I'm using LOVE2D to get used to lua a bit more, and I am trying to call a function to make a circle appear on screen, there's 5 arguments, and I have a table known as 'button' with the required arguments in it. I want to use table.concat to to fill in all the blank arguments but it won't let me. Is there anyway to do this?
function toRGB(r,g,b)
return r/255,g/255,b/255
end
function love.load()
button = {}
button.mode = "fill"
button.x = 0
button.y = 0
button.size = 30
end
function love.draw()
love.graphics.setColor(toRGB(60,60,60))
love.graphics.circle(table.concat(button))
end
table.concat returns a string. That's not what you want.
To get a list of table elements use table.unpack. But this function does only work with tables that have consecutive numeric indices starting from 1.
Also love.graphics.circle accesses its parameters by position, not by name. Hence you have to ensure that the expression list you put into that function has the right order.
So something like:
button = {"fill", 0, 0, 30}
love.graphics.circle(table.unpack(button))
would work.
If you're using other table keys as in your example you'll have to write a function that returns the values in the right order.
In the simplest case
button = {}
button.mode = "fill"
button.x = 0
button.y = 0
button.size = 30
button.unpack = function() return button.mode, button.x, button.y, button.size end
love.graphics.circle(button.unpack())
Or you can do something like this:
function drawCircle(params)
love.graphics.circle(params.mode, params.x, params.y, params.size)
end
drawCircle(button)
There are many other ways to achieve this.
Related
Im trying to generate a random map using a matrix but I dont really know how. Here is the
function for the matrix. wMap and hMap are the width and height, and mapSprites is a table containing some ground sprites. Also how can I draw the matrix? Im sorry if this is too much of a question, but Im really in need for some help
function buildMap(wMap, hMap)
for i = 1, wMap do
mt[i] = {}
for j = 1, hMap do
mt[i][j] = math.random(mapSprites)
end
end
end
Generating a random map in any programming language will utilize two core concepts: The language's random function and nested for loops, two for the case of a map/matrix/2d array.
The first problem, is you may or may not have mt initialized outside the function. This function assumes the variable exists outside of the function and each time the function is called it will overwrite mt (or initialize it for the first function call) with random values.
The second problem, the width, wMap, and height, hMap, of the map are in the wrong order, as maps/matrices/2d arrays first iterate over the height (y dimension) and then the width (x dimension).
The last problem, mapSpripes also has to be declared outside the function (which is not clear with your code snippet), which will be the highest possible value the random function can generate. You can read more about math.random here: http://lua-users.org/wiki/MathLibraryTutorial
Consider this function I wrote that makes those adjustments as well as has some additional variables for the minimum and maximum random value. Of course, you can remove these to have it fit your intended purposes.
function buildMap(wMap, hMap)
local minRand = 10
local maxRand = 20
for y = 1, hMap do
matrix[y] = {}
for x = 1, wMap do
matrix[y][x] = math.random(minRand, maxRand)
end
end
end
I suggest you use this function as inspiration for your future iteratins. You can make minRand and maxRand parameters or make matrix a returned value rather than manipulating an already declared matrix value outside of the function.
Best of luck!
EDIT:
Regarding your second question. Look back at the section I wrote about nested for loops. This will be crucial to "drawing" your map. I believe you have the building blocks to resolve this issue yourself as there isn't enough context provided about what "drawing" looks like. Here is a fundamentally similiar function, based on my previous function, on printing the map:
function printMap(matrix)
for i = 1, #matrix do
for j = 1, #matrix[i] do
io.write(matrix[i][j] .. " ")
end
io.write("\n")
end
end
For choosing random sprite, I recommend you to create a table of sprites and then save index of sprite in matrix. Then you can draw it in same loop, but now, you will iterate over matrix and draw sprite based on sprite index saved in matrix in position given by matrix position (x and y in loop) times size of sprite.
local sprites, mt = {}, {}
local spriteWidth, spriteHeight = 16, 16 -- Width and height of sprites
function buildMap(wMap, hMap)
mt = {}
for i = 1, wMap do
mt[i] = {}
for j = 1, hMap do
mt[i][j] = math.random(#sprites) -- We choose random sprite index (#sprites is length of sprites table)
end
end
end
function love.load()
sprites = {
love.graphics.newImage('sprite1.png'),
love.graphics.newImage('sprite2.png'),
-- ...
}
buildMap()
end
function love.draw()
for y, row in ipairs(mt) do
for x, spriteIndex in ipairs(row) do
-- x - 1, because we want to start at 0, 0, but lua table indexing starts at 1
love.graphics.draw(sprites[spriteIndex], (x - 1) * spriteWidth, (y - 1) * spriteHeight)
end
end
end
I have been trying to make a box for a user to input data once the user clicks the box. This is what I have so far, but clicking the box does not cause text input to be added to it. Where is the issue?
function love.load ()
txt1 = ""
columnx = { 50, 160, 260, 375, 495, 600, 710 }
columny = { 130, 230, 330, 440, 540, 640 }
if show1 == true then
function love.textinput(t)
txt1 = t
end
end
end
function love.mousepressed (x, y)
if
x >= columnx[4] and
x <= 435 and
y >= columny[1] and
y >= 145 then
show1 = true
end
end
function love.draw ()
love.graphics.print(txt1, columnx[4], columny[1])
end
You're pretty much on the way, but I'll give you some tips on how to create a basic textbox.
Firstly, consider a conceptual textbox to be a singular table, that contains everything it needs to know about itself to properly update and render. It's much easier to reason about something that is self contained.
A textbox needs to know its position, its size, whether it is active, and which text it contains. We can condense that into a table that looks like the following.
local textbox = {
x = 40,
y = 40,
width = 400,
height = 200,
text = '',
active = false,
colors = {
background = { 255, 255, 255, 255 },
text = { 40, 40, 40, 255 }
}
}
(We also store some color info.)
After that the simple way to add text is through love.textinput, as you've seen. In your code we only check if the textbox is active once, in love.load, which it of course isn't since we likely haven't taken any user input yet. Instead of attempting to overload the function, we simply check if the textbox is active or not inside the handler, and proceed accordingly.
function love.textinput (text)
if textbox.active then
textbox.text = textbox.text .. text
end
end
We've covered how to check if the user has clicked within a rectangular area in the question: Love2d cursor positions. We want to deactivate the textbox if it is currently active and the user clicks outside of its space.
function love.mousepressed (x, y)
if
x >= textbox.x and
x <= textbox.x + textbox.width and
y >= textbox.y and
y <= textbox.y + textbox.height
then
textbox.active = true
elseif textbox.active then
textbox.active = false
end
end
And finally we need to render our textbox. We use unpack to expand our color tables, and love.graphics.printf to make sure our text wraps within our textbox's space.
function love.draw ()
love.graphics.setColor(unpack(textbox.colors.background))
love.graphics.rectangle('fill',
textbox.x, textbox.y,
textbox.width, textbox.height)
love.graphics.setColor(unpack(textbox.colors.text))
love.graphics.printf(textbox.text,
textbox.x, textbox.y,
textbox.width, 'left')
end
These are the basic ideas of creating a very rough textbox. It's not perfect. Note that you will need to consider what happens when the text gets longer height-wise than we initially set our textbox's height to, as the two are only loosely related.
To make your program easier to read, and easier to extend, everything you've seen above should really be placed into their own functions that handle textbox tables, instead of cluttering the love handlers with common code. Take a look at Chapter 16 of Programming in Lua, which covers Object-Oriented Programming - a generally vital topic for game development.
See the love.textinput page on how to handle a backspace, to delete characters.
Some extra things to think about:
How can we distinguish an active textbox from an inactive one?
How can we create a list of textboxes, so we can have multiple on screen (but only one active)?
I guess, the love.textinput() callback function is what you are looking for. But as the term 'callback' implies, it will be called by the LÖVE engine, not your code. It will be called whenever the user inputs some text while your game is running. Therefore you need to put it outside the love.load() function.
In the love2d.org wiki is an example for this (the lower one).
As for your example, move the love.textinput() out of love.load() and add an if statement:
function love.load()
txt1 = ""
columnx = {50, 160, 260, 375, 495, 600, 710}
columny = {130, 230, 330, 440, 540, 640}
end
function love.textinput(t)
if (show1) then
txt1 = txt1 .. t
end
end
-- The rest of your code.
-- And maybe mix it with the 'backspace example' from the wiki...
-- But you also might want to have some function to set 'show1' back to 'false' after the text input. Maybe something like this:
function love.keypressed(key)
if (key == "return") and (show1) then
show1 = false
end
end
I hope I could help you a bit!
I'm trying trying to have users name fade in one letter at a time vertically. Example: Adam "A" would appear after 1 second , "d" would appear after 3 seconds under the displayed A, "a" would appear after 5 seconds under the displayed d, "m" would appear after 7 seconds under the displayed a. The visuals would have a sort of domino effect.When they appear they would stay displayed on screen.
When if I comment out userNameField:removeSelf () then the code works fine. I get the effect I want, but the problem is that I still have the userNamefield showing.
Please let me know if you need to see more code.
local greeting = display.newText( "Greetings, enter your name",0,0,native.systemFont, 20 )
greeting.x = display.contentWidth/2
greeting.y = 100
local submitButton = display.newImage( "submit.png" ,display.contentWidth/2, display.contentHeight - 50 )
local userNameField = native.newTextField( display.contentWidth * 0.5 , 150, 250, 45)
userNameField.inputtype = "defualt"
local incrementor = 0
function showNameLetters()
userNameField:removeSelf( )
if incrementor <= string.len ("userNameField.text") then
incrementor = incrementor + 1
personLetters = string.sub (userNameField.text, incrementor,incrementor)
display_personLetters = display.newText (personLetters, 290,30*incrementor, native.systemFont, 30)
display_personLetters.alpha = 0
transition.to(display_personLetters,{time = 3000, alpha = 1, onComplete = showNameLetters})
end
end
Update:
I've found a solution to my problem, by adding userNameField.isVisible = false in my function.
I've also found something very weird, and wish to have someone explain why this happens. If I add greeting:removeSelf() and submitButton:removeSelf() (I've commented them out in my code below to show you where I put them for testing). I get weird result of only the first letter fading in. If i set greeting.isVisible = false and submitButton.isVisible = false. The code works fine.
I'm so confused why object:removeSelf() wouldn't work. Can someone please clear this up for me.
That is, if I replace the following line:
userNameField:removeSelf( )
with:
userNameField.isVisible = false
then the app works fine. Please suggest me why/ any solution for the question. THanks in advance...
It seems like you're calling the showNameLetters multiple times, this means that you're removing the native text field more than once. Nil it and check for nil before removing it like this:
if userNameField ~= nil then
userNameField:removeSelf()
userNameField = nil
end
It shows that you are using data from userNameField after removing it (in the line below):
personLetters = string.sub (userNameField.text, incrementor,incrementor)
As well as you are calling object:removeSelf() again and again without checking its existance (as mentioned by hades2510). So before removing userNameField, check for it's existance:
if userNameField ~= nil then
userNameField:removeSelf()
userNameField = nil
end
And you won't get userNameField.text while userNameField is nil. So use a temporary variable to hold the previous userNameField.text and get the saved data from that variable when needed.
Extra note: Are you sure, you have to check the length of the text "userNameField.text" in the following line, or the variable userNameField.text? If you have to use the data from the text field, then this will also matter.
if incrementor <= string.len ("userNameField.text") then
........
end
Keep coding....................... :)
I have a model called door
Inside I have a BoolValue named Open
I have a model called Top that has all of the door blocks named Work Mabey Comeon and Proboblynot
And I have Block that when touched is supposed to make Top move up
Directly inside door I have this script
door = script.Parent
open = door.Open
Top = door.Top
opener = 18
speed = 100
steps = speed
startl = Top.CFrame
function MoveDoorToCFrame(cfrm,dr)
dr.Work.CFrame = cfrm
dr.Mabey.CFrame = dr.Work.CFrame * CFrame.new(0,-7.2,0)
dr.Comeon.CFrame = dr.Work.CFrame * CFrame.new(0,10.8,0)
dr.Problynot.CFrame = dr.Work.CFrame * CFrame.new(0,10.8,0)
end
function Update()
if speed/steps < 0.5 then
calc = 1-math.cos(math.rad((-90/speed)*steps*2))
else
calc = 1+math.sin(math.rad((90/speed)*((speed/2)-steps)*2))
end
MoveDoorToCFrame(startl * CFrame.new(0,(calc/2)*opener,0),Top)
end
Update()
while true do
wait()
if not open.Value and steps < speed then
steps = steps + 1
Update()
elseif open.Value and steps > 0 then
steps = steps - 1
Update()
end
end
Inside the button that is supposed to activate on touch I have
script.Parent.Touched:connect(function()
script.Parent.Parent.Open.Value = not script.Parent.Parent.Open.Value
end)
script.Parent.Parent.Open.Changed:connect(Update)
Update()
If you know how to fix this it would be gladly appreciated.
Update November 2015:
Using PrimaryPart
Since writing this post, ROBLOX has changed a lot in regards to the API. To move a model like requested, you should set the PrimaryPart property of the model to a central part inside the model. This will act as the origin for the model's movements.
You can then use model:SetPrimaryPartCFrame(cframe) to set the CFrame of the model. You can also retrieve this property by using model:GetPrimaryPartCFrame(), although I believe that is just a shortcut method for model.PrimaryPart.CFrame.
In code, it would look like this:
-- Set PrimaryPart:
MODEL.PrimaryPart = MODEL.SomeCentralPart
...
-- CFrame movement:
local movement = CFrame.new(0, 10, 0)
-- Move the model:
MODEL:SetPrimaryPartCFrame(MODEL:GetPrimaryPartCFrame() * movement)
Option A: Use Model's methods
I think you are making this much more difficult than it needs to be. Whenever you run into an issue like this, be sure to check the current APIs provided. The ROBLOX Model object contains a nifty method called 'TranslateBy' which takes a Vector3 argument to translate the model.
Using MODEL:TranslateBy(Vector3) is similar to moving a model via CFrame, since it ignores collisions.
Another alternative is MODEL:MoveTo(Vector3) which moves a whole model to the given Vector3 world position. The downside to this is that it does collide.
One way to get the same MoveTo effect but without collisions can be done with the TranslateBy method:
MODEL:TranslateBy(Vector3Position - MODEL:GetModelCFrame().p)
Option B: Write a custom function to manipulate the model's CFrame
Another alternative would be to manipulate the whole model's CFrame entirely. To do this, you can write a clever function that will move a whole model relative to an 'origin' point. This is similar to moving shapes on a grid given their points and an origin, except in three dimensions. Using ROBLOX's built-in functions, this is much easier though.
A good way to do this would be to write a function that lets you actually assign a CFrame value to a whole model. Another way would be to allow a translation via CFrame too.
Here's an example:
function ModelCFrameAPI(model)
local parts = {} -- Hold all BasePart objects
local cf = {} -- API for CFrame manipulation
do
-- Recurse to get all parts:
local function Scan(parent)
for k,v in pairs(parent:GetChildren()) do
if (v:IsA("BasePart")) then
table.insert(parts, v)
end
Scan(v)
end
end
Scan(model)
end
-- Set the model's CFrame
-- NOTE: 'GetModelCFrame()' will return the model's CFrame
-- based on the given PrimaryPart. If no PrimaryPart is provided
-- (which by default is true), ROBLOX will try to determine
-- the center CFrame of the model and return that.
function cf:SetCFrame(cf)
local originInverse = model:GetModelCFrame():inverse()
for _,v in pairs(parts) do
v.CFrame = (cf * (originInverse * v.CFrame))
end
end
-- Translate the model's CFrame
function cf:TranslateCFrame(deltaCf)
local cf = (model:GetModelCFrame() * deltaCf)
self:SetCFrame(cf)
end
return cf
end
-- Usage:
local myModel = game.Workspace.SOME_MODEL
local myModelCF = ModelCFrameAPI(myModel)
-- Move to 10,10,10 and rotate Y-axis by 180 degrees:
myModelCF:SetCFrame(CFrame.new(10, 10, 10) * CFrame.Angles(0, math.pi, 0))
-- Translate by 30,0,-10 and rotate Y-axis by 90 degrees
myModelCF:TranslateCFrame(CFrame.new(30, 0, -10) * CFrame.Angles(0, math.pi/2, 0))
This might be hard.
You might want to look to free models for this one unless the people above get it to work.
I, however, do have a script to move a model:
game.Workspace.Model:MoveTo(Vector3.new(0,0,0))
Your code indeed needs fixing.
You should NOT use a never-ending loop to make your stuff work (unless that is the only way).
You should rather base actions on events.
Consider to use this:
Structure:
Door [Model]
DoorScript [Script]
Button [Part]
DoorOpen [BoolValue]
Top [Model]
Mabey [Part]
Comeon [Part]
Problynot [Part]
DoorScript:
local Model = script.Parent
local Door = Model.Top
local Button = Model.Button
local DoorOpen = Model.DoorOpen
local Offset = 0
local ToOffset = 100
local Direction = 1
local StepLength = 0.1
local Moving = false
function StartMoving()
if Moving then return end
Moving = true
while (DoorOpen.Value and Offset ~= ToOffset) or (not DoorOpen.Value and Offset ~= 0) do
local Change = Offset
Offset = math.max(0,math.min(ToOffset,Offset + StepLength * (DoorOpen.Value and 1 or -1)))
Change = Offset - Change
Top:TranslateBy(Vector3.new(0,Change,0))
wait()
end
Moving = false
end
StartMoving()
DoorOpen.Changed:connect(StartMoving)
local Debounce = false
Button.Touched:connect(function()
if Debounce then return end
Debounce = true
DoorOpen.Value = not DoorOpen.Value
wait(4)
Debounce = false
end)
You might want to adjust the speed tho.
This can be used to move models, try adding something like this into your code. It's more dynamic.
a = Workspace.Model
for i=0.1,40 do
for i,v in pairs(a:getChildren()) do
if v:IsA("Part") then
v.CFrame = CFrame.new(v.CFrame + Vector3.new(0,0.1,0))
else print("Not a part")
end
end
end
I want to create a table with display Objects on specific positions. I wrote the following
for i=0, 5 do
life[i] = display.newImage( "life.png" )
end
but when I am trying this:
for i=0, 5 do
life[i] = display.newImage( "life.png" )
life[i].x=i*Space_
end
compiler complains attemp to index field ? nil value
Any idea why this happen or how can I solve it? I want to use a for loop to add objects in a table (or maybe group? ) on specific positions.
Show us where Space_ is in your code.
Try this:
local SpaceX = 10
for i=0, 5 do
life[i] = display.newImage( "life.png" )
life[i].x = i * SpaceX
end
Corona doesn't find your image and returns nil as the result of display.newImage call. When you try then to access field x of a nil value, you get the error.
Make sure your image is available to your script.
This assert should probably trigger, because life.png could not be found
for i=0, 5 do
life[i] = assert(display.newImage("life.png"), "image could not be found")
life[i].x=i*Space_
end