c4test

-- X and Y dimensions of the playfield
local boardX, boardY = 7, 6
-- Colors of the different sides
local pone_col, ptwo_col = colors.black, colors.red
-- Color of board and board frame
local board_col, boardframe_col = colors.yellow, colors.blue
-- Color of background
local bg_col = colors.cyan

local scr_x,scr_y = term.getSize()

local makeNewBoard = function()
    local output = {}
    for a = 1, boardY do
        output[#output+1] = ("0"):rep(boardX)
    end
    return output
end

local grid = makeNewBoard()

local substrrepl = function(str,char,pos)
    return str:sub(1,pos-1)..char:sub(1,1)..str:sub(pos+1)
end

local placePiece = function(pos,side)
    grid[1] = substrrepl(grid[1],side,pos)
end

local boardGravity = function()
    local hadFallen = false
    for y = 1, boardY-1 do
        for x = 1, boardX do
            if grid[y+1]:sub(x,x) == "0" then
                grid[y+1] = substrrepl(grid[y+1],grid[y]:sub(x,x),x)
                grid[y] = substrrepl(grid[y],"0",x)
                hadFallen = true
            end
        end
    end
    return hadFallen
end

local renderBoard = function(row,posX,posY)
    for y = 1, boardX do
        for x = row or 1, row or boardY do
            term.setCursorPos(posX + x, posY + y)
            if grid[y][x] == "0" then
                term.setTextColor(bg_col)
            elseif grid[y][x] == "1" then
                term.setTextColor(pone_col)
            elseif grid[y][x] == "2" then
                term.setTextColor(ptwo_col)
            end
            term.setBackgroundColor(bg_col)
            term.clearLine()
            term.setBackgroundColor(board_col)
            term.write(string.char(7))
        end
    end
end