I've created a folder MySprites.spritepack in the Codea documents folder, stuck a load of pngs in there, added an Info.plist that I cribbed from https://github.com/TwoLivesLeft/Codea-Runtime/blob/master/CodeaTemplate/SpritePacks/Cargo Bot.spritepack/Info.plist, but it doesn't work.

I get a list of the pngs but no images and all are reported as being 0x0. When I try to use one in my code then Codea crashes. The pngs work fine if they are dumped in the main Codea documents folder but I'd rather segregate them a little otherwise it gets too crowded in there.

What's the secret?

Goal: Draw a dot on the screen that shrinks in size. Then, by touching a button, make it happen again -- by which I mean the dot goes back to its initial size and starts shrinking again.

Code: (This code is retyped, not copied-and-pasted, so if there are minor typos, I apologize. They are probably not the issue.)

function setup()
    length = 100
    dot = {diam = length}
    parameter.action("Reset", ResetTweens)
end

function draw()
    background(57, 57, 57, 255)
    strokeWidth(10)
    stroke(255)
    fill(0, 0, 0, 0)
    rectMode(CENTER)
    rect(WIDTH/2, HEIGHT/2, length, length)

    pushMatrix()
    DrawDot()
    popMatrix()
end

function DrawDot()
    id = tween(1, dot, {diam = 0.6*length})
    noStroke()
    fill(255,0,0)
    ellipse(WIDTH/2, HEIGHT/2, dot.diam)
end

function ResetTweens()
    tween.reset(id)
end

Two issues with this code. 1. When the dot gets close to its final size, it stutters a bit, bouncing around slightly in size. I tried explicitly setting the easing to linear, but that didn't solve the problem. 2. Pressing the reset parameter button doesn't do anything. I can see that I go into the Reset function (by adding a print statement to ResetTweens() ), but nothing happens to the red dot.

So, clearly, there are some things I don't get. I have tried moving the push and pop of the matrix to within the DrawDot() function. I have moved the declaration of the tween around to various places. I have tried calling tween.reset() from within draw() and setup(). I have also tried using tween.resetAll(). But I can't get the dot to behave the way I want. I feel like I'm basically trying stuff at random, and would love some guidance / explanation.

Thanks! -B

I found two things: 1 - setContext(img) seems to require clip() to be turned off. I had a clipping window set, and was not getting any images. It seems to be. Because: 2 - sprite respects clip(data...) while setContext(img) is on.

This seems to be wrong...I guess someone could want to clip)) when drawing to an image, but would one?

This is outside my expertise, and I know Codea isn't strong in sound, but I thought I'd ask anyway if this sounds feasible.

I have finally setup an apple developer account published a few simple apps and thought it was time to tackle something 3d and fun.

I started looking at OpenGL samples and it doesn't look hard, but I remembered the many nights I played with codea and thought I'd relook at it.

So my question is in general what are benefits of each and the draw backs. I remember codea itself being limited it things like access to mp3 files, voice and custom images. I think with the runtime tool kit I can get around those?

function Results:init(x)
    showKeyboard() 
end

function Results:draw()
    buffer = keyboardBuffer()
    if buffer then
        buffer = tbuffer{a,b,c}
        d = math.pow(b,2)- 4 * a * c
        x1 = (-b + math.sqrt(d))/2*a
        x2 = (-b-math.sqrt(d))/2*a
        fill(255)
        fontSize(40)
        font("AmericanTypewriter-Bold")
        textWrapWidth(WIDTH)   
        text(a.."x^2+"..b.."x+" ..c.. " = 0", WIDTH/2,HEIGHT -100)
        fill(255, 0, 0, 255)
        text("Delta = "..b.."^2 - 4*"..a.."*"..c,WIDTH/2,HEIGHT -150)
        text("Delta = "..b*b.." - "..4*a*c,WIDTH/2,HEIGHT -200)
        text("Delta = "..d,WIDTH/2, HEIGHT-250)
        fill(0, 21, 255, 255)
        text("X1 = ",201,HEIGHT -315)
        text(-b.."+".."√"..d,WIDTH/2,HEIGHT-300)
        text("____________",WIDTH/2,HEIGHT-300)
        text("2 * "..a,WIDTH/2,HEIGHT-340)
        text("X1 = ",201,HEIGHT-405)
        text(-b.."+"..math.sqrt(d),WIDTH/2,HEIGHT-390)
        text("____________",WIDTH/2,HEIGHT-390)
        text(2*a,WIDTH/2,HEIGHT-430)
        text("X1 = "..x1,WIDTH/2,HEIGHT-480)
        fill(255, 158, 0, 255)
        text("X2 = ",201,HEIGHT -545)
        text(-b.."-".."√"..d,WIDTH/2,HEIGHT-530)
        text("____________",WIDTH/2,HEIGHT-530)
        text("2 * "..a,WIDTH/2,HEIGHT-570)    
        text(-b.."-"..math.sqrt(d),WIDTH/2,HEIGHT-620)
        text("____________",WIDTH/2,HEIGHT-620)
        text(2*a,WIDTH/2,HEIGHT-660)
        text("X2 = ",201,HEIGHT -635)
        text("X2 = "..x2,WIDTH/2,HEIGHT-710)
    end
end

What i inteded here is to input for example 1,-6,5 and it would return a=1,b=-6,c=5. The program says tbuffer = nil, and i dont know how to get multiple values from the keyboard. Sorry for the messy code, its my first one

ifile acess it

Codea Rookie

error: [string "--tween.lua..."]:472 :attempt to perform arithmetic on local 'd' (a nil value)

I didn't use d as a variable in my code. Can someone explain what this means?

So i want to Save the photo and i want that the screen changes to the photo after shooting it. So i can edit or crop it. Thanks

(PS... I'm not a "native English speaker"... please forgive my poor prose and the spelling mistakes ... ;-) tks )

My next question is, how can you call Objective-C code from within your LUA classes? (and the other way round) Where do you put your functions and how do you call them? (for example, It would be nice to call an Obj-C function that plays audio).

So, as a 'stripped down' example - we can represent 'position' using vec2 within a simple class to hold the x,y coords:

self.pos = vec2(0,0)

and then tween by referencing directly the x index as a target:

subject = self.pos
target =  {x = WIDTH}
tweenID = tween(5, subject, target)

All fine and dandy!

However, how would this work with a single variable and what should 'target' in this instance be?

self.rotate = 0
subject = self.rotate
target = ??????
tweenID = tween(5, subject, target)

I guess the issue is that self.rotate is not 'userdata' (ie vec2 etc) and hence I can't seem to work out the correct syntax or a 'simple' way of representing easily what a 'target' should be.

As a hack, this works fine if a treat pos and rotate as a vec3 (using the z index as the rotate) - but there must be an easier way of tweening a single (non user-data) variable within a class?

:-(

It World be nice if Someone could help me or send me a link Where the Code Stands.

Sry if the englisch isnt Fine but im from Germany and my ipad is Always changing my english words into sth German.

Thanks for all answers

    (function (a,b) print(a+b) end)(10, 20)

He said, 'It creates an anonymous function that prints the sum of its two parameters and applies that function to arguments 10 and 20'. I had never seen a function like this before, so I tried to put it into Codea for closer examination and experimentation. Unfortunately, Codea returns an error at this line when I hit 'Run.' What am I missing here? My presumption was that the a and b variables would get their values from the parameters 10 and 20, add them together and then print them.

if a-n <= x <= a+n and b-m <= y <= b+m then ... end (x,y,a,b are variable integers and n,m are constant integers)

But I can't. Are there any type of conditional that I can use in this way without creating a loop?

I was hoping someone could help me. I am making a program in which you can enter some data and the program should mail the output of the program. My program gives the correct output. But I was wondering if there is a way to copy this output to an email? Thanks in advance :).

Thanks in advance! Steffen

• 3D graphics, through the use of triangles and everything that goes with that
• Faster 2D graphics, by adding rectangles to a mesh and then adding image based textures to them

First, is the ability to add rectangles purely aimed at 2D speed (it seems a bit odd to be adding a rectangle to a structure made up of triangles), or does it have some function in 3D as well? Or am I completely misunderstanding something?

My second question is about using a mesh to speed up 2D graphics. I can see how it works with rectangular images or shapes, but what if you're drawing lines, ellipses or other odd shapes as well? How would you get them into a mesh, or even into a texture? To make it clearer, suppose I have this code in draw()

sprite(img,100,100)
ellipse(200,200,50)
line(400,450,500,550)

..and I want to do this with a mesh instead, having defined this in setup already

g=mesh()
g.texture="ImageName"

So in draw, I put

local d=g:addRect(100,100,img.width,img.height) --add image to mesh
g:setRectTex(d,0,0,1,1)
      --<< it's here I'm stuck. What do I do with the ellipse and line?
g:draw() --draw

link = 'http://twolivesleft.com/Codea'

openURL(link)

I want to have an array with links so that when the user touches a certain area of the application they are sent to one of the links in the array. This is what I have, not sure if it works (I can't test it right now).

http://pastebin.com/xXa4gvgP

I found how to open an URL if a certain are is touched, but I want to use an array to have better control on the urls and that I don't have to use a lot of if's:

http://pastebin.com/kb3VFUGS

And I don't know if the validTouch really returns the bool value I want it to.

Thanks! :)

I am new to both Lua and Codea and just ran into a problem I cannot get my head around.

I am trying to use a repeat until loop to simply print the numbers 400 to 800. As soon as I execute that piece of code Codea freezes. I get similar problems when using while loops.

Can anybody tell me whats going on? Thank you!

-- Use this function to perform your initial setup
function setup()
    -- Variables
    i = 400
end

-- This function gets called once every frame
function draw()
    -- This sets a dark background color 
    background(255, 255, 255, 255)

    -- Do your drawing here
    repeat
         print (i)
         i = i + 1
    until i == 800
end

Cheers

Can I position the slidebar elsewhere? What about Vertical ? Is their special "view" I can use?

I am trying to get two VERTICLE slider bars on left and right side of a landscape screen. Basically I want the user's thumbs to move a slider bar up and down.

I'm new to Codea so be gentle.

Thanks, Troy

I want to declare my own matrix in codea and bind it to a uniform mat4 in a shader, but it seens to be empty in the shader. My code is basically:

m0={1,0,3,0,          0,1,0,0,          3,0,1,0,          0,0,0,1} Then I assign it to my shader ( in my vertex shader I have "uniform mat4 mymat4;" already declared) mymesh.shader.mymat4=m0

But if I make any operation like position = mymat4* position, my result is null so I guess I have a problem with the input. Anyone has an idea?

Thanks

My question: is there a better way to draw large numbers of sprites? These sprites are transparent PNG's with retina versions. I am testing on iPad 3. My Code:

function draw()
   for i=#self.allSprites,1,-1 do 
      self.allSprites[i]:draw()
   end
end

function setup()
    --create objects

    --first the rectangle
    rect_width=100 --size of rectangle
    rect_height=50
    --now create the physics object that behaves like a real block, it will tell us where to draw our rectangle
    --think of it as a GPS navigator that guides us
    p_rect = physics.body(POLYGON, vec2(-rect_width / 2, -rect_height / 2),vec2(-rect_width / 2, rect_height / 2),vec2(rect_width / 2, rect_height / 2),vec2(rect_width / 2, -rect_height / 2))
    p_rect.x = math.random(60,250) -- choose a random position between 30 and the screen width minus 30
    p_rect.y = math.random(60,250) -- same for the y position
    p_rect.angle=math.random(0,360) -- and rotation
    p_rect.gravityScale = 0 -- no gravity - if there was, the ball would fall to the bottom of screen
    p_rect.restitution = 1 -- this circle is bouncy
    p_rect.friction = 0.1 -- the amount of friction to be applied to the circle
    p_rect.linearVelocity = vec2(100+math.random(400),100+math.random(400))  --velocity (pixels per second = 60 redraws)
    --p_rect.linearDamping = 0.2
    --p_rect.angularDamping = 0.2

    p_rect.info="rect" --so when collisions occur, we can figure out which object was involved

    --now much the same for the image
    img=readImage("Tyrian Remastered:Mine Spiked Huge")
    img_diam=(img.width+img.height)/2 --use average of width and height as diameter
    --create the physics object
    p_img = physics.body(CIRCLE,img_diam/2) --physics bodies use radius not diameter
    p_img.x = math.random(60,250) -- choose a random position 
    p_img.y = math.random(60,250) -- same for the y position
    p_img.angle=math.random(0,360)
    p_img.gravityScale = 0 -- no gravity
    p_img.restitution = 0.8 -- this image is not so bouncy
    p_img.friction = 0.4 -- the amount of friction to be applied to the image
    p_img.linearVelocity = vec2(math.random(400),math.random(400))  -- velocity
    p_img.info="mine" --so when collisions occur, we can figure out which object was involved
    --p_img.linearDamping = 0.9 -- WHAT DO THESE DO?
    --p_img.angularDamping = 0.9

    --finally the walls
    CreateWalls()
end

--create the walls - physics objects can only bounce off each other
function CreateWalls()
    leftWall = physics.body(EDGE,vec2(1,1),vec2(1,HEIGHT-1)) -- vec2 is a "vector" consisting of an x,y pair
    rightWall = physics.body(EDGE,vec2(WIDTH-1,0),vec2(WIDTH-1,HEIGHT-1)) -- HEIGHT and WIDTH give us screen dimensions
    bottomWall = physics.body(EDGE,vec2(1,1),vec2(WIDTH-1,1)) 
    topWall = physics.body(EDGE,vec2(1,HEIGHT-1),vec2(WIDTH-1,HEIGHT-1))
    --set the bounciness of the walls
    leftWall.restitution=1.0 --no slowing
    rightWall.restitution=0.9 --some slowing
    bottomWall.restitution=0.2 
    rightWall.restitution=0.7
end

function draw()
    background(200,200,200,255)

    --draw the rectangle --
    pushStyle()
    fill(255,0,0,255)
    pushMatrix()
        translate(p_rect.x, p_rect.y)
        rotate(p_rect.angle)
        rect(-rect_width / 2, -rect_height / 2, rect_width, rect_height)
    popMatrix() 
    popStyle()
     -------------------------------

    --draw image ---
    pushMatrix()
        translate(p_img.x, p_img.y)
        rotate(p_img.angle)
        sprite(img,0,0)
    popMatrix() 
    -------------------------------

end

Anything besides blueA, blueB, RedA,RedB isnt working. Each has this error: the initial time comes up, then it counts down 1 second and puts that on top of that initial time. It's weird because its almost the same code for BlueA and Baron, yet Baron has the error. Thanks for helping, i look forward to your replies.

The problem, as this little video shows

Perhaps I shouldn't be using raycast, but I thought it was a nice way to get to grips with it.

If we were to include a JSON library in the next version of Codea, which one would you like to see? Or what would your ideal Lua interface for JSON look like?