Collision Program

-- Clear the screen --
term.clear()

-- Character position --
pos = {x = 25, y = 9}

-- List of all solids. c defines character, b defines if in background --
solids = {
    {x = 1, y = 1, c = '@'},

    {x = 1, y = 3},
    {x = 2, y = 3, c = '-'},
    {x = 3, y = 3},

    {x = 5, y = 1},
    {x = 5, y = 2},
    {x = 5, y = 3},

    {x = 50, y = 1, c = ':'},
    {x = 51, y = 1, c = 'O'},
    {x = 50, y = 2, c = '|'},
    {x = 51, y = 2, c = '-'},

    {x = 24, y = 8, c = 'X', b = true},
    {x = 25, y = 8, c = 'X', b = true},
    {x = 26, y = 8, c = 'X', b = true}
}

-- Function to draw scene --
function drawScene()
    -- Draw objects --
    for _, solid in pairs(solids) do
        term.setCursorPos(solid.x, solid.y)

        -- Check if solid has a specific character --
        if solid.c then
            term.write(solid.c)
        else
            term.write("#")
        end
    end

    -- Draw player --
    term.setCursorPos(pos.x, pos.y)
    term.write("@")
end

-- The last character that the player went on top of --
lastchar = '!'

-- Function to move character --
function move(newPos)
    -- Clear old pos --
    term.setCursorPos(pos.x, pos.y)
    term.write(" ")

    -- Set new pos --
    pos = {x = newPos.x, y = newPos.y}

    -- Draw char at new pos --
    term.setCursorPos(newPos.x, newPos.y)
    term.write("@")
end

-- Draw the scene for first time --
drawScene()

while true do
    event, key = os.pullEvent("key")

    -- Set default values for variables --
    local collide = false
    local newPos = {x = pos.x, y = pos.y}
    local speed = 1

    -- If key is UP
    if key == 200 then
        newPos.y = newPos.y - speed
    -- If key is DOWN
    elseif key == 208 then
        newPos.y = newPos.y + speed
    -- If key is LEFT
    elseif key == 203 then
        newPos.x = newPos.x - speed
    -- If key is RIGHT
    elseif key == 205 then
        newPos.x = newPos.x + speed
    end

    -- Make sure doesn't go off screen --
    sizeX, sizeY = term.getSize()
    if newPos.x > sizeX or newPos.x < 1 then
        collide = true
    elseif newPos.y > sizeY or newPos.y < 1 then
        collide = true
    else
        -- Make sure newPos does not collide solids --
        for _, solid in pairs(solids) do
            if not solid.b and newPos.x == solid.x and newPos.y == solid.y then
                collide = true
                break -- Exit the for loop
            end
        end
    end

    -- Move if not colliding and newPos is not old pos --
    if not collide then
        move(newPos)
    end
end