The libimage API does not include the original image in the returned mip
array, which might make sense when generating individual files, but for
a KTX bundle, we want to include level 0.
I tested the validity of the resulting KTX files by using macOS Preview,
which can read some types of KTX files. (!)
This CL also adds mipgen to the WebGL build, although its outputs are
not yet used by the sample apps.
This remapping can be confused with roughness, because
linear_roughness = roughness*roughness and
lod = sqrt(linear_roughness)
so the value of lod is roughness, but conceptually
it’s not.
Sometimes the source image might have a useless 1-bit alpha channel
which our image-processing pipeline expands into a proper alpha channel.
This consumes memory and breaks an assertion in our encoder.
I ran into this while testing mipgen with the Suzanne textures.
f90=0, which is nonsensical.
We now assume f0=f90=1, meaning the fresnel term
always evaluates to 1.
Thankfully this didn’t impact the prefilter too much.
IBLs MUST BE REGENERATED
KtxBundle is basically an in-memory representation of a KTX file.
Our primary motivation for introducing this class is to have a
structured container for block-compressed textures.
Note that this class is defined in libimage rather than libimageio.
There are several reasons for this:
1. The texel data in a KtxBundle is not meant to be decoded by the CPU.
2. It has no dependendencies on any libraries (stb_image tinyexr etc).
3. We wish to use it with WebGL, which needs to avoid using imageio.
* better comments on calculating the DFG lookup tables
* add comments about computing the “LD” term
* add comments about computing IBL diffuse pre-integration
* be clearer about the determinant of the jacobian
This looks for VULKAN_SDK at build time, and if present it tells
Filament to use the `libvulkan.1.dylib` that's located there. Otherwise
it falls back to our old loading strategy, which uses a bundled version
of MoltenVK that allows us to avoid requiring installation of the
LunarG SDK.
I tried this out an it works for me...
Closes issue #238.
This will be useful for testing and can be
enabled at compile time by setting
IBL_INTEGRATION to IBL_INTEGRATION_IMPORTANCE_SAMPLING
in *both* indirectLight.cpp and light_indirect.fs
BUGS: clearcoat and subsurface won’t
work well when this is enabled since the prefiltered
cubemap is not available and, we don’t evaluate
those lobes with importance sampling (yet).
Additionally, anisotropy can’t work with our
prefiltered importance sampling, so it still uses
the emulation by bending the normal.
This adds a new demo that leverages ImGui. It looks very similar to the
existing material_sandbox demo we have for desktop, with a few
differences:
1. Does not use FilamentApp.
2. Does not draw a shadow plane.
3. Does not use a TrueType font in ImGui. (improves load time)
4. Does not allow the user to spin the model. (will fix soon)
We now have a triumvirate of web demos with a progression in complexity:
1. triangle
2. suzanne
3. sandbox
This is a sufficient set of WebGL samples for now, at least until we
finish creating a proper JavaScript API.
This CL factors out some of the common code with the native sandbox
demo, but keeps the UI definition separate since the web demo has some
minor differences (e.g., there is no shadow plane yet).
Note that using viewport units for height was wrong; it caused a bad
aspect ratio on Android while the URL bar was visible. This is explained
in an article:
https://developers.google.com/web/updates/2016/12/url-bar-resizing
