Projective Texturing

[jessepmason]

Hello everyone... sorry for another noob question but I am learning and loving babylon!

I am curious if babylon can project a texture onto multiple objects... similiar to how this is: http://playground.babylonjs.com/#1215MA

but I want to be able to project from a specific point in the scene.. not from the active camera but maybe another camera in the scene?

 

Thanks!

 

[GameMonetize]

Hey Jesse! No problem There is no dumb question in this forum!

 

So far if you need to project from a specific point in the scene you have to change the shader here:

https://github.com/BabylonJS/Babylon.js/blob/master/src/Shaders/default.fragment.fx#L204

[iiceman]

Maybe the mirrorTexture or the reflectionProbe thingies might help you, too?

 

mirrorTexture: http://doc.babylonjs.com/tutorials/01._Advanced_Texturing (under the heading "mirror" pretty much at the top )

reflectionProbe: http://doc.babylonjs.com/tutorials/How_to_use_Reflection_probes

 

And wouldn't it somehow be possible to use a dynamicTexture to display certain camera view? Somehow I think I saw something like this already, but I can't remember where... maybe I am confusing things here, so don't pin me down on that

[jessepmason]

Thanks guys! I will have a look at the references and let you know if i come up with somethin! 

 

@iceman -- no your right.. i have seen that somewhere too

[jessepmason]

Well... I got something.. it its no where near what i need

but atleast i got a shader that projects something from a different camera... haha... sigh

I think this is a little out of my league right now

 

http://www.vrmodify.com/projectionShader.html

[iiceman]

I am pretty sure that this can't be that hard... nobody else an idea? I think the reflectionProbes somehow sound like they do what you want... but I somehow don't think I really understand them :-/

[jessepmason]

yeah thats what I thought before i dug into it and got really confused

I thought the reflectionProbe might be what I was looking for too since you can set your position but I cant get it to do what i want

Ill continue to think about it

 

Thanks!

[jessepmason]

I think i am getting there

 

http://www.vrmodify.com/projectionShade2r.html

 

woo hoo

[iiceman]

Cool! With the custom shader..hmm.. I really thought it should be easier... but if it works for you... keep us uptated!

[jessepmason]

haha yeah, I wish it was more straight forward to do it...

I kind of found a three.js example and tried to mimic it but there are a few things i need to fix:

 

1) stop the image from changing position when you change the size of the browser at load time

2) there is a weird white ring behind the camera

 

is there a way I can share my scene in a babylon Playground with the custom shader?

[iiceman]

I think they talked about it here: http://www.html5gamedevs.com/topic/17660-shader-inside-a-variable/?hl=%2Bshader+%2Bvariable

 

Does that help? (I try to avoid shaders, so I didn't read, just remembered there was a thread about it)

[jessepmason]

thanks!

 

may I ask why you try and avoid shaders?.... should i be avoiding also?

[iiceman]

No no, of course not. Shaders are awesome as far as I know. I just never took the time to learn how to use them (yet). And I am kinda scared of them... looks like complicated jibber jabber to me. But you can do alot of great stuff with them, so if you already figured it all out, good for you! I'll catch up some time later... maybe

[jessepmason]

haha gotchya... yeah it still is to me too

[jessepmason]

Would any shader gurus be able to help me out here?

I am trying to get rid of the gigantic ring is this example:

 

http://www.babylonjs-playground.com/#26UUE1

 

my cameras projection  matrix is being plugged into my shader and whenever i do that I get this ring...sad face

Also the ring gets bigger the farther you dolly out with the render camera :S

 

I feel like its a simple fix and I am just missing something

 

thanks!

[GameMonetize]

Something like this?

http://www.babylonjs-playground.com/#26UUE1#1

[jessepmason]

unfortunately doesn't work for all scenarios :S

 

http://vrmodify.com/projectionShader3_test2.html

 

you can see by the time i am done clipping all the errors it starts clipping my projection :S

something weird is goin on

[jessepmason]

I feel like this might have something to do with it?

if i dont use an image with a black border around it the images edges get stretched

 

http://www.babylonjs-playground.com/#26UUE1#2

[GameMonetize]

actually you want to clamp the border and detect the corresponding .w

[jessepmason]

please forgive me aren't I doing that? :S

 

clamping:

mainTexture.wrapU  = BABYLON.Texture.CLAMP_ADDRESSMODE

 

.w:

if (texCoordProj.w > -2.){

[GameMonetize]

Clamping is done by keeping values between 0 to 1

 

but the test returns a black value which is different

[jessepmason]

okay thanks! I really appreciate your help!