feat: Handle signed integer data types

[kylebarron]

What I am changing

How I did it

How you can test it

Related Issues

[mdsumner]

my digital friend tells me that for signed integer textures (like this one https://projects.pawsey.org.au/image-cogs/images/gebco_boxmerc_8192.tif) this also needs

create-texture.ts

Signed integer COGs sampler type switching—it's a non-trivial fix involving shader generation or variants.

The CreateTexture module hardcodes uniform sampler2D textureName; on line 16.

For PR #180 to work with signed integer textures, you need:

A variant module (or dynamic generation) that declares uniform isampler2D textureName; for signed integers
Logic to select the correct module based on the COG's SampleFormat and BitsPerSample
The fix could be either:

• Option A: Create separate modules (CreateTextureInt, CreateTextureUint)

• Option B: Make the sampler type a template/parameter that gets substituted at runtime

Will also need to check if luma.gl is uploading the texture with the correct WebGL internal format (R16I for Int16). If it's normalizing the data to float on upload, then sampler2D would still be correct—but the console errors suggest it's keeping the integer format.

[kylebarron]

This is not strictly true. Integer textures can use unorm samplers.

[mdsumner]

Ok, apologies for the noise (and I will pursue this more so I'm personally familiar with it).