This commit contains all the remained parts needed for initial integration of
OpenSubdiv into Blender's subdivision surface code. Includes both GPU and CPU
backends which works in the following way:
- When SubSurf modifier is the last in the modifiers stack then GPU pipeline
of OpenSubdiv is used, making viewport performance as fast as possible.
This also requires graphscard with GLSL 1.5 support. If this requirement is
not met, then no GPU pipeline is used at all.
- If SubSurf is not a last modifier or if DerivesMesh is being evaluated for
rendering then CPU limit evaluation API from OpenSubdiv is used. This only
replaces the legacy evaluation code from CCGSubSurf_legacy, but keeps CCG
structures exactly the same as they used to be for ages now.
This integration is fully covered with ifdef and not enabled by default
because there are several TODOs to be solved first:
- Face varying data interpolation is not really cleanly implemented for GPU
in OpenSubdiv 3.0. It is also not implemented for limit evaluation API.
This basically means we'll have really hard time supporting UVs.
- Limit evaluation only works with adaptivly subdivided meshes so far, which
basically means all the points of CCG are pushed to the limit. This gives
different result from old code.
- There are some serious optimizations possible on the topology refiner
creation, which would speed up initial OpenSubdiv mesh creation.
- There are some hardcoded asumptions in the GPU and DerivedMesh areas which
could be generalized.
That's something where Antony and Campbell can help, making it so the code
is structured in a way which is reusable by all planned viewport projects.
- There are also some workarounds in the dependency graph to make sure OpenGL
buffers are only freed from the main thread.
Those who'll be wanting to make experiments with this code should grab dev
branch (NOT master) from
https://github.com/Nazg-Gul/OpenSubdiv/tree/dev
There are some patches applied in there which we're working on on getting
into upstream.
Quite a few things wrong here:
* Mac did not support EXT_draw_instanced, only ARB_draw_instanced
* Draw instanced did not work unless data came from vertex buffer, which
is second time we see weird things with vertex arrays in mac
* There were a few stupid mistakes by me as well, such as binding to
uniform locations for the wrong shaders (it's a wonder it ever worked
:p)
A new checkbox "High quality" is provided in camera settings to enable
this. This creates a depth of field that is much closer to the rendered
result and even supports aperture blades in the effect, but it's more
expensive too. There are optimizations to do here since the technique is
very fill rate heavy.
People, be careful, this -can- lock up your screen if depth of field
blurring is too extreme.
Technical details:
This uses geometry shaders + instancing and is an adaptation of
techniques gathered from
http://bartwronski.com/2014/04/07/bokeh-depth-of-field-going-insane-http://advances.realtimerendering.com/s2011/SousaSchulzKazyan%20-
%20in%20Real-Time%20Rendering%20Course).ppt
TODOs:
* Support dithering to minimize banding.
* Optimize fill rate in geometry shader.
* Rename functions and move to own header.
* Add wrapper functions for glLight.
* Auto detect if we can use faster code for solid lighting.
* Various fixes for textured draw mode.
