From a8d4514a1b3e6b27d9af42e859c1cf2645c12347 Mon Sep 17 00:00:00 2001 From: vangel76 Date: Mon, 19 Oct 2026 12:08:26 +0200 Subject: [PATCH] Glow: per-channel bright pass with After Effects' gain, glows above the threshold as bright as After Effects With Glow Colors = Original Colors, After Effects thresholds each channel of the straight colour separately and the glow is 8 x (value - threshold + 0.061) per channel (times Intensity), nothing below: fitted to AE 2026 renders of grey 0.65 / 0.8 / 0.9 / 1, orange (1, 0.5, 0) and (0.2, 0.6, 1) solids at Threshold 40 / 60 / 80 % and Radius 10 / 30 (36 channel values, exact to the 8-bit capture; an orange solid glows red only). EffectCraft scaled the colour by a luminance threshold (k = (L - thr) / (1 - thr)), about 3.7 x too dim on white. Cases 806 / 810 / 811 (32 bpc): outside the layer now within 3/255 of AE (806 white at Intensity 1: 119 = AE, was 32); grid 0 points off for 806-810. The glow's alpha (the blurred layer alpha) and the Arbitrary Map / A & B colours and alpha-based glows are unchanged. Stacked on fix-glow-halo (same lines). Not changed: Composite Original's semantics are swapped against AE's names (EffectCraft's "On Top" adds the glow over the original, which AE calls "Behind"; AE's "On Top" keeps the original over the glow), so imported AE Glows at the default Behind show no glow inside the layer (811 interior 204 vs AE 255). Co-Authored-By: Claude Opus 5.5 --- crates/effects/src/misc.rs | 52 ++++++++++++++++++++++++++++- crates/gpu/src/shaders/kernels.wgsl | 6 +++- docs/effects-parity.md | 3 +- 3 files changed, 58 insertions(+), 3 deletions(-) diff --git a/crates/effects/src/misc.rs b/crates/effects/src/misc.rs index 58e2b2c55..23e9a6844 100644 --- a/crates/effects/src/misc.rs +++ b/crates/effects/src/misc.rs @@ -127,6 +127,20 @@ pub fn glow_sigma(radius: f64) -> f64 { (radius * 0.384).max(0.5) } +/// Glow's bright pass for the original colours, per channel of the straight colour `v`: +/// `8 × (v − threshold + 0.0611)`, nothing below. Fitted to After Effects 2026 renders of grey +/// 0.65 / 0.8 / 0.9 / 1, orange and light-blue solids at Threshold 40 / 60 / 80 % and Radius 10 +/// / 30 (36 channel values, exact to the 8-bit capture): the glow is linear in each channel, +/// its gain is the same at every threshold and radius, and channels below the threshold add +/// nothing (an orange solid glows red only). +pub fn glow_bright_channel(v: f32, thr: f32) -> f32 { + (GLOW_GAIN * (v - thr + GLOW_KNEE)).max(0.0) +} + +/// [`glow_bright_channel`]'s gain and threshold offset. +pub const GLOW_GAIN: f32 = 8.0; +pub const GLOW_KNEE: f32 = 0.0611; + /// Glow Operation options (blend modes the glow is applied with). pub const GLOW_OPERATIONS: [&str; 17] = [ "Normal", @@ -201,8 +215,12 @@ fn glow(ctx: &EffectCtx, mut b: Buf) -> Buf { let t = glow_ab_t(l, looping, loops, phase, mid); let c = [ca[0] + (cb[0] - ca[0]) * t, ca[1] + (cb[1] - ca[1]) * t, ca[2] + (cb[2] - ca[2]) * t]; *px = [c[0] * k * a, c[1] * k * a, c[2] * k * a, ga]; - } else { + } else if alpha_based { *px = [px[0] * k, px[1] * k, px[2] * k, ga]; + } else { + // Original colours: each channel of the straight colour against the threshold. + let c = [px[0] / a, px[1] / a, px[2] / a].map(|v| glow_bright_channel(v, thr) * a); + *px = [c[0], c[1], c[2], ga]; } }); let s = glow_sigma(radius); @@ -792,6 +810,38 @@ mod tests { } } + /// After Effects 2026, Glow at Threshold 60 %, Radius 10, Intensity 0.25 on 200 × 200 + /// solids over red: the glow 1.5 px outside the left edge, premultiplied (the green / blue + /// channels of the render, where the red background adds nothing), and its alpha 0.353. + #[test] + fn glow_brightness_matches_after_effects() { + // (solid colour, channel, AE glow value 0..255) + let cases = [ + ([0.65, 0.65, 0.65], 1, 20.0), + ([0.8, 0.8, 0.8], 1, 47.0), + ([0.9, 0.9, 0.9], 1, 65.0), + ([1.0, 1.0, 1.0], 1, 83.0), + ([1.0, 0.5, 0.0], 1, 0.0), + ([0.2, 0.6, 1.0], 1, 11.0), + ([0.2, 0.6, 1.0], 2, 83.0), + ]; + for (c, ch, ae) in cases { + let img = effectcraft_raster::Image::filled(200, 200, [c[0], c[1], c[2], 1.0]); + let set = [("threshold", num(60.0)), ("radius", num(10.0)), ("intensity", num(0.25))]; + let o = run_fx("ec.stylize.glow", &set, img, 0.0, EffectEnv::default()); + let (bx, by) = o.to_px([-1.5, 100.0]); + let p = o.img.get(bx.floor() as i64, by.floor() as i64); + assert!((p[ch] * 255.0 - ae).abs() <= 2.5, "{c:?} channel {ch}: {} vs AE {ae}", p[ch] * 255.0); + assert!((p[3] - 0.353).abs() < 3.0 / 255.0, "{c:?}: alpha {}", p[3]); + } + // Intensity scales the colour linearly: white at Intensity 1 is 3.7 × its alpha. + let white = effectcraft_raster::Image::filled(200, 200, [1.0, 1.0, 1.0, 1.0]); + let o = run_fx("ec.stylize.glow", &[("threshold", num(60.0)), ("radius", num(10.0))], white, 0.0, EffectEnv::default()); + let (bx, by) = o.to_px([-1.5, 100.0]); + let p = o.img.get(bx.floor() as i64, by.floor() as i64); + assert!((p[1] / p[3] - 3.69).abs() < 0.05, "{p:?}"); + } + #[test] fn glow_operation_and_arbitrary_map() { // Pixels addressed in layer space (Glow pads its buffer). diff --git a/crates/gpu/src/shaders/kernels.wgsl b/crates/gpu/src/shaders/kernels.wgsl index 5ee02c69a..ca28e4fc7 100644 --- a/crates/gpu/src/shaders/kernels.wgsl +++ b/crates/gpu/src/shaders/kernels.wgsl @@ -391,8 +391,12 @@ fn glow_bright(@builtin(global_invocation_id) gid: vec3) { let cb = P.f[2].xyz; let c = ca + (cb - ca) * t; textureStore(out, p, vec4(c * k * a, ga)); - } else { + } else if (P.u[0].y != 0u) { textureStore(out, p, vec4(px.xyz * k, ga)); + } else { + // Original colours, per channel (effects::misc::glow_bright_channel). + let c = max(8.0 * (px.xyz / a - vec3(thr - 0.0611)), vec3(0.0)); + textureStore(out, p, vec4(c * a, ga)); } } diff --git a/docs/effects-parity.md b/docs/effects-parity.md index 3fd188d9f..67b02d8bd 100644 --- a/docs/effects-parity.md +++ b/docs/effects-parity.md @@ -42,7 +42,7 @@ corpus compares renders, each effect is assumed to differ somewhere, and users k | Paint | 1 | 0 | Tablet pressure not read ([hardware-parity.md](hardware-parity.md)) | | Perspective | 10 | 9 | Chromatic Aberrations pan/tilt crash (#580) | | Simulation | 18 | 18 | Particle Playground lacks Particle Exploder, text particles, ephemeral mapper; CC Particle World camera fixed (#397) | -| Stylize | 25 | 25 | Glow's halo (coverage of a dim layer's edge) and blur width match After Effects 2026 renders; the brightness of glows above the threshold is not matched yet; Motion Tile output size (#369) | +| Stylize | 25 | 25 | Glow's halo (coverage of a dim layer's edge) and blur width match After Effects 2026 renders; glows above the threshold match too (each channel 8 × (value − threshold + 0.061), measured at three thresholds and two radii); Composite Original's labels are swapped against After Effects (EffectCraft's On Top adds the glow over the original, which After Effects calls Behind); Motion Tile output size (#369) | | Text | 2 | 2 | — | | Time | 8 | 8 | #535 (Pixel Motion Blur, Vector Detail) is closed | | Transition | 17 | 17 | — | @@ -64,6 +64,7 @@ the GPU is performance, not parity. | Date | Change | Summary | |---|---|---| +| 2026-10-19 | minor | Glow (original colours): bright pass per channel, 8 × (value − threshold + 0.061), measured against After Effects 2026 (CPU and GPU) | | 2026-10-19 | minor | Glow (colour channels): the glow covers the layer's blurred alpha, blur σ = 0.384 × radius, measured against After Effects 2026 renders (CPU and GPU) | | 2026-10-12 | minor | Parameters 3,014 to 3,017 (effects.md); #303, #514, #526, #533–#536 marked closed instead of pending | | 2026-10-12 | minor | Effect colour labels (26.5) added in Effect Controls |