I'm trying to make a checkers game as a first game, and have the function loc_type(loc) which should return 1 if the location has a black piece and a 2 if the location has a white piece, and zero if it's empty.
This works perfectly well for setting up the board but I'm now trying to code selecting a piece. But when I call loc_type, it seems to think that pos = {5,7} (Which is the last white piece I spawn).
I'm really unsure how to fix this. Any thoughts?
Code for reference
--game logic
function _init()
-- enable mouse
poke(0x5f2d, 1)
curr_peice = nil
val = {-1,-1}
-- starting places for peices (might want to automate this?)
blacks = {{0,0},{0,2},{0,4},{0,6},{1,1},{1,3},{1,5},{1,7},{2,0},{2,2},{2,4},{2,6}}
whites = {{7,1},{7,3},{7,5},{7,7},{6,0},{6,2},{6,4},{6,6},{5,1},{5,3},{5,5},{5,7}}
end
function _draw()
--clear screen
cls(0)
-- draw board and peices
draw_board()
draw_peices()
-- draw cursor
spr(9,curr_x*16,curr_y*16,2,2)
print(val,3)
if curr_peice != nil then
spr(9,curr_peice[1]*16,curr_peice[2]*16,2,2)
end
end
function _update()
-- calculate current square
curr_x = mid(0,stat(32)\16,7)
curr_y = mid(0,stat(33)\16,7)
val = loc_type({curr_x,curr_y})
end
-- graphics
function draw_board()
for i=0,7 do
for j=0,7 do
-- checks if square is black
is_black = ((i+j)%2)
rectfill(i*16,j*16,(i+1)*16-1,(j+1)*16-1,is_black*7)
end
end
end
function draw_single(single)
piece_type = loc_type(single)
-- draws the peice
if piece_type == 1 then
spr(1,single[1]*16,single[2]*16,2,2)
elseif piece_type == 2 then
spr(3,single[1]*16,single[2]*16,2,2)
else
print("error: no peice here")
end
end
function draw_peices()
foreach(blacks,draw_single)
foreach(whites,draw_single)
end
-- utility functions
function loc_type(loc)
is_black = object_in_table(loc,blacks)
is_white = object_in_table(loc,whites)
if is_black and is_white then
print("error: two peices in the same place")
return -1
end
if is_black then
return 1
elseif is_white then
return 2
else
return 0
end
end
function object_in_table(obj,t)
for t_obj in all(t) do
if t_obj == obj then
return true
end
end
return false
end |
I am unclear what you mean regarding "But when I call loc_type, it seems to think that pos = {5,7} (Which is the last white piece I spawn)."
That aside:
"Lua compares tables, userdata, and functions by reference, that is, two such values are considered equal only if they are the very same object." Source: https://www.lua.org/pil/3.2.html
So two tables with the same values in are not the same table (unless they are also the same object).
In object_in_table change the check for equality from if t_obj == obj then to:
if t_obj[1]==obj[1] and t_obj[2]==obj[2] then |
Does that fix the bug, or could you explain it further?
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