wave.lua

--initialize

local timer = require "lua.timer"
local setColorFX = ts.func("FxDTSBrick", "setColorFX")
local fakeKillBrick = ts.func("FxDTSBrick", "fakeKillBrick")
local setColor = ts.func("FxDTSBrick", "setColor")
local group = SimSet("BrickGroup_46342")
local width, height = 64, 128
local grid = {}

for x = 0, width - 1 do
	grid[x] = {}
	for y = 0, height - 1 do
		grid[x][y] = group:getObject((y * width + x + 1) % 8192)
	end
end

--initialize state

-- local fixed = {}
-- local state = {}
-- _G.gfixed = fixed
-- _G.gstate = state
-- local dt = 0.1
--
-- for x = 0, width - 1 do
-- 	fixed[x] = {}
-- 	state[x] = {}
-- 	for y = 0, height - 1 do
-- 		if x == 0 or x == (width - 1) or y == 0 or y == (height - 1) then
-- 			fixed[x][y] = true
-- 			state[x][y] = {0, 0}
-- 		else
-- 			fixed[x][y] = false
-- 			state[x][y] = {math.exp((-(x - width / 2) ^ 2 - (y - height / 2) ^ 2) / width * 6) * 4, 0}
-- 		end
-- 	end
-- end

local fixed = {}
local state = {}
_G.gfixed = fixed
_G.gstate = state
local dt = 0.01
local pwidth = 0.1
local mfreq = 8
local direction = math.pi / -2

-- local slit = {[25] = true, [26] = true, [27] = true, [37] = true, [38] = true, [39] = true}
local slit = {[31] = true, [32] = true, [33] = true}

for x = 0, width - 1 do
	fixed[x] = {}
	state[x] = {}
	for y = 0, height - 1 do
		if x == 0 or x == (width - 1) or y == 0 or y == (height - 1) or (y == 64 and not slit[x]) then
			fixed[x][y] = true
			state[x][y] = {0, 0}
		else
			xl = (x - 32) / 32
			yl = (y - 32) / 32
			v = math.exp(-(xl ^ 2 + yl ^ 2) / pwidth) * 2
			fixed[x][y] = false
			state[x][y] = {v * math.sin((math.cos(direction) * xl +
							             math.sin(direction) * yl) * math.pi * mfreq),
						   v * math.cos((math.cos(direction) * xl +
							             math.sin(direction) * yl) * math.pi * mfreq)}
		end
	end
end

--run every iteration

local function update()
for i = 1, 128 do
	for x = 0, width - 1 do
		for y = 0, height - 1 do
			if not fixed[x][y] then
				state[x][y][1] = state[x][y][1] + state[x][y][2] * dt
			end
		end
	end

	for x = 0, width - 1 do
		for y = 0, height - 1 do
			if not fixed[x][y] then
				state[x][y][2] = state[x][y][2] +
							    (state[(x + 1) % width][y               ][1] +
						         state[(x - 1) % width][y               ][1] +
						         state[x              ][(y + 1) % height][1] +
						         state[x              ][(y - 1) % height][1] -
						         4 * state[x][y][1]) * dt
			end
		end
	end
end
	for x = 0, width - 1 do
		for y = 0, height - 1 do
			setColor(grid[x][y], fixed[x][y] and 0 or math.max(0, math.min(63, state[x][y][1] * 64 + 32)))
		end
	end

	_G.sched = timer(64, update)
end

ts.func("cancel")(_G.sched)
update()