use super::super::{
BokehShape, MAX_INSTANCE_COUNT, Particle, ParticleShape, ParticleStyle, StyleOptions, invalid,
limit,
};
use super::ExtendedBatch;
use super::sampling::support;
use motion_core::instances::{
ExtendedInstanceRecord, InstanceBatch, InstanceBlend, InstanceKind, InstanceRecord,
};
use motion_core::{Node, SceneContext, Time, ValidationError};
use std::sync::Arc;
pub(crate) fn render(
style: &ParticleStyle,
options: &StyleOptions,
context: &SceneContext<'_>,
states: Arc<[Particle]>,
mut sample: impl FnMut(Time) -> Result<Arc<[Particle]>, ValidationError>,
) -> Result<Node, ValidationError> {
if options.parallax.iter().any(|value| !value.is_finite())
|| !(1..=64).contains(&options.trails.segments)
{
return Err(invalid("style", "Invalid parallax or trail segment count"));
}
if options.sheet.is_some() && !matches!(style, ParticleStyle::Sprites { .. }) {
return Err(invalid("sheet", "Flipbook requires Sprites"));
}
if options.flip
&& !matches!(
style,
ParticleStyle::Shape {
shape: ParticleShape::Quad { .. },
..
}
)
{
return Err(invalid("flip", "Confetti flip requires Quad"));
}
if let Some(stretch) = options.stretch
&& (!stretch.scale.is_finite()
|| stretch.scale < 0.0
|| !stretch.maximum.is_finite()
|| !(1.0..=64.0).contains(&stretch.maximum))
{
return Err(invalid("stretch", "Invalid velocity stretch"));
}
let mut sprite = None;
let (radius, kind, extra, align) = match style {
ParticleStyle::Dots { radius } => {
(*radius, InstanceKind::Disc, [0.0, 0.0, 1.0, 0.0], false)
}
ParticleStyle::GlowDots { radius } => {
(*radius, InstanceKind::Glow, [0.0, 0.0, 1.0, 0.0], false)
}
ParticleStyle::Sprites {
image,
size,
align_to_velocity,
} => {
sprite = Some(
image
.get()
.map_err(|_| invalid("sprite", "Configured sprite material is unavailable"))?,
);
(
*size * 0.5,
InstanceKind::Sprite,
[0.0, 0.0, 1.0, 0.0],
*align_to_velocity,
)
}
ParticleStyle::Shape { radius, shape } => {
let (kind, extra) = match shape {
ParticleShape::Polygon { sides } if (3..=32).contains(sides) => {
(InstanceKind::Polygon, [f32::from(*sides), 0.0, 1.0, 0.0])
}
ParticleShape::Ring { thickness }
if thickness.is_finite() && *thickness > 0.0 && *thickness <= 1.0 =>
{
(InstanceKind::Ring, [*thickness, 0.0, 1.0, 0.0])
}
ParticleShape::Capsule { aspect }
if aspect.is_finite() && (1.0..=64.0).contains(aspect) =>
{
(InstanceKind::Capsule, [0.0, 0.0, *aspect, 0.0])
}
ParticleShape::Soft { hardness }
if hardness.is_finite() && (0.0..=1.0).contains(hardness) =>
{
(InstanceKind::Soft, [*hardness, 0.0, 1.0, 0.0])
}
ParticleShape::Quad { aspect }
if aspect.is_finite() && *aspect > 0.0 && *aspect <= 64.0 =>
{
(InstanceKind::Quad, [0.0, 0.0, *aspect, 0.0])
}
_ => return Err(invalid("shape", "Invalid analytic shape parameters")),
};
(*radius, kind, extra, true)
}
ParticleStyle::Bokeh {
radius,
aperture,
focus,
shape,
ring,
hardness,
highlight,
} => {
if [aperture, focus, ring, hardness, highlight]
.iter()
.any(|value| !value.is_finite())
|| *aperture < 0.0
|| *highlight < 0.0
|| *highlight > 65504.0
|| !(0.0..=1.0).contains(ring)
|| !(0.0..=1.0).contains(hardness)
{
return Err(invalid("bokeh", "Invalid finite aperture/focus/energy"));
}
let sides = match shape {
BokehShape::Disc => 0.0,
BokehShape::Polygon(sides) if (3..=32).contains(sides) => f32::from(*sides),
_ => return Err(invalid("bokeh", "Require 3..=32 aperture blades")),
};
(
*radius,
InstanceKind::Bokeh,
[sides, *ring, *hardness, 0.0],
false,
)
}
ParticleStyle::Trails { width, .. } => {
(*width * 0.5, InstanceKind::TaperedSegment, [0.0; 4], false)
}
ParticleStyle::Plexus { radius, .. } => {
(*radius, InstanceKind::Disc, [0.0, 0.0, 1.0, 0.0], false)
}
_ => {
return Err(invalid(
"style",
"Configured style must be a built-in, non-nested style",
));
}
};
if !radius.is_finite() || !(0.0..=4096.0).contains(&radius) {
return Err(invalid("style", "Style radius must be finite in 0..=4096"));
}
if let Some(sheet) = options.sheet {
sheet.frame(&Particle::default())?;
if let Some(image) = &sprite
&& (image.width() % u32::from(sheet.columns) != 0
|| image.height() % u32::from(sheet.rows) != 0)
{
return Err(invalid(
"sheet",
"Texture dimensions must divide into whole cells",
));
}
}
let mut records = Vec::new();
let mut sorted = states.to_vec();
if options.sort_depth || kind == InstanceKind::Bokeh {
sorted.sort_by(|first, second| {
second.custom[1]
.total_cmp(&first.custom[1])
.then(first.index.cmp(&second.index))
});
}
let mut append = |mut particle: Particle,
start: [f32; 2],
endpoint: Option<([f32; 4], f32)>,
progress: f32|
-> Result<(), ValidationError> {
particle.validate()?;
if records.len() >= MAX_INSTANCE_COUNT {
return Err(limit("Extended particle instance allowance exhausted"));
}
let focus = if let ParticleStyle::Bokeh { focus, .. } = style {
*focus
} else {
0.0
};
let start = std::array::from_fn(|axis| {
start[axis] + options.parallax[axis] * (particle.custom[1] - focus)
});
for axis in 0..2 {
particle.position[axis] += options.parallax[axis] * (particle.custom[1] - focus);
}
let mut record = ExtendedInstanceRecord {
base: InstanceRecord {
position: particle.position,
start,
color: particle.color,
radius: radius as f32 * particle.size,
rotation: particle.rotation,
width: 1.0,
kind,
},
extra,
};
if (align || options.stretch.is_some()) && particle.velocity != [0.0; 2] {
record.base.rotation += libm::atan2f(particle.velocity[1], particle.velocity[0]);
}
if let Some(stretch) = options.stretch {
record.extra[2] = (1.0
+ libm::hypotf(particle.velocity[0], particle.velocity[1]) * stretch.scale)
.min(stretch.maximum);
if kind == InstanceKind::Disc {
record.base.kind = InstanceKind::Capsule;
}
}
if let Some(sheet) = options.sheet {
record.base.width = record.extra[2].max(1.0);
record.extra = sheet.uv(&particle)?;
record.base.kind = InstanceKind::SpriteSheet;
}
if options.flip {
let flip = libm::cosf(particle.age * 5.0 + particle.custom[2]).abs();
record.extra[2] *= flip.max(0.01);
for channel in &mut record.base.color[..3] {
*channel *= 0.35 + flip * 0.65;
}
}
if let ParticleStyle::Bokeh {
aperture,
highlight,
..
} = style
{
let coc = (1.0 + aperture * (particle.custom[1] - focus).abs()).min(64.0);
record.base.radius *= coc;
for channel in &mut record.base.color[..3] {
*channel *= highlight / (coc * coc);
}
}
if let Some((color, width)) = endpoint {
record.base.kind = InstanceKind::TaperedSegment;
record.extra = color;
record.base.width = width;
if let Some(taper) = &options.trails.taper {
record.base.radius *= taper.sample(progress)?;
}
if let Some(fade) = &options.trails.fade {
let fade = fade.sample(progress)?;
if fade > 1.0 {
return Err(invalid("trail", "Trail fade must be in 0..=1"));
}
record.base.color = record.base.color.map(|value| value * fade);
}
if options.trails.ribbon {
record.base.kind = InstanceKind::Ribbon;
}
}
records
.try_reserve(1)
.map_err(|_| limit("Extended record allocation failed"))?;
records.push(record);
Ok(())
};
if let ParticleStyle::Trails { length, .. } = style {
if *length <= Time::ZERO || length.as_seconds() > 60.0 {
return Err(invalid("trail", "Trail duration must be in (0,60]"));
}
let count = options.trails.segments;
let max_bends = if options.trails.ribbon { 8.0 } else { 4.0 };
let mut retained = 0_u64;
let samples = (0..=count)
.map(|index| {
let states = sample(
context.time() - *length
+ Time::from_ticks(length.ticks() * i64::from(index) / i64::from(count)),
)?;
retained = retained
.checked_add(states.len() as u64 * 160)
.ok_or_else(|| limit("Historical particle payload overflow"))?;
if retained > 64 * 1024 * 1024 {
return Err(limit("Historical samples and ID lookups exceed 64 MiB"));
}
Ok(states)
})
.collect::<Result<Vec<_>, _>>()?;
let lookups = samples
.iter()
.map(|states| {
states
.iter()
.map(|particle| (particle.index, particle))
.collect::<std::collections::BTreeMap<_, _>>()
})
.collect::<Vec<_>>();
for segment in 1..=usize::from(count) {
for particle in samples[segment].iter() {
if let Some(before) = lookups[segment - 1].get(&particle.index) {
let bends = if options.trails.smooth {
let previous = lookups[segment.saturating_sub(2)]
.get(&particle.index)
.copied()
.unwrap_or(before);
let next = lookups[(segment + 1).min(usize::from(count))]
.get(&particle.index)
.copied()
.unwrap_or(particle);
(libm::hypotf(
particle.position[0]
- before.position[0]
- (next.position[0] - previous.position[0]) * 0.5,
particle.position[1]
- before.position[1]
- (next.position[1] - previous.position[1]) * 0.5,
) / radius.max(0.1) as f32)
.ceil()
.clamp(1.0, max_bends) as usize
} else {
1
};
let mut prior = before.position;
for division in 1..=bends {
let amount = division as f32 / bends as f32;
let progress = (segment as f32 - 1.0 + amount) / f32::from(count);
let previous_progress = (segment as f32 - 1.0
+ (division - 1) as f32 / bends as f32)
/ f32::from(count);
let mut endpoint = *particle;
endpoint.color = std::array::from_fn(|channel| {
before.color[channel] * (1.0 - amount)
+ particle.color[channel] * amount
});
endpoint.size = before.size * (1.0 - amount) + particle.size * amount;
let previous_amount = (division - 1) as f32 / bends as f32;
let start_color = std::array::from_fn::<_, 4, _>(|channel| {
before.color[channel] * (1.0 - previous_amount)
+ particle.color[channel] * previous_amount
});
let start_size =
before.size * (1.0 - previous_amount) + particle.size * previous_amount;
if !options.trails.smooth {
endpoint.position = std::array::from_fn(|axis| {
before.position[axis] * (1.0 - amount)
+ particle.position[axis] * amount
});
}
if options.trails.smooth {
let previous = lookups[segment.saturating_sub(2)]
.get(&particle.index)
.copied()
.unwrap_or(before);
let next = lookups[(segment + 1).min(usize::from(count))]
.get(&particle.index)
.copied()
.unwrap_or(particle);
endpoint.position = std::array::from_fn(|axis| {
catmull(
previous.position[axis],
before.position[axis],
particle.position[axis],
next.position[axis],
amount,
)
});
}
let taper = options
.trails
.taper
.as_ref()
.map_or(Ok(1.0), |curve| curve.sample(previous_progress))?;
let fade = options
.trails
.fade
.as_ref()
.map_or(Ok(1.0), |curve| curve.sample(previous_progress))?;
if fade > 1.0 {
return Err(invalid("trail", "Trail fade must be in 0..=1"));
}
append(
endpoint,
prior,
Some((
start_color.map(|value| value * fade),
radius as f32 * 2.0 * start_size * taper,
)),
progress,
)?;
prior = endpoint.position;
}
}
}
}
} else {
for particle in &sorted {
append(*particle, particle.position, None, 0.0)?;
}
if let ParticleStyle::Plexus { max_distance, .. } = style {
for (first, second) in
super::super::neighbors::pairs(&sorted, *max_distance, 100_000_000)?
{
append(
sorted[first],
sorted[second].position,
Some((sorted[second].color, radius as f32 * 2.0)),
0.0,
)?;
}
}
}
if records.is_empty() {
return Ok(Node::empty());
}
let bounds = records
.iter()
.map(|record| support(record, 0.0))
.reduce(|first, second| first.union(second))
.unwrap_or_default();
let batch = ExtendedBatch::new(
records.into(),
sprite,
bounds,
options
.blend
.unwrap_or(if matches!(style, ParticleStyle::GlowDots { .. }) {
InstanceBlend::Plus
} else {
InstanceBlend::SourceOver
}),
);
batch.validate()?;
Ok(Node::from(batch))
}
fn catmull(first: f32, second: f32, third: f32, fourth: f32, amount: f32) -> f32 {
0.5 * ((2.0 * second)
+ (-first + third) * amount
+ (2.0 * first - 5.0 * second + 4.0 * third - fourth) * amount * amount
+ (-first + 3.0 * second - 3.0 * third + fourth) * amount * amount * amount)
}