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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
use crate::{
binding_model::{BindGroup, PipelineLayout},
device::SHADER_STAGE_COUNT,
hub::{GfxBackend, Storage},
id::{BindGroupId, BindGroupLayoutId, PipelineLayoutId, Valid},
Stored, MAX_BIND_GROUPS,
};
use arrayvec::ArrayVec;
use std::slice;
use wgt::DynamicOffset;
type BindGroupMask = u8;
#[derive(Clone, Debug)]
pub(super) struct BindGroupPair {
layout_id: Valid<BindGroupLayoutId>,
group_id: Stored<BindGroupId>,
}
#[derive(Debug)]
pub(super) enum LayoutChange<'a> {
Unchanged,
Match(Valid<BindGroupId>, &'a [DynamicOffset]),
Mismatch,
}
#[derive(Debug)]
pub enum Provision {
Unchanged,
Changed { was_compatible: bool },
}
#[derive(Clone)]
pub(super) struct FollowUpIter<'a> {
iter: slice::Iter<'a, BindGroupEntry>,
}
impl<'a> Iterator for FollowUpIter<'a> {
type Item = (Valid<BindGroupId>, &'a [DynamicOffset]);
fn next(&mut self) -> Option<Self::Item> {
self.iter
.next()
.and_then(|entry| Some((entry.actual_value()?, entry.dynamic_offsets.as_slice())))
}
}
#[derive(Clone, Default, Debug)]
pub(super) struct BindGroupEntry {
expected_layout_id: Option<Valid<BindGroupLayoutId>>,
provided: Option<BindGroupPair>,
dynamic_offsets: Vec<DynamicOffset>,
}
impl BindGroupEntry {
fn provide<B: GfxBackend>(
&mut self,
bind_group_id: Valid<BindGroupId>,
bind_group: &BindGroup<B>,
offsets: &[DynamicOffset],
) -> Provision {
debug_assert_eq!(B::VARIANT, bind_group_id.0.backend());
let was_compatible = match self.provided {
Some(BindGroupPair {
layout_id,
ref group_id,
}) => {
if group_id.value == bind_group_id && offsets == self.dynamic_offsets.as_slice() {
assert_eq!(layout_id, bind_group.layout_id);
return Provision::Unchanged;
}
self.expected_layout_id == Some(layout_id)
}
None => false,
};
self.provided = Some(BindGroupPair {
layout_id: bind_group.layout_id,
group_id: Stored {
value: bind_group_id,
ref_count: bind_group.life_guard.add_ref(),
},
});
self.dynamic_offsets.clear();
self.dynamic_offsets.extend_from_slice(offsets);
Provision::Changed { was_compatible }
}
pub fn expect_layout(
&mut self,
bind_group_layout_id: Valid<BindGroupLayoutId>,
) -> LayoutChange {
let some = Some(bind_group_layout_id);
if self.expected_layout_id != some {
self.expected_layout_id = some;
match self.provided {
Some(BindGroupPair {
layout_id,
ref group_id,
}) if layout_id == bind_group_layout_id => {
LayoutChange::Match(group_id.value, &self.dynamic_offsets)
}
Some(_) | None => LayoutChange::Mismatch,
}
} else {
LayoutChange::Unchanged
}
}
fn is_valid(&self) -> Option<bool> {
match (self.expected_layout_id, self.provided.as_ref()) {
(None, None) => Some(true),
(None, Some(_)) => None,
(Some(_), None) => Some(false),
(Some(layout), Some(pair)) => Some(layout == pair.layout_id),
}
}
fn actual_value(&self) -> Option<Valid<BindGroupId>> {
self.expected_layout_id.and_then(|layout_id| {
self.provided.as_ref().and_then(|pair| {
if pair.layout_id == layout_id {
Some(pair.group_id.value)
} else {
None
}
})
})
}
}
#[derive(Debug)]
pub struct Binder {
pub(super) pipeline_layout_id: Option<Valid<PipelineLayoutId>>, //TODO: strongly `Stored`
pub(super) entries: ArrayVec<[BindGroupEntry; MAX_BIND_GROUPS]>,
}
impl Binder {
pub(super) fn new(max_bind_groups: u32) -> Self {
Self {
pipeline_layout_id: None,
entries: (0..max_bind_groups)
.map(|_| BindGroupEntry::default())
.collect(),
}
}
pub(super) fn reset(&mut self) {
self.pipeline_layout_id = None;
self.entries.clear();
}
pub(super) fn change_pipeline_layout<B: GfxBackend>(
&mut self,
guard: &Storage<PipelineLayout<B>, PipelineLayoutId>,
new_id: Valid<PipelineLayoutId>,
) {
let old_id_opt = self.pipeline_layout_id.replace(new_id);
let new = &guard[new_id];
let length = if let Some(old_id) = old_id_opt {
let old = &guard[old_id];
if old.push_constant_ranges == new.push_constant_ranges {
new.bind_group_layout_ids.len()
} else {
0
}
} else {
0
};
for entry in self.entries[length..].iter_mut() {
entry.expected_layout_id = None;
}
}
/// Attempt to set the value of the specified bind group index.
/// Returns Some() when the new bind group is ready to be actually bound
/// (i.e. compatible with current expectations). Also returns an iterator
/// of bind group IDs to be bound with it: those are compatible bind groups
/// that were previously blocked because the current one was incompatible.
pub(super) fn provide_entry<'a, B: GfxBackend>(
&'a mut self,
index: usize,
bind_group_id: Valid<BindGroupId>,
bind_group: &BindGroup<B>,
offsets: &[DynamicOffset],
) -> Option<(Valid<PipelineLayoutId>, FollowUpIter<'a>)> {
tracing::trace!("\tBinding [{}] = group {:?}", index, bind_group_id);
debug_assert_eq!(B::VARIANT, bind_group_id.0.backend());
match self.entries[index].provide(bind_group_id, bind_group, offsets) {
Provision::Unchanged => None,
Provision::Changed { was_compatible, .. } => {
let compatible_count = self.compatible_count();
if index < compatible_count {
let end = compatible_count.min(if was_compatible {
index + 1
} else {
self.entries.len()
});
tracing::trace!("\t\tbinding up to {}", end);
Some((
self.pipeline_layout_id?,
FollowUpIter {
iter: self.entries[index + 1..end].iter(),
},
))
} else {
tracing::trace!("\t\tskipping above compatible {}", compatible_count);
None
}
}
}
}
pub(super) fn list_active(&self) -> impl Iterator<Item = Valid<BindGroupId>> + '_ {
self.entries.iter().filter_map(|e| match e.provided {
Some(ref pair) if e.expected_layout_id.is_some() => Some(pair.group_id.value),
_ => None,
})
}
pub(super) fn invalid_mask(&self) -> BindGroupMask {
self.entries.iter().enumerate().fold(0, |mask, (i, entry)| {
if entry.is_valid().unwrap_or(true) {
mask
} else {
mask | 1u8 << i
}
})
}
fn compatible_count(&self) -> usize {
self.entries
.iter()
.position(|entry| !entry.is_valid().unwrap_or(false))
.unwrap_or_else(|| self.entries.len())
}
}
struct PushConstantChange {
stages: wgt::ShaderStage,
offset: u32,
enable: bool,
}
/// Break up possibly overlapping push constant ranges into a set of non-overlapping ranges
/// which contain all the stage flags of the original ranges. This allows us to zero out (or write any value)
/// to every possible value.
pub fn compute_nonoverlapping_ranges(
ranges: &[wgt::PushConstantRange],
) -> ArrayVec<[wgt::PushConstantRange; SHADER_STAGE_COUNT * 2]> {
if ranges.is_empty() {
return ArrayVec::new();
}
debug_assert!(ranges.len() <= SHADER_STAGE_COUNT);
let mut breaks: ArrayVec<[PushConstantChange; SHADER_STAGE_COUNT * 2]> = ArrayVec::new();
for range in ranges {
breaks.push(PushConstantChange {
stages: range.stages,
offset: range.range.start,
enable: true,
});
breaks.push(PushConstantChange {
stages: range.stages,
offset: range.range.end,
enable: false,
});
}
breaks.sort_unstable_by_key(|change| change.offset);
let mut output_ranges = ArrayVec::new();
let mut position = 0_u32;
let mut stages = wgt::ShaderStage::NONE;
for bk in breaks {
if bk.offset - position > 0 && !stages.is_empty() {
output_ranges.push(wgt::PushConstantRange {
stages,
range: position..bk.offset,
})
}
position = bk.offset;
stages.set(bk.stages, bk.enable);
}
output_ranges
}
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