler iterable one

---
 technic/tools/mining_lasers.lua | 123 +++++++++++++++++++++++---------
 technic/tools/vector_line.lua   |  83 ---------------------
 2 files changed, 89 insertions(+), 117 deletions(-)
 delete mode 100644 technic/tools/vector_line.lua

diff --git a/technic/tools/mining_lasers.lua b/technic/tools/mining_lasers.lua
index 5c8d1e4..872271c 100644
--- a/technic/tools/mining_lasers.lua
+++ b/technic/tools/mining_lasers.lua
@@ -32,64 +32,119 @@ minetest.register_craft({
 	}
 })
 
-local function table_icontains(t, v)
-	for i = 1,#t do
-		if v == t[i] then
-			return true
-		end
+-- Based on code by Uberi: https://gist.github.com/Uberi/3125280
+local function rayIter(pos, dir, range)
+	local p = vector.round(pos)
+	local x_step,      y_step,      z_step      = 0, 0, 0
+	local x_component, y_component, z_component = 0, 0, 0
+	local x_intersect, y_intersect, z_intersect = 0, 0, 0
+
+	if dir.x == 0 then
+		x_intersect = math.huge
+	elseif dir.x > 0 then
+		x_step = 1
+		x_component = 1 / dir.x
+		x_intersect = x_component
+	else
+		x_step = -1
+		x_component = 1 / -dir.x
+	end
+	if dir.y == 0 then
+		y_intersect = math.huge
+	elseif dir.y > 0 then
+		y_step = 1
+		y_component = 1 / dir.y
+		y_intersect = y_component
+	else
+		y_step = -1
+		y_component = 1 / -dir.y
+	end
+	if dir.z == 0 then
+		z_intersect = math.huge
+	elseif dir.z > 0 then
+		z_step = 1
+		z_component = 1 / dir.z
+		z_intersect = z_component
+	else
+		z_step = -1
+		z_component = 1 / -dir.z
+	end
+
+	return function()
+		if x_intersect < y_intersect then
+			if x_intersect < z_intersect then
+				p.x = p.x + x_step
+				x_intersect = x_intersect + x_component
+			else
+				p.z = p.z + z_step
+				z_intersect = z_intersect + z_component
+			end
+		elseif y_intersect < z_intersect then
+			p.y = p.y + y_step
+			y_intersect = y_intersect + y_component
+		else
+			p.z = p.z + z_step
+			z_intersect = z_intersect + z_component
+		end
+		if vector.distance(pos, p) > range then
+			return nil
+		end
+		return p
 	end
-	return false
 end
 
-local function laser_node(pos, player)
-	local node = minetest.get_node(pos)
-	if table_icontains({"air", "ignore", "default:lava_source", "default:lava_flowing"}, node.name) then
-		return
-	end
-	local pname = player:get_player_name()
-	if minetest.is_protected(pos, pname) then
-		minetest.record_protection_violation(pos, pname)
-		return
-	end
-	if table_icontains({"default:water_flowing", "default:water_source"}, node.name) then
+local function laser_node(pos, node, player)
+	local def = minetest.registered_nodes[node.name]
+	if def and def.liquidtype ~= "none" then
 		minetest.remove_node(pos)
 		minetest.add_particle({
 			pos = pos,
 			vel = {x=0, y=2, z=0},
 			acc = {x=0, y=-1, z=0},
 			expirationtime = 1.5,
-			size = 6+math.random()*2,
-			texture = "smoke_puff.png^[transform"..math.random(0,7),
+			size = 6 + math.random() * 2,
+			texture = "smoke_puff.png^[transform" .. math.random(0, 7),
 		})
 		return
 	end
-	if player then
-		minetest.node_dig(pos, node, player)
-	end
-end
-
-if not vector.line then
-	dofile(technic.modpath.."/tools/vector_line.lua")
+	minetest.node_dig(pos, node, player)
 end
 
+local no_destroy = {
+	["air"] = true,
+	["default:lava_source"] = true,
+	["default:lava_flowing"] = true,
+}
 local function laser_shoot(player, range, particle_texture, sound)
-	local playerpos = player:getpos()
+	local player_pos = player:getpos()
+	local player_name = player:get_player_name()
 	local dir = player:get_look_dir()
 
-	local startpos = {x = playerpos.x, y = playerpos.y + 1.625, z = playerpos.z}
-	local mult_dir = vector.multiply(dir, 50)
+	local start_pos = vector.new(player_pos)
+	-- Adjust to head height
+	start_pos.y = start_pos.y + 1.9
 	minetest.add_particle({
 		pos = startpos,
 		vel = dir,
-		acc = mult_dir,
+		acc = vector.multiply(dir, 50),
 		expirationtime = range / 11,
 		size = 1,
-		texture = particle_texture.."^[transform"..math.random(0,7),
+		texture = particle_texture .. "^[transform" .. math.random(0, 7),
 	})
-	for _,pos in ipairs(vector.line(vector.round(startpos), dir, range)) do
-		laser_node(pos, player)
+	minetest.sound_play(sound, {pos = player_pos, max_hear_distance = range})
+	for pos in rayIter(start_pos, dir, range) do
+		if minetest.is_protected(pos, player_name) then
+			minetest.record_protection_violation(pos, player_name)
+			break
+		end
+		local node = minetest.get_node_or_nil(pos)
+		if not node then
+			break
+		end
+		if not no_destroy[node.name] then
+			laser_node(pos, node, player)
+		end
 	end
-	minetest.sound_play(sound, {pos = playerpos, max_hear_distance = range})
 end
 
 
diff --git a/technic/tools/vector_line.lua b/technic/tools/vector_line.lua
deleted file mode 100644
index 950c93b..0000000
--- a/technic/tools/vector_line.lua
+++ /dev/null
@@ -1,83 +0,0 @@
-local twolines = {}
-function vector.twoline(x, y)
-	local pstr = x.." "..y
-	local line = twolines[pstr]
-	if line then
-		return line
-	end
-	line = {}
-	local n = 1
-	local dirx = 1
-	if x < 0 then
-		dirx = -dirx
-	end
-	local ymin, ymax = 0, y
-	if y < 0 then
-		ymin, ymax = ymax, ymin
-	end
-	local m = y/x --y/0 works too
-	local dir = 1
-	if m < 0 then
-		dir = -dir
-	end
-	for i = 0,x,dirx do
-		local p1 = math.max(math.min(math.floor((i-0.5)*m+0.5), ymax), ymin)
-		local p2 = math.max(math.min(math.floor((i+0.5)*m+0.5), ymax), ymin)
-		for j = p1,p2,dir do
-			line[n] = {i, j}
-			n = n+1
-		end
-	end
-	twolines[pstr] = line
-	return line
-end
-
-local threelines = {}
-function vector.threeline(x, y, z)
-	local pstr = x.." "..y.." "..z
-	local line = threelines[pstr]
-	if line then
-		return line
-	end
-	if x ~= math.floor(x) then
-		print("[technic] INFO: The position used for vector.threeline isn't round.")
-	end
-	local two_line = vector.twoline(x, y)
-	line = {}
-	local n = 1
-	local zmin, zmax = 0, z
-	if z < 0 then
-		zmin, zmax = zmax, zmin
-	end
-	local m = z/math.hypot(x, y)
-	local dir = 1
-	if m < 0 then
-		dir = -dir
-	end
-	for _,i in ipairs(two_line) do
-		local px, py = unpack(i)
-		local ph = math.hypot(px, py)
-		local z1 = math.max(math.min(math.floor((ph-0.5)*m+0.5), zmax), zmin)
-		local z2 = math.max(math.min(math.floor((ph+0.5)*m+0.5), zmax), zmin)
-		for pz = z1,z2,dir do
-			line[n] = {px, py, pz}
-			n = n+1
-		end
-	end
-	threelines[pstr] = line
-	return line
-end
-
-function vector.line(pos, dir, range)
-	if range then --dir = pos2
-		dir = vector.round(vector.multiply(dir, range))
-	else
-		dir = vector.subtract(dir, pos)
-	end
-	local line,n = {},1
-	for _,i in ipairs(vector.threeline(dir.x, dir.y, dir.z)) do
-		line[n] = {x=pos.x+i[1], y=pos.y+i[2], z=pos.z+i[3]}
-		n = n+1
-	end
-	return line
-end