The attribute node already allows accessing attributes associated
with objects and meshes, which allows changing the behavior of the
same material between different objects or instances. The same idea
can be extended to an even more global level of layers and scenes.
Currently view layers provide an option to replace all materials
with a different one. However, since the same material will be applied
to all objects in the layer, varying the behavior between layers while
preserving distinct materials requires duplicating objects.
Providing access to properties of layers and scenes via the attribute
node enables making materials with built-in switches or settings that
can be controlled globally at the view layer level. This is probably
most useful for complex NPR shading and compositing. Like with objects,
the node can also access built-in scene properties, like render resolution
or FOV of the active camera. Lookup is also attempted in World, similar
to how the Object mode checks the Mesh datablock.
In Cycles this mode is implemented by replacing the attribute node with
the attribute value during sync, allowing constant folding to take the
values into account. This means however that materials that use this
feature have to be re-synced upon any changes to scene, world or camera.
The Eevee version uses a new uniform buffer containing a sorted array
mapping name hashes to values, with binary search lookup. The array
is limited to 512 entries, which is effectively limitless even
considering it is shared by all materials in the scene; it is also
just 16KB of memory so no point trying to optimize further.
The buffer has to be rebuilt when new attributes are detected in a
material, so the draw engine keeps a table of recently seen attribute
names to minimize the chance of extra rebuilds mid-draw.
Differential Revision: https://developer.blender.org/D15941
This replaces the direct shader uniform layout declaration by a linear
search through a global buffer.
Each instance has an attribute offset inside the global buffer and an
attribute count.
This removes any padding and tighly pack all uniform attributes inside
a single buffer.
This would also remove the limit of 8 attribute but it is kept because of
compatibility with the old system that is still used by the old draw
manager.
Workaround the issue by adding an intermediate function. This is usually
the case when working with attributes.
Reviewed By: jbakker
Differential Revision: https://developer.blender.org/D15860
This is to make the codegen and shading nodes object type agnostic. This
is essential for flexibility of the engine to use the nodetree as it see
fits.
The essential volume attributes struct properties are moved to the
`GPUMaterialAttribute` which see its final input name set on creation.
The binding process is centralized into `draw_volume.cc` to avoid
duplicating the code between multiple engines. It mimics the hair attributes
process.
Volume object grid transforms and other per object uniforms are packed into
one UBO per object. The grid transform is now based on object which simplify
the matrix preparations.
This also gets rid of the double transforms and use object info orco factors
for volume objects.
Tagging @brecht because he did the initial implementation of Volume Grids.
Add a new Alpha socket to the Attribute node that outputs the
fourth component of the attribute. Currently the only such
attribute is vertex color, but there may be more in the future.
If the attribute has no alpha channel, the expected value is 1.
The Cycles code is already refactored and committed by Brecht.
Ref D2057
This patch continue the efforts to split the `gpu_shader_material` file
started in D5569.
Dependency resolution is now recursive. Each shading node gets its own
file. Additionally, some utility files are added to be shared between
files, like `math_util`, `color_util`, and `hash`. Some files are always
included because they may be used in the execution function, like
`world_normals`.
Some glsl functions appeared to be unused, so they were removed, like
`output_node`, `bits_to_01`, and `exp_blender`. Other functions have
been renamed to be more general and get used as utils, like `texco_norm`
which became `vector_normalize`.
A lot of the opengl tests fails, but those same tests also fail in
master, so this is probably unrelated to this patch.
Reviewers: brecht
Differential Revision: https://developer.blender.org/D5616
