Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

ReSTIR loop architecture #175

Draft
wants to merge 1 commit into
base: local-restir
Choose a base branch
from
Draft

ReSTIR loop architecture #175

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion blade-render/code/debug-param.inc.wgsl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,8 @@

struct DebugParams {
view_mode: u32,
pass_index: u32,
draw_flags: u32,
texture_flags: u32,
pad: u32,
mouse_pos: vec2<u32>,
};
261 changes: 132 additions & 129 deletions blade-render/code/ray-trace.wgsl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -232,12 +232,15 @@ fn evaluate_brdf(surface: Surface, dir: vec3<f32>) -> f32 {
return lambert_brdf * max(0.0, lambert_term);
}

fn check_ray_occluded(acs: acceleration_structure, position: vec3<f32>, direction: vec3<f32>) -> bool {
fn check_ray_occluded(prev_frame: bool, position: vec3<f32>, direction: vec3<f32>) -> bool {
var rq: ray_query;
let flags = RAY_FLAG_TERMINATE_ON_FIRST_HIT | RAY_FLAG_CULL_NO_OPAQUE;
rayQueryInitialize(&rq, acs,
RayDesc(flags, 0xFFu, parameters.t_start, camera.depth, position, direction)
);
let desc = RayDesc(flags, 0xFFu, parameters.t_start, camera.depth, position, direction);
if (prev_frame) {
rayQueryInitialize(&rq, prev_acc_struct, desc);
} else {
rayQueryInitialize(&rq, acc_struct, desc);
}
rayQueryProceed(&rq);
let intersection = rayQueryGetCommittedIntersection(&rq);

Expand Down Expand Up @@ -273,7 +276,7 @@ fn make_target_score(color: vec3<f32>) -> TargetScore {
}

fn estimate_target_score_with_occlusion(
surface: Surface, position: vec3<f32>, light_index: u32, light_uv: vec2<f32>, acs: acceleration_structure,
surface: Surface, position: vec3<f32>, light_index: u32, light_uv: vec2<f32>, prev_frame: bool,
) -> TargetScore {
if (light_index != 0u) {
return TargetScore();
Expand All @@ -287,7 +290,7 @@ fn estimate_target_score_with_occlusion(
return TargetScore();
}

if (check_ray_occluded(acs, position, direction)) {
if (check_ray_occluded(prev_frame, position, direction)) {
return TargetScore();
}

Expand All @@ -312,7 +315,7 @@ fn evaluate_sample(ls: LightSample, surface: Surface, start_pos: vec3<f32>) -> f
return 0.0;
}

if (check_ray_occluded(acc_struct, start_pos, dir)) {
if (check_ray_occluded(false, start_pos, dir)) {
return 0.0;
}

Expand Down Expand Up @@ -402,62 +405,54 @@ struct ResampleBase {
world_pos: vec3<f32>,
accepted_count: f32,
}
struct ResampleResult {
selected: bool,

struct ShiftSample {
reservoir: LiveReservoir,
mis_canonical: f32,
mis_sample: f32,
}

// Resample following Algorithm 8 in section 9.1 of Bitterli thesis
fn resample(
dst: ptr<function, LiveReservoir>, color_and_weight: ptr<function, vec4<f32>>,
base: ResampleBase, other: PixelCache, other_acs: acceleration_structure,
fn shift_sample(
base: ResampleBase, other: PixelCache, other_prev_frame: bool,
max_confidence: f32,
) -> ResampleResult {
var src: LiveReservoir;
) -> ShiftSample {
var ss = ShiftSample();
let neighbor = other.reservoir;
var rr = ResampleResult();
if (parameters.use_pairwise_mis != 0u) {
let canonical = base.canonical;
let neighbor_history = min(neighbor.confidence, max_confidence);
{ // scoping this to hint the register allocation
let t_canonical_at_neighbor = estimate_target_score_with_occlusion(
other.surface, other.world_pos, canonical.selected_light_index, canonical.selected_uv, other_acs);
other.surface, other.world_pos, canonical.selected_light_index, canonical.selected_uv, other_prev_frame);
let nom = canonical.selected_target_score * canonical.history / base.accepted_count;
let denom = t_canonical_at_neighbor.score * neighbor_history + nom;
rr.mis_canonical = select(0.0, nom / denom, denom > 0.0);
ss.mis_canonical = select(0.0, nom / denom, denom > 0.0);
}

let canonical_prev_frame = false;
let t_neighbor_at_canonical = estimate_target_score_with_occlusion(
base.surface, base.world_pos, neighbor.light_index, neighbor.light_uv, acc_struct);
base.surface, base.world_pos, neighbor.light_index, neighbor.light_uv, canonical_prev_frame);
let nom = neighbor.target_score * neighbor_history;
let denom = nom + t_neighbor_at_canonical.score * canonical.history / base.accepted_count;
let mis_neighbor = select(0.0, nom / denom, denom > 0.0);
rr.mis_sample = mis_neighbor;
ss.mis_sample = mis_neighbor;

var src: LiveReservoir;
src.history = neighbor_history;
src.selected_light_index = neighbor.light_index;
src.selected_uv = neighbor.light_uv;
src.selected_target_score = t_neighbor_at_canonical.score;
src.weight_sum = t_neighbor_at_canonical.score * neighbor.contribution_weight * mis_neighbor;
src.radiance = t_neighbor_at_canonical.color;
ss.reservoir = src;
} else {
rr.mis_canonical = 0.0;
rr.mis_sample = 1.0;
ss.mis_canonical = 0.5;
ss.mis_sample = 0.5;
let radiance = evaluate_reflected_light(base.surface, neighbor.light_index, neighbor.light_uv);
src = unpack_reservoir(neighbor, max_confidence, radiance);
}

if (DECOUPLED_SHADING) {
*color_and_weight += src.weight_sum * vec4<f32>(neighbor.contribution_weight * src.radiance, 1.0);
}
if (src.weight_sum <= 0.0) {
bump_reservoir(dst, src.history);
} else {
merge_reservoir(dst, src);
rr.selected = true;
ss.reservoir = unpack_reservoir(neighbor, max_confidence, radiance);
}
return rr;
return ss;
}

struct ResampleOutput {
Expand Down Expand Up @@ -503,115 +498,123 @@ fn finalize_resampling(
return ro;
}

fn resample_temporal(
surface: Surface, cur_pixel: vec2<i32>, position: vec3<f32>,
local_index: u32, tr: TemporalReprojection,
) -> ResampleOutput {
if (surface.depth == 0.0) {
return ResampleOutput();
}

let canonical = produce_canonical(surface, position);
if (parameters.temporal_tap == 0u || !tr.is_valid) {
return finalize_canonical(canonical);
}

var reservoir = LiveReservoir();
var color_and_weight = vec4<f32>(0.0);
let base = ResampleBase(surface, canonical, position, 1.0);

let prev_dir = get_ray_direction(prev_camera, tr.pixel);
let prev_world_pos = prev_camera.position + tr.surface.depth * prev_dir;
let other = PixelCache(tr.surface, tr.reservoir, prev_world_pos);
let rr = resample(&reservoir, &color_and_weight, base, other, prev_acc_struct, parameters.temporal_tap_confidence);
let mis_canonical = 1.0 + rr.mis_canonical;

if (WRITE_DEBUG_IMAGE && debug.view_mode == DebugMode_TemporalMatch) {
textureStore(out_debug, cur_pixel, vec4<f32>(1.0));
}
if (WRITE_DEBUG_IMAGE && debug.view_mode == DebugMode_TemporalMisCanonical) {
let mis = mis_canonical / (1.0 + base.accepted_count);
textureStore(out_debug, cur_pixel, vec4<f32>(mis));
}

return finalize_resampling(&reservoir, &color_and_weight, base, mis_canonical);
}

fn resample_spatial(
surface: Surface, cur_pixel: vec2<i32>, position: vec3<f32>,
group_id: vec3<u32>, canonical: LiveReservoir,
) -> ResampleOutput {
if (surface.depth == 0.0) {
let dir = normalize(position - camera.position);
var ro = ResampleOutput();
ro.color = evaluate_environment(dir);
return ro;
}

// gather the list of neighbors (within the workgroup) to resample.
var accepted_count = 0u;
var accepted_local_indices = array<u32, MAX_RESAMPLE>();
let max_accepted = min(MAX_RESAMPLE, parameters.spatial_taps);
let num_candidates = parameters.spatial_taps * 4u;
for (var i = 0u; i < num_candidates && accepted_count < max_accepted; i += 1u) {
let other_cache_index = random_u32(&p_rng) % GROUP_SIZE_TOTAL;
let diff = thread_index_to_coord(other_cache_index, group_id) - cur_pixel;
if (dot(diff, diff) < parameters.spatial_min_distance * parameters.spatial_min_distance) {
continue;
}
let other = pixel_cache[other_cache_index];
// if the surfaces are too different, there is no trust in this sample
if (other.reservoir.confidence > 0.0 && compare_surfaces(surface, other.surface) > 0.1) {
accepted_local_indices[accepted_count] = other_cache_index;
accepted_count += 1u;
}
}

var reservoir = LiveReservoir();
var color_and_weight = vec4<f32>(0.0);
let base = ResampleBase(surface, canonical, position, f32(accepted_count));
var mis_canonical = 1.0;

// evaluate the MIS of each of the samples versus the canonical one.
for (var lid = 0u; lid < accepted_count; lid += 1u) {
let other = pixel_cache[accepted_local_indices[lid]];
let rr = resample(&reservoir, &color_and_weight, base, other, acc_struct, parameters.spatial_tap_confidence);
mis_canonical += rr.mis_canonical;
}

if (WRITE_DEBUG_IMAGE && debug.view_mode == DebugMode_SpatialMatch) {
let value = base.accepted_count / max(1.0, f32(parameters.spatial_taps));
textureStore(out_debug, cur_pixel, vec4<f32>(value));
}
if (WRITE_DEBUG_IMAGE && debug.view_mode == DebugMode_SpatialMisCanonical) {
let mis = mis_canonical / (1.0 + base.accepted_count);
textureStore(out_debug, cur_pixel, vec4<f32>(mis));
}
return finalize_resampling(&reservoir, &color_and_weight, base, mis_canonical);
struct Pass {
is_temporal: bool,
confidence: f32,
taps: u32,
candidates: u32,
}

fn compute_restir(
rs: RichSurface, pixel: vec2<i32>, local_index: u32, group_id: vec3<u32>,
) -> vec3<f32> {
let center_coord = vec2<f32>(pixel) + 0.5 + select(vec2<f32>(0.0), rs.motion, parameters.use_motion_vectors != 0u);
//TODO: recompute this at the end?
let tr = find_temporal(rs.inner, pixel, center_coord);
let motion_sqr = dot(rs.motion, rs.motion);

let temporal = resample_temporal(rs.inner, pixel, rs.position, local_index, tr);
pixel_cache[local_index] = PixelCache(rs.inner, temporal.reservoir, rs.position);
var prev_pixel = select(vec2<i32>(-1), tr.pixel, tr.is_valid);
let motion_sqr = dot(rs.motion, rs.motion);

// sync with the workgroup to ensure all reservoirs are available.
workgroupBarrier();
var result = ResampleOutput();
if (rs.inner.depth == 0.0) {
let dir = normalize(rs.position - camera.position);
result.color = evaluate_environment(dir);
} else {
let canonical = produce_canonical(rs.inner, rs.position);
result = finalize_canonical(canonical);

var num_passes = 0u;
var passes = array<Pass, 2>();
if (parameters.temporal_tap != 0u) {
passes[num_passes] = Pass(true, parameters.temporal_tap_confidence, 1, 0);
num_passes += 1u;
}
if (parameters.spatial_taps > 0) {
passes[num_passes] = Pass(false, parameters.spatial_tap_confidence, parameters.spatial_taps, parameters.spatial_taps * 4u);
num_passes += 1u;
}

let temporal_live = revive_canonical(temporal);
let spatial = resample_spatial(rs.inner, pixel, rs.position, group_id, temporal_live);
for(var pass_i = 0u; pass_i < num_passes; pass_i += 1u) {
let ps = passes[pass_i];
var reservoir = LiveReservoir();
var color_and_weight = vec4<f32>(0.0);
var mis_canonical = 0.0;
var accepted_count = 0u;
var accepted_local_indices = array<u32, MAX_RESAMPLE>();

if (ps.is_temporal) {
if (tr.is_valid) {
let prev_dir = get_ray_direction(prev_camera, tr.pixel);
let prev_world_pos = prev_camera.position + tr.surface.depth * prev_dir;
pixel_cache[local_index] = PixelCache(tr.surface, tr.reservoir, prev_world_pos);
accepted_local_indices[0] = local_index;
accepted_count += 1u;
}
} else {
pixel_cache[local_index] = PixelCache(rs.inner, result.reservoir, rs.position);
// sync with the workgroup to ensure all reservoirs are available.
workgroupBarrier();

// gather the list of neighbors (within the workgroup) to resample.
let max_accepted = min(MAX_RESAMPLE, ps.taps);
for (var i = 0u; i < ps.candidates && accepted_count < max_accepted; i += 1u) {
let other_cache_index = random_u32(&p_rng) % GROUP_SIZE_TOTAL;
let diff = thread_index_to_coord(other_cache_index, group_id) - pixel;
if (dot(diff, diff) < parameters.spatial_min_distance * parameters.spatial_min_distance) {
continue;
}
let other = pixel_cache[other_cache_index];
// if the surfaces are too different, there is no trust in this sample
if (other.reservoir.confidence > 0.0 && compare_surfaces(rs.inner, other.surface) > 0.1) {
accepted_local_indices[accepted_count] = other_cache_index;
accepted_count += 1u;
}
}
}

if (accepted_count == 0u) {
continue;
}

let input = revive_canonical(result);
let base = ResampleBase(rs.inner, input, rs.position, f32(accepted_count));

mis_canonical = 1.0;
// evaluate the MIS of each of the samples versus the canonical one.
for (var lid = 0u; lid < accepted_count; lid += 1u) {
let other = pixel_cache[accepted_local_indices[lid]];

let ss = shift_sample(base, other, ps.is_temporal, ps.confidence);
mis_canonical += ss.mis_canonical;

if (DECOUPLED_SHADING) {
let stored = pack_reservoir(ss.reservoir);
color_and_weight += ss.reservoir.weight_sum * vec4<f32>(stored.contribution_weight * ss.reservoir.radiance, 1.0);
}
if (ss.reservoir.weight_sum <= 0.0) {
bump_reservoir(&reservoir, ss.reservoir.history);
} else {
merge_reservoir(&reservoir, ss.reservoir);
}
}

if (WRITE_DEBUG_IMAGE && pass_i == debug.pass_index) {
if (debug.view_mode == DebugMode_PassMatch) {
textureStore(out_debug, pixel, vec4<f32>(1.0));
}
if (debug.view_mode == DebugMode_PassMisCanonical) {
let mis = mis_canonical / f32(1u + accepted_count);
textureStore(out_debug, pixel, vec4<f32>(mis));
}
}
result = finalize_resampling(&reservoir, &color_and_weight, base, mis_canonical);
}
}

let pixel_index = get_reservoir_index(pixel, camera);
reservoirs[pixel_index] = spatial.reservoir;
reservoirs[pixel_index] = result.reservoir;

accumulate_temporal(pixel, spatial.color, parameters.temporal_accumulation_weight, prev_pixel, motion_sqr);
return spatial.color;
accumulate_temporal(pixel, result.color, parameters.temporal_accumulation_weight, prev_pixel, motion_sqr);
return result.color;
}

@compute @workgroup_size(GROUP_SIZE.x, GROUP_SIZE.y)
Expand Down
Loading
Loading