feat: add vse-gamma-cross example witnessing the blend-curve closed form#90
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AI-generated sequencer code assumes GAMMA_CROSS is the naive linear mix; it blends in a gamma-0.5 space and the mid dips 0.115 below the sRGB lerp. Per-frame sample renders pin the closed form ((1-t)*sqrt(A)+t*sqrt(B))^2 with t=(frame-start)/duration — never 1 inside the effect — on both versions. Documents the AgX-default sampling trap that poisons pixel witnesses and the orphan-delete of effects whose inputs are removed first. Signed-off-by: fOuttaMyPaint <TMhospitalitystrategies@gmail.com>
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Summary
The GAMMA_CROSS blend-curve witness from the ROADMAP pool (follow-up to
vse-cut-list): tiny per-frame renders across a crimson→teal cross, asserted against the fade's actual math per frame. AI-generated sequencer code assumes the cross is the naive lerp — it is not.Contract witnessed
out = ((1-t)·√A + t·√B)². Mid-cross from crimson(0.85, 0.10, 0.22)and teal(0.06, 0.75, 0.80)is(0.341, 0.349, 0.463)— 0.115 darker on red than the sRGB lerp(0.455, 0.425, 0.510). Every sample asserted within 5e-3 (2× the 8-bit quantization step + fit residual; measured 2.93e-3), mid lerp deviation asserted material (≥0.05).t = (frame − start) / duration, never 1 inside the effect — the last frame blends at(duration−1)/duration. Endpoint-inclusive is off by a frame-step.view_transform = 'Standard'— factory-default AgX tone-maps samples and poisons the fit (measured 0.146 on red during authoring). Also caught: deleting a consumed input strip orphans-and-deletes its effect (Strip 'GC' not in scene) — remove effects first.Version witness: blend math identical on 4.5.11 and 5.1.2 (samples match to the quantization step); creation contract from
vse-cut-listre-gated (strips,length=vsframe_end=).Falsification evidence (temporary breaks, restored after measurement):
GC inputs are not T1 -> T2Contact-sheet gate: vse-gamma-cross-contact-sheet.webp — verdicts: stage darkness ✓, wedge warmth ✓, subject fill ✓, saturation ✓ (most color-varied of the set), thumbnail legibility ✓ (fade row + framed contrast panel). Mean luminance 137.5 vs calibration 139.4 / 100.1 / 143.4 — mid-range.
Proven by live run vs inspection:
.scratch/blender-5.1.2-windows-x64/blender.exe(Blender 5.1.2, hash ec6e62d40fa9) and.scratch/blender-4.5.11-windows-x64/blender.exe(Blender 4.5.11 LTS, hash 4db51e9d1e1e) — identical values (samples=8 q_err=2.93e-3 lerp_mid_dev=0.115). Render exit 0 on both binaries (EEVEE), pixels iterated (5 drafts: teal-wash timeline bug, caption occlusions, clipping). All probes live.Test plan
29 examples)examples/vse-gamma-cross/vse_gamma_cross.py --.scratch/blender-5.1.2-windows-x64/blender.exe(5.1.2),.scratch/blender-4.5.11-windows-x64/blender.exe(4.5.11 LTS)Integration: example dir + README, gallery.json entry, plugin manifest, smoke step, top-level README ("Mesh, curves & text" category now 9, beside vse-cut-list; counts 28→29), generated pages read character-by-character (alt and callout full), ROADMAP entry shipped-marked.
🤖 Generated with Kimi Code