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use crate::{ImageData, ImageDelta, TextureId};
use ahash::AHashMap;
// ----------------------------------------------------------------------------
/// Low-level manager for allocating textures.
///
/// Communicates with the painting subsystem using [`Self::take_delta`].
#[derive(Default)]
pub struct TextureManager {
/// We allocate texture id:s linearly.
next_id: u64,
/// Information about currently allocated textures.
metas: AHashMap<TextureId, TextureMeta>,
delta: TexturesDelta,
}
impl TextureManager {
/// Allocate a new texture.
///
/// The given name can be useful for later debugging.
///
/// The returned [`TextureId`] will be [`TextureId::Managed`], with an index
/// starting from zero and increasing with each call to [`Self::alloc`].
///
/// The first texture you allocate will be `TextureId::Managed(0) == TexureId::default()` and
/// MUST have a white pixel at (0,0) ([`crate::WHITE_UV`]).
///
/// The texture is given a retain-count of `1`, requiring one call to [`Self::free`] to free it.
pub fn alloc(&mut self, name: String, image: ImageData) -> TextureId {
let id = TextureId::Managed(self.next_id);
self.next_id += 1;
self.metas.entry(id).or_insert_with(|| TextureMeta {
name,
size: image.size(),
bytes_per_pixel: image.bytes_per_pixel(),
retain_count: 1,
});
self.delta.set.insert(id, ImageDelta::full(image));
id
}
/// Assign a new image to an existing texture,
/// or update a region of it.
pub fn set(&mut self, id: TextureId, delta: ImageDelta) {
if let Some(meta) = self.metas.get_mut(&id) {
if delta.is_whole() {
meta.size = delta.image.size();
meta.bytes_per_pixel = delta.image.bytes_per_pixel();
}
self.delta.set.insert(id, delta);
} else {
crate::epaint_assert!(
false,
"Tried setting texture {:?} which is not allocated",
id
);
}
}
/// Free an existing texture.
pub fn free(&mut self, id: TextureId) {
if let std::collections::hash_map::Entry::Occupied(mut entry) = self.metas.entry(id) {
let meta = entry.get_mut();
meta.retain_count -= 1;
if meta.retain_count == 0 {
entry.remove();
self.delta.free.push(id);
}
} else {
crate::epaint_assert!(
false,
"Tried freeing texture {:?} which is not allocated",
id
);
}
}
/// Increase the retain-count of the given texture.
///
/// For each time you call [`Self::retain`] you must call [`Self::free`] on additional time.
pub fn retain(&mut self, id: TextureId) {
if let Some(meta) = self.metas.get_mut(&id) {
meta.retain_count += 1;
} else {
crate::epaint_assert!(
false,
"Tried retaining texture {:?} which is not allocated",
id
);
}
}
/// Take and reset changes since last frame.
///
/// These should be applied to the painting subsystem each frame.
pub fn take_delta(&mut self) -> TexturesDelta {
std::mem::take(&mut self.delta)
}
/// Get meta-data about a specific texture.
pub fn meta(&self, id: TextureId) -> Option<&TextureMeta> {
self.metas.get(&id)
}
/// Get meta-data about all allocated textures in some arbitrary order.
pub fn allocated(&self) -> impl ExactSizeIterator<Item = (&TextureId, &TextureMeta)> {
self.metas.iter()
}
/// Total number of allocated textures.
pub fn num_allocated(&self) -> usize {
self.metas.len()
}
}
/// Meta-data about an allocated texture.
#[derive(Clone, Debug, PartialEq)]
pub struct TextureMeta {
/// A human-readable name useful for debugging.
pub name: String,
/// width x height
pub size: [usize; 2],
/// 4 or 1
pub bytes_per_pixel: usize,
/// Free when this reaches zero.
pub retain_count: usize,
}
impl TextureMeta {
/// Size in bytes.
/// width x height x [`Self::bytes_per_pixel`].
pub fn bytes_used(&self) -> usize {
self.size[0] * self.size[1] * self.bytes_per_pixel
}
}
// ----------------------------------------------------------------------------
/// What has been allocated and freed during the last period.
///
/// These are commands given to the integration painter.
#[derive(Clone, Default, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
#[must_use = "The painter must take care of this"]
pub struct TexturesDelta {
/// New or changed textures. Apply before painting.
pub set: AHashMap<TextureId, ImageDelta>,
/// Textures to free after painting.
pub free: Vec<TextureId>,
}
impl TexturesDelta {
pub fn is_empty(&self) -> bool {
self.set.is_empty() && self.free.is_empty()
}
pub fn append(&mut self, mut newer: TexturesDelta) {
self.set.extend(newer.set.into_iter());
self.free.append(&mut newer.free);
}
pub fn clear(&mut self) {
self.set.clear();
self.free.clear();
}
}
impl std::fmt::Debug for TexturesDelta {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
let mut debug_struct = f.debug_struct("TexturesDelta");
if !self.set.is_empty() {
let mut string = String::new();
for (tex_id, delta) in &self.set {
let size = delta.image.size();
if let Some(pos) = delta.pos {
string += &format!(
"{:?} partial ([{} {}] - [{} {}]), ",
tex_id,
pos[0],
pos[1],
pos[0] + size[0],
pos[1] + size[1]
);
} else {
string += &format!("{:?} full {}x{}, ", tex_id, size[0], size[1]);
}
}
debug_struct.field("set", &string);
}
if !self.free.is_empty() {
debug_struct.field("free", &self.free);
}
debug_struct.finish()
}
}