A step by step tutorial on creating a simple lunar lander game in Codea. Contains 13 tabs. Each tab contains one step in the tutorial and successive tabs build on each other. Drag the tab you wish to run to the far right then press the run button

Noob lander

--# Main
-- Noob Lander
-- by West
-- This is a very simple example lunar lander game.  It is intended for use as an introduction into creating your first game in codea and is aimed at absolute beginners.

--ONLY THE FURTHEST RIGHT HAND TAB WILL BE EXECUTED. DRAG THE TAB FOR THE STEP YOU WISH TO RUN TO THE FAR RIGHT THEN PRESS RUN

--The game was built using the following steps.  Each step is provided in its own tab and builds upon the previous one.  For each tab only comments related to that particular step are provided but a fully commented version is provided below.

--1. Place the ship sprite on the screen at a pre-defined position (use one of the pre-loaded sprite packs)
--2. Add x, y and shipsize variables to set up and use these to position the sprite. Try different values of x,y and shipsize
--3. Set y=HEIGHT-100 and x=WIDTH/2 to position the ship near the top centre of the screen. A default shipsize of 25 works well
--4. Add a y=y-1 in the draw loop (ship should move down the screen).
--5. Add in a tap function - if the current touch is BEGAN or MOVING then draw a second "Thruster jet" sprite at the x, y-offset location
--6. Modify 4 to introduce gravity
--7. Add thrust when the screen is touched. This should be factored into the equations of motion
--8. Draw a line to represent the ground
--9. Test to see if the ship has gone below the line (this will be a test on the y coordinate plus an offset equal to half the height of the sprite). If it has, test the current speed of the ship - too fast then crash otherwise win
--10. Implement the "Crash" and "Win" screens 
--11. Add a fuel parameter - can only thrust if there is fuel in the tank. Display current fuel on the screen
--12. Add sounds for thrust and explosions

-- I've tried to associate comments with most of the steps but the program is the result after all 12 have been implemented.  I could separate out the code if there was real interest in a broken down step by step tutorial.

-- Code modification challenges
--These are aimed at taking this code and tweaking it to see the effects
--1. Double the size of the ship
--2. Change the level of the ground
--3. Decrease the amount of fuel you start with
--4. Make it harder by reducing the fastest speed at which you can land.  at the moment this is hard coded - can you make this a parameter which is set in setup?
--5. Turn the ground into a solid filled rectangle which extends to the bottom of the screen

--Code addition challenges
-- These are aimed at improving the code by adding extra functions. Please share your updates on the forum to help/inspire others
--1. Add a starfield to the background
--2. Turn the thrust into a spray of particles..
--2b ..that bounce off the ground and fade with time
--3. Add a start screen
--4. Add a high score table
--5. change the controls to use tilting the ipad for thrust
--6. Add horizontal thrusting (and a safe landing area)
--7. implement the graphics as a sprite sheet using meshes (this may be required to keep the performance up if you have a starfield and particle based thrust)

--Test yourself!
--Can you take the 12 steps above and without looking at the code implement a version of the lander game?

--Hide the sidebar from the screen
displayMode(FULLSCREEN)
-- Use this function to perform your initial setup
function setup()
--2. add x and y variables and use to position the sprite   
x=300 --x position of the centre of the ship on the screen
y=300 --y position of the centre of the ship on the screen
--set up a parameter to hold the size of the ship sprite in pixels assume the ship image is a square so the width and height of the ship are the same
shipsize=25

--3. position ship near top of screen
x=WIDTH/2 --x position of the ship on the screen - set to half the width of the screen
y=HEIGHT-100 --y position of the ship on the screen - set to the height of the screen minus 100 pixels

--10. Set up a simple finite state machine which will control what parts of the program are run.  Finite State Machine sounds fancy but all it means is that there is a limited number of known states (finite) which can be swapped between by some program (machine)
--setting CONSTANT parameters makes for more meaningful code, and by convention CONSTANTS are written in captials (WIDTH and HEIGHT are special types of constant)
--The three possible states are as follows
PLAYING=1
CRASHED=2
LANDED=3
--set up a parameter which will hold the current state of the game
gamestate=PLAYING

--8. set a parameter to hold the level of the ground in pixels from the bottom of the screen
groundlevel=50
--6. set a parameter to hold the speed of the ship
speed=0
--6. set a parameter to hold the strength of gravity
gravity=-0.02
--6. set a parameter to hold the level of thrust of the ship
thrust=0
--11.set a parameter to hold the fuel level
fuel=500
end

-- This function gets called once every frame
function draw()
--This sets a dark background color 
    background(40, 40, 50)
-- 1. display the ship sprite on the screen
--sprite("Space Art:Red Ship",300,300)
--10. if the current state of the game is playing then do the following
if gamestate==PLAYING or gamestate==LANDED then
--5. Thrust sprite - want this to appear behind spaceship so draw before it
--test to see if the screen is being touched
    if (CurrentTouch.state==BEGAN or CurrentTouch.state==MOVING) and gamestate==PLAYING and fuel>0 then
        --draw the flames from the ship
        sprite("Tyrian Remastered:Flame 2",x,y-shipsize,shipsize,shipsize)
        --increase the thrust
        thrust = thrust + 0.005
        --reduce the fuel level
        fuel = fuel -1
        --12. play a thrust sound
        sound(SOUND_HIT, 16609)
        --limit the thrust to a maximum level
        if thrust>0.05 then
            thrust=0.05
        end
    else
        --the screen is no longer being touched so remove the thrust
        thrust=0
    end
    --2 add x and y variables and use to position the sprite and a variable to set the size of the sprite
    sprite("Space Art:Red Ship",x,y,shipsize,shipsize)
    --4. Move ship down the screen
    --y = y -1

    --6. and 7. add gravity and thrust
    -- use variable a to calculate the difference between the amount of thrust and gravity (equivalent of acceleration)
    a=gravity+thrust
    --alter the speed of the ship
    speed=speed+a
    -- add terminal velocity constraint - sets a maximum speed for the ship
    --a positive speed means upward travel, the larger the speed then the faster the upward speed
    --a negative speed means downward travel.  The more negative the speed, the faster the ship moves down the screen
    if speed<-3 then
        speed=-3
    end
    --use this version of the equation of motion to calculate the distance to move the ship in the y direction between frames
    y=y+speed+0.5*a
    --10. if the game state has been set to crashed then draw the explosion and show a message()
elseif gamestate==CRASHED then
    --add the explosion sprite to the screen at the ship position. Each frame add adjust the size of the ship by a random amount - this will give a wobbly explosion effect
    sprite("Tyrian Remastered:Explosion Huge",x,y,shipsize+math.random(10),shipsize+math.random(10))
    text("Crash",WIDTH/2,HEIGHT/2)    
end
--
--8.draw line representing the ground
--set the thickness of the line
strokeWidth(3)
--set the colour of the line
stroke(48, 216, 25, 255)
--draw the line at the level set by the groundlevel parameter
line(0,groundlevel,WIDTH,groundlevel)
--9. check to see if the y position of the ship is less than the ground level to see if the ship has reached the ground.
--note that we need to take into account the height of the sprite as the y vale is the centre of the ship sprite
    if y-shipsize/2<groundlevel then
        --the ship has reached the ground so check to see what speed it was travelling at
        --the speed must be negative because the ship is moving down towards the ground.
        --if the speed is slow (close to zero) then have a successful landing
        if speed>-1 then
            text("Landed",WIDTH/2,HEIGHT/2)
            --10 change the gamestate to landed
            gamestate=LANDED
        --otherwise the ship is travelling too fast and has crashed
        else
            --12. play an explosion sound
            sound(SOUND_EXPLODE, 23062)
            --10.change the state of the game to crashed
            gamestate=CRASHED
        end
        --set the position of the ship to rest on the ground. It is possible that the ship will have overshot the ground level as when travelling fast the ship can cover more than 1 pixel at a time between frames
        y=groundlevel+shipsize/2
        --set the speed and thrust of the ship to 0
        speed=0
        thrust=0
    end
    --11. print out the current fuel level
    --pick a font
    font("Courier-Bold")
    --set the size of the font
    fontSize(30)
    --print in the top left corner of the screen. Use .. to join bits of string tp parameters
    text("Fuel:"..fuel,150,HEIGHT-50)
end

--# Step1
-- Noob Lander
-- by West
-- This is a very simple example lunar lander game.  It is intended for use as an introduction into creating your first game in codea and is aimed at absolute beginners.
--This is the first step
--1. Place the ship sprite on the screen at a pre-defined position (use one of the pre-loaded sprite packs)

--Hide the sidebar from the screen
displayMode(FULLSCREEN)
-- Use this function to perform your initial setup
function setup()
--at the moment nothing is needed here
end

-- This function gets called once every frame
function draw()
--This sets a dark background color 
    background(40, 40, 50)
-- 1. display the red ship sprite on the screen at position 300 pixels along the x axis from the left and 300 pixels up from the bottom of the screen. The size of the ship is set to be 50 pixels wide and 50 pixels high
    sprite("Space Art:Red Ship",300,300,50,50)
--Tap "Space Art:Red Ship" to bring up the sprite picker. Select a new image and run. Adjust the 4 numbers to alter the x position ,y position ,width and height of the image
end

--# Step2
-- Noob Lander
-- by West
-- This is a very simple example lunar lander game.  It is intended for use as an introduction into creating your first game in codea and is aimed at absolute beginners.
--Assuming you have already got the ship to show on the screen from step 1
--2. Add x, y and shipsize variables to set up and use these to position the sprite. Try different values of x,y and shipsize

displayMode(FULLSCREEN)

function setup()
    --2. add x and y variables and use to position the sprite   
    x=300 --x position of the centre of the ship on the screen
    y=300 --y position of the centre of the ship on the screen
    --set up a parameter to hold the size of the ship sprite in pixels assume the ship image is a square so the width and height of the ship are the same
    shipsize=25
end

function draw()
    background(40, 40, 50)
    --2 add x and y variables and use to position the sprite and a variable to set the size of the sprite
    --command is the same as step 1 but parameters now represent the numbers
    sprite("Space Art:Red Ship",x,y,shipsize,shipsize)
    --Change the values of the parameters in the setup to change the size and position of the ship
end

--# Step3
-- Noob Lander
-- by West
-- This is a very simple example lunar lander game.  It is intended for use as an introduction into creating your first game in codea and is aimed at absolute beginners.
--Assume you have completed steps 1 and 2 to get the ship on the screen and adjust its size and position
--3. Set y=HEIGHT-100 and x=WIDTH/2 to position the ship near the top centre of the screen. A default shipsize of 25 works well

displayMode(FULLSCREEN)

function setup()
    --3. position ship near top of screen
    --Use special parameters HEIGHT and WIDTH (note the capital letters). These are used in place of numbers and are useful for making games work across different devices. For example the width of an iPhone screen in pixels is different from an iPad. Using these parameters takes care of this potential issue
    x=WIDTH/2 --x position of the ship on the screen - set to half the width of the screen
    y=HEIGHT-100 --y position of the ship on the screen - set to the height of the screen minus 100 pixels
    shipsize=25
end

function draw()
    background(40, 40, 50)
    sprite("Space Art:Red Ship",x,y,shipsize,shipsize)
end

--# Step4
-- Noob Lander
-- by West
-- This is a very simple example lunar lander game.  It is intended for use as an introduction into creating your first game in codea and is aimed at absolute beginners.
--Assume you have completed steps 1, 2 and 3 to get the ship on the screen and adjust its size and position and have set the position to near the top of the screen
--4. Add a y=y-1 in the draw loop (ship should move down the screen).

displayMode(FULLSCREEN)

function setup()
    x=WIDTH/2
    y=HEIGHT-100 
    shipsize=25
end

function draw()
    background(40, 40, 50)
    sprite("Space Art:Red Ship",x,y,shipsize,shipsize)
    --4. Each time the main draw function is executed, reduce the value held in the y variable
    y=y-1
    --this will make the ship move down the screen. Try subtracting different values. You can also remove fractions of a number. try y=y-0.05. This will make the ship move really slowly
end

--# Step5
-- Noob Lander
-- by West
-- This is a very simple example lunar lander game.  It is intended for use as an introduction into creating your first game in codea and is aimed at absolute beginners.
--The game was built using the following steps:

--5. Add in a tap function - if the current touch is BEGAN or MOVING then draw a second "Thruster jet" sprite at the x, y-offset location

function setup()
    x=WIDTH/2
    y=HEIGHT-100 
    shipsize=25
end

function draw()
    background(40, 40, 50)
    --5. Thrust sprite - want this to appear behind spaceship so draw before it
    --test to see if the screen is being touched
    --This uses a special input called current touch to test if the screen is being touched. The .state part gives the state of the touch. Current touch also has other properties such as .x and .y which will return the position of the touch, but these aren't required here
    if (CurrentTouch.state==BEGAN or CurrentTouch.state==MOVING) then
        --draw the flames from the ship
        --draw the flames using the same x and y positions except move it down.  We could use y-100 to move the flames 1pp pixels but this moves the flames 100 pixels regardless of the size of the image.  If we use the shipsize parameter then this will allow us to scale the ship and flames together and makes sure the sizes and locations are relative to each other.
        sprite("Tyrian Remastered:Flame 2",x,y-shipsize,shipsize,shipsize)
    end
    sprite("Space Art:Red Ship",x,y,shipsize,shipsize)
    y = y -1
    --Try going back and altering the shipsize parameter now
end

--# Step6
-- Noob Lander
-- by West
-- This is a very simple example lunar lander game.  It is intended for use as an introduction into creating your first game in codea and is aimed at absolute beginners.
--By now you should have your ship on the screen which slowly moves to the bottom and when you touch the screen then thrust appears

-- 6. change the downward movement to simulate gravity

displayMode(FULLSCREEN)
-- Use this function to perform your initial setup
function setup()
    x=WIDTH/2
    y=HEIGHT-100
    shipsize=25
    --6. set a parameter to hold the speed of the ship. set to zero to start with
    speed=0
    --6. set a parameter to hold the strength of gravity
    gravity=-0.005
end

function draw()
    background(40, 40, 50)
    if (CurrentTouch.state==BEGAN or CurrentTouch.state==MOVING) then
        sprite("Tyrian Remastered:Flame 2",x,y-shipsize,shipsize,shipsize)
    end
    sprite("Space Art:Red Ship",x,y,shipsize,shipsize)
    --add gravity
    --increase the speed of the ship by the value of gravity each time round the loop
    speed=speed+gravity
    -- add terminal velocity constraint - sets a maximum speed for the ship
    --a positive speed means upward travel, the larger the speed then the faster the upward speed
    --a negative speed means downward travel.  The more negative the speed, the faster the ship moves down the screen
   if speed<-15 then
        speed=-15
    end
    --use this version of the equation of motion to calculate the distance to move the ship in the y direction between frames
    y=y+speed
end

--# Step7
-- Noob Lander
-- by West
-- This is a very simple example lunar lander game.  It is intended for use as an introduction into creating your first game in codea and is aimed at absolute beginners.

-- The ship should move under gravity and tapping the screen makes the thrust flames appear but has no effect

--7. Add thrust effect on the ship when the screen is touched. This should be factored into the equations of motion


--Hide the sidebar from the screen
displayMode(FULLSCREEN)
-- Use this function to perform your initial setup
function setup()
    x=WIDTH/2 
    y=HEIGHT-100
    shipsize=25
    speed=0
    gravity=-0.02
    --7. set a parameter to hold the level of thrust of the ship
    thrust=0
end

function draw()
    background(40, 40, 50)
    if (CurrentTouch.state==BEGAN or CurrentTouch.state==MOVING) then
        sprite("Tyrian Remastered:Flame 2",x,y-shipsize,shipsize,shipsize)
        --increase the thrust
        thrust = thrust + 0.005
        --limit the thrust to a maximum level
        if thrust>0.05 then
            thrust=0.05
        end
    else
        --the screen is no longer being touched so remove the thrust
        thrust=0
    end
    sprite("Space Art:Red Ship",x,y,shipsize,shipsize)
    -- 7. add the effects of thrust 
    -- use variable a to calculate the difference between the amount of thrust and gravity (equivalent of acceleration)
    a=gravity+thrust
    --alter the speed of the ship
    speed=speed+a
    -- add terminal velocity constraint - sets a maximum speed for the ship
    --a positive speed means upward travel, the larger the speed then the faster the upward speed
    --a negative speed means downward travel.  The more negative the speed, the faster the ship moves down the screen
    if speed<-3 then
        speed=-3
    end
    --use this version of the equation of motion to calculate the distance to move the ship in the y direction between frames
    y=y+speed+0.5*a
end

--# Step8
-- Noob Lander
-- by West
-- This is a very simple example lunar lander game.  It is intended for use as an introduction into creating your first game in codea and is aimed at absolute beginners.

-- The ship should move under gravity and tapping the screen makes the ship respond to thrust

--8. Draw a line to represent the ground

displayMode(FULLSCREEN)

function setup()
    x=WIDTH/2
    y=HEIGHT-100
    shipsize=25
    speed=0
    gravity=-0.02
    thrust=0
    --add a variable to store the ground level
    groundlevel=50
end

function draw()
    background(40, 40, 50)
    if (CurrentTouch.state==BEGAN or CurrentTouch.state==MOVING) then
        sprite("Tyrian Remastered:Flame 2",x,y-shipsize,shipsize,shipsize)
        thrust = thrust + 0.005
        if thrust>0.05 then
            thrust=0.05
        end
    else
        thrust=0
    end
    sprite("Space Art:Red Ship",x,y,shipsize,shipsize)
    a=gravity+thrust
    speed=speed+a
    if speed<-3 then
        speed=-3
    end
    y=y+speed+0.5*a

    --8.draw line representing the ground
    --set the thickness of the line
    strokeWidth(3)
    --set the colour of the line 
    stroke(48, 216, 25, 255)
    --draw the line at the level set by the groundlevel parameter. it runs for position x1,y1 to x2,y2. setting x1 to 0 and x2 to the width of the screen ensures it covers the full length.
    line(0,groundlevel,WIDTH,groundlevel)
end

--# Step9
-- Noob Lander
-- by West
-- This is a very simple example lunar lander game.  It is intended for use as an introduction into creating your first game in codea and is aimed at absolute beginners.

-- The ship should move under gravity and tapping the screen makes the ship respond to thrust. A line to represent the ground is added though there is no interaction with it.

--9. Test to see if the ship has gone below the line (this will be a test on the y coordinate plus an offset equal to half the height of the sprite). If it has, test the current speed of the ship - too fast then crash otherwise win

displayMode(FULLSCREEN)

function setup()
    x=WIDTH/2
    y=HEIGHT-100
    shipsize=25
    speed=0
    gravity=-0.02
    thrust=0
    groundlevel=50
end

function draw()
    background(40, 40, 50)
    if (CurrentTouch.state==BEGAN or CurrentTouch.state==MOVING) then
        sprite("Tyrian Remastered:Flame 2",x,y-shipsize,shipsize,shipsize)
        thrust = thrust + 0.005
        if thrust>0.05 then
            thrust=0.05
        end
    else
        thrust=0
    end
    sprite("Space Art:Red Ship",x,y,shipsize,shipsize)
    a=gravity+thrust
    speed=speed+a
    if speed<-3 then
        speed=-3
    end
    y=y+speed+0.5*a
    strokeWidth(3)
    stroke(48, 216, 25, 255)
    line(0,groundlevel,WIDTH,groundlevel)
    if y-shipsize/2<groundlevel then
        --the ship has reached the ground so check to see what speed it was travelling at
        --the speed must be negative because the ship is moving down towards the ground.
        --if the speed is slow (close to zero) then have a successful landing
        if speed>-1 then
            text("Landed",WIDTH/2,HEIGHT/2)
        --otherwise the ship is travelling too fast and has crashed
        else
            text("Crashed",WIDTH/2,HEIGHT/2)
        end
        --set the position of the ship to rest on the ground. It is possible that the ship will have overshot the ground level as when travelling fast the ship can cover more than 1 pixel at a time between frames
        y=groundlevel+shipsize/2
    end
end

--# Step10
-- Noob Lander
-- by West
-- This is a very simple example lunar lander game.  It is intended for use as an introduction into creating your first game in codea and is aimed at absolute beginners.
-- The ship should move under gravity and tapping the screen makes the ship respond to thrust. A line to represent the ground is added and when the ship crosses the line a check is done to see if there is a successful landing
--10. Implement the "Crash" and "Win" screens 

displayMode(FULLSCREEN)

function setup()
x=WIDTH/2 
y=HEIGHT-100
shipsize=25
--10. Set up a simple finite state machine which will control what parts of the program are run.  Finite State Machine sounds fancy but all it means is that there is a limited number of known states (finite) which can be swapped between by some program (machine)
--setting CONSTANT parameters makes for more meaningful code, and by convention CONSTANTS are written in captials (WIDTH and HEIGHT are special types of constant)
--The three possible states are as follows
PLAYING=1
CRASHED=2
LANDED=3
--set up a parameter which will hold the current state of the game
gamestate=PLAYING

groundlevel=50
speed=0
gravity=-0.02
thrust=0
end

function draw()
    background(40, 40, 50)
    --10. if the current state of the game is playing then do the following
    if gamestate==PLAYING or gamestate==LANDED then
        if (CurrentTouch.state==BEGAN or CurrentTouch.state==MOVING) and gamestate==PLAYING then
            sprite("Tyrian Remastered:Flame 2",x,y-shipsize,shipsize,shipsize)
            thrust = thrust + 0.005
            if thrust>0.05 then
                thrust=0.05
            end
        else
            thrust=0
        end
        sprite("Space Art:Red Ship",x,y,shipsize,shipsize)
        a=gravity+thrust
        speed=speed+a
        if speed<-3 then
            speed=-3
        end
        y=y+speed+0.5*a
        --10. if the game state has been set to crashed then draw the explosion and show a message()
    elseif gamestate==CRASHED then
        sprite("Tyrian Remastered:Explosion Huge",x,y,shipsize+math.random(10),shipsize+math.random(10))
        text("Crash",WIDTH/2,HEIGHT/2)    
    end
    strokeWidth(3)
    stroke(48, 216, 25, 255)
    line(0,groundlevel,WIDTH,groundlevel)
    if y-shipsize/2<groundlevel then
        if speed>-1 then
            text("Landed",WIDTH/2,HEIGHT/2)
            --10 change the gamestate to landed
            gamestate=LANDED
        else
            --10.change the state of the game to crashed
            gamestate=CRASHED
        end
        y=groundlevel+shipsize/2
        --set the speed and thrust of the ship to 0
        speed=0
        thrust=0
    end
end

--# Step11
-- Noob Lander
-- by West
-- This is a very simple example lunar lander game.  It is intended for use as an introduction into creating your first game in codea and is aimed at absolute beginners.
-- The ship should move under gravity and tapping the screen makes the ship respond to thrust. A line to represent the ground is added and when the ship crosses the line a check is done to see if there is a successful landing. A finite state machine controls the order of the game.
--11. Add a fuel parameter - can only thrust if there is fuel in the tank. Display current fuel on the screen

displayMode(FULLSCREEN)

function setup()
    x=WIDTH/2
    y=HEIGHT-100
    shipsize=25
    PLAYING=1
    CRASHED=2
    LANDED=3
    gamestate=PLAYING
    groundlevel=50
    speed=0
    gravity=-0.02
    thrust=0
    --11.set a parameter to hold the fuel level
    fuel=500
end

function draw()
    background(40, 40, 50)
    if gamestate==PLAYING or gamestate==LANDED then
        if (CurrentTouch.state==BEGAN or CurrentTouch.state==MOVING) and gamestate==PLAYING and fuel>0 then
            sprite("Tyrian Remastered:Flame 2",x,y-shipsize,shipsize,shipsize)
            thrust = thrust + 0.005
            fuel = fuel -1
            if thrust>0.05 then
                thrust=0.05
            end
        else
            thrust=0
        end
        sprite("Space Art:Red Ship",x,y,shipsize,shipsize)
        a=gravity+thrust
        speed=speed+a
        if speed<-3 then
            speed=-3
        end
        y=y+speed+0.5*a
    elseif gamestate==CRASHED then
        sprite("Tyrian Remastered:Explosion Huge",x,y,shipsize+math.random(10),shipsize+math.random(10))
        text("Crash",WIDTH/2,HEIGHT/2)    
    end
    strokeWidth(3)
    stroke(48, 216, 25, 255)
    line(0,groundlevel,WIDTH,groundlevel)
    if y-shipsize/2<groundlevel then
        if speed>-1 then
            text("Landed",WIDTH/2,HEIGHT/2)
            gamestate=LANDED
        else
            gamestate=CRASHED
        end
        y=groundlevel+shipsize/2
        speed=0
        thrust=0
    end
    --11. print out the current fuel level
    --pick a font
    font("Courier-Bold")
    --set the size of the font
    fontSize(30)
    --print in the top left corner of the screen. Use .. to join bits of string tp parameters
    text("Fuel:"..fuel,150,HEIGHT-50)
end

--# Step12
-- Noob Lander
-- by West
-- This is a very simple example lunar lander game.  It is intended for use as an introduction into creating your first game in codea and is aimed at absolute beginners.
-- The ship should move under gravity and tapping the screen makes the ship respond to thrust. A line to represent the ground is added and when the ship crosses the line a check is done to see if there is a successful landing. A finite state machine controls the order of the game. The ship has limited fuel.
--12. Add sound effects

displayMode(FULLSCREEN)

function setup()
    x=WIDTH/2
    y=HEIGHT-100
    shipsize=25
    PLAYING=1
    CRASHED=2
    LANDED=3
    gamestate=PLAYING
    groundlevel=50
    speed=0
    gravity=-0.02
    thrust=0
    fuel=500
end

function draw()
    background(40, 40, 50)
    if gamestate==PLAYING or gamestate==LANDED then
        if (CurrentTouch.state==BEGAN or CurrentTouch.state==MOVING) and gamestate==PLAYING and fuel>0 then
            sprite("Tyrian Remastered:Flame 2",x,y-shipsize,shipsize,shipsize)
            thrust = thrust + 0.005
            fuel = fuel -1
            --12. play a thrust sound
            sound(SOUND_HIT, 16609)       
            if thrust>0.05 then
                thrust=0.05
            end
        else
            thrust=0
        end
        sprite("Space Art:Red Ship",x,y,shipsize,shipsize)
        a=gravity+thrust
        speed=speed+a
        if speed<-3 then
            speed=-3
        end
        y=y+speed+0.5*a
    elseif gamestate==CRASHED then
        sprite("Tyrian Remastered:Explosion Huge",x,y,shipsize+math.random(10),shipsize+math.random(10))
        text("Crash",WIDTH/2,HEIGHT/2)    
    end
    strokeWidth(3)
    stroke(48, 216, 25, 255)
    line(0,groundlevel,WIDTH,groundlevel)
    if y-shipsize/2<groundlevel then
        if speed>-1 then
            text("Landed",WIDTH/2,HEIGHT/2)
            gamestate=LANDED
        else
            --12. play an explosion sound
            sound(SOUND_EXPLODE, 23062)
            gamestate=CRASHED
        end
        y=groundlevel+shipsize/2
        speed=0
        thrust=0
    end
    font("Courier-Bold")
    fontSize(30)
    text("Fuel:"..fuel,150,HEIGHT-50)
end