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Age	Commit message (Collapse)	Author
2018-03-27	Fix T54420: too much volume render noise with multiple volume objects.	Brecht Van Lommel
	Random numbers for step offset were correlated, now use stratified samples which reduces noise as well for some types of volumes, mainly procedural ones where the step size is bigger than the volume features.
2018-03-10	Code refactor: use KernelShader and KernelParticle instead of float arrays.	Stefan Werner
	Original patch by Stefan with modifications by Brecht.
2018-02-23	Code refactor: improve attribute handling for optional volume attributes.	Brecht Van Lommel
	A volume shader should be able to request attributes, and still be rendered as homogeneous if no volume attributes are available for the object.
2018-02-22	Cycles: better path termination for transparency.	Brecht Van Lommel
	We now continue transparent paths after diffuse/glossy/transmission/volume bounces are exceeded. This avoids unexpected boundaries in volumes with transparent boundaries. It is also required for MIS to work correctly with transparent surfaces, as we also continue through these in shadow rays. The main visible changes is that volumes will now be lit by the background even at volume bounces 0, same as surfaces. Fixes T53914 and T54103.
2018-02-09	Cycles: random walk subsurface scattering.	Brecht Van Lommel
	It is basically brute force volume scattering within the mesh, but part of the SSS code for faster performance. The main difference with actual volume scattering is that we assume the boundaries are diffuse and that all lighting is coming through this boundary from outside the volume. This gives much more accurate results for thin features and low density. Some challenges remain however: * Significantly more noisy than BSSRDF. Adding Dwivedi sampling may help here, but it's unclear still how much it helps in real world cases. * Due to this being a volumetric method, geometry like eyes or mouth can darken the skin on the outside. We may be able to reduce this effect, or users can compensate for it by reducing the scattering radius in such areas. * Sharp corners are quite bright. This matches actual volume rendering and results in some other renderers, but maybe not so much real world objects. Differential Revision: https://developer.blender.org/D3054
2017-11-10	Cycles: better distance sampling for chromatic volume extinction.	Brecht Van Lommel
	Previously we picked one of the RGB channels with equal probability, but this works poorly in a dense volume after many bounces. Now we take into account the throughput and single scattering albedo. This makes it a little more practical to do brute force SSS with volumes, but is still very inefficient because we do direct light sampling at every volume bounce even when inside an opaque mesh. In theory there could be a light inside the mesh so we can't automatically disable direct lighting.
2017-11-09	Cycles: Replace __MAX_CLOSURE__ build option with runtime integrator variable	Mai Lavelle
	Goal is to reduce OpenCL kernel recompilations. Currently viewport renders are still set to use 64 closures as this seems to be faster and we don't want to cause a performance regression there. Needs to be investigated. Reviewed By: brecht Differential Revision: https://developer.blender.org/D2775
2017-11-05	Cycles: reduce closure memory usage for emission/shadow shader data.	Brecht Van Lommel
	With a Titan Xp, reduces path trace local memory from 1092MB to 840MB. Benchmark performance was within 1% with both RX 480 and Titan Xp. Original patch was implemented by Sergey. Differential Revision: https://developer.blender.org/D2249
2017-11-05	Code refactor: sum transparent and absorption weights outside closures.	Brecht Van Lommel

2017-11-05	Code refactor: remove emission and background closures, sum directly.	Brecht Van Lommel

2017-10-08	Code refactor: use DeviceInfo to enable QBVH and decoupled volume shading.	Brecht Van Lommel

2017-09-20	Cycles: slightly improve BSDF sample stratification for path tracing.	Brecht Van Lommel
	Similar to what we did for area lights previously, this should help preserve stratification when using multiple BSDFs in theory. Improvements are not easily noticeable in practice though, because the number of BSDFs is usually low. Still nice to eliminate one sampling dimension.
2017-09-20	Code cleanup: remove hack to avoid seeing transparent objects in noise.	Brecht Van Lommel
	Previously the Sobol pattern suffered from some correlation issues that made the outline of objects like a smoke domain visible. This helps simplify the code and also makes some other optimizations possible.
2017-09-13	Code cleanup: abstract shadow catcher logic more into accumulation code.	Brecht Van Lommel

2017-09-12	Fix rare firefly in volume equiangular sampling when sampling short distance.	Brecht Van Lommel

2017-08-24	Code cleanup: remove shader context.	Brecht Van Lommel
	This was needed when we accessed OSL closure memory after shader evaluation, which could get overwritten by another shader evaluation. But all closures are immediatley converted to ShaderClosure now, so no longer needed.
2017-08-19	Code cleanup: move rng into path state.	Brecht Van Lommel
	Also pass by value and don't write back now that it is just a hash for seeding and no longer an LCG state. Together this makes CUDA a tiny bit faster in my tests, but mainly simplifies code.
2017-06-13	Cycles: Fix compilation error of OpenCL mega kernel	Sergey Sharybin
	Was some mismatch in address space. Seems to be caused by recent additions. Additionally, moved decoupled ray marching functions under ifdef, so they don't try to use malloc() functions. Thanks Mai for testing the patch!
2017-03-27	Cycles: Remove ccl_addr_space from RNG passed to functions	Hristo Gueorguiev
	Simplifies code quite a bit, making it shorter and easier to extend. Currently no functional changes for users, but is required for the upcoming work of shadow catcher support with OpenCL.
2017-03-17	Cycles: Cleanup, indentation	Sergey Sharybin

2017-03-09	Cycles: SSS and Volume rendering in split kernel	Hristo Gueorguiev
	Decoupled ray marching is not supported yet. Transparent shadows are always enabled for volume rendering. Changes in kernel/bvh and kernel/geom are from Sergey. This simiplifies code significantly, and prepares it for record-all transparent shadow function in split kernel.
2017-02-28	Cycles: Fix division by zero in volume code which was producing -nan	Sergey Sharybin

2016-12-08	Fix emissive volumes generates unexpected fireflies around intersections	Sergey Sharybin
	Discard the whole volume stack on the last bounce (but keep world volume if present). Volumes are expected to be closed manifol meshes, meaning if ray entered the volume there should be an intersection event of ray exisintg the volume. Case when ray hit nothing and there are still non-world volumes in the stack can happen in either of cases. 1. Mesh is not closed manifold. Such configurations are not really supported anyway and should not be used. Previous code would have consider the infinite length of the ray to sample across, so render result wasn't really correct anyway. 2. Exit intersection is more far away than the camera far clip distance. This case also will behave differently now, but previously it wasn't really correct either, so it's not like we're breaking something which was working as expected. 3. We missed exit event due to intersection precision issues. This is exact the case which this patch fixes and avoid fireflies. 4. Volume has Camera only visibility (all the rest visibility is set to off) This is what could be considered a regression but could be solved quite easily by checking volume stack's objects flags and keep entries which doesn't have Volume Scatter visibility (or even better: ensure Volume Scatter visibility for objects with volume closure), Fixes T46108: Cycles - Overlapping emissive volumes generates unexpected bright hotspots around the intersection Also fixes fireflies appearing on the edges of cube with emissive volue. Reviewers: juicyfruit, brecht Reviewed By: brecht Maniphest Tasks: T46108 Differential Revision: https://developer.blender.org/D2212
2016-12-01	Cycles: Fix correlation issues in certain cases	Sergey Sharybin
	There were two cases where correlation issues were obvious: - File from T38710 was giving issues in 2.78a again - File from T50116 was having totally different shadow between sample 1 and sample 32. Use some more simplified version of CMJ hash which seems to give nice randomized value which solves the correlation. This commit will break all unit test files, but it's a bug fix so perhaps OK to commit this. This also fixes T41143: Sobol gives nonuniform noise Proper science paper about hash function is coming. Reviewers: brecht Reviewed By: brecht Subscribers: lukasstockner97 Differential Revision: https://developer.blender.org/D2385
2016-11-24	Cycles: Avoid divisions by zero in volume sampling code	Sergey Sharybin
	Was giving huge artifacts in the barber shop file here in the studio, Maybe not fully optimal solution, but committing it for now to have closer look later.
2016-09-14	Cycles: Also support the constant emission speedup for mesh lights	Lukas Stockner
	Reviewers: brecht, sergey, dingto, juicyfruit Differential Revision: https://developer.blender.org/D2220
2016-08-25	Fix T49078: Cycles tries to render volume from another render layer when ↵	Sergey Sharybin
	camera is in volume
2016-08-01	Cycles: Tweaks to support CUDA 8 toolkit	Sergey Sharybin
	All the changes are mainly giving explicit tips on inlining functions, so they match how inlining worked with previous toolkit. This make kernel compiled by CUDA 8 render in average with same speed as previous kernels. Some scenes are somewhat faster, some of them are somewhat slower. But slowdown is within 1% so far. On a positive side it allows us to enable newer generation cards on buildbots (so GTX 10x0 will be officially supported soon).
2016-07-26	Cycles: Proper fix for buffer overflow in volume intersect all	Sergey Sharybin

2016-06-08	Cycles: Fix two numerical issues in the volume code	Lukas Stockner
	This hopefully fixes T48383 by avoiding two numerical problems that I found in the volume code. Reviewers: sergey, dingto, brecht Reviewed By: sergey, dingto, brecht Maniphest Tasks: T48383 Differential Revision: https://developer.blender.org/D2051
2016-06-06	Fix T48571: Cycles/GPU - A lot of fireflies on SSS+Volume	Sergey Sharybin
	Was some accumulated precision error happening.
2016-05-23	Cycles CUDA: reduce stack memory by reusing ShaderData.	Brecht Van Lommel
	57% less for path and 48% less for branched path.
2016-05-22	Cleanup: remove Cycles layer bits checking in the kernel.	Brecht Van Lommel
	At some point the idea was that we could have an optimization where we could render multiple render layers without re-exporting the scene, by just updating the layer bits. We are not doing this now and in practice with the available render layer control like exclude layers it's not always possible anyway. This makes it easier to support an arbitrary number of layers in the future (hopefully this summer), and frees up some useful bits in the kernel. Reviewed By: sergey, dingto Differential Revision: https://developer.blender.org/D2020
2016-05-18	Cycles: Fix compilation error of CUDA kernels after recent volume commit	Sergey Sharybin
	Apparently the code path with malloc() was enabled for CUDA.
2016-05-18	Cycles: Reduce amount of malloc() calls from the kernel	Sergey Sharybin
	This commit makes it so malloc() is only happening once per volume and once per transparent shadow query (per thread), improving scalability of the code to multiple CPU cores. Hard to measure this with a low-bottom i7 here currently, but from quick tests seems volume sampling gave about 3-5% speedup. The idea is to store allocated memory in kernel globals, which are per thread on CPU already. Reviewers: dingto, juicyfruit, lukasstockner97, maiself, brecht Reviewed By: brecht Subscribers: Blendify, nutel Differential Revision: https://developer.blender.org/D1996
2016-04-20	Fix T48162: GPU render gives wrong results in certain volume setups	Sergey Sharybin
	ideally this part of code should be de-duplicated across __VOLUME_INTERSECT_ALL and regular code.
2016-04-14	Cycles: Yet another fix for camera in volume	Sergey Sharybin
	Was an embarrassing glitch in original optimization policy, the for-loops can't be de-duplicated here.
2016-04-04	Cycles: Fix wrong camera in volume check when domain is only visible to ↵	Sergey Sharybin
	camera rays
2016-04-04	Cycles: Fix regression caused by recent camera-in-volume commit	Sergey Sharybin
	Stupid me forgot that we don't have stop-element in the stack yet.
2016-04-01	Cycles: Fix wrong camera-in-volume stack when camera ray hits volume domain ↵	Sergey Sharybin
	twice
2016-03-25	Cycles: Cleanup, indent nested preprocessor directives	Sergey Sharybin
	Quite straightforward, main trick is happening in path_source_replace_includes(). Reviewers: brecht, dingto, lukasstockner97, juicyfruit Differential Revision: https://developer.blender.org/D1794
2016-01-24	Cleanup: Remove outdated comment in volume code.	Thomas Dinges
	Thanks to jesterking for finding this one.
2016-01-07	Cycles: Refactor how we pass bounce info to light path node.	Thomas Dinges
	This commit changes the way how we pass bounce information to the Light Path node. Instead of manualy copying the bounces into ShaderData, we now directly pass PathState. This reduces the arguments that we need to pass around and also makes it easier to extend the feature. This commit also exposes the Transmission Bounce Depth to the Light Path node. It works similar to the Transparent Depth Output: Replace a Transmission lightpath after X bounces with another shader, e.g a Diffuse one. This can be used to avoid black surfaces, due to low amount of max bounces. Reviewed by Sergey and Brecht, thanks for some hlp with this. I tested compilation and usage on CPU (SVM and OSL), CUDA, OpenCL Split and Mega kernel. Hopefully this covers all devices. :)
2015-08-31	Cleanup: Fix some typos in volume code comments.	Thomas Dinges

2015-07-04	Cleanup: Typo in comment.	Thomas Dinges

2015-04-30	Cycles: Record all possible volume intersections for SSS and camera checks	Thomas Dinges
	This replaces sequential ray moving followed with scene intersection with single BVH traversal, which gives us all possible intersections. Only implemented for CPU, due to qsort and a bigger memory usage on GPU which we rather avoid. GPU still uses the regular bvh volume intersection code, while CPU now uses the new code. This improves render performance for scenes with: a) Camera inside volume mesh b) SSS mesh intersecting a volume mesh/domain In simple volume files (not much geometry) performance is roughly the same (slightly faster). In files with a lot of geometry, the performance increase is larger. bmps.blend with a volume shader and camera inside the mesh, it renders ~10% faster here. Patch by Sergey and myself. Differential Revision: https://developer.blender.org/D1264
2015-04-29	Cycles: Fix wrong termination criteria in SSS volume stack update	Sergey Sharybin
	Another issue spotted with Thomas.
2015-04-28	Cleanup: Move Cycles volume stack update for subsurface into kernel_volume.h.	Thomas Dinges

2015-03-27	Cycles: Code cleanup, spaces around keywords	Sergey Sharybin
	This inconsistency drove me totally crazy, it's really confusing when it's inconsistent especially when you work on both Cycles and Blender sides. Shouldn;t cause merge PITA, it's whitespace changes only, Git should be able to merge it nicely.
2015-03-12	Cycles / Decoupled Ray Marching: Skip consecutive empty steps.	Thomas Dinges
	This merges consecutive empty steps in the decoupled record function, which can lead to fewer iterations in the scatter functions. Only helps slightly though (1%), but doesn't hurt to have this. Differential Revision: https://developer.blender.org/D873