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img2sky - img2sky is a vertex-color mesh builder tool for skyboxes, as seen in HomeWorld 2 .HOD files.
- img2sky reads texture files and outputs portable vertex-color plane/sphere meshes, that can be later reexported/transformed/quantized/binarized as desired.
- img2sky creates meshes that are more vertex dense on bright areas and less dense in obscure areas, according to human eye perception.
- That said, resulting vertex-color meshes are good as a background of your skybox. Once rendered, you are supposed to top it with shiny billboards, submeshes, stars, galaxies, nebulas, suns, clouds, zeppelins and flying cows.
Download
v0.0.3 (win32 pre-built binary)
Usage and options
~/prj/img2sky> img2sky
img2sky.exe: img2sky 0.0.3 (RELEASE). Compiled on May 28 2015 - https://github.com/r-lyeh/img2sky
Usage:
img2sky [options] input.img [...]
-q,--quality float Quality for vertex density [0..100] (lowest..highest) (default: 50.00)
-v,--vertices integer Specify maximum number of vertices [4..N] (default: disabled)
-p,--plane Create plane mesh of given (default geometry)
-s,--sphere float Create sphere mesh of given float radius (default: 10.00)
-h,--hemisphere float Create hemisphere mesh of given float radius (default: 10.00)
-c,--curve float Create a curved plane, displacement along z can be specified next (default: 10.00)
-f,--fast Disable triangle stripification (default: slow)
img2sky reads .bmp, .dds, .gif, .hdr, .jpg, .pic, .pkm, .png, .psd, .pvr, .svg, .tga, .webp, .pnm, .pug texture files.
img2sky writes .ply mesh files.
Quality and number of vertices should be mutually exclusive options. You can specify both at same time, but does not make much sense at all.
And if you are the expensive/smooth meshes guy kind, then use larger textures, increase quality and/or number of vertices.
~/prj/img2sky> img2sky --quality 12.5 images/*.webp --curve 30.0
[ OK ] image.webp -> image.webp.curve.ply (error-threshold: 4.15888) (curve-displacement: 30) (max-error: 4.13793) (vertices: 1656) (tris: 3292) (102 KiB)
Sample showcase
input preview |
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![]() 512x256 texture 4 KiB .webp (q=90) |
Redistribution
echo windows && cl src\*.c* /Feimg2sky.exe /Ox /Oy /DNDEBUG /MT /EHsc /link setargv.obj
echo others && gcc -o img2sky src/*.c* -O2
Details
- Input texture is read, processed and mapped.
- Vertices are greedy grouped, then projected to a plane (or to a sphere).
- Mesh is written to disk as .PLY mesh format (vertex-color friendly format).
- Additional tech information can be found on following links:
Changelog
- v0.0.3 (2015/05/28)
- Options for plane and custom curved planes and hemispheres (@perfectforwarding)
- Bugfixed vertically flipped geometries
- v0.0.2 (2015/03/27)
- Customizable radius sphere
- v0.0.1 (2015/03/26)
- Initial revision
Licenses
- Original hw2bgbuilder code v1.3 by 4E534B, Michael Garland and evillejedi, unknown license.
- tri_stripper.h/.cpp by Tanguy Fautré, ZLIB/libPNG licensed.
- Additional code by r-lyeh, Public Domain.
Credits
- Sample images taken from Walter Nest's hw2 deviantart library.