Just thinking ahead - picking a model format, then allowing import/export/picking of models like you do for images and shaders would be keen.
I’d like to say ‘m = mesh(“Documents:Teapot”)’
I’d also like to say ‘m = mesh(“http://home.bortels.us/teapot.ply”)’
or image() or shader() for that matter. Just suggestions.
I can load the 2.7 meg teapot in under 2 seconds. NOT TOO SHABBY. Haven’t parsed it yet.
So - not all PLY is PLY. Just sayin.
PS. I just caught myself; this happens every time. What I want to be doing is learning shaders and finding bugs in 1.5 - and what I’ve done for the last hour is research into writing a PLY loader (a robust one) in lua. Good stuff - worth doing - and completely irrelevant to something that might be useful for a beta test.
Yak Shaving. It is my life.
Works really nice, good job! Will try it out a bit more this weekend! It would be nice if the shader lab populated the time variable if it exists in the shader.
Bug with watch. The first two watches are a bit funny. The first gets an extra table, the second is always nil. After that they straighten out.
.@tnlogy the plan is to have those variables become interactive — like the colour picker in the main editor. So you could tap the time variable and slide a slider to change it. Or tap a texture to choose a new sample texture, and so on.
No, it was the first two in a project and after those two then all the others were fine.
I was experimenting with the camera project. I added watch("camWidth") and watch("camHeight") and got the first as table:<junk> 480 and the second as nil. This puzzled me somewhat as if I printed those two then I got 0 and 0 (the discrepancy on values is because I was printing from setup before the camera had been initialised). So then I added dummy variables testa = camWidth and testb= camHeight to the camera setup routine and watched those. They were fine and gave the expected result. So then I added watch("nothing") watch("nothingelse") at the start and those two were table:<junk> nil and nil and all the other watches then worked just fine (there were six in total by this stage).
I am running out of superlatives for Codea. Christmas has come early.
It would be good if the final version of version 1.5 could fix issue #203, so that it is easy again to take screen shots of what can be produced with the extended API.
Hi @Simeon - my impression of the beta is that it is great! I liked how you kept the examples simple. I would like the code arguments things to stick around rather than fade - I like to mull over my options. 
The camera is wonderful and shaders will be an interesting area of growth. I presume you will ship a few more sample ones with it. Although I will have to learn how shaders work, I was able to mess around and alter the colours. A question: if your shader is like the ripple one, how does the preview work if there is no frequency input that you get with parameter() in the actual project?
Interactive sounds great
It’s nice to easely edit the shaders from the Lua code view. But, maybe there is a need for a pause button in the shader view. When I modified an ink shader (used for my profile picture) I crashed Codea when I changed the step parameter in a for-loop and it was x+= .0 before I changed it to 1.0.
.@tnlogy yeah the immediate re-compilation can cause issues like that. I was thinking to have Codea recompile the shader on a short timer, about 0.2-0.5 seconds after your last key press. So rapid typing doesn’t continuously recompile at every keystroke.
However I definitely think we need a pause button too (this would also be a way of hiding obtrusive error messages).
that, or have a “see it now” button. (Plus maybe “revert to last working” option)
tween() confuses me. I can interrupt it (in the example) - but not always? I think it’s a bug in the “tapCount” count in the example, actually. (Ah - yes. A bug in me - I tend to double-tap, which set the count > 1. Changing “== 1” to “> 0” made it work better for me)
Just trying to understand it - you tween(), and that essentially runs as a background thread, until the animation is complete - right? Unless you tween.resetAll(). Is there a way to reset a specific tween?
To reset a particular tween you can use the ID returned from tween()
local tid = tween( 1.0, someObject, {someTarget} )
tween.reset( tid )
tween.stop( tid )
```
Tween doesn't run in a background thread, but it does get updated automatically at the same rate as the draw() function is called.
Is there a good tutorial on shaders somewhere? I’m trying some experiments and I don’t know if it is shaders that I don’t understand or Codea’s implementation of them.
Nope.
But having said that, this one is better than most: http://www.aerotwist.com/tutorials/an-introduction-to-shaders-part-1/
it’s based on webgl and three.js, so at least it’s accessible. (Part 2 is actually more “meaty”, but you go thru part 1 to get there)
Okay, here’s my first go.
Codea program
function setup()
m = mesh()
local nsteps = 200
local w = 5
local h = 1/nsteps
for n=1,nsteps do
m:addRect(0,(n-.5)*h,w,h)
end
m.shader = shader("Documents:ExperimentOne")
m.shader.time = 1
a = vec2(0,0)
b = vec2(100,0)
c = vec2(200,200)
d = vec2(200,300)
m.shader.a = a
m.shader.b = b
m.shader.c = c
m.shader.d = d
m:setColors(255,255,25)
end
function draw()
background(75, 104, 90, 255)
strokeWidth(5)
line(a.x,a.y,b.x,b.y)
line(b.x,b.y,c.x,c.y)
line(c.x,c.y,d.x,d.y)
fill(160, 172, 22, 255)
noStroke()
ellipse(a.x,a.y,20)
ellipse(b.x,b.y,20)
ellipse(c.x,c.y,20)
ellipse(d.x,d.y,20)
m:draw()
end
function touched(touch)
if touch.state == BEGAN then
for k,v in ipairs({a,b,c,d}) do
if v:distSqr(vec2(touch.x,touch.y)) < 900 then
pt = v
end
end
elseif pt then
pt.x = touch.x
pt.y = touch.y
m.shader.a = a
m.shader.b = b
m.shader.c = c
m.shader.d = d
end
end
Vertex Shader
//
// A basic vertex shader
//
//This is the current model * view * projection matrix
// Codea sets it automatically
uniform mat4 modelViewProjection;
//This is the current mesh vertex position, color and tex coord
// Set automatically
attribute vec4 position;
attribute vec4 color;
attribute vec2 texCoord;
//This is an output variable that will be passed to the fragment shader
varying lowp vec4 vColor;
varying highp vec2 vTexCoord;
uniform vec2 a;
uniform vec2 b;
uniform vec2 c;
uniform vec2 d;
uniform float time;
void main()
{
highp float t = position.y/time;
highp float tt = 1.0 - t;
highp vec2 bpos = tt*tt*tt*a + 3.0*tt*tt*t*b
+ 3.0*tt*t*t*c + t*t*t*d;
highp vec2 bdir = tt*tt*(b-a) + 2.0*tt*t*(c-b) + t*t*(d-c);
bdir = vec2(bdir.y,-bdir.x);
bdir = position.x*bdir/length(bdir);
bpos = bpos + bdir;
highp vec4 bzpos = vec4(bpos.x,bpos.y,0,1);
//Pass the mesh color to the fragment shader
vColor = color;
vTexCoord = vec2(texCoord.x, 1.0 - texCoord.y);
//Multiply the vertex position by our combined transform
gl_Position = modelViewProjection * bzpos;
}
Fragment shader
//
// A basic fragment shader
//
//This represents the current texture on the mesh
uniform lowp sampler2D texture;
//The interpolated vertex color for this fragment
varying lowp vec4 vColor;
//The interpolated texture coordinate for this fragment
varying highp vec2 vTexCoord;
void main()
{
//Sample the texture at the interpolated coordinate
lowp vec4 col = vColor;
if (vTexCoord.x < .2)
col.a = col.a*vTexCoord.x/.2;
if (vTexCoord.x > .8)
col.a = col.a*(1.-vTexCoord.x)/.2;
//Set the output color to the texture color
gl_FragColor = col;
}
What I need now is a list of available functions, a bit of guidence on syntax (what language is this?) and an explanation of what lowp and highp mean.
In other news: