egui/emigui/src/texture_atlas.rs
2020-05-12 18:21:09 +02:00

149 lines
4.5 KiB
Rust

#[derive(Clone, Default)]
pub struct Texture {
/// e.g. a hash of the data. Use this to detect changes!
pub id: u64, // TODO
pub width: usize,
pub height: usize,
pub pixels: Vec<u8>,
}
impl std::ops::Index<(usize, usize)> for Texture {
type Output = u8;
fn index(&self, (x, y): (usize, usize)) -> &u8 {
assert!(x < self.width);
assert!(y < self.height);
&self.pixels[y * self.width + x]
}
}
impl std::ops::IndexMut<(usize, usize)> for Texture {
fn index_mut(&mut self, (x, y): (usize, usize)) -> &mut u8 {
assert!(x < self.width);
assert!(y < self.height);
&mut self.pixels[y * self.width + x]
}
}
/// A texture pixels, used for fonts.
#[derive(Clone, Default)]
pub struct TextureAtlas {
texture: Texture,
/// Used for when adding new rects
cursor: (usize, usize),
row_height: usize,
}
impl TextureAtlas {
pub fn new(width: usize, height: usize) -> Self {
Self {
texture: Texture {
id: 0,
width,
height,
pixels: vec![0; width * height],
},
..Default::default()
}
}
pub fn texture(&self) -> &Texture {
&self.texture
}
pub fn texture_mut(&mut self) -> &mut Texture {
self.texture.id += 1;
&mut self.texture
}
pub fn clear(&mut self) {
self.cursor = (0, 0);
self.row_height = 0;
}
/// Returns the coordinates of where the rect ended up.
pub fn allocate(&mut self, (w, h): (usize, usize)) -> (usize, usize) {
assert!(w <= self.texture.width);
if self.cursor.0 + w > self.texture.width {
// New row:
self.cursor.0 = 0;
self.cursor.1 += self.row_height;
self.row_height = 0;
}
self.row_height = self.row_height.max(h);
while self.cursor.1 + self.row_height >= self.texture.height {
self.texture.height *= 2;
}
if self.texture.width * self.texture.height > self.texture.pixels.len() {
self.texture
.pixels
.resize(self.texture.width * self.texture.height, 0);
}
let pos = self.cursor;
self.cursor.0 += w;
self.texture.id += 1;
(pos.0 as usize, pos.1 as usize)
}
}
impl Texture {
pub fn ui(&self, ui: &mut crate::Ui) {
use crate::{color::WHITE, label, layout::show_tooltip, math::*, Mesh, PaintCmd, Vertex};
ui.add(label!(
"Texture size: {} x {} (hover to zoom)",
self.width,
self.height
));
let mut size = vec2(self.width as f32, self.height as f32);
if size.x > ui.available().width() {
size *= ui.available().width() / size.x;
}
let interact = ui.reserve_space(size, None);
let rect = interact.rect;
let top_left = Vertex {
pos: rect.min,
uv: (0, 0),
color: WHITE,
};
let bottom_right = Vertex {
pos: rect.max,
uv: (self.width as u16 - 1, self.height as u16 - 1),
color: WHITE,
};
let mut mesh = Mesh::default();
mesh.add_rect(top_left, bottom_right);
ui.add_paint_cmd(PaintCmd::Mesh(mesh));
if interact.hovered {
show_tooltip(ui.ctx(), |ui| {
let pos = ui.top_left();
let zoom_rect = ui.reserve_space(vec2(128.0, 128.0), None).rect;
let u = remap_clamp(pos.x, rect.range_x(), 0.0..=self.width as f32 - 1.0).round();
let v = remap_clamp(pos.y, rect.range_y(), 0.0..=self.height as f32 - 1.0).round();
let texel_radius = 32.0;
let u = clamp(u, texel_radius..=self.width as f32 - 1.0 - texel_radius);
let v = clamp(v, texel_radius..=self.height as f32 - 1.0 - texel_radius);
let top_left = Vertex {
pos: zoom_rect.min,
uv: ((u - texel_radius) as u16, (v - texel_radius) as u16),
color: WHITE,
};
let bottom_right = Vertex {
pos: zoom_rect.max,
uv: ((u + texel_radius) as u16, (v + texel_radius) as u16),
color: WHITE,
};
let mut mesh = Mesh::default();
mesh.add_rect(top_left, bottom_right);
ui.add_paint_cmd(PaintCmd::Mesh(mesh));
});
}
}
}