Learning by doing. Simple Game project.

[Sweetgebus]

Hello all, in my attempt to learn scripting in Leadwerks 5, I figured I could start a thread here and update my progress.  I have a small understanding of some things so far. I’ve been working on a learning project for the past week. The idea is a Flappy Bird-style game, or an old-school helicopter game if any of you are old enough to remember that game. The player, “Cube,” flies forward at a constant velocity without player input. When the player hits the space key, the cube will jump. If the player hits the ground or any object, they reset to the beginning.

 

Learns goals for this project include

• Storing the distance traveled by the player.
• Saving the highest distance traveled as a high score.
• Adding power-ups, such as momentarily slowed movement, that the player can use for difficult sections.
• Said power-ups, when collided with, would be stored rather than immediately executed, so the player can use them when they need them.

 

I figured this would be a good starting point for learning. I will post screenshots and code throughout the game's progress, along with the current goal I’m working on. Any help and advice would be greatly appreciated. I’ve always wanted to learn scripting, and once I found Leadwerks, I knew it would be my engine of choice.

[Sweetgebus]

So far, I’ve achieved basic player control. The player flies forward at a constant speed. I’ve set the player's starting point via script, and the player successfully resets to that point when it makes contact with the ground or other game objects.

 

I achieved collision detection by checking the struck entity's collision type. This works in this case, but perhaps there is a better way?

 

Utilizing a timer, I’ve successfully added a 3-second delay after opening the game, before the player starts moving forward.  This has caused an issue that I’m currently trying to overcome. Gravity still acts even when the timer is active. I thought maybe setting self:SetGravity(0) from the start and calling self:SetGravity(1) after checking if the game has started would be the key, but this has a logic error. Perhaps someone here can offer some advice?

	
	-- create start timer
	gracetimer = CreateTimer(3000)
	ListenEvent(EVENT_TIMERTICK,gracetimer,OnGraceTimer)
	
    -- Enable physics
    self:SetPhysicsMode(PHYSICS_RIGIDBODY)
    self:SetCollisionType(COLLISION_PLAYER)
    self:SetMass(1)

    -- Create camera
    self.camera = CreateCamera(self.world)
    self.camera:SetPosition(self.entity:GetPosition())
	
	--we need to save the position of the entity so that we can reset to it
	startpos = self:GetPosition()
end

--timer callbacks
function OnGraceTimer()
	Print("timer Worked")
	gracetimer:Stop()
	gamestarted = true
end

function myPlayer:Sound()
	hit = LoadSound("Sound/Music/hit.mp3")
end

	-- collision
function myPlayer:Collide(entity)
	if entity:GetCollisionType() == COLLISION_SCENE then
		hit = LoadSound("Sound/Music/hit.mp3")
		hit:Play()
		Print("Game Over!")
		isgameover = true end
	end 
	
	--player movement
function myPlayer:Update()

		local vel = self:GetVelocity()
		if gamestarted == true then
			vel.z = self.speed end
		vel.x = 0
		self.entity:SetRotation(0,0,0) 
	
	if self.window:KeyDown(KEY_SPACE) then
		vel.y = self.jumpforce end 
    self:SetVelocity(vel)
	
	-- Game is over, so lets reset the player back to the starting position and resume after 3 seconds
	if isgameover == true then
		self:SetPosition(startpos)
		 isgameover = false end

		 
    -- Update camera
    self.camera:SetPosition(self.entity:GetPosition())
    self.camera:Move(0,1,-3)
end

 

Edited Friday at 10:28 AM by Sweetgebus

[Sweetgebus]

I'm convinced that I'm using Self:SetGravity() incorrectly. With gravity disabled in the editor, I thought that self:SetGravity(-10) would add the gravity to the player, but it doesn't. 

Scratch that, SetGravity doesn't seem to enable gravity, it modifies its value.

 

Edited Saturday at 03:01 PM by Sweetgebus

[Sweetgebus]

Ok, working code bellow. I have my 3 second delayed start, with the gravity issue solved. I also implemented a max jump height to prevent the player from just going over top of the game objects. This code works, but if anyone would care to look over it and tell me if things are wrong, or if I should have done something else, I'd really appreciate it. I don't want to create bad habits from the start.

myPlayer = {
name = player
}
myPlayer.name = "myPlayer"
myPlayer.speed = 10
myPlayer.jumpforce = 5
myPlayer.maxheight = 10


function myPlayer:Start()
    self.window = ActiveWindow()
	
	-- create start timer
	gracetimer = CreateTimer(3000)
	ListenEvent(EVENT_TIMERTICK,gracetimer,OnGraceTimer)
	
    -- Enable physics
    self:SetPhysicsMode(PHYSICS_RIGIDBODY)
    self:SetCollisionType(COLLISION_PLAYER)
    self:SetMass(1)
	self:SetGravity(0)
	
    -- Create camera
    self.camera = CreateCamera(self.world)
    self.camera:SetPosition(self.entity:GetPosition())
	
	--we need to save the position of the entity so that we can reset to it
	startpos = self:GetPosition()
end

--timer callbacks
function OnGraceTimer()
	Print("timer Worked")
	gracetimer:Stop()
	gamestarted = true
	gravity = -10
end

function myPlayer:Sound()
	hit = LoadSound("Sound/Music/hit.mp3")
end

	-- collision
function myPlayer:Collide(entity)
	if entity:GetCollisionType() == COLLISION_SCENE then
		hit = LoadSound("Sound/Music/hit.mp3")
		hit:Play()
		Print("Game Over!")
		isgameover = true end
	end 
	
	--player movement
function myPlayer:Update()
	local pos = self:GetPosition()
	local vel = self:GetVelocity()
	if gamestarted == true then
		self:SetGravity(-10)
		vel.z = self.speed end
		vel.x = 0
		self.entity:SetRotation(0,0,0) 
	if pos.y > self.maxheight then
		pos.y = self.maxheight
		self:SetPosition(pos) end
	
	if self.window:KeyDown(KEY_SPACE) then
		vel.y = self.jumpforce end 
		
		
    self:SetVelocity(vel)
	
	-- Game is over, so lets reset the player back to the starting position and resume after 3 seconds
	if isgameover == true then
		self:SetPosition(startpos)
		 isgameover = false end

		 
    -- Update camera
    self.camera:SetPosition(self.entity:GetPosition())
    self.camera:Move(0,1,-3)
end

 

Edited Saturday at 06:30 PM by Sweetgebus

[Sweetgebus]

I'm attempting to set up a gui item for distance traveled. I'm not sure what I'm doing wrong here. When I run the game, it just crashed immediately without any errors. Any ideas?

[Sweetgebus]

myPlayer = {
name = player
}
myPlayer.name = "myPlayer"
myPlayer.speed = 10
myPlayer.jumpforce = 5
myPlayer.maxheight = 10


function myPlayer:Start()
    self.window = ActiveWindow()
	self.maxdist = 0
	
	-- create start timer
	gracetimer = CreateTimer(3000)
	ListenEvent(EVENT_TIMERTICK,gracetimer,OnGraceTimer)
	
	--create gui
	local font = LoadFont("Fonts/arial.ttf")
	scoretile = CreateTile(world, font, "Score: 0", 32, TEXT_LEFT)
		
    -- Enable physics
    self:SetPhysicsMode(PHYSICS_RIGIDBODY)
    self:SetCollisionType(COLLISION_PLAYER)
    self:SetMass(1)
	self:SetGravity(0)
	
    -- Create camera
    self.camera = CreateCamera(self.world)
    self.camera:SetPosition(self.entity:GetPosition())
	
	--we need to save the position of the entity so that we can reset to it
	self.startpos = self:GetPosition()
end

--timer callbacks
function OnGraceTimer()
	Print("timer Worked")
	gracetimer:Stop()
	gamestarted = true
	gravity = -10
end
	--I set up sound in this funciton, I'm not entirely sure if it needs it own function or not
function myPlayer:Sound()
	hit = LoadSound("Sound/Music/hit.mp3")
end

	-- collision
function myPlayer:Collide(entity)
	if entity:GetCollisionType() == COLLISION_SCENE then
		hit = LoadSound("Sound/Music/hit.mp3")
		hit:Play()
		Print("Game Over!")
		isgameover = true end
	end 
	
	--player movement
function myPlayer:Update()
	local pos = self:GetPosition()
	local vel = self:GetVelocity()
	
	--keep track of distance traveled
	--local dist = pos.z - self.startpos.z 
	
	--if the game is started, we apply movement and gravity
	if gamestarted == true then
		self:SetGravity(-10)
		vel.z = self.speed end
		
		vel.x = 0
		self.entity:SetRotation(0,0,0)
		
	-- Set a max jump height so that the player can't cheat
	if pos.y > self.maxheight then
		pos.y = self.maxheight
		self:SetPosition(pos) end
		
	--added jumping using the spacebar
	if self.window:KeyDown(KEY_SPACE) and gamestarted == true then
		vel.y = self.jumpforce end 
		
	Current code, attempting to set up gui to show total distanced traveled by the player.	
    self:SetVelocity(vel)
	
	-- Game is over, so lets reset the player back to the starting position and resume after 3 seconds
	if isgameover == true then
		self:SetPosition(self.startpos)
		 isgameover = false end

		 
    -- Update camera
    self.camera:SetPosition(self.entity:GetPosition())
    self.camera:Move(0,1,-3)
	
end

 

[Josh]

I would use table fields instead of global variables:

	-- create start timer
	self.gracetimer = CreateTimer(3000)
	ListenEvent(EVENT_TIMERTICK,self.gracetimer,OnGraceTimer)
	
	--create gui
	local font = LoadFont("Fonts/arial.ttf")
	self.scoretile = CreateTile(world, font, "Score: 0", 32, TEXT_LEFT)

Other than that, what is the problem with this code?

[Sweetgebus]

1 minute ago, Josh said:

I would use table fields instead of global variables:

	-- create start timer
	self.gracetimer = CreateTimer(3000)
	ListenEvent(EVENT_TIMERTICK,self.gracetimer,OnGraceTimer)
	
	--create gui
	local font = LoadFont("Fonts/arial.ttf")
	self.scoretile = CreateTile(world, font, "Score: 0", 32, TEXT_LEFT)

Other than that, what is the problem with this code?

I'll read on tables, but when I run this code, the game opens and closes immediately. No errors given.

[Josh]

Run in debug or fast debug mode. If there is still no error, set a breakpoint to figure out where the problem is.

[Sweetgebus]

Just now, Josh said:

Run in debug or fast debug mode. If there is still no error, set a breakpoint to figure out where the problem is.

I'm use the integrated code editor, does it work in that? The code runs fine if I comment out the CreateTile() line

 

[Josh]

Just now, Sweetgebus said:

I'm use the integrated code editor, does it work in that? The code runs fine if I comment out the CreateTile() line

I don't understand this statement?

[Sweetgebus]

Sorry, I'm not using visual studio. I actually didn't know how to do breakpoints in the leadwerks script editor.

 

 

[Josh]

I think you will have a very difficult time without it!:
https://www.leadwerks.com/learn/Debugging?lang=lua&nocpp=1

 

[Sweetgebus]

Oh boy, that just opened up a whole new chapter of confusion for me. I don't know how to decipher what I'm looking at.

[Josh]

Really? What are you confused about?

[Josh]

Maybe start here. This explains from the beginning how the script editor works:
https://www.leadwerks.com/learn/Programming?lang=lua

[Josh]

I must go to sleep, but I will remain with you in the videos. I think the Lua programming series will help you.

[Sweetgebus]

I watching now

 

[Sweetgebus]

Thank you Josh 

[Sweetgebus]

Only TEXT_LEFT is in view for me. Anything else doesn't show. I have self.window = ActiveWindow(), is there something else I'm missing?

 

[Sweetgebus]

Disregard, searching through discord I found the answer. Apparently I need to add a variable, framebuffer = self.window:GetFramebuffer(). And set the postion of the tile. 

[Josh]

It would be better to declare it as a local variable:

local framebuffer

In this case, it probably won't matter, but in the future it's a good idea to declare local variables whenever possible.