There were several issues involved into triangle ribbons hair:
- Even for the viewport rendering the blender scene camera was
used for orientation. This made hair triangles oriented to
the scene camera, not to the viewport camera.
- Triangle orientation was actually supposing the camera is
perspective. Triangles weren't oriented properly for the
orthographic camera resulting in different hair width across
it's length.
This issues are solved now, but there are some related TODOs:
- Rotating viewport doesn't re-orient the triangles, so after
viewport navigation hair might not look correct. However,
with this fix toggling viewport render (to force hair sync)
makes viewport render correct.
This isn't so much trivial fix, would require making BVH
aware of the dynamic triangle orientation, so they get
properly oriented without full hair re-sync.
- Panorama camera behavior didn't change but looks like it
should, however not really sure atm what's the right thing
to do here.
* Added support for uchar4 attributes to Cycles' attribute system.
* This is used for Vertex Colors now, which saves some memory (4 unsigned characters, instead of 4 floats).
* GPU Texture Limit on sm_20 and sm_21 decreased from 95 to 94, because we need a new texture for the uchar4 attributes. This is no problem for sm_30 or newer.
Part of my GSoC 2014.
This now supports multiple steps and subframe sampling of motion.
There is one difference for object and camera transform motion blur. It still
only supports two steps there, but the transforms are now sampled at subframe
times instead of the previous and next frame and then interpolated/extrapolated.
This will give different render results in some cases but it's more accurate.
Part of the code is from the summer of code project by Gavin Howard, but it has
been significantly rewritten and extended.
* UI: Remove deprecated condition (CURVE_RIBBONS) and hide backface property, when it's hardcoded in C (Curve/Line segments && Ribbons).
* Remove "use_tangent_normal" and "CURVE_KN_TANGENTGNORMAL" as its unused (follow up for last commit).
* Remove dead code from line segments BVH refine.
CURVE_KN_TANGENTGNORMAL and CURVE_KN_TRUETANGENTGNORMAL are either both true, or both false. Therefore a true/false condition is impossible.
This was a leftover of CURVE_CUSTOM, which was removed in r59234.
* Use "else if" in blender_curves.cpp.
- add missing headers from cmake (own omission)
- quiet rna_test.c unused define warnings.
- minor style edits
- spelling corrections and ignore all uppercase words with spell checking script.
- Removed the cycles subdivision and interpolation of hairkeys.
- Removed the parent settings.
- Removed all of the advanced settings and presets.
- This simplifies the UI to a few settings for the primitive type and a shape mode.
* Revert r57203 (len() renaming)
There seems to be a problem with nVidia OpenCL after this and I haven't figured out the real cause yet.
Better to selectively enable native length() later, after figuring out what's wrong.
This fixes [#35612].
* Rename some math functions:
len -> length
len_squared -> length_squared
normalize_len -> normalize_length
* This way OpenCL uses its inbuilt length() function, rather than our own. The other two functions have been renamed for consistency.
* Tested CPU, CUDA and OpenCL compile, should be no functional changes.
Code is added to restrict the pixel size of strands in cycles. It works best with ribbon primitives and a preset for these is included. It uses distance dependent expansion of the strands and then stochastic strand removal to give a fading. To prevent a slowdown for triangle mesh objects in the BVH an extra visibility flag has been added. It is also only applied for camera rays.
The strand width settings are also changed, so that the particle size is not included in the width calculation. Instead there is a separate particle system parameter for width scaling.
When using triangle primitives this fix enables 'closed tip'.
UVs and vertex colours are added when using triangle primitives for hair.
Two new preset modes have also been included to allow easy access to curves and triangle planes.
Addition of a RNA function to toggle between the hair settings and rebuild the cache. This enables the usage of the render step, child number and full display percentage with f12 rendering.
A scaling to the strand radius has also been added for the static bvh. This only matches up with dynamic for uniform scaling.
A very small fix is included for multiple uvs/vertex colours when using child particles.
Added export of multiple UV coordinates and vertex colour attributes.
A debugging option to export the strands without using the cache has also been removed.
The curve segment primitive has been added. This includes an intersection function and changes to the BVH.
A few small errors in the line segment intersection routine are also fixed.
should be no functional changes yet. UV, tangent and intercept are now stored
as attributes, with the intention to add more like multiple uv's, vertex
colors, generated coordinates and motion vectors later.
Things got a bit messy due to having both triangle and curve data in the same
mesh data structure, which also gives us two sets of attributes. This will get
cleaned up when we split the mesh class.
