instead of storing two counters for point and spot lights, we now
only have a single counter for both, and the light data structure
has a type, the shader can use to decide what to do -- instead of
using two loops. In practice spot and point light code is very similar
anyways.
This simplify a lot the CPU side (as in make it less complex) and frees
up 8-bits in the per-froxel GPU data structure.
- contact shadows are now supported for point and spot lights
- and are now independent from regular shadows, that is they can
be enabled without enabling regular shadows
The only limitation currently is that the distance and step count for
ALL contact shadow are taken from the directional light options.
The user can now choose amongst 3 specular AO methods:
- None, specAO is off
- Simple, specAO is inferred from roughness and diffuse AO
- Bent normals, specAO is computed accurately from cone intersections
The last method is more expensive but produces the best results.
This change also fixes a few issues:
- Rename materialRefraction() and materialRefractionType() for
consistency
- Fixes user time in shaders
* Add support for bent normals
Bent normals can be enabled via the bentNormal property of a material.
When specular occlusion is enabled, bent normals improve the quality
of the computation.
* Save a couple of multiplications in bent specular AO
* Add support for screen-space contact shadows
This CL adds support and always enables it.
toggles and setting in the next CL (same PR).
* Plumb settings for screen-space contact shadows
screen-space contact shadows is handled like a shadow option,
parameters (including on/off) are set in the LightManager, using
the existing ShadowOptions API.
Additionally there is a per-renderable toggle.
Both toggles are off by default.
* Allow contact shadows when shadowing is auto-disabled
Shadowing can be auto-disabled when for instance there are no
shadow casters in the scene. We still allow contact shadows in
that case.
This would allow for instance, to make the vegetation on a terrain
not shadow-casting, and still get some shadowing there by using
contact shadows instead.
* apply micro-shadowing after contact shadows
also, don't compute contact shadows when we know we're fully shadowed.
We now use a fixed-size kernel (right now 17), for each mip-level.
And we workout the mapping from roughness to such mip.
This improves performance by reducing significantly the number of taps
per mip, however, we don't control how much blur is actually applied
at each level. This gives a mip-chain that is proportional to
'roughness'.
It's now easier to tune quality vs. speed by tweaking the kernel's width
as well as how we map 'sigma' to a the kernel width.
With this PR screen-space refraction is functional.
Caveats:
The blur passes for supporting rough refractive materials is quite
heavy and increases with the resolution.
SSR uses a gaussian approximation for the brdf and therefore doesn’t
match perfectly cubemap-based refraction and IBL.
The use of MSAA with screen-space effects, while working, is going
to incur a large cost, especially on tilers.
When dealing with thin objects we really have two thicknesses to
consider, the thickness in the direction of the normal, which
corresponds to the value used for solid objects, and the thickness of
the object's walls, which generally is a constant.
Reusing thickness in the later case is problematic for assets that have
a thickness map, but are rendered hollow.
In the future we can even imagine handling double-sided hollow objects
by using the thickness information -- e.g. a hollow cube.
Normally the IOR is deduced from the reflectance, but now we allow to
specify the IOR instead or in addition to the reflectance.
In the later case, it's possible to create physically impossible
materials, but this can be useful for artistic reasons.
This works by aliasing CUSTOM0 - CUSTOM7 to morphing attributes, and by
extending our existing skinning variant.
This PR was tested against some upcoming changes to gltfio.
Issue #1149, #1417
This combines two constants into one, and changes it into a value that
is actually correct. :)
Technically the movement of the CUSTOM attributes will change the layout
qualifier and therefore merits a materials version bump, however custom
attributes were only recently introduced so this seems unnecessary.
Did some quick testing with 3 samples: gltf_viewer, lucy_bloom, and
point_sprites.
This is a prep step for the upcoming morph feature and does not require
a bump to our material version number.
Stay tuned for a new sample app that demonstrates this feature.
⚠️ breaks materials
There used to be a constraint that ibl cubemap needed to be
256x256. This constraint is now relaxed. IBL cubemaps can be any size.
We also add 16 float4 of padding to the frameUniform, which brings
its size to 1 KiB, the idea is to prevent more breakages in the
future.
* Add screen and multiply blending modes
This change also fixes a sorting issue: different sorting modes
were sorted in different buckets which is incorrect. We want
to sort only by distance.
* Update release notes and Java API
* Fix build error
This replaces the previous "curvature to roughness" method. Both are related
and rely on the screen space variance of geometric normals but this new
solution offers more control (the screen space variance and the clamping
threshold can be controlled).
* Add new shading model to Filament for specularGlossiness.
This adds a shading model based on KHR_materials_pbrSpecularGlossiness.
The corollary gltfio change will be in an upcoming PR.
* Improve documentation for specular-glossiness
