Cannot get rid of texture wrapping seam in OpenGL -

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take @ following image - see clouds in background have annoying seam:

http://simoneschbach.com/seam.png

this seam occurring when wrap around occurs, supplying texture coordinates programmatically following code:

gbackgroundpos += 0.0003f;  // gbackgroundpos climbs indefinitely... glfloat bgcoords[] = {  gbackgroundpos, 1.0,              gbackgroundpos + 0.5f,  1.0,              gbackgroundpos, 0.0,              gbackgroundpos + 0.5f,  0.0  };

i have enabled texture wrapping during texture init follows:

gltexparameteri(gl_texture_2d, gl_texture_wrap_s, gl_repeat); gltexparameteri(gl_texture_2d, gl_texture_wrap_t, gl_repeat);

does know can here rid of visible seam?

the problem have solved technique, extremely simple implement:

http://vcg.isti.cnr.it/~tarini/no-seams/

there open-source demo @ link, exposes used fragment shader.

the trick easy adopt without complete understanding of why works, explained in journal of graphic tools article: "cylindrical , toroidal parameterizations without vertex seams" can found, example, @ http://vcg.isti.cnr.it/publications/2012/tar12/.

unfortunately, other solutions listed here won't work:

  • gl_repeat (as gl_texture_wrap), alone, not need. problem, noted, triangle connecting point s = 0.9 , s = 0.1 interpolates way across cylinder, not forward across seam.

  • replicating vertices on "cut" (the texture seam) work on static geometries, texture coordinates sent attributes (but, then, drawbacks many: introduces replication, , seams breaking geometry: 2 sides of texture cut topologically disconnected). in case specific case, texture coordinates produced procedurally that's not option.


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