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Basic Map Operations: Fix distance check being 2d

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rubenwardy 2020-12-24 19:44:51 +00:00
parent bca09bd7ab
commit 84aadea47a
2 changed files with 8 additions and 6 deletions
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11
_en/map/environment.md
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@ -13,11 +13,11 @@ In this chapter, you will learn how to perform basic actions on the map.
- [Map Structure](#map-structure) - [Map Structure](#map-structure)
- [Reading](#reading) - [Reading](#reading)
- [Reading Nodes](#reading-nodes) - [Reading Nodes](#reading-nodes)
- [Finding Nodes](#finding-nodes) - [Finding Nodes](#finding-nodes)
- [Writing](#writing) - [Writing](#writing)
- [Writing Nodes](#writing-nodes) - [Writing Nodes](#writing-nodes)
- [Removing Nodes](#removing-nodes) - [Removing Nodes](#removing-nodes)
- [Loading Blocks](#loading-blocks) - [Loading Blocks](#loading-blocks)
- [Deleting Blocks](#deleting-blocks) - [Deleting Blocks](#deleting-blocks)
@ -106,13 +106,14 @@ local pos_list =
local grow_speed = 1 local grow_speed = 1
for i=1, #pos_list do for i=1, #pos_list do
local delta = vector.subtract(pos_list[i], pos) local delta = vector.subtract(pos_list[i], pos)
if delta.x*delta.x + delta.y*delta.y <= 5*5 then if delta.x*delta.x + delta.y*delta.y + delta.z*delta.z <= 5*5 then
grow_speed = grow_speed + 1 grow_speed = grow_speed + 1
end end
end end
``` ```
Now your code will correctly increase `grow_speed` based on mese nodes in range. Now your code will correctly increase `grow_speed` based on mese nodes in range.
Note how we compared the squared distance from the position, rather than square Note how we compared the squared distance from the position, rather than square
rooting it to obtain the actual distance. This is because computers find square rooting it to obtain the actual distance. This is because computers find square
roots computationally expensive, so you should avoid them as much as possible. roots computationally expensive, so you should avoid them as much as possible.

3
_it/map/environment.md
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@ -98,13 +98,14 @@ local lista_pos =
local vel_crescita = 1 local vel_crescita = 1
for i=1, #lista_pos do for i=1, #lista_pos do
local delta = vector.subtract(lista_pos[i], pos) local delta = vector.subtract(lista_pos[i], pos)
if delta.x*delta.x + delta.y*delta.y <= 5*5 then if delta.x*delta.x + delta.y*delta.y + delta.z*delta.z <= 5*5 then
vel_crescita = vel_crescita + 1 vel_crescita = vel_crescita + 1
end end
end end
``` ```
Ora il codice aumenterà correttamente `vel_crescita` basandosi su quanti nodi di pietra ci sono in un intervallo. Ora il codice aumenterà correttamente `vel_crescita` basandosi su quanti nodi di pietra ci sono in un intervallo.
Notare come si sia comparata la distanza al quadrato dalla posizione, invece che calcolarne la radice quadrata per ottenerne la distanza vera e propria. Notare come si sia comparata la distanza al quadrato dalla posizione, invece che calcolarne la radice quadrata per ottenerne la distanza vera e propria.
Questo perché i computer trovano le radici quadrate computazionalmente pesanti, quindi dovresti evitare di usarle il più possibile. Questo perché i computer trovano le radici quadrate computazionalmente pesanti, quindi dovresti evitare di usarle il più possibile.