diff --git a/crates/effects/src/color_fx.rs b/crates/effects/src/color_fx.rs index 705cc3c7..4dd800fa 100644 --- a/crates/effects/src/color_fx.rs +++ b/crates/effects/src/color_fx.rs @@ -59,18 +59,22 @@ fn tritone(ctx: &EffectCtx, mut b: Buf) -> Buf { /// power toward white (`1-(1-v)^e`) or black (`v^e`); contrast uses `g = 1 + 0.53 c` instead of /// the old `2^(2c)` (that crushed 0.25 to ~8/255 at Contrast 100; AE is ~40/255). Values above 1 /// pass through. The GPU kernel mirrors it. +/// +/// Negative Brightness and Contrast are the inverse curves of the positive ones (After Effects +/// 2026 ramps: Brightness −40 is Brightness +40 inverted within 2.6/255, Contrast −50 likewise), +/// so they use the reciprocal exponents: Brightness −40 was 20/255 off AE, now 6.2. pub fn bc_modern(v: f32, b: f32, c: f32) -> f32 { if v >= 1.0 { return v; } let mut v = v.max(0.0); - if b > 0.0 { - v = 1.0 - (1.0 - v).powf(2f32.powf(1.24 * b)); - } else if b < 0.0 { - v = v.powf(2f32.powf(-1.32 * b)); + if b != 0.0 { + let e = 2f32.powf(1.24 * b.abs()); + v = 1.0 - (1.0 - v).powf(if b > 0.0 { e } else { 1.0 / e }); } if c != 0.0 { - let g = (1.0 + 0.53 * c).max(0.05); + let g = (1.0 + 0.53 * c.abs()).max(0.05); + let g = if c > 0.0 { g } else { 1.0 / g }; v = if v < 0.5 { 0.5 * (2.0 * v).powf(g) } else { 1.0 - 0.5 * (2.0 - 2.0 * v).max(0.0).powf(g) }; } v @@ -1340,6 +1344,32 @@ mod tests { } } + /// After Effects 2026 ramps (RENDERER round 2, session R8): negative Brightness and Contrast + /// are the inverses of the positive curves. (brightness, contrast, input, AE 8-bit) + #[test] + fn negative_brightness_and_contrast_invert_the_positive_curves() { + let go = |b: f64, c: f64, x: u8| { + let v = x as f32 / 255.0; + (px("ec.color.brightnesscontrast", &[("brightness", num(b)), ("contrast", num(c))], [v, v, v, 1.0])[0] * 255.0).round() as i32 + }; + let samples: &[(f64, f64, u8, u8)] = &[ + (-40.0, 0.0, 64, 50), + (-40.0, 0.0, 128, 99), + (-40.0, 0.0, 191, 155), + (-40.0, 0.0, 234, 207), + (0.0, -50.0, 21, 28), + (0.0, -50.0, 64, 76), + (0.0, -50.0, 191, 179), + (0.0, -50.0, 234, 227), + (40.0, 0.0, 128, 162), + (0.0, 50.0, 64, 52), + ]; + for &(b, c, x, ae) in samples { + let got = go(b, c, x); + assert!((got - ae as i32).abs() <= 7, "B{b} C{c} in {x}: got {got} AE {ae}"); + } + } + /// #1463: Black & White's sliders set the gray of each pure hue and blend between /// neighbouring hues; neutral pixels keep their value, overbright ones too, and an overbright /// colour stays finite (it used to divide by zero). diff --git a/crates/gpu/src/shaders/kernels.wgsl b/crates/gpu/src/shaders/kernels.wgsl index 00d75fe2..45cb9efe 100644 --- a/crates/gpu/src/shaders/kernels.wgsl +++ b/crates/gpu/src/shaders/kernels.wgsl @@ -624,14 +624,20 @@ fn pointwise(@builtin(global_invocation_id) gid: vec3) { } else if (P.u[0].y == 2u) { // Brightness & Contrast tone curves (effects crate bc_modern, AE-fitted #681). var o = c; - let g = max(1.0 + 0.53 * ct, 0.05); + // Negative settings invert the positive curves (reciprocal exponents). + var g = max(1.0 + 0.53 * abs(ct), 0.05); + if (ct < 0.0) { + g = 1.0 / g; + } + var e = exp2(1.24 * abs(br)); + if (br < 0.0) { + e = 1.0 / e; + } for (var i = 0; i < 3; i++) { if (c[i] < 1.0) { var v = max(c[i], 0.0); - if (br > 0.0) { - v = 1.0 - powz(1.0 - v, exp2(1.24 * br)); - } else if (br < 0.0) { - v = powz(v, exp2(-1.32 * br)); + if (br != 0.0) { + v = 1.0 - powz(1.0 - v, e); } if (ct != 0.0) { if (v < 0.5) { diff --git a/docs/effects-parity.md b/docs/effects-parity.md index 2d59c6b4..d072c49c 100644 --- a/docs/effects-parity.md +++ b/docs/effects-parity.md @@ -30,7 +30,7 @@ corpus compares renders, each effect is assumed to differ somewhere, and users k | Audio | 13 | 0 | CPU by design (applied in the mixdown) | | Blur & Sharpen | 16 | 15 | Gaussian Blur interaction and output to be measured first ([fidelity/ae-2026-acceptance.md](fidelity/ae-2026-acceptance.md)) | | Channel | 13 | 13 | — | -| Color Correction | 40 | 40 | Tint, Tritone and Black & White (sliders and Tint) match After Effects 2026 renders (Rec. 601 luminance); Levels (Individual Controls) matches After Effects 2026 in 32 bpc (channel controls before RGB, "Off for 32 bpc Color" unclipped; plain Levels' channel order not measured); Tint has Swap Colors (#963); ACES 2.0 / OCIO 2.5 (26.5); Apply Color LUT (#514) and 32-bpc blending (#494) are closed | +| Color Correction | 40 | 40 | Tint, Tritone and Black & White (sliders and Tint) match After Effects 2026 renders (Rec. 601 luminance); Levels (Individual Controls) matches After Effects 2026 in 32 bpc (channel controls before RGB, "Off for 32 bpc Color" unclipped; plain Levels' channel order not measured); Brightness & Contrast (non-legacy) within about 6/255 of After Effects 2026 ramps (negative settings invert the positive curves); Tint has Swap Colors (#963); ACES 2.0 / OCIO 2.5 (26.5); Apply Color LUT (#514) and 32-bpc blending (#494) are closed | | Distort | 39 | 35 | Liquify has no viewer brush; #303 (Mesh Warp drag) and #534 (CC Power Pin Unstretch) are closed | | Expression Controls | 9 | 9 | — | | Generate | 26 | 25 | Fractal on the CPU (needs f64); #526 (Reset) and #536 (Write-on marks) are closed | @@ -67,8 +67,8 @@ the GPU is performance, not parity. | 2026-10-19 | minor | Tritone uses Rec. 601 luminance, measured against After Effects 2026 renders of a red solid and a grey ramp (CPU and GPU) | | 2026-10-19 | minor | Black & White's Tint keeps the gray's luminosity (Color blend), measured against After Effects 2026 renders (CPU and GPU) | | 2026-10-19 | minor | Levels: "Off for 32 bpc Color" no longer clips in 32 bpc projects, unclipped values extrapolate below Output Black; Levels (Individual Controls) applies the channel controls before the RGB ones, measured against After Effects 2026 (CPU and GPU) | +| 2026-10-19 | minor | Brightness & Contrast: negative Brightness / Contrast are the inverse curves of the positive ones (Brightness −40: 20/255 → 6/255 off After Effects 2026), CPU and GPU | | 2026-10-18 | minor | Tint uses Rec. 601 luminance weights, measured against After Effects 2026 renders of red, green, blue and grey solids (CPU and GPU) | -| 2026-10-18 | minor | Exposure converts to linear light with a pure 2.2 power curve, as measured in After Effects (Offset 0.0005 / 0.002 / 0.02 / 0.1 on black: 8 / 15 / 43 / 90), not the piecewise sRGB curve | | 2026-10-18 | minor | Exposure converts to linear light with a pure 2.2 power curve, as measured in After Effects (Offset 0.0005 / 0.002 / 0.02 / 0.1 on black: 8 / 15 / 43 / 90), not the piecewise sRGB curve; its sliders take After Effects' ranges (Exposure −100..100, slider −4..4; Offset −2..2, slider −0.5..0.5; Gamma Correction 0.1..10) | | 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 |