bendns' repos / fimg
fast image operations
Diffstat (limited to 'src/overlay.rs')
-rw-r--r--src/overlay.rs43
1 files changed, 17 insertions, 26 deletions
diff --git a/src/overlay.rs b/src/overlay.rs
index 8b19c1a..8733f20 100644
--- a/src/overlay.rs
+++ b/src/overlay.rs
@@ -70,45 +70,36 @@ pub trait ClonerOverlay<const W: usize, const C: usize>: Sealed {
/// # Safety
/// - UB if rgb.len() % 3 != 0
/// - UB if rgba.len() % 4 != 0
-unsafe fn blit(rgb: &mut [u8], rgba: &[u8]) {
- let mut srci = 0;
- let mut dsti = 0;
- while dsti + 16 <= rgb.len() {
- // SAFETY: i think it ok
- let old: Simd<u8, 16> = Simd::from_slice(unsafe { rgb.get_unchecked(dsti..dsti + 16) });
- // SAFETY: definitly ok
- let new: Simd<u8, 16> = Simd::from_slice(unsafe { rgba.get_unchecked(srci..srci + 16) });
+unsafe fn blit(mut rgb: &mut [u8], mut rgba: &[u8]) {
+ while rgb.len() >= 16 {
+ let dst = rgb.first_chunk_mut::<16>().unwrap();
+ let src = rgba.first_chunk::<16>().unwrap();
+ let old = Simd::from_slice(dst);
+ let new: u8x16 = Simd::from_slice(src);
let threshold = new.simd_ge(Simd::splat(128)).to_int().cast::<u8>();
let mut mask = simd_swizzle!(
threshold,
+ // [r, g, b, a (3)] [r, g, b, a(7)]
[3, 3, 3, 7, 7, 7, 11, 11, 11, 15, 15, 15, 0, 0, 0, 0]
);
mask &= Simd::from_array([
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 0, 0, 0, 0,
]);
-
+ // [r(0), g, b] <skip a> [r(4), g, b]
let new_rgb = simd_swizzle!(new, [0, 1, 2, 4, 5, 6, 8, 9, 10, 12, 13, 14, 0, 0, 0, 0]);
let blended = (new_rgb & mask) | (old & !mask);
- // SAFETY: 4 * 4 == 16, so in bounds
- blended.copy_to_slice(unsafe { rgb.get_unchecked_mut(dsti..dsti + 16) });
-
- srci += 16;
- dsti += 12;
+ blended.copy_to_slice(dst);
+ rgb = &mut rgb[12..];
+ rgba = &rgba[16..];
}
-
- while dsti + 3 <= rgb.len() {
- // SAFETY: caller guarantees slice is big enough
- if unsafe { *rgba.get_unchecked(srci + 3) } >= 128 {
- // SAFETY: slice is big enough!
- let src = unsafe { rgba.get_unchecked(srci..=srci + 2) };
- // SAFETY: i hear it bound
- let end = unsafe { rgb.get_unchecked_mut(dsti..=dsti + 2) };
- end.copy_from_slice(src);
+ while rgb.len() >= 3 {
+ // SAFETY: guaranteed
+ if unsafe { *rgba.get_unchecked(3) } >= 128 {
+ rgb[..3].copy_from_slice(&rgba[..3]);
}
-
- srci += 4;
- dsti += 3;
+ rgba = &rgba[4..];
+ rgb = &mut rgb[3..];
}
}