Organize builtin into subdirectories

builtin/common/vector.lua

@@ -0,0 +1,146 @@
+
+vector = {}
+
+local function assert_vector(v)
+	assert(type(v) == "table" and v.x and v.y and v.z, "Invalid vector")
+end
+
+function vector.new(a, b, c)
+	if type(a) == "table" then
+		assert(a.x and a.y and a.z, "Invalid vector passed to vector.new()")
+		return {x=a.x, y=a.y, z=a.z}
+	elseif a then
+		assert(b and c, "Invalid arguments for vector.new()")
+		return {x=a, y=b, z=c}
+	end
+	return {x=0, y=0, z=0}
+end
+
+function vector.equals(a, b)
+	assert_vector(a)
+	assert_vector(b)
+	return a.x == b.x and
+	       a.y == b.y and
+	       a.z == b.z
+end
+
+function vector.length(v)
+	assert_vector(v)
+	return math.hypot(v.x, math.hypot(v.y, v.z))
+end
+
+function vector.normalize(v)
+	assert_vector(v)
+	local len = vector.length(v)
+	if len == 0 then
+		return {x=0, y=0, z=0}
+	else
+		return vector.divide(v, len)
+	end
+end
+
+function vector.round(v)
+	assert_vector(v)
+	return {
+		x = math.floor(v.x + 0.5),
+		y = math.floor(v.y + 0.5),
+		z = math.floor(v.z + 0.5)
+	}
+end
+
+function vector.distance(a, b)
+	assert_vector(a)
+	assert_vector(b)
+	local x = a.x - b.x
+	local y = a.y - b.y
+	local z = a.z - b.z
+	return math.hypot(x, math.hypot(y, z))
+end
+
+function vector.direction(pos1, pos2)
+	assert_vector(pos1)
+	assert_vector(pos2)
+	local x_raw = pos2.x - pos1.x
+	local y_raw = pos2.y - pos1.y
+	local z_raw = pos2.z - pos1.z
+	local x_abs = math.abs(x_raw)
+	local y_abs = math.abs(y_raw)
+	local z_abs = math.abs(z_raw)
+	if x_abs >= y_abs and
+	   x_abs >= z_abs then
+		y_raw = y_raw * (1 / x_abs)
+		z_raw = z_raw * (1 / x_abs)
+		x_raw = x_raw / x_abs
+	end
+	if y_abs >= x_abs and
+	   y_abs >= z_abs then
+		x_raw = x_raw * (1 / y_abs)
+		z_raw = z_raw * (1 / y_abs)
+		y_raw = y_raw / y_abs
+	end
+	if z_abs >= y_abs and
+	   z_abs >= x_abs then
+		x_raw = x_raw * (1 / z_abs)
+		y_raw = y_raw * (1 / z_abs)
+		z_raw = z_raw / z_abs
+	end
+	return {x=x_raw, y=y_raw, z=z_raw}
+end
+
+
+function vector.add(a, b)
+	assert_vector(a)
+	if type(b) == "table" then
+	    assert_vector(b)
+		return {x = a.x + b.x,
+			y = a.y + b.y,
+			z = a.z + b.z}
+	else
+		return {x = a.x + b,
+			y = a.y + b,
+			z = a.z + b}
+	end
+end
+
+function vector.subtract(a, b)
+	assert_vector(a)
+	if type(b) == "table" then
+	    assert_vector(b)
+		return {x = a.x - b.x,
+			y = a.y - b.y,
+			z = a.z - b.z}
+	else
+		return {x = a.x - b,
+			y = a.y - b,
+			z = a.z - b}
+	end
+end
+
+function vector.multiply(a, b)
+	assert_vector(a)
+	if type(b) == "table" then
+	    assert_vector(b)
+		return {x = a.x * b.x,
+			y = a.y * b.y,
+			z = a.z * b.z}
+	else
+		return {x = a.x * b,
+			y = a.y * b,
+			z = a.z * b}
+	end
+end
+
+function vector.divide(a, b)
+	assert_vector(a)
+	if type(b) == "table" then
+        assert_vector(b)
+		return {x = a.x / b.x,
+			y = a.y / b.y,
+			z = a.z / b.z}
+	else
+		return {x = a.x / b,
+			y = a.y / b,
+			z = a.z / b}
+	end
+end
+