Dinosaurs Game

main.lua

WINDOW_WIDTH = 512
WINDOW_HEIGHT = 712

RUNAWAY_HEIGHT = 40

CHARACTER_WIDTH = 24
CHARACTER_HEIGHT = 24
CHARACTER_SCALE = 4
CHARACTER_ANIMATION_CHANGE = 0.065
CHARACTER_VERTICAL_SPEED = -500
CHARACTER_VERTICAL_ACCELERATION = 800
CHARACTER_MAX_Y = (WINDOW_HEIGHT - CHARACTER_HEIGHT * CHARACTER_SCALE - RUNAWAY_HEIGHT) + 4 * CHARACTER_SCALE

CACTUS_WIDTH = 32
CACTUS_HEIGHT = 32
CACTUS_HORIZONTAL_SPEED = -60
CACTUS_HORIZONTAL_ACCELERATION = -10
CACTUS_SPAWN_TIME = 5
CACTUS_SCALE = 2

function math.clamp(low, n, high)
    return math.min(math.max(n, low), high)
end

-- s1   f1
--    s2   f2
local function intersection(s1, f1, s2, f2)
    if (math.max(s1, s2) <= math.min(f1, f2)) then
        return true
    else
        return false
    end
end

local function hitsCactus(cx1, cx2, cy1, cy2)
    local op = 8 * CHARACTER_SCALE
    local ox1 = (WINDOW_WIDTH - CHARACTER_WIDTH * CHARACTER_SCALE) // 2 + op
    local ox2 = (WINDOW_WIDTH + CHARACTER_WIDTH * CHARACTER_SCALE) // 2 - op
    local oy1 = character_origin_y + op
    local oy2 = character_origin_y + CHARACTER_HEIGHT * CHARACTER_SCALE - op
    return intersection(ox1, ox2, cx1 + 4 * CACTUS_SCALE, cx2) and intersection(oy1, oy2, cy1, cy2)
end

function engine.start()
    engine.window.setTitle("Run dino 🦖")
    engine.window.setSize(WINDOW_WIDTH, WINDOW_HEIGHT)

    -- See /gameplay/resources
    font = engine.graphics.newFont("PixeloidSans.ttf", 72)

    runaway = engine.graphics.newRect(WINDOW_WIDTH, RUNAWAY_HEIGHT, {210, 210, 207})

    plants_atlas = engine.graphics.loadTexture("pixel_cactus.png")
    cactus_quad = engine.graphics.newQuad(32, 0, CACTUS_WIDTH, CACTUS_HEIGHT)

    star = engine.graphics.loadTexture("star.png")
    particles_system = engine.graphics.newParticlesSystem(50)

    particles_system:setTexture(star)
    particles_system:setEmissionRate(10)
    particles_system:setCenterPosition(WINDOW_WIDTH // 2, -40)
    particles_system:setParticlesLifetime(0.5, 5.5)
    particles_system:setAcceleration(-30, -50, 70, 120)
    particles_system:setAngularMomentum(-50, 50)
    particles_system:setScale(1, 1.8)
    particles_system:setAlphaDecay(1.0, 0.0)

    particles_system:setRectangularEmitter(WINDOW_WIDTH, 40)

    character_atlas = engine.graphics.loadTexture("Dino.png")
    character_running_animation = {
        engine.graphics.newQuad(24*5, 0, CHARACTER_WIDTH, CHARACTER_HEIGHT),
        engine.graphics.newQuad(24*6, 0, CHARACTER_WIDTH, CHARACTER_HEIGHT),
        engine.graphics.newQuad(24*7, 0, CHARACTER_WIDTH, CHARACTER_HEIGHT),
        engine.graphics.newQuad(24*8, 0, CHARACTER_WIDTH, CHARACTER_HEIGHT),
    }
    character_animation_timer = 0
    character_animation_frame = 0
    character_origin_y = CHARACTER_MAX_Y
    character_vspeed = 0
    character_state = "running"

    score = 0
    score_text = engine.graphics.newText(font, tostring(score), { 27, 18, 18 })

    music = engine.audio.newMusic("music.mp3")
    music:setRepeatCount(-1)
    jump_up_effect = engine.audio.newEffect("jump.mp3")
    coin_effect = engine.audio.newEffect("coin.mp3")
    trombone_effect = engine.audio.newEffect("trombone.mp3")

    enemies_spawner = CACTUS_SPAWN_TIME
    enemies_positions = {}
    
    game_state = "finish"
end

local function onInput()
    if (game_state == "finish") then
        character_animation_timer = 0
        character_animation_frame = 0
        character_origin_y = CHARACTER_MAX_Y
        character_vspeed = 0
        character_state = "running"
    
        score = 0
        score_text = engine.graphics.newText(font, tostring(score), { 27, 18, 18 })
    
        enemies_spawner = CACTUS_SPAWN_TIME
        enemies_positions = {}
        
        game_state = "running"

        CACTUS_HORIZONTAL_SPEED = -60
        music:play()
        return
    end

    if (character_state == "running") then
        character_state = "jumping"
        character_vspeed = CHARACTER_VERTICAL_SPEED
        jump_up_effect:play()
        return
    end
end

function engine.onMouseDown(e)
    if (e:button() == "left") then
        onInput()
    end
end

function engine.onKeyDown(e)
    if (e:keycode() == "space") then
        onInput()
    end
end

function engine.update(dt)
    if game_state ~= "running" then
        return
    end

    particles_system:update(dt)

    if (character_state == "jumping") then
        character_vspeed = character_vspeed + CHARACTER_VERTICAL_ACCELERATION * dt
        character_origin_y = math.clamp(character_origin_y + character_vspeed * dt, 0, CHARACTER_MAX_Y)

        if (character_origin_y >= CHARACTER_MAX_Y) then
            character_vspeed = 0
            character_state = "running"
        end
    end

    character_animation_timer = character_animation_timer + dt
    if (character_animation_timer > CHARACTER_ANIMATION_CHANGE) then
        character_animation_frame = (character_animation_frame + 1) % #character_running_animation
        character_animation_timer = 0
    end

    for i, _ in pairs(enemies_positions) do
        enemies_positions[i] = enemies_positions[i] + CACTUS_HORIZONTAL_SPEED * dt

        local cx1 = enemies_positions[i]
        local cx2 = cx1 + CACTUS_WIDTH * CACTUS_SCALE
        local cy1 = WINDOW_HEIGHT - CACTUS_HEIGHT * CACTUS_SCALE - RUNAWAY_HEIGHT
        local cy2 = cy1 + CACTUS_HEIGHT * CACTUS_SCALE
        if hitsCactus(cx1, cx2, cy1, cy2) then
            game_state = "finish"
            trombone_effect:play();
            music:stop();
        end
    end

    for i, _ in pairs(enemies_positions) do
        if (enemies_positions[i] < -CACTUS_WIDTH * CACTUS_SCALE) then
            table.remove(enemies_positions, i)
            score = score + 1
            score_text = engine.graphics.newText(font, tostring(score), { 27, 18, 18 })
            coin_effect:play()
        end
    end

    enemies_spawner = enemies_spawner + dt
    if (enemies_spawner > CACTUS_SPAWN_TIME) then
        enemies_spawner = 0
        table.insert(enemies_positions, WINDOW_WIDTH)
    end

    CACTUS_HORIZONTAL_SPEED = CACTUS_HORIZONTAL_SPEED + CACTUS_HORIZONTAL_ACCELERATION * dt
end

function engine.draw()
    engine.graphics.clear(175, 225, 175)

    particles_system:draw()

    engine.graphics.draw(runaway,
        (WINDOW_WIDTH - runaway:width()) // 2,
        (WINDOW_HEIGHT - runaway:height()))

    engine.graphics.draw(score_text,
        (WINDOW_WIDTH - score_text:width()) // 2,
        (WINDOW_HEIGHT - score_text:height()) // 2)

    for _, enemy in pairs(enemies_positions) do
        engine.graphics.draw(plants_atlas,
            cactus_quad,
            math.ceil(enemy),
            math.ceil(WINDOW_HEIGHT - CACTUS_HEIGHT * CACTUS_SCALE - RUNAWAY_HEIGHT),
            0, CACTUS_SCALE, CACTUS_SCALE)
    end

    engine.graphics.draw(character_atlas,
        character_running_animation[character_animation_frame + 1],
        (WINDOW_WIDTH - CHARACTER_WIDTH * CHARACTER_SCALE) // 2,
        math.ceil(character_origin_y),
        0, CHARACTER_SCALE, CHARACTER_SCALE)
end