Realtime Compositor: Support full float compositing #113476

Omar Emara · 2023-10-10T08:10:38+02:00

Omar Emara commented

2023-10-10 08:10:38 +02:00

This patch adds support for full float compositing for the Realtime
Compositor. A new precision option was added to the experimental GPU
render compositor to change between half and full float compositing,
while the viewport compositor remains unchanged at half float for now.

The compositor context now need to implement the get_precision() method
to indicate its preferred precision. Intermediate results will be stored
using the context's precision, with a number of exceptions that can use
a different precision regardless of the context's precision. For
instance, summed area tables are always stored in full float results
even if the context specified half float. Conversely, jump flooding
tables are always stored in half integer results even if the context
specified full float. The former requires full float while the latter
has no use for it.

Since shaders are created for a specific precision, we need two variants
of each compositor shader to account for the context's possible
precision. However, to avoid doubling the shader info count and reduce
boilerplate code and development time, an automated mechanism was
employed. A single shader info of whatever precision needs to be added,
then, at runtime, the shader info can be adjusted to change the
precision of the outputs. That shader variant is then cached in the
static cache manager for future processing-free shader retrieval.
Therefore, the shader manager was removed in favor of a cached shader
container in the static cache manager.

A number of utilities were added to make the creation of results as well as
the retrieval of shader with the target precision easier. Further, a
number of precision-specific shaders were removed in favor of more
generic ones that utilizes the aforementioned shader retrieval
mechanism.

This patch adds support for full float compositing for the Realtime Compositor. A new precision option was added to the experimental GPU render compositor to change between half and full float compositing, while the viewport compositor remains unchanged at half float for now. The compositor context now need to implement the get_precision() method to indicate its preferred precision. Intermediate results will be stored using the context's precision, with a number of exceptions that can use a different precision regardless of the context's precision. For instance, summed area tables are always stored in full float results even if the context specified half float. Conversely, jump flooding tables are always stored in half integer results even if the context specified full float. The former requires full float while the latter has no use for it. Since shaders are created for a specific precision, we need two variants of each compositor shader to account for the context's possible precision. However, to avoid doubling the shader info count and reduce boilerplate code and development time, an automated mechanism was employed. A single shader info of whatever precision needs to be added, then, at runtime, the shader info can be adjusted to change the precision of the outputs. That shader variant is then cached in the static cache manager for future processing-free shader retrieval. Therefore, the shader manager was removed in favor of a cached shader container in the static cache manager. A number of utilities were added to make the creation of results as well as the retrieval of shader with the target precision easier. Further, a number of precision-specific shaders were removed in favor of more generic ones that utilizes the aforementioned shader retrieval mechanism.

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Realtime Compositor: Support full float compositing #113476