Hi everyone (I'm FR, sorry for my english)! I have my own projectile trajectory system based on the reality.
This cool system allows me to predict the trajectory of my projectile even before firing (in 1 tick)!

How to calculate a projectile rebound against a block ?
(I'm talking about a projectile but it's an armorstand and not an arrow)

You can have your own technique for this problem.
Here is what I propose:

INFO:
With my current code the location of impact is ({_x}, {_y}, {_z});
The previous location is ({_x.old}, {_y.old}, {_z.old});
The location of the center of the block on which the projectile must bounce ({_bx}, {_by}, {_bz})

my idea :
1) We consider the block as a sphere and not a cube, we draw a vector between the point of impact and the current position.
2) A reflection effect of the previous location with respect to the vector is applied (vector which will be positioned from the point of impact)
Info: The old position, the point of impact and the vector are necessarily on the SAME plane which makes the operation possible.
3) A vector is drawn between the point of impact and the mirror point.
4) We recover the yaw and pitch of this vector with "vector yaw of %vector%"
5) It's over! The rest of my code takes care of considering the point of impact as if it is a new shot = D

This method is like folding a sheet of paper


To help I have a lot of addon that can be used to solve this problem (Umbaska is removed voluntarily and I do not want to use it anymore).



Help link :
https://skripthub.net/docs/?search=id:1345 (I need this but it seem to not result the correct location)
https://github.com/bi0qaw/Vectors-Skript (A secret addon ^^)

The part to modify is between the "================="
The rest of the code works very well

Code (Skript):

1. on script load:
2.   import "java.lang.System"
3.   import "java.lang.Math"
4.  
5. command /rr <number> <number>:             #this is just a test
6.     trigger:
7.         set {_x} to arg-1
8.         set {_z} to arg-2
9.         set {_pi} to {Math}.PI!
10.         set {_atan2} to {Math}.atan2({_x} and {_z})
11.         set {_yaw} to {_atan2}*180/{_pi}
12.         broadcast "%{_yaw}% %vector yaw of vector {_x}, 0, {_z}%"   #2 method to get yaw, first between [-180,180] , second between [0,360]
13.        
14.        
15. function Shoot(shooter: player, type: string, force: number, predict: boolean):
16.     set {_pi} to {Math}.PI!
17.     set {_x0} to x-location of {_shooter}
18.     set {_y0} to y-location of {_shooter}
19.     set {_z0} to z-location of {_shooter}
20.     set {_pitch} to pitch of {_shooter}*-1  #The rotation of player
21.     set {_yaw} to yaw of {_shooter}*-1
22.     set {_v0} to 17.7*{_force}              #17.7 is my own chosen number randomly for the velocity
23.     set {_cosPitch} to cos ({_pitch}*3.14/180)
24.     set {_cosx} to (sin ({_yaw}*3.14/180) )* {_cosPitch}
25.     set {_cosz} to (cos ({_yaw}*3.14/180) )* {_cosPitch}
26.     set {_t} to 0
27.    
28.     set {_RotPitch} to {_pitch}             #The rotation of projectile
29.     set {_RotYaw} to {_yaw}
30.    
31.    
32.     if {_predict} is false:
33.         set {_ID} to "Shoot_%{_shooter}%_%{game.timer}%"
34.         run {_shooter} command "/summon ArmorStand %x-location of {_shooter}% %y-location of {_shooter}% %z-location of {_shooter}% {CustomName:""%{_ID}%"",Tags:[""Shoot"",""Shoot_%{_shooter}%""],NoGravity:1b,Small:1b,Marker:1b,Invisible:1,Invulnerable:0,DisabledSlots:2039583}" as op
35.         loop all armor stands:
36.             loop-entity's name is "%{_ID}%"
37.             set {_entity} to loop-entity    #not used for now
38.             execute console command "/execute @e[type=ArmorStand,name=%{_ID}%] ~ ~ ~ /playsound minecraft:entity.irongolem.attack master @a %{_x0}% %{_y0}% %{_z0}% 1 1"
39.             if "%{player::*}%" contain "%{_shooter}%":
40.                 execute console command "/mycmd add %{_shooter}% stats.use.%{_type}% 1"
41.             if "%{_type}%" is "fragmentation":
42.                 set helmet of loop-entity to yellow dye
43.                 set {_color} to "0 1 0"
44.             if "%{_type}%" is "retardement":
45.                 set helmet of loop-entity to red dye
46.                 set {_color} to "0 0 0"
47.             if "%{_type}%" is "chimique":
48.                 set helmet of loop-entity to light green dye
49.                 set {_color} to "0.27 0.77 0.18"
50.             if "%{_type}%" is "flame":
51.                 set helmet of loop-entity to orange dye
52.                 set {_color} to "1 0.5 0.1"
53.             if "%{_type}%" is "implosion":
54.                 set helmet of loop-entity to light blue dye
55.                 set {_color} to "0.1 0.9 1"
56.             if {_color} is not set:
57.                 set {_color} to "1 1 1"
58.                
59.     loop 900 times:
60.         set {_xt} to {_v0}* {_cosx}         #I put this here cause of the speed {_v0} can be modified (exemple: in water)
61.         set {_zt} to {_v0}* {_cosz}
62.         set {_x} to {_x0}+{_xt}*{_t}
63.         set {_y} to (-12/2*{_t}^2) +{_v0}*{_t}*sin ({_Pitch}*3.14/180) +1.52 +{_y0}     #+1.52 is for eye's position
64.         set {_z} to {_z0}+{_zt}*{_t}
65.        
66.         set {_vectorx} to {_x} - {_x.old}           #I prefer use %vector% only if a complex math operation is more easy with an addon
67.         set {_vectory} to {_y} - {_y.old}
68.         set {_vectorz} to {_z} - {_z.old}
69.         set {_norme} to sqrt ( {_vectorx}^2 + {_vectory}^2 + {_vectorz}^2 )
70.         set {_vectordirx} to {_vectorx} / {_norme}
71.         set {_vectordiry} to {_vectory} / {_norme}
72.         set {_vectordirz} to {_vectorz} / {_norme}
73.        
74.  
75.         set {_RotPitch} to -57.2958* arc sin ({_vectordiry})
76.         set {_atan2} to {Math}.atan2({_vectordirx} and {_vectordirz})
77.         set {_RotYaw} to {_atan2}*180/{_pi}
78.         broadcast "<cyan>%vector pitch of vector {_vectorx}, {_vectory}, {_vectorz}% %vector yaw of vector {_vectorx}, {_vectory}, {_vectorz}%"
79.         broadcast "<gold>%{_RotPitch}% %{_RotYaw}%"
80.         #Same pitch and yaw : Yaw between [0,360] and [-180,180]
81.        
82.        
83.        
84.         set {_block} to block at location ({_x}, {_y}, {_z}) in world "%{map}%"
85.         if {_block} is air or water or any glass pane or carpet or pressure plate or window glass or painting or item frame or sign or button or flower pot or ladder or torch or redstone torch or wire:
86.             if {_block} is water:
87.                 if {_predict} is false:
88.                     if block upward {_block} is air:
89.                         execute console command "/execute @e[type=ArmorStand,name=%{_ID}%] ~ ~ ~ /particle splash %{_x}% %{_y}+1% %{_z}% 0.1 0 0.1 0 50 force"
90.                 set {_v0} to {_v0}*0.98
91.                 if {_v0} < 5:
92.                     set {_v0} to 5
93.             if {_block} is glass pane or window glass:
94.                 if {_predict} is false:
95.                     set {_blockID} to id of block at location ({_x}, {_y}, {_z}) in world "%{map}%"
96.                     execute console command "/execute @e[type=ArmorStand,name=%{_ID}%] ~ ~ ~ /particle blockcrack %x-location of {_block}% %y-location of {_block}% %z-location of {_block}% 0.1 0.1 0.1 1 10 force @a %{_blockID} + data of {_block}*4096%"
97.                     set block at location ({_x}, {_y}, {_z}) in world "%{map}%" to air
98.                 set {_v0} to {_v0}*0.7
99.             if {_predict} is false:
100.                 execute console command "/tp @e[type=ArmorStand,name=%{_ID}%] %{_x}% %{_y}-1% %{_z}% %{_RotYaw}% ~"
101.                # execute console command "/entitydata @e[type=ArmorStand,name=%{_ID}%] {Pose:{Head:[%({_RotPitch} -90)*-1%f,0f,0f]}}"
102.                 execute console command "/execute @e[type=ArmorStand,name=%{_ID}%] ~ ~ ~ /particle reddust %{_x}% %{_y}% %{_z}% %{_color}% 1 0 force"
103.                 execute console command "/execute @e[type=ArmorStand,name=%{_ID}%] ~ ~ ~ /playsound minecraft:entity.guardian.ambient master @a %{_x}% %{_y}% %{_z}% 0.1 2"
104.             add 0.01 to {_t}
105.            
106.         else:
107.             if {_v0} > 5:                                   #no bounce if velocity is under 5 cube/s
108.                 set {_bx} to x-location of {_block}
109.                 set {_by} to y-location of {_block}
110.                 set {_bz} to z-location of {_block}
111.                
112.                 #==============
113.                 #CODE OF BOUNCE
114.                 #NEED HELP HERE
115.                 #==============
116.  
117.                
118.                 #set {_pitch} to ???????                                 #NEED to know the new pitch
119.                 #set {_yaw} to ???????                                   #NEED to know the new yaw
120.                 #================
121.                 #NEED HELP UPWARD
122.                 #================
123.                
124.                 #Code below = set the coord of the impact as a new shoot location reference with new pitch and yaw              
125.                 set {_v0} to {_v0}*0.8
126.                 set {_x0} to {_x}                                       #{_x}, {_y}, {_z} = Impact location
127.                 set {_y0} to {_y}
128.                 set {_z0} to {_z}
129.                 set {_cosPitch} to cos ({_pitch}*3.14/180)              #Need to know the new {_pitch}
130.                 set {_cosx} to (sin ({_yaw}*3.14/180) )* {_cosPitch}    #Need to know the new {_yaw}
131.                 set {_cosz} to (cos ({_yaw}*3.14/180) )* {_cosPitch}
132.                
133.                
134.                
135.             else:
136.                 exit loop
137.         set {_x.old} to {_x}
138.         set {_y.old} to {_y}
139.         set {_z.old} to {_z}
140.         if {_predict} is false:
141.             if {_t}*100 is divisible by 5:
142.                 wait 1 tick
143.     if {_predict} is true:
144.         set block at location ({_x}, {_y}, {_z}) in world "%{map}%" to glowstone
145.     execute console command "/kill @e[type=ArmorStand,name=%{_ID}%]"
146.  
147. command /predict:                        #the command to do
148.     trigger:
149.         Shoot(player,"retardement", 1.4, false)     #set to "true" to predict the trajectory in a 1 tick
150.         set {map} to event-world                    #DEBUG : I use this on my server
151.         set {game.timer} to 0                       #DEBUG : I use this on my server
152.  

use command "/predict" to see what happen

Anybody who want help : I have made a test server.rar (28Mo) included all addons +the skript +Viaversion for 1.10.x to 1.11.2
The first shoot does not works but all other worked
https://drive.google.com/open?id=1AnvC_spWVg2d4TXAPU86cGD5PjsS_Sv-
Thank you very much for your help !!

 

"bounced" from the impact location (in yellow on my picture)
The vector Center>>>Impact can be replace as an infinite line

you can Imagine a normal paper in 2D like in real life,
you draw 2 dot of fresh ink anywhere,
you draw a line in a random direction going through one of two points,
you fold the sheet following this line,
and a third dot appear (cause it's fresh ink) ... I need to know where is this dot in 3D space

I can do it if this code :

Code (Skript):

1. send "%location at (-1, 0, -1) mirrored at location at (0, 0, 0) in direction of vector 0, 0, -1%"

but this code result (0, 0, -1) ITS WRONG !! I need (1, 0, -1)

Anybody who want help : I have made a test server.rar (28Mo) included all addons +the skript +Viaversion for 1.10.x to 1.11.2
The first shoot does not works but all other worked
https://drive.google.com/open?id=1AnvC_spWVg2d4TXAPU86cGD5PjsS_Sv-

EDIT : IF it's possible to rebounce as it's a cube and not a sphere is awesome, but realy more difficult :/ (I guess ... no ?) Maybe by the same operation BUT the vector mirror is rouded to 90 degree

 

nowp, does not work.
This make just a rebound in your face ^^

 

this work for upward and downward faces of a block, not horizontal faces :/

 

i have an other idea (i know how to code 50%)
1) Need to know the neerest round 90 degree of vector between the point of impact and the current position = know the one of all 6 Faces of the impact. # I don't know how to do it
2) Set a mirrored loc at future loc # I can do it
3) found lenght of h (see the picture below) # I don't know
4) set lenght of vector to 2*h # I can do it
5) put the vector to futur loc and apply a translation with vector # I can
6) Done, you get the Real mirrored dot location

It's different from my original idea, same result. What is the most easy way? (idk)




@Donut, yes it can work, but how to know the impact faces ?

 

Interesting,
Nowp, i'm not familar with it, I had download it today haha (and i don't know how to read java)

I have made this :

TO TEST :

Code (Skript):

1. on script load:
2.   import "java.lang.System"
3.   import "java.lang.Math"
4.   import "java.lang.Integer" #This exist ?
5.  
6. command /rr <integer=1> <integer=1>:
7.     trigger:
8.         set {_x} to arg-1
9.         set {_y} to 100
10.         set {_z} to arg-2
11.         set {_world} to player's world
12.         set {_Mirror.block} to {_world}.getBlockAt( {_x} and {_y} and {_z} )
13.         broadcast "%{_Mirror.block}%"
14.         add 1 to {_y}
15.         set {_Mirror.target} to world.getBlockAt( {_x} and {_y} and {_z} )
16.         send "%{_Mirror.block}.getFace({_Mirror.target})%"

Upward work 100% without any problem

Code (Skript):

1.                 set {_bx} to x-location of {_block}
2.                 set {_by} to y-location of {_block}
3.                 set {_bz} to z-location of {_block}
4.  
5.                 #==============
6.                 #CODE OF BOUNCE
7.                 #NEED HELP HERE
8.                 #==============
9.                 set {_world} to {_shooter}'s world
10.                 set {_Mirror.block} to {_world}.getBlockAt( {_bx} and {_by} and {_bz} )
11.                 broadcast "%{_Mirror.block}%"
12.                 set {_Mirror.old} to {_world}.getBlockAt( {_x.old} and {_y.old} and {_z.old} )
13.                 broadcast "%{_Mirror.old}%"
14.                 set {_Mirror.face} to {_Mirror.block}.getFace({_Mirror.old})
15.                 broadcast "%{_Mirror.face}%"           #YEAH I have NORTH :)
16.                 exit loop

But in a function this work ... and 3 seconds after 1000 lines of [ERROR] appear on my console + the world "{_world}" is DELETED and recreate with a random seed. This appear every time with the function but not with the "/rr"
If i do :
!set {test} to player's world
!send "%{test}.getBlockAt( 0 and 0 and 0 )%"
This work fine, no crash ... so the Function is the problem ?

 

Thx, this reflected expression is perfectly what I

need but the part "[ (in|with) direction [of ]%-vector%]" is broken, as i said upward in my second reply :

Or maybe i don't kow how to us this part :/ (If i know how to use it, all of my problem can be solved )

Ok now i have debug my world reset (the problem was just a # blabla # blabla)
and i can get the Face of the impact = i can get the vector 90°

Code (Skript):

1.                 set {_bx} to x-location of {_block}
2.                 set {_by} to y-location of {_block}
3.                 set {_bz} to z-location of {_block}
4.  
5.                 #==============
6.                 #CODE OF BOUNCE
7.                 #NEED HELP HERE
8.                 #==============
9.                 set {_face} to Face({_world}, {_bx}, {_by}, {_bz}, {_x.old}, {_y.old}, {_z.old})
10.                 broadcast "%{_face}%"
11.                 if "%{_face}%" is "UP":
12.                     set {_vector90} to vector 0, 1, 0
13.                 if "%{_face}%" is "DOWN":
14.                     set {_vector90} to vector 0, -1, 0
15.                 if "%{_face}%" is "EAST":
16.                     set {_vector90} to vector 1, 0, 0
17.                 if "%{_face}%" is "WEST":
18.                     set {_vector90} to vector -1, 0, 0
19.                 if "%{_face}%" is "SOUTH":
20.                     set {_vector90} to vector 0, 0, 1
21.                 if "%{_face}%" is "NORTH":
22.                     set {_vector90} to vector 0, 0, -1
23.              
24.                

(Yeah this is a progress ^^ ... I hope my {_vector90} are in right direction)

i would like to know the angle between {_vector90} and input vector with basic trigonometry but it's 3D and not 2D and i'm not an expert with that :'(
(cause of the input vector have a yaw and pitch )

the code "angle between %vector% and %vector%" does not work and return "can't understand this expression"

 

Guys ... it ... IT'S WORKING =D !!

thx everyone !

Code (Skript):

1. on script load:
2.   import "java.lang.System"
3.   import "java.lang.Math"
4.   import "java.lang.Integer"
5.  
6.  
7. function Face(world: world, x1: number, y1: number, z1: number, x2: number, y2: number, z2: number) :: string:
8.     set {_Mirror.block1} to {_world}.getBlockAt( {_x1} and {_y1} and {_z1} )
9.     set {_Mirror.block2} to {_world}.getBlockAt( {_x2} and {_y2} and {_z2} )
10.     set {_mirror.face} to {_Mirror.block1}.getFace({_Mirror.block2})
11.     return "%{_mirror.face}%"
12.  
13. function Shoot(shooter: player, type: string, force: number, predict: boolean):
14.     set {_world} to {_shooter}'s world
15.     set {_pi} to {Math}.PI!
16.     set {_x0} to x-location of {_shooter}
17.     set {_y0} to y-location of {_shooter}
18.     set {_z0} to z-location of {_shooter}
19.     set {_v0} to 17.7*{_force}              #17.7 is my own chosen number randomly for the velocity
20.     set {_pitch} to pitch of {_shooter}*-1  #The rotation of player
21.     set {_yaw} to yaw of {_shooter}*-1
22.     set {_cosPitch} to cos ({_pitch}*3.14/180)
23.     set {_cosx} to (sin ({_yaw}*3.14/180) )* {_cosPitch}
24.     set {_cosz} to (cos ({_yaw}*3.14/180) )* {_cosPitch}
25.     set {_t} to 0
26.     set {_colorRandom} to "1 0 0"
27.     set {_RotPitch} to {_pitch}             #The initial rotation of projectile
28.     set {_RotYaw} to {_yaw}
29.  
30.     if {_predict} is false:
31.         set {_ID} to "Shoot_%{_shooter}%_%{game.timer}%"
32.         run {_shooter} command "/summon ArmorStand %x-location of {_shooter}% %y-location of {_shooter}% %z-location of {_shooter}% {CustomName:""%{_ID}%"",Tags:[""Shoot"",""Shoot_%{_shooter}%""],NoGravity:1b,Small:1b,Marker:1b,Invisible:1,Invulnerable:0,DisabledSlots:2039583}" as op
33.         loop all armor stands:
34.             loop-entity's name is "%{_ID}%"
35.             set {_entity} to loop-entity    #not used for now
36.             execute console command "/execute @e[type=ArmorStand,name=%{_ID}%] ~ ~ ~ /playsound minecraft:entity.irongolem.attack master @a %{_x0}% %{_y0}% %{_z0}% 1 1"
37.             if "%{player::*}%" contain "%{_shooter}%":
38.                 execute console command "/mycmd add %{_shooter}% stats.use.%{_type}% 1"
39.             if "%{_type}%" is "fragmentation":
40.                 set helmet of loop-entity to yellow dye
41.                 set {_color} to "0 1 0"
42.             if "%{_type}%" is "retardement":
43.                 set helmet of loop-entity to red dye
44.                 set {_color} to "0 0 0"
45.             if "%{_type}%" is "chimique":
46.                 set helmet of loop-entity to light green dye
47.                 set {_color} to "0.27 0.77 0.18"
48.             if "%{_type}%" is "flame":
49.                 set helmet of loop-entity to orange dye
50.                 set {_color} to "1 0.5 0.1"
51.             if "%{_type}%" is "implosion":
52.                 set helmet of loop-entity to light blue dye
53.                 set {_color} to "0.1 0.9 1"
54.             if {_color} is not set:
55.                 set {_color} to "1 1 1"
56.                
57.     loop 900 times:
58.         set {_xt} to {_v0}* {_cosx}         #I put this here cause of the speed {_v0} can be modified (exemple: in water)
59.         set {_zt} to {_v0}* {_cosz}
60.         set {_x} to {_x0}+{_xt}*{_t}
61.         set {_y} to (-12/2*{_t}^2) +{_v0}*{_t}*sin ({_Pitch}*3.14/180) +1.52 +{_y0}     #+1.52 is for eye's position
62.         set {_z} to {_z0}+{_zt}*{_t}
63.        
64.         set {_vectorx} to {_x} - {_x.old}           #I prefer use %vector% only if a complex math operation is more easy with an addon
65.         set {_vectory} to {_y} - {_y.old}
66.         set {_vectorz} to {_z} - {_z.old}
67.         set {_norme} to sqrt ( {_vectorx}^2 + {_vectory}^2 + {_vectorz}^2 )
68.         set {_vectordirx} to {_vectorx} / {_norme}
69.         set {_vectordiry} to {_vectory} / {_norme}
70.         set {_vectordirz} to {_vectorz} / {_norme}
71.        
72.  
73.         set {_RotPitch} to -57.2958* arc sin ({_vectordiry})
74.         set {_atan2} to {Math}.atan2({_vectordirx} and {_vectordirz})
75.         set {_RotYaw} to {_atan2}*180/{_pi}
76.         #broadcast "<cyan>%vector pitch of vector {_vectorx}, {_vectory}, {_vectorz}% %vector yaw of vector {_vectorx}, {_vectory}, {_vectorz}%"
77.         #broadcast "<gold>%{_RotPitch}% %{_RotYaw}%"
78.         #Same pitch and yaw : Yaw between [0,360] and [-180,180]
79.        
80.        
81.         set {_block} to block at location ({_x}, {_y}, {_z}) in world "%{map}%"
82.         if {_block} is air or water or any glass pane or carpet or pressure plate or window glass or painting or item frame or sign or button or flower pot or ladder or torch or redstone torch or wire:
83.             if {_block} is water:
84.                 if {_predict} is false:
85.                     if block upward {_block} is air:
86.                         execute console command "/execute @e[type=ArmorStand,name=%{_ID}%] ~ ~ ~ /particle splash %{_x}% %{_y}+1% %{_z}% 0.1 0 0.1 0 50 force"
87.                 set {_v0} to {_v0}*0.98
88.                 if {_v0} < 5:
89.                     set {_v0} to 5
90.             if {_block} is glass pane or window glass:
91.                 if {_predict} is false:
92.                     set {_blockID} to id of block at location ({_x}, {_y}, {_z}) in world "%{map}%"
93.                     execute console command "/execute @e[type=ArmorStand,name=%{_ID}%] ~ ~ ~ /particle blockcrack %x-location of {_block}% %y-location of {_block}% %z-location of {_block}% 0.1 0.1 0.1 1 10 force @a %{_blockID} + data of {_block}*4096%"
94.                     set block at location ({_x}, {_y}, {_z}) in world "%{map}%" to air
95.                 set {_v0} to {_v0}*0.7
96.             if {_predict} is false:
97.                 execute console command "/tp @e[type=ArmorStand,name=%{_ID}%] %{_x}% %{_y}-1% %{_z}% %{_RotYaw}% ~"
98.                # execute console command "/entitydata @e[type=ArmorStand,name=%{_ID}%] {Pose:{Head:[%({_RotPitch} -90)*-1%f,0f,0f]}}"
99.                 execute console command "/execute @e[type=ArmorStand,name=%{_ID}%] ~ ~ ~ /particle reddust %{_x}% %{_y}% %{_z}% %{_color}% 1 0 force"
100.                 execute console command "/execute @e[type=ArmorStand,name=%{_ID}%] ~ ~ ~ /playsound minecraft:entity.guardian.ambient master @a %{_x}% %{_y}% %{_z}% 0.1 2"
101.             add 0.01 to {_t}
102.         else:
103.             if {_v0} > 5:                                   #no bounce if velocity is under 5 cube/s
104.                 #broadcast "impact: %{_x}% %{_y}% %{_z}%"
105.                 #broadcast "velocity: %{_v0}% angle: %{_pitch}% %{_yaw}%"
106.                 set {_bx} to x-location of {_block}
107.                 set {_by} to y-location of {_block}
108.                 set {_bz} to z-location of {_block}
109.                 set {_inputVector} to vector {_x.old}-{_x}, {_y.old}-{_y}, {_z.old}-{_z}
110.                 #==============
111.                 #CODE OF BOUNCE
112.                 #NEED HELP HERE
113.                 #==============
114.                 set {_face} to Face({_world}, {_bx}, {_by}, {_bz}, {_x.old}, {_y.old}, {_z.old})
115.                 if "%{_face}%" is "<none>":
116.                     if {_RotPitch} > 0:
117.                         set {_face} to "UP"
118.                     else:
119.                         set {_face} to "DOWN"
120.                 if "%{_face}%" is "UP":
121.                     set {_vector90} to vector 0, 1, 0
122.                 if "%{_face}%" is "DOWN":
123.                     set {_vector90} to vector 0, -1, 0
124.                 if "%{_face}%" is "EAST":
125.                     set {_vector90} to vector 1, 0, 0
126.                 if "%{_face}%" is "WEST":
127.                     set {_vector90} to vector -1, 0, 0
128.                 if "%{_face}%" is "SOUTH":
129.                     set {_vector90} to vector 0, 0, 1
130.                 if "%{_face}%" is "NORTH":
131.                     set {_vector90} to vector 0, 0, -1
132.                 if "%{_face}%" is "SOUTH_WEST":
133.                     set {_vector90} to vector -1, 0, 1
134.                 if "%{_face}%" is "SOUTH_EAST":
135.                     set {_vector90} to vector 1, 0, 1
136.                 if "%{_face}%" is "NORTH_WEST":
137.                     set {_vector90} to vector -1, 0, -1
138.                 if "%{_face}%" is "NORTH_EAST":
139.                     set {_vector90} to vector 1, 0, -1
140.                 set {_angle} to {_inputVector}.angle({_vector90}) *180/{_pi}
141.                 set {_length} to 2* vector length of {_inputVector}
142.                 set {_length} to {_length} * cos({_angle})
143.                 set {_vector90} to {_vector90} normalized ** {_length}
144.                 set {_mirror1} to location ({_x.old}, {_y.old}, {_z.old}) in world "%{_world}%" mirrored at location ({_x}, {_y}, {_z}) in world "%{_world}%"
145.                 set {_mirror2} to {_mirror1} ~ {_vector90}      #Offset a location by a vector : %location% ~ %vector%
146.                 set {_VectorRebound} to vector x-location of {_mirror2} - {_x}, y-location of {_mirror2} - {_y}, z-location of {_mirror2} - {_z}
147.                
148.                 #loop 90 times:
149.                 #    execute console command "/execute @e[type=ArmorStand,name=%{_ID}%] ~ ~ ~ /particle reddust %{_x}% %{_y}% %{_z}% 1 0 0 1 0 force"
150.                 #    execute console command "/execute @e[type=ArmorStand,name=%{_ID}%] ~ ~ ~ /particle reddust %{_x.old}% %{_y.old}% %{_z.old}% 0 1 0 1 0 force"
151.                 #    execute console command "/execute @e[type=ArmorStand,name=%{_ID}%] ~ ~ ~ /particle reddust %x-location of {_mirror2}% %y-location of {_mirror2}% %z-location of {_mirror2}% 0 0 1 1 0 force"
152.                 #    wait a tick
153.                    
154.                 set {_pitch} to vector pitch of {_VectorRebound}
155.                 set {_yaw} to vector yaw of {_VectorRebound}
156.                 set {_pitch} to {_pitch} *-1
157.                 set {_yaw} to {_yaw} *-1
158.                 #broadcast "<cyan>%{_pitch}% %{_yaw}%"
159.                 #================
160.                 #NEED HELP UPWARD
161.                 #================
162.                
163.                 #Code below = set the coord of the impact as a new shoot location reference with new pitch and yaw              
164.                 set {_v0} to {_v0}*0.8                               #change to 0.2 for normal rebound
165.                 set {_x0} to {_x}                                       #{_x}, {_y}, {_z} = Impact location
166.                 set {_y0} to {_y} -1.52
167.                 set {_z0} to {_z}
168.                 set {_cosPitch} to cos ({_pitch}*3.14/180)
169.                 set {_cosx} to (sin ({_yaw}*3.14/180) )* {_cosPitch}
170.                 set {_cosz} to (cos ({_yaw}*3.14/180) )* {_cosPitch}
171.                 set {_t} to 0.05
172.                 set {_RotPitch} to {_pitch}
173.                 set {_RotYaw} to {_yaw}
174.                 set {_colorRandom} to a random element out of "1 1 1", "0 1 0" and "0 0 1"
175.             else:
176.                 exit loop
177.         execute console command "/execute @r ~ ~ ~ /particle reddust %{_x}% %{_y}% %{_z}% %{_colorRandom}% 1 0 force"
178.         set {_x.old} to {_x}
179.         set {_y.old} to {_y}
180.         set {_z.old} to {_z}
181.         if {_predict} is false:
182.             if {_t}*100 is divisible by 5:
183.                 wait 1 tick
184.     if {_predict} is true:
185.         set block at location ({_x}, {_y}, {_z}) in world "%{map}%" to glowstone
186.     execute console command "/kill @e[type=ArmorStand,name=%{_ID}%]"
187.  
188. command /predict:
189.     trigger:
190.         loop 10 times:
191.             Shoot(player,"retardement", 1.4, true)      #set to "true" to predict the trajectory in a 1 tick
192.             wait a second
193.         #set {map} to event-world                    #DEBUG : I use this on my server
194.         #set {game.timer} to 0                       #DEBUG : I use this on my server

You can try this code, (parameter for a lot of rebounce with a lot of color ^^), if you don't have all plugins use this pack:

and a little bonus bonus, the code for correct mirroring "location at (-1, 0, -1) mirrored at location at (0, 0, 0) in direction of vector 0, 0, -1" of @bi0

Code (Skript):

1. on script load:
2.   import "java.lang.System"
3.   import "java.lang.Math"
4.   import "java.lang.Integer"
5.  
6.  
7. command /mirror <integer= 1> <integer= 0> <integer= 0>:
8.     trigger:
9.         set {_pi} to {Math}.PI!
10.         set {_vector90} to vector arg-1, arg-2, arg-3
11.         set {_inputVector} to vector -1, 0, -1              #=direction of the bullet inverted
12.         set {_angle} to {_inputVector}.angle({_vector90}) *180/{_pi}
13.         set {_length} to 2* vector length of {_inputVector}
14.         set {_length} to {_length} * cos({_angle})
15.  
16.         set {_vector90} to {_vector90} normalized ** {_length}
17.         set {_mirror1} to location (-1, 0, -1) in world "%event-world%" mirrored at location (0, 0, 0) in world "%event-world%"
18.         set {_vectorMirror1} to vector x-location of {_mirror1}, y-location of {_mirror1}, z-location of {_mirror1}
19.         set {_mirror2} to {_vectorMirror1} ++ {_vector90}
20.         broadcast "angle: %{_angle}% cos: %cos({_angle})% length of InputVector: %vector length of {_inputVector}% length: %{_length}%"
21.         broadcast "<cyan>mirror : %{_mirror2}%"

I have against some problem with my trajectory but i have learn a lot of thing. I will try to solve them alone.

 

ok

Code (Skript):

1. set {_pi} to {Math}.PI!

Does not return a good Pi ?