5246fb5a57
This patch implements blue-noise dithered sampling as described by Nathan Vegdahl (https://psychopath.io/post/2022_07_24_owen_scrambling_based_dithered_blue_noise_sampling), which in turn is based on "Screen-Space Blue-Noise Diffusion of Monte Carlo Sampling Error via Hierarchical Ordering of Pixels"(https://repository.kaust.edu.sa/items/1269ae24-2596-400b-a839-e54486033a93). The basic idea is simple: Instead of generating independent sequences for each pixel by scrambling them, we use a single sequence for the entire image, with each pixel getting one chunk of the samples. The ordering across pixels is determined by hierarchical scrambling of the pixel's position along a space-filling curve, which ends up being pretty much the same operation as already used for the underlying sequence. This results in a more high-frequency noise distribution, which appears smoother despite not being less noisy overall. The main limitation at the moment is that the improvement is only clear if the full sample amount is used per pixel, so interactive preview rendering and adaptive sampling will not receive the benefit. One exception to this is that when using the new "Automatic" setting, the first sample in interactive rendering will also be blue-noise-distributed. The sampling mode option is now exposed in the UI, with the three options being Blue Noise (the new mode), Classic (the previous Tabulated Sobol method) and the new default, Automatic (blue noise, with the additional property of ensuring the first sample is also blue-noise-distributed in interactive rendering). When debug mode is enabled, additional options appear, such as Sobol-Burley. Note that the scrambling distance option is not compatible with the blue-noise pattern. Pull Request: https://projects.blender.org/blender/blender/pulls/118479
149 lines
8.3 KiB
C
149 lines
8.3 KiB
C
/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
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*
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* SPDX-License-Identifier: Apache-2.0 */
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/************************************ Path State *****************************/
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KERNEL_STRUCT_BEGIN(path)
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/* Index of a pixel within the device render buffer where this path will write its result.
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* To get an actual offset within the buffer the value needs to be multiplied by the
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* `kernel_data.film.pass_stride`.
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*
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* The multiplication is delayed for later, so that state can use 32bit integer. */
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KERNEL_STRUCT_MEMBER(path, uint32_t, render_pixel_index, KERNEL_FEATURE_PATH_TRACING)
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/* Current sample number. */
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KERNEL_STRUCT_MEMBER(path, uint32_t, sample, KERNEL_FEATURE_PATH_TRACING)
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/* Current ray bounce depth. */
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KERNEL_STRUCT_MEMBER(path, uint16_t, bounce, KERNEL_FEATURE_PATH_TRACING)
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/* Current transparent ray bounce depth. */
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KERNEL_STRUCT_MEMBER(path, uint16_t, transparent_bounce, KERNEL_FEATURE_PATH_TRACING)
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/* Current diffuse ray bounce depth. */
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KERNEL_STRUCT_MEMBER(path, uint16_t, diffuse_bounce, KERNEL_FEATURE_PATH_TRACING)
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/* Current glossy ray bounce depth. */
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KERNEL_STRUCT_MEMBER(path, uint16_t, glossy_bounce, KERNEL_FEATURE_PATH_TRACING)
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/* Current transmission ray bounce depth. */
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KERNEL_STRUCT_MEMBER(path, uint16_t, transmission_bounce, KERNEL_FEATURE_PATH_TRACING)
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/* Current volume ray bounce depth. */
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KERNEL_STRUCT_MEMBER(path, uint16_t, volume_bounce, KERNEL_FEATURE_PATH_TRACING)
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/* Current volume bounds ray bounce depth. */
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KERNEL_STRUCT_MEMBER(path, uint16_t, volume_bounds_bounce, KERNEL_FEATURE_PATH_TRACING)
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/* DeviceKernel bit indicating queued kernels. */
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KERNEL_STRUCT_MEMBER(path, uint16_t, queued_kernel, KERNEL_FEATURE_PATH_TRACING)
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/* Random number generator per-pixel info. */
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KERNEL_STRUCT_MEMBER(path, uint32_t, rng_pixel, KERNEL_FEATURE_PATH_TRACING)
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/* Random number dimension offset. */
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KERNEL_STRUCT_MEMBER(path, uint16_t, rng_offset, KERNEL_FEATURE_PATH_TRACING)
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/* enum PathRayFlag */
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KERNEL_STRUCT_MEMBER(path, uint32_t, flag, KERNEL_FEATURE_PATH_TRACING)
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/* enum PathRayMNEE */
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KERNEL_STRUCT_MEMBER(path, uint8_t, mnee, KERNEL_FEATURE_PATH_TRACING)
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/* Multiple importance sampling
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* The PDF of BSDF sampling at the last scatter point, which is at ray distance
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* zero and distance. Note that transparency and volume attenuation increase
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* the ray tmin but keep P unmodified so that this works. */
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KERNEL_STRUCT_MEMBER(path, float, mis_ray_pdf, KERNEL_FEATURE_PATH_TRACING)
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/* Object at last scatter point for light linking. */
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KERNEL_STRUCT_MEMBER(path, int, mis_ray_object, KERNEL_FEATURE_LIGHT_LINKING)
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/* Normal at last scatter point for light tree. */
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KERNEL_STRUCT_MEMBER(path, packed_float3, mis_origin_n, KERNEL_FEATURE_PATH_TRACING)
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/* Filter glossy. */
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KERNEL_STRUCT_MEMBER(path, float, min_ray_pdf, KERNEL_FEATURE_PATH_TRACING)
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/* Continuation probability for path termination. */
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KERNEL_STRUCT_MEMBER(path, float, continuation_probability, KERNEL_FEATURE_PATH_TRACING)
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/* Throughput. */
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KERNEL_STRUCT_MEMBER(path, PackedSpectrum, throughput, KERNEL_FEATURE_PATH_TRACING)
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/* Factor to multiple with throughput to get remove any guiding PDFS.
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* Such throughput without guiding PDFS is used for Russian roulette termination. */
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KERNEL_STRUCT_MEMBER(path, float, unguided_throughput, KERNEL_FEATURE_PATH_GUIDING)
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/* Ratio of throughput to distinguish diffuse / glossy / transmission render passes. */
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KERNEL_STRUCT_MEMBER(path, PackedSpectrum, pass_diffuse_weight, KERNEL_FEATURE_LIGHT_PASSES)
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KERNEL_STRUCT_MEMBER(path, PackedSpectrum, pass_glossy_weight, KERNEL_FEATURE_LIGHT_PASSES)
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/* Denoising. */
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KERNEL_STRUCT_MEMBER(path, PackedSpectrum, denoising_feature_throughput, KERNEL_FEATURE_DENOISING)
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/* Shader sorting. */
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/* TODO: compress as uint16? or leave out entirely and recompute key in sorting code? */
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KERNEL_STRUCT_MEMBER(path, uint32_t, shader_sort_key, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_END(path)
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/************************************** Ray ***********************************/
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KERNEL_STRUCT_BEGIN_PACKED(ray, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_MEMBER_PACKED(ray, packed_float3, P, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_MEMBER_PACKED(ray, float, dP, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_MEMBER_PACKED(ray, packed_float3, D, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_MEMBER_PACKED(ray, float, dD, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_MEMBER_PACKED(ray, float, tmin, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_MEMBER_PACKED(ray, float, tmax, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_MEMBER_PACKED(ray, float, time, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_MEMBER(ray, float, previous_dt, KERNEL_FEATURE_LIGHT_TREE)
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KERNEL_STRUCT_END(ray)
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/*************************** Intersection result ******************************/
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/* Result from scene intersection. */
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KERNEL_STRUCT_BEGIN_PACKED(isect, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_MEMBER_PACKED(isect, float, t, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_MEMBER_PACKED(isect, float, u, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_MEMBER_PACKED(isect, float, v, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_MEMBER_PACKED(isect, int, prim, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_MEMBER_PACKED(isect, int, object, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_MEMBER_PACKED(isect, int, type, KERNEL_FEATURE_PATH_TRACING)
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KERNEL_STRUCT_END(isect)
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/*************** Subsurface closure state for subsurface kernel ***************/
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KERNEL_STRUCT_BEGIN_PACKED(subsurface, KERNEL_FEATURE_SUBSURFACE)
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KERNEL_STRUCT_MEMBER_PACKED(subsurface, PackedSpectrum, albedo, KERNEL_FEATURE_SUBSURFACE)
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KERNEL_STRUCT_MEMBER_PACKED(subsurface, PackedSpectrum, radius, KERNEL_FEATURE_SUBSURFACE)
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KERNEL_STRUCT_MEMBER_PACKED(subsurface, float, anisotropy, KERNEL_FEATURE_SUBSURFACE)
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KERNEL_STRUCT_MEMBER_PACKED(subsurface, packed_float3, N, KERNEL_FEATURE_SUBSURFACE)
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KERNEL_STRUCT_END(subsurface)
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/********************************** Volume Stack ******************************/
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KERNEL_STRUCT_BEGIN(volume_stack)
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KERNEL_STRUCT_ARRAY_MEMBER(volume_stack, int, object, KERNEL_FEATURE_VOLUME)
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KERNEL_STRUCT_ARRAY_MEMBER(volume_stack, int, shader, KERNEL_FEATURE_VOLUME)
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KERNEL_STRUCT_END_ARRAY(volume_stack,
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KERNEL_STRUCT_VOLUME_STACK_SIZE,
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KERNEL_STRUCT_VOLUME_STACK_SIZE)
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/************************************ Path Guiding *****************************/
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KERNEL_STRUCT_BEGIN(guiding)
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#ifdef __PATH_GUIDING__
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/* Current path segment of the random walk/path. */
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KERNEL_STRUCT_MEMBER(guiding,
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openpgl::cpp::PathSegment *,
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path_segment,
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KERNEL_FEATURE_PATH_GUIDING)
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#else
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/* Current path segment of the random walk/path. */
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KERNEL_STRUCT_MEMBER(guiding, uint64_t, path_segment, KERNEL_FEATURE_PATH_GUIDING)
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#endif
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/* If surface guiding is enabled */
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KERNEL_STRUCT_MEMBER(guiding, bool, use_surface_guiding, KERNEL_FEATURE_PATH_GUIDING)
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/* Random number used for additional guiding decisions (e.g., cache query, selection to use guiding
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* or BSDF sampling) */
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KERNEL_STRUCT_MEMBER(guiding, float, sample_surface_guiding_rand, KERNEL_FEATURE_PATH_GUIDING)
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/* The probability to use surface guiding (i.e., diffuse sampling prob * guiding prob)*/
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KERNEL_STRUCT_MEMBER(guiding, float, surface_guiding_sampling_prob, KERNEL_FEATURE_PATH_GUIDING)
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/* Probability of sampling a BSSRDF closure instead of a BSDF closure. */
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KERNEL_STRUCT_MEMBER(guiding, float, bssrdf_sampling_prob, KERNEL_FEATURE_PATH_GUIDING)
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/* If volume guiding is enabled */
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KERNEL_STRUCT_MEMBER(guiding, bool, use_volume_guiding, KERNEL_FEATURE_PATH_GUIDING)
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/* Random number used for additional guiding decisions (e.g., cache query, selection to use guiding
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* or BSDF sampling) */
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KERNEL_STRUCT_MEMBER(guiding, float, sample_volume_guiding_rand, KERNEL_FEATURE_PATH_GUIDING)
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/* The probability to use surface guiding (i.e., diffuse sampling prob * guiding prob). */
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KERNEL_STRUCT_MEMBER(guiding, float, volume_guiding_sampling_prob, KERNEL_FEATURE_PATH_GUIDING)
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KERNEL_STRUCT_END(guiding)
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/******************************* Shadow linking *******************************/
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KERNEL_STRUCT_BEGIN(shadow_link)
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KERNEL_STRUCT_MEMBER(shadow_link, float, dedicated_light_weight, KERNEL_FEATURE_SHADOW_LINKING)
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/* Copy of primitive and object from the last main path intersection. */
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KERNEL_STRUCT_MEMBER(shadow_link, int, last_isect_prim, KERNEL_FEATURE_SHADOW_LINKING)
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KERNEL_STRUCT_MEMBER(shadow_link, int, last_isect_object, KERNEL_FEATURE_SHADOW_LINKING)
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KERNEL_STRUCT_END(shadow_link)
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