Re: [PyOpenGL-Users] Drawing a bitmap at "native" resolution

[Ian M. <geo...@gm...>]

On Mon, May 2, 2011 at 3:18 PM, Christopher Barker <Chr...@no...>wrote:

> Hi folks,
>
> Anyone know of a performant way to draw a bitmap at its "native"
> resolution -- i.e. one pixel in the bitmap is one pixel on screen,
> regardless of zoom level, etc. I think I've heard this referred to as
> "billboard" view, but that may be a term specific to one visualization
> lib (VTK, maybe)?
>
> Anyway, the task at hand is using bitmaps fonts as textures to do simple
> text labels, lot of them, in a scientific visualization app.
>
> For each data point ( up to 100s of thousands ) we need a little text
> label. But we want the text to not change size as the user zooms in or out.
>
There's not a way to get around projecting the labels' locations on screen.
You'd have to use gluProject(...).  If you want to be fancy, you can use a
vertex shader to project to get each coordinate.

>From there, set up a 2D view.  Then, draw each label at the screen
coordinate of its projected location, using textured quads the same size as
your textures.

Ian