Processing 1.0 - Processing Discourse - image texture rendering problems

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Index › Programming Questions & Help › OpenGL and 3D Libraries › image texture rendering problems

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image texture rendering problems (Read 1016 times)

kidult

image texture rendering problems
Feb 22^nd, 2006, 4:48am

To create the warped image I segmented the image into polygons and then reapplyed them as texture maps to the polygonsand rendered the image using the OpenGL graphics renderer. The problem is there are thin lines between the polygons although, when I use the P3D graphics renderer the lines disappear but the image is not comparable in smoothness.

http://newmedia.rit.edu/allclasses/ve_2005/students/bryanIjeoma/AVLS_DEMO/4.tiff

JohnG

Re: image texture rendering problems
Reply #1 - Feb 22^nd, 2006, 11:22am

If you've got smooth turned on in OpenGL mode, that'd explain the edges. The processing smooth() command only uses some "easy" GL smoothing coommands, which are quick, but don't necessarily make the result look it's best.

If you want, you could try setting the smoothing options manually. smooth() just does:

Code:

    gl.glEnable(GL.GL_POINT_SMOOTH);
    gl.glEnable(GL.GL_LINE_SMOOTH);
    gl.glEnable(GL.GL_POLYGON_SMOOTH);

To do these by hand you'll need to add:

Code:


.. other imports here ..
import net.java.games.jogl.*;

GL gl;

void setup()
{
  .. normal setup stuff ..
  gl=((PGraphicsGL)g).gl;
  gl.glEnable(GL.GL_POINT_SMOOTH);  //try all combinations...
//  gl.glEnable(GL.GL_LINE_SMOOTH);
  gl.glEnable(GL.GL_POLYGON_SMOOTH);
}

kidult

Re: image texture rendering problems
Reply #2 - Feb 22^nd, 2006, 4:22pm

Thanks JohnG, but I tried all the different OpenGL settings and the lines did not disappear. The lines are not intentional; noStroke() is specified before the beginShape() call. What other issues would possibly cause this bug if it at all it is a bug and not my code? The lines do not appear when I render the image with P3D. Is there a smoothing algorithm I can apply to achieve the smoothness I get when I use OpenGL?

P3D
http://newmedia.rit.edu/allclasses/ve_2005/students/bryanIjeoma/AVLS_DEMO/7.tiff

OPENGL (noSmooth() enabled)
http://newmedia.rit.edu/allclasses/ve_2005/students/bryanIjeoma/AVLS_DEMO/6.tiff

TomC

Re: image texture rendering problems
Reply #3 - Feb 22^nd, 2006, 6:12pm

It's worth checking the antialiasing settings on your graphics card are set to off, or application dependent.

I fixed this problem by doing noSmooth() before drawing textured polys, and then turning smooth() back on afterwards if I needed it.

My own pet theory for this problem is that it has something to do with using floats for coordinates internally (rather than doubles) but it's just a hunch and I haven't tested it.

{sketches,links,blogs,hacks}

Ricard

Re: image texture rendering problems
Reply #4 - Feb 22^nd, 2006, 6:56pm

I also have an own pet theory for this and it's that since Processing passes only triangles to OpenGL, if smoothing is set to ON, then OpenGL will smooth all the edges of the triangles, creating these artifacts.

I guess that if PGraphicsGL, passed more high level shapes to OpenGL, then it would probably deal better for when to do antialiasing and when not.

Well, I really don't know much about the internal machinery of all this, it's just a guess. I have the same problem and still wasn't able to solve it.

Anyway if it helps, try running that applet under GNU/Linux, it seems to do much better rendering, at least for me. Maybe the OpenGL drivers on GNU/Linux work better for these cases.

kidult Junior Member Offline Posts: 84	Re: image texture rendering problems Reply #5 - Feb 22^nd, 2006, 7:10pm I may be misunderstanding something but wether or not I have smooth() or noSmooth() enable the lines still appear so I dont think the issue is with the smoothing. Im not sure though. So excepting this issue w/ OpenGL how can I fix the smoothness in the P3D rendering?

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