OBJLoader - Draw to Offscreen Buffer

sgregson

OBJLoader - Draw to Offscreen Buffer

in Contributed Library Questions • 2 years ago

Is it possible to draw an .OBJ model to an offscreen buffer?

I'd like to be able to pick distinct .OBJ models in 3D using a color buffer, as in the example http://wiki.processing.org/w/Picking_with_a_color_buffer , but with imported .OBJ geometry instead of boxes.

Replies(5)

PhiLho

Re: OBJLoader - Draw to Offscreen Buffer

2 years ago

As long as you don't use an OpenGL renderer, you can do in a PGraphics anything you do in a sketch. Unless you use a library not designed for that...

sgregson

Re: OBJLoader - Draw to Offscreen Buffer

2 years ago

The buffer is rendered using P3D while the visible display is in OPENGL (as in the picking example I quoted in the first post).

I think the issue is more that the library isn't designed for it, since it creates the object model by sending a PApplet reference, not a PGraphics object (as in code below). But I have no idea - I wouldn't know where to start looking in the library's files.

model = new OBJModel(this); //targets PApplet, not a PGraphics object

Thanks!

PhiLho

Re: OBJLoader - Draw to Offscreen Buffer

2 years ago

Which library? You haven't mentioned one in the first post.
The picking library mentioned in the wiki page is quite simple: it takes everything drawn on the PApplet and draws it flat, with a color set by the id you associate with the object to be drawn. Thus when you look at a given place on the sketch area, it looks at the color and deduces the id.

sgregson

Re: OBJLoader - Draw to Offscreen Buffer

2 years ago

I'm sorry, it's the objloader library. http://code.google.com/p/saitoobjloader/

The 3D scene contains hovering icons and (.obj) geometry. I used the picker method to make the icons "selectable", but I don't know how I can make the 3D masses in the same or similar manner.

PhiLho

Re: OBJLoader - Draw to Offscreen Buffer

2 years ago

Ah, OK, I didn't see it was mentioned in the subject (I use to skim through these, supposing the info they hold is given in the message itself...).

Anyway, a quick look at this library shows it expects an OpenGL PGraphics to do the drawing job, but alas these cannot be off-screen (with stock Processing at least). I suppose a rewrite of the library is needed to support your needs, or perhaps OpenGL offers picking facilities.

Top Reply