mirror of
https://github.com/sbrl/Minetest-WorldEditAdditions.git
synced 2024-11-16 21:12:59 +00:00
57 lines
No EOL
2 KiB
Lua
57 lines
No EOL
2 KiB
Lua
local wea_c = worldeditadditions_core
|
|
|
|
--- Interpolates between the 2 given points
|
|
-- @param a Vector3|number The starting point.
|
|
-- @param b Vector3|number The ending point.
|
|
-- @param time number The percentage between 0 and 1 to interpolate to.
|
|
-- @returns Vector3|number The interpolated point.
|
|
local function linear_interpolate(a, b, time)
|
|
return ((b - a) * time) + a
|
|
end
|
|
|
|
--- Chaikin curve smoothing implementation.
|
|
-- This algorithm works by taking a list of points that define a segmented line,
|
|
-- and then interpolating between them to smooth the line.
|
|
-- @source Ported from https://git.starbeamrainbowlabs.com/sbrl-GitLab/Chaikin-Generator/src/branch/master/ChaikinGenerator/ChaikinCurve.cs
|
|
-- @param arr_pos Vector3[] A list of points to interpolate.
|
|
-- @param steps number The number of interpolatioon passes to do.
|
|
-- @returns Vector3[] A (longer) list of interpolated points.
|
|
local function chaikin(arr_pos, steps)
|
|
-- print("DEBUG:chaikin START", wea_c.inspect(arr_pos))
|
|
local result = wea_c.table.shallowcopy(arr_pos)
|
|
|
|
local pos_start = result[1]
|
|
local pos_end = result[#result]
|
|
|
|
for pass = 1, steps do
|
|
local result_nextpass = {}
|
|
-- local offset = 0
|
|
for i = 1,#result-1,1 do
|
|
local pos_cur = result[i]
|
|
local pos_next = result[i+1]
|
|
-- print("DEBUG:chaikin SUBSTEP i", i, "pos_cur", pos_cur, "pos_next", pos_next)
|
|
|
|
table.insert(result_nextpass, linear_interpolate(pos_cur, pos_next, 0.25))
|
|
table.insert(result_nextpass, linear_interpolate(pos_cur, pos_next, 0.75))
|
|
-- result[i+offset] = linear_interpolate(pos_cur, pos_next, 0.25)
|
|
-- table.insert(result, i+1+offset, linear_interpolate(pos_cur, pos_next, 0.75))
|
|
-- offset = offset + 1
|
|
end
|
|
|
|
-- table.remove(result, #result-1) -- In the original, but I don't know why
|
|
|
|
result = result_nextpass
|
|
-- Keep the starting & ending positions the same
|
|
result[1] = pos_start
|
|
result[#result] = pos_end
|
|
|
|
-- print("DEBUG:chakin STEP", wea_c.inspect(result))
|
|
end
|
|
|
|
return result
|
|
end
|
|
|
|
return {
|
|
chaikin = chaikin,
|
|
linear_interpolate = linear_interpolate
|
|
} |