Blender Git Loki

Cycles: Cleanup, style and unused arguments

- Some arguments were inapproriatry tagged as unused
using (void)foo semantic.

Only use such semantic in tricky casses, when something
needs to be ignored in release builds or something is
dependent on tricky ifndef policy.

For rest of the cases just use void foo(int /bar*/)
semantic, which ensures variable is not used. Solves
confusion and code running out of sync with later
development.

- Used proper unused semantic to some arguments.

- Added braces to make code easier to follow, tricky
indentation with ifdef, uh.

Merge branch 'blender2.8' into greasepencil-object

Cleanup: Change some xray strings and parameter names

Cleanup: Remove unused code

THis code has been ported to new shaders

Merge branch 'master' into blender2.8

CMake: Use GCC7's -Wimplicit-fallthrough=5

Use to avoid accidental missing break statements,
use ATTR_FALLTHROUGH to suppress.

Cycles Denoising: Prevent overfitting when using a very low radius

For example, when using a radius of 1, only 9 pixels (due to weighting maybe
even less) will be used, but the transform code may still decide to use a
5-dimensional (or even higher) fit.
This causes severe overfitting and therefore weird pixel values.

To avoid this, this commit limits the amount of dimensions to a third of the
pixel number. For a radius of 3 or more, this doesn't change anything, but
for 1 and 2 it can prevent fireflies and/or negative values being produced.

Fix T51560: Black pixels on a denoising render

Once again, numerical instabilities causing the Cholesky decomposition to fail.

However, further increasing the diagonal correction just because of a few
pixels in very specific scenes and settings seems unjustified.
Therefore, this commit simply falls back to the basic NLM-filtered pixel
if the more advanced model fails.

Cycles: Reload kernels from Session when requested features change

This fixes T49496.

Clay/Eevee: fix more crash when entering edit mode

Shader stages need to agree about interpolation qualifiers. Apparently implicit smooth (the default) and explicit smooth are considered different by some GLSL compilers. Found by @letterrip on Linux + Intel.

Follow-up to 941e739d703542af1637c6a37953adac5f6b36bb

Implement Xray mode for strokes

Now support 3 modes: Front, 3D space and Back.

Still some problems with zfighting with layers that need to be fixed

OpenGL: cleanup material shader GLSL

prefer vector math over scalar
prefer * over /
shorten vec3(x, x, x) to vec3(x)
use clamp, max, etc. instead of custom logic
declare loop vars as part of for loop
spacing

OpenGL: cleanup edit overlay shaders

Mostly simple fixes to spacing & comments.

Clay/Eevee: fix crash when entering edit mode

vertexColor output was not being written --> shader failed to link --> assert hit while setting that shader's uniforms.

Vertex attribs are smooth by default, so I shortened the declaration.

@fclem or @dfelinto: is color = 0 ok here?

Fix T51524: Instantiated Hair Object which has dupligroup children and hidden orig objects of group crash at render.

Note that this is speculative fix, actually precisely understanding what
happens in this code is... not easy.

Move particle drawing to object mode

OpenGL: remove BIT_OPERATIONS check from GLSL

Since the upgrade we can use bitwise operations without checking. No more lame fallbacks!

Fix issue with alpha layering for AA dot drawing

Implement particle drawing with draw manager

This still has a couple of issues:
* Instancing is not working when multiple particle systems use the same
primitive. Only the last particle system to be drawn with a particular
primitive shows up.

* Because of colors being passed as uniforms with static variables, the
color of the collection of the last object to be evauluated is used for
all particles being displayed.

Also, note that while this is being drawn in the clay engine, this might
be moved to the object mode later intead.

Part of T51378

Change particle draw_size default and limits

Particle draw size can now no longer be less than 1px, and the default
value has been changed to 4.