singe/docs/learn/12-score.singe

-- Lesson 12:  Score, Lives, And Game Over.  The finished script, exactly as the lesson ends.
dofile("Singe/Framework.singe")

local SHIP_WIDTH  = 32
local SHIP_HEIGHT = 24
local SHIP_PAD_X  = 6
local SHIP_PAD_Y  = 5
local SHIP_SPEED  = 3
local ROCK_WIDTH  = 24
local ROCK_HEIGHT = 24
local ROCK_PAD    = 4
local ROCK_SPEED  = 1
local ROCK_CHANCE = 40
local ROCK_POINTS = 10
local SHOT_WIDTH  = 4
local SHOT_HEIGHT = 10
local SHOT_SPEED  = 6
local START_LIVES = 3

local TITLE   = "title"
local PLAYING = "playing"
local OVER    = "over"

local shipSprite = spriteLoad(DIR .. "art/ship.png")
local rockSprite = spriteLoad(DIR .. "art/rock.png")
local shotSprite = spriteLoad(DIR .. "art/shot.png")
local shootSound = soundLoad(DIR .. "art/shoot.wav")
local boomSound  = soundLoad(DIR .. "art/boom.wav")

local state       = TITLE
local score       = 0
local lives       = START_LIVES
local best        = saveGet("highScore", 0)
local shipX       = (overlayGetWidth() - SHIP_WIDTH) / 2
local shipY       = overlayGetHeight() - SHIP_HEIGHT - 8
local movingLeft  = false
local movingRight = false
local rocks       = {}
local shots       = {}


local function addRock()
    local rock = {}
    rock.x = math.random(0, overlayGetWidth() - ROCK_WIDTH)
    rock.y = -ROCK_HEIGHT
    rocks[#rocks + 1] = rock
end


local function fireShot()
    local shot = {}
    shot.x = shipX + SHIP_WIDTH / 2 - SHOT_WIDTH / 2
    shot.y = shipY - SHOT_HEIGHT
    shots[#shots + 1] = shot
    soundPlay(shootSound)
end


local function rockBox(rock)
    return rock.x + ROCK_PAD, rock.y + ROCK_PAD, ROCK_WIDTH - ROCK_PAD * 2, ROCK_HEIGHT - ROCK_PAD * 2
end


local function shipBox()
    return shipX + SHIP_PAD_X, shipY + SHIP_PAD_Y, SHIP_WIDTH - SHIP_PAD_X * 2, SHIP_HEIGHT - SHIP_PAD_Y * 2
end


local function shipHitsRock(rock)
    local sx, sy, sw, sh = shipBox()
    local rx, ry, rw, rh = rockBox(rock)
    return collideRects(sx, sy, sw, sh, rx, ry, rw, rh)
end


local function shotHitsRock(shot, rock)
    local rx, ry, rw, rh = rockBox(rock)
    return collidePointRect(shot.x + SHOT_WIDTH / 2, shot.y, rx, ry, rw, rh)
end


local function startGame()
    score       = 0
    lives       = START_LIVES
    rocks       = {}
    shots       = {}
    shipX       = (overlayGetWidth() - SHIP_WIDTH) / 2
    movingLeft  = false
    movingRight = false
    state       = PLAYING
end


local function endGame()
    if score > best then
        best = score
        saveSet("highScore", best)
        saveFlush()
    end
    state = OVER
end


local function moveShip()
    if movingLeft then
        shipX = shipX - SHIP_SPEED
    end
    if movingRight then
        shipX = shipX + SHIP_SPEED
    end
    if shipX < 0 then
        shipX = 0
    end
    if shipX > overlayGetWidth() - SHIP_WIDTH then
        shipX = overlayGetWidth() - SHIP_WIDTH
    end
end


local function moveRocks()
    if math.random(ROCK_CHANCE) == 1 then
        addRock()
    end
    for i = #rocks, 1, -1 do
        local rock = rocks[i]
        rock.y = rock.y + ROCK_SPEED
        if rock.y > overlayGetHeight() then
            table.remove(rocks, i)
        end
    end
end


local function moveShots()
    for i = #shots, 1, -1 do
        local shot = shots[i]
        shot.y = shot.y - SHOT_SPEED
        if shot.y + SHOT_HEIGHT < 0 then
            table.remove(shots, i)
        end
    end
end


local function checkHits()
    for s = #shots, 1, -1 do
        for r = #rocks, 1, -1 do
            if shotHitsRock(shots[s], rocks[r]) then
                table.remove(rocks, r)
                table.remove(shots, s)
                soundPlay(boomSound)
                score = score + ROCK_POINTS
                break
            end
        end
    end
    for r = #rocks, 1, -1 do
        if shipHitsRock(rocks[r]) then
            table.remove(rocks, r)
            soundPlay(boomSound)
            lives = lives - 1
            if lives <= 0 then
                endGame()
            end
        end
    end
end


local function drawWorld()
    spriteDraw(shipSprite, shipX, shipY)
    for _, rock in ipairs(rocks) do
        spriteDraw(rockSprite, rock.x, rock.y)
    end
    for _, shot in ipairs(shots) do
        spriteDraw(shotSprite, shot.x, shot.y)
    end
end


local function drawScore()
    overlayPrint(1, 1, "SCORE " .. score)
    overlayPrint(25, 1, "BEST " .. best)
    overlayPrint(48, 1, "LIVES " .. lives)
end


local function updateTitle()
    overlayPrint(25, 5, "R O C K S")
    overlayPrint(24, 8, "BEST " .. best)
    overlayPrint(21, 11, "PRESS FIRE TO PLAY")
end


local function updatePlaying()
    moveShip()
    moveRocks()
    moveShots()
    checkHits()
    drawWorld()
    drawScore()
end


local function updateOver()
    drawWorld()
    drawScore()
    overlayPrint(25, 8, "GAME OVER")
    overlayPrint(21, 11, "PRESS FIRE TO PLAY")
end


function onInputPressed(what)
    if state == PLAYING then
        if what == SWITCH_LEFT then
            movingLeft = true
        elseif what == SWITCH_RIGHT then
            movingRight = true
        elseif what == SWITCH_BUTTON1 then
            fireShot()
        end
    elseif what == SWITCH_BUTTON1 or what == SWITCH_START1 then
        startGame()
    end
end


function onInputReleased(what)
    if what == SWITCH_LEFT then
        movingLeft = false
    elseif what == SWITCH_RIGHT then
        movingRight = false
    end
end


function onOverlayUpdate()
    overlayClear()

    if state == TITLE then
        updateTitle()
    elseif state == PLAYING then
        updatePlaying()
    else
        updateOver()
    end

    return OVERLAY_UPDATED
end