16-bit texture lost a lot of values when used in shader

Unity Engine
1

Hi guys. I’m trying trying to render earth from a 16-bit heightmap, but for some reason I lost a lot of detail.
In these screenshots the red pixels all get the same value from the texture, even though the texture is very detailed.
This is a big problem since I need to clearly distinguish land from sea.

8232732--1075956--Unity_Th2ELn5x6B.jpg
8232732--1075956--Unity_Th2ELn5x6B.jpg2560×1307 629 KB
8232732--1075959--Unity_f4Nbs7LWvO.jpg
8232732--1075959--Unity_f4Nbs7LWvO.jpg2560×1307 465 KB

I suspect image import settings might be the problem, but I’ve tried all values and I never get the correct result.

8232732--1075962--Unity_p8ASkY8Sdv.png
8232732--1075962--Unity_p8ASkY8Sdv.png605×1307 150 KB

My shader code:

void vert(inout appdata_full v, out Input o)
{
    v.vertex.xyz = normalize(v.vertex.xyz);
    o.position = v.vertex.xyz;
}

void surf(Input IN, inout SurfaceOutputStandard o)
{
    float2 uv = sphere2map(normalize(IN.position));
    float h = tex2D(_Heightmap, uv);
    static float waterLevel = 0.57254907;
    o.Albedo = h == waterLevel ?
        float3(1, 0, 0) : // red at water level
        h > waterLevel ?
            float3(0, (h - waterLevel) / (1 - waterLevel), 0) : // green above
            float3(0, 0, h / waterLevel); // blue below
}

Any tips would be really appreciated!

2

Hi, have you tried ticking “Ignore PNG file gamma”?

If not working, can you try disabling “Generate Mip Maps”?

Or try both of them.

3

Thanks for the tip, but I’m afraid it didn’t help.

“Ignore PNG file gamma” doesn’t change anything, probably because this is a tif file.

Disabling “Generate Mip Maps” still leaves me with the same red areas. Since I’d primarily display earth up close, I don’t actually use mip maps anyway, so I can leave them disabled.

1 Like
4

AFAIK Unity doesn’t support 16 bit tiff files in the base image importer. You must use jpg png, exr, or hdr file formats for importing > 8 bit data formats. A 16 bit tiff gets quantized to 8 bit on import regardless of the target image format you use.

edit: png, not jpg. jpg doesn’t support 16 bit at all.

1 Like