Hello, I've been working on a RPG lately, and I've hit a snag. When the fight sequence starts, I want the party members to appear in the screen, but I want it to sort their sprites as more members come. Kinda like a card algorithm, in the sense that you have one object, but when a new object appear, they get separated by some type of padding, and then when a third object comes around, the first object is at the right, the second at the left, and the third one in the middle, and so on? I have no idea what this can be called, but id love it if someone could help.
TL;DR:
This gif is what I wanna do with a table:
I have no idea how to approach it. Thank you in advance.
Help with sorting algorithm
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Re: Help with sorting algorithm
local t = {}
table.insert( t, 1 + math.ceil(#t/2), 1 )
table.insert( t, 1 + math.ceil(#t/2), 2 )
table.insert( t, 1 + math.ceil(#t/2), 3 )
table.insert( t, 1 + math.ceil(#t/2), 4 )
table.insert( t, 1 + math.ceil(#t/2), 5 )
This creates a table with in the following order
1  3  5  4  2
table.insert( t, 1 + math.ceil(#t/2), 1 )
table.insert( t, 1 + math.ceil(#t/2), 2 )
table.insert( t, 1 + math.ceil(#t/2), 3 )
table.insert( t, 1 + math.ceil(#t/2), 4 )
table.insert( t, 1 + math.ceil(#t/2), 5 )
This creates a table with in the following order
1  3  5  4  2
 Joelrodiel
 Prole
 Posts: 27
 Joined: Wed Apr 20, 2016 3:40 am
Re: Help with sorting algorithm
Hi Nelvin, sorry I don't think I was specific enough. I have the table and everything, all I need to know is how to draw the sprites in a way where they push each other to the sides corresponding on the amount in the table, like the gif showsNelvin wrote: ↑Tue Nov 13, 2018 12:05 amlocal t = {}
table.insert( t, 1 + math.ceil(#t/2), 1 )
table.insert( t, 1 + math.ceil(#t/2), 2 )
table.insert( t, 1 + math.ceil(#t/2), 3 )
table.insert( t, 1 + math.ceil(#t/2), 4 )
table.insert( t, 1 + math.ceil(#t/2), 5 )
This creates a table with in the following order
1  3  5  4  2
Re: Help with sorting algorithm
Well, I'd start from the roof
That is, start by determining the final position of each character, e.g. when you have two and you're going to make a 3rd one enter the scene, first determine the final positions of all three. This is easy if all of them are the same size, but it gets a bit complicated when the sizes may vary.
The initial and final Y positions are both constant, so let's not worry about it.
When there are going to be N characters, the total size from centre to centre of each character once they are in their positions is: size_c2c = (N  1) * character_width + (N  1) * padding. The leftmost character centre's X coordinate, relative to the centre of the screen, is minus half that number (because they will be distributed half that size in the negative direction and half that size in the positive direction, with respect to the centre). Let's call that left_base. So, left_base = size_c2c / 2.
Now, for any character index 'j' from 1 to N, the final coordinate of that character will be: xpos[j] = left_base + (j  1) * (character_width + padding).
With that, we have the positions necessary for N characters. Now all you have to do is tween all characters except the one that is coming in, from their previous position to their newly calculated position, and the one that is coming in, from the bottom of the screen at its final X position to the row's Y position.
But, wait, there's still something else to do. We have to insert the new character into its new position. That position is math.floor(N/2) + 1. Insert the element and you're ready for the next iteration.
For best effect, the padding could be calculated depending on N, like in your gif. A formula that might work is the inverse of N plus a minimum, for example math.floor(character_width/(N  0.5) + 5) or something like that.
Putting everything together and in order, into Lualike pseudocode:
Edit: Proof of concept attached. Note it uses twimer.lua, which is my own timer/tween library that has not been publicly released, therefore don't use that library! Use some other one instead.
That is, start by determining the final position of each character, e.g. when you have two and you're going to make a 3rd one enter the scene, first determine the final positions of all three. This is easy if all of them are the same size, but it gets a bit complicated when the sizes may vary.
The initial and final Y positions are both constant, so let's not worry about it.
When there are going to be N characters, the total size from centre to centre of each character once they are in their positions is: size_c2c = (N  1) * character_width + (N  1) * padding. The leftmost character centre's X coordinate, relative to the centre of the screen, is minus half that number (because they will be distributed half that size in the negative direction and half that size in the positive direction, with respect to the centre). Let's call that left_base. So, left_base = size_c2c / 2.
Now, for any character index 'j' from 1 to N, the final coordinate of that character will be: xpos[j] = left_base + (j  1) * (character_width + padding).
With that, we have the positions necessary for N characters. Now all you have to do is tween all characters except the one that is coming in, from their previous position to their newly calculated position, and the one that is coming in, from the bottom of the screen at its final X position to the row's Y position.
But, wait, there's still something else to do. We have to insert the new character into its new position. That position is math.floor(N/2) + 1. Insert the element and you're ready for the next iteration.
For best effect, the padding could be calculated depending on N, like in your gif. A formula that might work is the inverse of N plus a minimum, for example math.floor(character_width/(N  0.5) + 5) or something like that.
Putting everything together and in order, into Lualike pseudocode:
Code: Select all
appearance_order = { player_to_appear_first, player_to_appear_second, player_to_appear_third }
function enter_next_character()
N = #characters_in_scene + 1
if N > #appearance_order then
appearance_finished()  We're done, we can advance to the battle or whatever.
return
end
 Start a timer that will call enter_next() after the time has passed
after(tween_time + pause_time, enter_next)
 Find insert point, add new character
local insert_point = math.floor(N / 2) + 1
table_insert(characters_in_scene, insert_point, { character = appearance_order[N] })
 Calculate a padding
local padding = math.floor(character_width / (N  0.5) + 5)
 Calculate size_c2c and left_base
local size_c2c = (N  1) * character_width + (N  1) * padding
local left_base = math.floor(size_c2c / 2)
 Prepare the next tween of each character and launch it
for j = 1, N do
local new_x = left_base + (j  1) * (character_width + padding)
local current = characters_in_scene[j]
if j == insert_point then
 Set the new character old_x the same as new_x, and old_y out of the screen
current.old_x = new_x
current.old_y = y_out_of_the_screen  e.g. love.graphics.getHeight() + character_height / 2 + 0.5
else
 Set the current character old coordinates to the previously used coordinates
current.old_x = current.new_x
current.old_y = current.new_y
end
 Update the new coordinates with the new values
current.new_x = new_x
current.new_y = final_row_y  your final 'y' value, maybe the centre of the screen?
 Tween current.x and current.y at the same time from old_* to new_*  see your tweening library's manual
tween(tween_time, current, {"x", "y"}, {current.old_x, current.old_y}, {current.new_x, current.new_y})
end
end
function love.draw()
for i = 1, #characters_in_scene do
local current = characters_in_scene[i]
 Draw the characters appropriately centred
love.graphics.draw(current.character.image,
math.floor(current.x + 0.5) + screen_centre_x,
math.floor(current.y + 0.5),
0, 1, 1,  angle, scale_x, scale_y
 centre of the image
math.floor(current.character.image:getWidth() * 0.5),
math.floor(current.character.image:getHeight() * 0.5)
)
end
end
 Attachments

 insertexample.love
 (5.17 KiB) Downloaded 30 times
 Joelrodiel
 Prole
 Posts: 27
 Joined: Wed Apr 20, 2016 3:40 am
Re: Help with sorting algorithm
Wow thank you so much for this response, this is just amazing. I will try to wrap my head around it haha, but again thank you so much. Also dont worry I wont copy and paste.pgimeno wrote: ↑Tue Nov 13, 2018 12:30 amWell, I'd start from the roof
That is, start by determining the final position of each character, e.g. when you have two and you're going to make a 3rd one enter the scene, first determine the final positions of all three. This is easy if all of them are the same size, but it gets a bit complicated when the sizes may vary.
The initial and final Y positions are both constant, so let's not worry about it.
When there are going to be N characters, the total size from centre to centre of each character once they are in their positions is: size_c2c = (N  1) * character_width + (N  1) * padding. The leftmost character centre's X coordinate, relative to the centre of the screen, is minus half that number (because they will be distributed half that size in the negative direction and half that size in the positive direction, with respect to the centre). Let's call that left_base. So, left_base = size_c2c / 2.
Now, for any character index 'j' from 1 to N, the final coordinate of that character will be: xpos[j] = left_base + (j  1) * (character_width + padding).
With that, we have the positions necessary for N characters. Now all you have to do is tween all characters except the one that is coming in, from their previous position to their newly calculated position, and the one that is coming in, from the bottom of the screen at its final X position to the row's Y position.
But, wait, there's still something else to do. We have to insert the new character into its new position. That position is math.floor(N/2) + 1. Insert the element and you're ready for the next iteration.
For best effect, the padding could be calculated depending on N, like in your gif. A formula that might work is the inverse of N plus a minimum, for example math.floor(character_width/(N  0.5) + 5) or something like that.
Putting everything together and in order, into Lualike pseudocode:
Edit: Proof of concept attached. Note it uses twimer.lua, which is my own timer/tween library that has not been publicly released, therefore don't use that library! Use some other one instead.Code: Select all
appearance_order = { player_to_appear_first, player_to_appear_second, player_to_appear_third } function enter_next_character() N = #characters_in_scene + 1 if N > #appearance_order then appearance_finished()  We're done, we can advance to the battle or whatever. return end  Start a timer that will call enter_next() after the time has passed after(tween_time + pause_time, enter_next)  Find insert point, add new character local insert_point = math.floor(N / 2) + 1 table_insert(characters_in_scene, insert_point, { character = appearance_order[N] })  Calculate a padding local padding = math.floor(character_width / (N  0.5) + 5)  Calculate size_c2c and left_base local size_c2c = (N  1) * character_width + (N  1) * padding local left_base = math.floor(size_c2c / 2)  Prepare the next tween of each character and launch it for j = 1, N do local new_x = left_base + (j  1) * (character_width + padding) local current = characters_in_scene[j] if j == insert_point then  Set the new character old_x the same as new_x, and old_y out of the screen current.old_x = new_x current.old_y = y_out_of_the_screen  e.g. love.graphics.getHeight() + character_height / 2 + 0.5 else  Set the current character old coordinates to the previously used coordinates current.old_x = current.new_x current.old_y = current.new_y end  Update the new coordinates with the new values current.new_x = new_x current.new_y = final_row_y  your final 'y' value, maybe the centre of the screen?  Tween current.x and current.y at the same time from old_* to new_*  see your tweening library's manual tween(tween_time, current, {"x", "y"}, {current.old_x, current.old_y}, {current.new_x, current.new_y}) end end function love.draw() for i = 1, #characters_in_scene do local current = characters_in_scene[i]  Draw the characters appropriately centred love.graphics.draw(current.character.image, math.floor(current.x + 0.5) + screen_centre_x, math.floor(current.y + 0.5), 0, 1, 1,  angle, scale_x, scale_y  centre of the image math.floor(current.character.image:getWidth() * 0.5), math.floor(current.character.image:getHeight() * 0.5) ) end end
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