[ pd-gem-Bugs-3281206 ] thin white primitive borders are shown despite texture - GEM-dev

16 Aug 2011


      Bugs item #3281206, was opened at 2011-04-08 21:07
Message generated for change (Comment added) made by nusmuk
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Category: rendering (e.g. display)
Group: any operating system
Status: Pending
Resolution: None
Priority: 7
Private: No
Submitted By: Matteo Sisti Sette (sistisette)
Assigned to: Nobody/Anonymous (nobody)
Summary: thin white primitive borders are shown despite texture
Initial Comment:
Sometimes, depending on their size and/or position, rectangles (and I guess other polygons too but I mainly work with rectangles) are shown with a thin white border even if they are textured with a pix that has no white pixel in the proximity of the border, e.g. a completely black image or an image whose pixels close to the border are all black or transparent.
This has been there for years, I've always seen this happen since I use gem, across many versions. This happens both with Linux and Windows, i don't know on Mac OS.
If a rectangle is moving or changing size, the borders appear and disappear. Most of the time they are absent, I mean the values of position and size that cause the borders to appear are just a small fraction of the total.
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Comment By: Cyrille Henry (nusmuk)
Date: 2011-08-16 19:25
Message:
hello,
yes, GL_CLAMP_TO_EDGE is better than GL_CLAMP.
The grep does not say a lot about the code. if you have a look in
pix_texture.cpp : 
  if (type)
    m_repeat = GL_REPEAT;
  else {
    if(GLEW_EXT_texture_edge_clamp)
      m_repeat = GL_CLAMP_TO_EDGE;
    else
      m_repeat = GL_CLAMP;
  }
when repeat mode = 0, then m_repeat is GL_CLAMP_TO_EDGE if possible, or
GL_CLAMP if not.
it's the same about pix_imageInPlace and pix_cubemap.
it's not the same for framebuffer, but there certainly is a good reason
for this.
c
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Comment By: Nobody/Anonymous (nobody)
Date: 2011-08-16 17:15
Message:
Guessing at the cause here, but I'm led to believe GL_CLAMP is mostly
wrong, and GL_CLAMP_TO_EDGE is to be preferred almost always...
http://www.opengl.org/wiki/Common_Mistakes#Texture_edge_color_problem
claude@zebimus:~/code/pd-gem$ grep -Rwn "GL_CLAMP" . | grep -v \.svn
./Gem/ChangeLog:4473:	  "GL_CLAMP" when doing rectangle-textures, as they
will ignore
./Gem/src/Pixes/pix_imageInPlace.cpp:216:      m_repeat = GL_CLAMP;
./Gem/src/Pixes/pix_cubemap.cpp:365:      m_repeat = GL_CLAMP;
./Gem/src/Pixes/pix_texture.cpp:118:        // NPOT: GL_CLAMP,
GL_CLAMP_TO_EDGE, GL_CLAMP_TO_BORDER
./Gem/src/Pixes/pix_texture.cpp:690:      m_repeat = GL_CLAMP;
./Gem/src/Gem/glew.h:698:#define GL_CLAMP 0x2900
./Gem/src/Controls/gemframebuffer.cpp:284:  glTexParameterf(m_texTarget,
GL_TEXTURE_WRAP_S, GL_CLAMP);
./Gem/src/Controls/gemframebuffer.cpp:285:  glTexParameterf(m_texTarget,
GL_TEXTURE_WRAP_T, GL_CLAMP);
./Gem/src/Utils/GLUtil_generated.h:86:        if (!strcmp(name,
"GL_CLAMP")) return GL_CLAMP;
./GemLibs/FTGL/test/FTTextureGlyph-Test.cpp:42:           
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
./GemLibs/FTGL/test/FTTextureGlyph-Test.cpp:43:           
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
./GemLibs/FTGL/test/FTTextureGlyph-Test.cpp:69:           
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
./GemLibs/FTGL/test/FTTextureGlyph-Test.cpp:70:           
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
./GemLibs/FTGL/src/FTGLTextureFont.cpp:128:    glTexParameteri(
GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
./GemLibs/FTGL/src/FTGLTextureFont.cpp:129:    glTexParameteri(
GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
./GemLibs/FTGL/include/FTGLTextureFont.h:85:         * GL_TEXTURE_WRAP_S =
GL_CLAMP
./GemLibs/FTGL/include/FTGLTextureFont.h:86:         * GL_TEXTURE_WRAP_T =
GL_CLAMP
Incidentally, could these better be ...i instead of ...f function calls?
claude@zebimus:~/code/pd-gem$ grep -Rn "glTexParameterf" . | grep -v
\.svn | grep -v GL_TEXTURE_PRIORITY | grep -v src/openGL | grep -v glew.h
| grep -v build/ | grep -v GEM
./Gem/src/Pixes/pix_imageInPlace.cpp:156:	  glTexParameterf(GL_TEXTURE_2D,
GL_TEXTURE_WRAP_S, m_repeat);
./Gem/src/Pixes/pix_imageInPlace.cpp:157:	  glTexParameterf(GL_TEXTURE_2D,
GL_TEXTURE_WRAP_T, m_repeat);
./Gem/src/Pixes/pix_cubemap.cpp:112:  glTexParameterf(m_textureType,
GL_TEXTURE_MIN_FILTER, m_textureQuality);
./Gem/src/Pixes/pix_cubemap.cpp:113:  glTexParameterf(m_textureType,
GL_TEXTURE_MAG_FILTER, m_textureQuality);
./Gem/src/Pixes/pix_cubemap.cpp:114:  glTexParameterf(m_textureType,
GL_TEXTURE_WRAP_S, m_repeat);
./Gem/src/Pixes/pix_cubemap.cpp:115:  glTexParameterf(m_textureType,
GL_TEXTURE_WRAP_T, m_repeat);
./Gem/src/Pixes/pix_cubemap.cpp:347:    glTexParameterf(m_textureType,
GL_TEXTURE_MAG_FILTER, m_textureQuality);
./Gem/src/Pixes/pix_cubemap.cpp:348:    glTexParameterf(m_textureType,
GL_TEXTURE_MIN_FILTER, m_textureQuality);
./Gem/src/Pixes/pix_cubemap.cpp:371:      glTexParameterf(m_textureType,
GL_TEXTURE_WRAP_S, m_repeat);
./Gem/src/Pixes/pix_cubemap.cpp:372:      glTexParameterf(m_textureType,
GL_TEXTURE_WRAP_T, m_repeat);
./Gem/src/Pixes/pix_snap2tex.cpp:90:  glTexParameterf(m_textureType,
GL_TEXTURE_WRAP_S, m_repeat);
./Gem/src/Pixes/pix_snap2tex.cpp:91:  glTexParameterf(m_textureType,
GL_TEXTURE_WRAP_T, m_repeat);
./Gem/src/Pixes/pix_snap2tex.cpp:365:      glTexParameterf(m_textureType,
GL_TEXTURE_WRAP_S, m_repeat);
./Gem/src/Pixes/pix_snap2tex.cpp:366:      glTexParameterf(m_textureType,
GL_TEXTURE_WRAP_T, m_repeat);
./Gem/src/Pixes/pix_texture.cpp:137:  glTexParameterf(m_textureType,
GL_TEXTURE_MIN_FILTER, m_textureQuality);
./Gem/src/Pixes/pix_texture.cpp:138:  glTexParameterf(m_textureType,
GL_TEXTURE_MAG_FILTER, m_textureQuality);
./Gem/src/Pixes/pix_texture.cpp:139:  glTexParameterf(m_textureType,
GL_TEXTURE_WRAP_S, m_repeat);
./Gem/src/Pixes/pix_texture.cpp:140:  glTexParameterf(m_textureType,
GL_TEXTURE_WRAP_T, m_repeat);
./Gem/src/Pixes/pix_texture.cpp:270:      glTexParameterf(m_textureType,
GL_TEXTURE_MAG_FILTER, m_textureQuality);
./Gem/src/Pixes/pix_texture.cpp:271:      glTexParameterf(m_textureType,
GL_TEXTURE_MIN_FILTER, m_textureQuality);
./Gem/src/Pixes/pix_texture.cpp:657:    glTexParameterf(m_textureType,
GL_TEXTURE_MAG_FILTER, m_textureQuality);
./Gem/src/Pixes/pix_texture.cpp:658:    glTexParameterf(m_textureType,
GL_TEXTURE_MIN_FILTER, m_textureQuality);
./Gem/src/Pixes/pix_texture.cpp:696:      glTexParameterf(m_textureType,
GL_TEXTURE_WRAP_S, m_repeat);
./Gem/src/Pixes/pix_texture.cpp:697:      glTexParameterf(m_textureType,
GL_TEXTURE_WRAP_T, m_repeat);
./Gem/src/Pixes/pix_movieOS.cpp:271:        glTexParameterf(GL_TEXTURE_2D,
GL_TEXTURE_WRAP_S, GL_REPEAT);
./Gem/src/Pixes/pix_movieOS.cpp:272:        glTexParameterf(GL_TEXTURE_2D,
GL_TEXTURE_WRAP_T, GL_REPEAT);
./Gem/src/Controls/gemframebuffer.cpp:284:  glTexParameterf(m_texTarget,
GL_TEXTURE_WRAP_S, GL_CLAMP);
./Gem/src/Controls/gemframebuffer.cpp:285:  glTexParameterf(m_texTarget,
GL_TEXTURE_WRAP_T, GL_CLAMP);
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Comment By: IOhannes m zmölnig (zmoelnig)
Date: 2011-08-16 16:33
Message:
it's hardware/driver specific as the openGL standard doesn't specify
exactly how it ought to be done (afair); i mainly follow cyrille's arguing
here.
the workaround is to e.g. set "repeat" mode and/or the "quality" mode of
texture.
you can apply a global defaul by adding lines for "texture.quality" and
"texture.repeat" to your gem.conf;
something like:
<gem.conf>
texture.quality 0
</gem.conf>
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Comment By: Matteo Sisti Sette (sistisette)
Date: 2011-08-16 16:27
Message:
Sorry it was me asking the last question (damn the fake  "remember me"
checkbox, I reported that but the admins like the way it is)
----------------------------------------------------------------------
Comment By: Nobody/Anonymous (nobody)
Date: 2011-08-16 16:24
Message:
What hardware/driver is this specific to? What's the workaround in
gem.conf?
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Comment By: IOhannes m zmölnig (zmoelnig)
Date: 2011-08-16 16:01
Message:
given that the problem is hardware/driver specific, there is a workaround
_and_ the workaround can be done globally using gem.conf (in >=0.93), i
think this can be closed.
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Comment By: Matteo Sisti Sette (sistisette)
Date: 2011-04-23 15:39
Message:
Does the hardware really interpolate textures the wrong way? Are we sure
Gem is asking the hardware the right thing? If "repeat" is the fix, i
suspect it may mask the issue (i.e. make it less evident in some but not
all situations) rather than fix it, but I haven't tried it actually.
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Comment By: Cyrille Henry (nusmuk)
Date: 2011-04-08 22:35
Message:
This is not a gem problem. it's the way the hardware interpolate a texture.
i don't remember the exact configuration, but changing the default value
of "quality" and/or "repeat" of pix_texture change can fix this problem.
since it's not gem fault, and gem offer a solution, i think this can be
closed.
----------------------------------------------------------------------
Comment By: Matteo Sisti Sette (sistisette)
Date: 2011-04-08 21:10
Message:
I hope it is ok to rise the priority. Though this is an old bug, it is a
real showstopper in a range of situations.
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https://sourceforge.net/tracker/?func=detail&atid=507079&aid=3281206...