Alpha blending edges of domain

  • Hi all,

    I am playing with Geoconverter, trying to convert a set of Open Data orthophotos of a small island. I try to use an alpha channel in my source geotiff so that the island blends smoothly with the low res default textures. Geoconvert runs fine but I get the following in-sim result, with bands rather than a transparency scale. Is that a known issue or limitation, or am I doing something wrong?



    Thanks,

    Sam

  • Alpha is available and it works fine. You need to edit your images in a photo application such as Gimp or Photoshop.

    Please follow the tutorial for this HERE

    IPACS Development Team Member

    I'm just a cook, I don't own the restaurant.
    On behalf of Torsten, Marc, and the rest of the IPACS team, we would all like to thank you for your continued support.


    Regards,


    Jeff

  • Alpha is available and it works fine. You need to edit your images in a photo application such as Gimp or Photoshop.

    Please follow the tutorial for this HERE

    SamSam said " I try to use an alpha channel in my source geotiff so that the island blends smoothly "


    Alpha support is either transparent or non transparent but not in between which I assumed SamSam was after for a smooth blend.

  • There are techniques to use to blend through alpha. I will work on a tutorial on how to accomplish this soon. Alpha blending also DOES work.

    IPACS Development Team Member

    I'm just a cook, I don't own the restaurant.
    On behalf of Torsten, Marc, and the rest of the IPACS team, we would all like to thank you for your continued support.


    Regards,


    Jeff

  • Thank you guys for your feedback on this question. Attached is an overview of my image, the tif file is and RGBA (32 bits) image and the alpha channel shade from 100% to 50% on the limit of the domain (for some reason GDAL did not use the full range of alpha). The bands that I get let me think that the alpha channel is not interpreted as I think it would.


    Jeff, thank you for writing a tutorial! Glad to hear that alpha blending also works.

  • Well I ended up giving it a try without success. Here is my recipe for binary dithering of the alpha channel with Gimp:

    1. Import your source image/tile that need to blend with the low res textures.
    2. Add a layer mask with the option 'transfer layer's alpha channel'
    3. Copy and paste it as a new image,
    4. Change mode to indexed colors, B&W color (1 bit) with Floyd-Steinberg dithering
    5. Copy it and paste it back on the original layermask
    6. Anchor the selection
    7. Apply the layer mask

    What are the values of the alpha channel pixels that are transparent?


    On a side note, my 10 years old computer Intel Q6400 and GTX 460 runs pretty smooth while I usually get a slideshow (and got tired of it) with any of the Microsoft ESP based products. Awesome.