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FA-50966 / Raster clipping / Open access

Winding event raster: double signed · case 01

The overlap clip test rejects negatively oriented double coverage.

Verified by executionVariant 1 · 12 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The overlap clip test rejects negatively oriented double coverage.

THE FAILURE

The overlap clip test rejects negatively oriented double coverage.

Unsuccessful approach: Testing exactly two loses regions covered three or more times.

Case contract

Signed crossing events occur before their integer sample coordinate. For each finite target sample, sum all event deltas at or to its left, including events outside the left target edge. Fill rules are nonzero, odd, positive, negative, or magnitude-at-least-two. Inverse filling complements the result inside the target. Zero deltas are inert and coincident events add.

Why this case matters

Raster clip state can leak coverage across draws even when every individual region is valid.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(commands, size):
    out=[]
    for events,rule,inverse in commands:
        deltas={}
        for x,delta in events: deltas[x]=deltas.get(x,0)+delta
        winding=sum(delta for x,delta in deltas.items() if x<0)
        covered=[]
        for x in range(size):
            winding+=deltas.get(x,0)
            if rule=='nonzero': inside=winding!=0
            elif rule=='odd': inside=abs(winding)%2==1
            elif rule=='positive': inside=winding>0
            elif rule=='negative': inside=winding<0
            else: inside=winding>=2
            if inside ^ inverse: covered.append(x)
        out.append(covered)
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
if N == 1:
    check('explicit sequence 0', solve([[[[0, 1], [0, 1], [2, -2]], 'nonzero', False]], 4), [[0, 1]])
    check('explicit sequence 1', solve([[[[-3, 1], [2, -1]], 'nonzero', False]], 4), [[0, 1]])
    check('explicit sequence 2', solve([[[[0, 1], [2, -1]], 'nonzero', False]], 4), [[0, 1]])
    check('explicit sequence 3', solve([[[[0, -1], [2, 1]], 'nonzero', False]], 4), [[0, 1]])
    check('explicit sequence 4', solve([[[[0, 3], [2, -3]], 'odd', False]], 4), [[0, 1]])
    check('explicit sequence 5', solve([[[[0, 2], [2, -2]], 'positive', False]], 4), [[0, 1]])
    check('explicit sequence 6', solve([[[[0, -2], [2, 2]], 'negative', False]], 4), [[0, 1]])
    check('explicit sequence 7', solve([[[[0, -3], [2, 3]], 'double', False]], 4), [[0, 1]])
    check('explicit sequence 8', solve([[[[0, 1], [2, -1]], 'nonzero', True]], 4), [[2, 3]])
    check('explicit sequence 9', solve([[[[0, 1], [1, 1], [3, -2]], 'nonzero', False]], 4), [[0, 1, 2]])
    check('explicit sequence 10', solve([[[[0, 1], [0, -1]], 'nonzero', False]], 4), [[]])
    check('explicit sequence 11', solve([[[], 'odd', False]], 4), [[]])
if N == 2:
    check('explicit sequence 0', solve([[[[0, 1], [0, 1], [2, -2]], 'nonzero', False]], 5), [[0, 1]])
    check('explicit sequence 1', solve([[[[-3, 1], [2, -1]], 'nonzero', False]], 5), [[0, 1]])
    check('explicit sequence 2', solve([[[[0, 1], [2, -1]], 'nonzero', False]], 5), [[0, 1]])
    check('explicit sequence 3', solve([[[[0, -1], [2, 1]], 'nonzero', False]], 5), [[0, 1]])
    check('explicit sequence 4', solve([[[[0, 3], [2, -3]], 'odd', False]], 5), [[0, 1]])
    check('explicit sequence 5', solve([[[[0, 2], [2, -2]], 'positive', False]], 5), [[0, 1]])
    check('explicit sequence 6', solve([[[[0, -2], [2, 2]], 'negative', False]], 5), [[0, 1]])
    check('explicit sequence 7', solve([[[[0, -3], [2, 3]], 'double', False]], 5), [[0, 1]])
    check('explicit sequence 8', solve([[[[0, 1], [2, -1]], 'nonzero', True]], 5), [[2, 3, 4]])
    check('explicit sequence 9', solve([[[[0, 1], [1, 1], [3, -2]], 'nonzero', False]], 5), [[0, 1, 2]])
    check('explicit sequence 10', solve([[[[0, 1], [0, -1]], 'nonzero', False]], 5), [[]])
    check('explicit sequence 11', solve([[[], 'odd', False]], 5), [[]])
if N == 3:
    check('explicit sequence 0', solve([[[[0, 1], [0, 1], [2, -2]], 'nonzero', False]], 6), [[0, 1]])
    check('explicit sequence 1', solve([[[[-3, 1], [2, -1]], 'nonzero', False]], 6), [[0, 1]])
    check('explicit sequence 2', solve([[[[0, 1], [2, -1]], 'nonzero', False]], 6), [[0, 1]])
    check('explicit sequence 3', solve([[[[0, -1], [2, 1]], 'nonzero', False]], 6), [[0, 1]])
    check('explicit sequence 4', solve([[[[0, 3], [2, -3]], 'odd', False]], 6), [[0, 1]])
    check('explicit sequence 5', solve([[[[0, 2], [2, -2]], 'positive', False]], 6), [[0, 1]])
    check('explicit sequence 6', solve([[[[0, -2], [2, 2]], 'negative', False]], 6), [[0, 1]])
    check('explicit sequence 7', solve([[[[0, -3], [2, 3]], 'double', False]], 6), [[0, 1]])
    check('explicit sequence 8', solve([[[[0, 1], [2, -1]], 'nonzero', True]], 6), [[2, 3, 4, 5]])
    check('explicit sequence 9', solve([[[[0, 1], [1, 1], [3, -2]], 'nonzero', False]], 6), [[0, 1, 2]])
    check('explicit sequence 10', solve([[[[0, 1], [0, -1]], 'nonzero', False]], 6), [[]])
    check('explicit sequence 11', solve([[[], 'odd', False]], 6), [[]])
if N == 4:
    check('explicit sequence 0', solve([[[[0, 1], [0, 1], [2, -2]], 'nonzero', False]], 7), [[0, 1]])
    check('explicit sequence 1', solve([[[[-3, 1], [2, -1]], 'nonzero', False]], 7), [[0, 1]])
    check('explicit sequence 2', solve([[[[0, 1], [2, -1]], 'nonzero', False]], 7), [[0, 1]])
    check('explicit sequence 3', solve([[[[0, -1], [2, 1]], 'nonzero', False]], 7), [[0, 1]])
    check('explicit sequence 4', solve([[[[0, 3], [2, -3]], 'odd', False]], 7), [[0, 1]])
    check('explicit sequence 5', solve([[[[0, 2], [2, -2]], 'positive', False]], 7), [[0, 1]])
    check('explicit sequence 6', solve([[[[0, -2], [2, 2]], 'negative', False]], 7), [[0, 1]])
    check('explicit sequence 7', solve([[[[0, -3], [2, 3]], 'double', False]], 7), [[0, 1]])
    check('explicit sequence 8', solve([[[[0, 1], [2, -1]], 'nonzero', True]], 7), [[2, 3, 4, 5, 6]])
    check('explicit sequence 9', solve([[[[0, 1], [1, 1], [3, -2]], 'nonzero', False]], 7), [[0, 1, 2]])
    check('explicit sequence 10', solve([[[[0, 1], [0, -1]], 'nonzero', False]], 7), [[]])
    check('explicit sequence 11', solve([[[], 'odd', False]], 7), [[]])
if N == 5:
    check('explicit sequence 0', solve([[[[0, 1], [0, 1], [2, -2]], 'nonzero', False]], 8), [[0, 1]])
    check('explicit sequence 1', solve([[[[-3, 1], [2, -1]], 'nonzero', False]], 8), [[0, 1]])
    check('explicit sequence 2', solve([[[[0, 1], [2, -1]], 'nonzero', False]], 8), [[0, 1]])
    check('explicit sequence 3', solve([[[[0, -1], [2, 1]], 'nonzero', False]], 8), [[0, 1]])
    check('explicit sequence 4', solve([[[[0, 3], [2, -3]], 'odd', False]], 8), [[0, 1]])
    check('explicit sequence 5', solve([[[[0, 2], [2, -2]], 'positive', False]], 8), [[0, 1]])
    check('explicit sequence 6', solve([[[[0, -2], [2, 2]], 'negative', False]], 8), [[0, 1]])
    check('explicit sequence 7', solve([[[[0, -3], [2, 3]], 'double', False]], 8), [[0, 1]])
    check('explicit sequence 8', solve([[[[0, 1], [2, -1]], 'nonzero', True]], 8), [[2, 3, 4, 5, 6, 7]])
    check('explicit sequence 9', solve([[[[0, 1], [1, 1], [3, -2]], 'nonzero', False]], 8), [[0, 1, 2]])
    check('explicit sequence 10', solve([[[[0, 1], [0, -1]], 'nonzero', False]], 8), [[]])
    check('explicit sequence 11', solve([[[], 'odd', False]], 8), [[]])
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
explicit sequence 0[[0, 1]][[0, 1]]Passed
explicit sequence 1[[0, 1]][[0, 1]]Passed
explicit sequence 2[[0, 1]][[0, 1]]Passed
explicit sequence 3[[0, 1]][[0, 1]]Passed
explicit sequence 4[[0, 1]][[0, 1]]Passed
explicit sequence 5[[0, 1]][[0, 1]]Passed
explicit sequence 6[[0, 1]][[0, 1]]Passed
explicit sequence 7[[]][[0, 1]]Failed
explicit sequence 8[[2, 3]][[2, 3]]Passed
explicit sequence 9[[0, 1, 2]][[0, 1, 2]]Passed
explicit sequence 10[[]][[]]Passed
explicit sequence 11[[]][[]]Passed

SHA-256 / fa207699b05c7cb97d27f4775aceac71ba8974c115816700f992d3a267c2c380

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(commands, size):
    out=[]
    for events,rule,inverse in commands:
        deltas={}
        for x,delta in events: deltas[x]=deltas.get(x,0)+delta
        winding=sum(delta for x,delta in deltas.items() if x<0)
        covered=[]
        for x in range(size):
            winding+=deltas.get(x,0)
            if rule=='nonzero': inside=winding!=0
            elif rule=='odd': inside=abs(winding)%2==1
            elif rule=='positive': inside=winding>0
            elif rule=='negative': inside=winding<0
            else: inside=abs(winding)==2
            if inside ^ inverse: covered.append(x)
        out.append(covered)
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
if N == 1:
    check('explicit sequence 0', solve([[[[0, 1], [0, 1], [2, -2]], 'nonzero', False]], 4), [[0, 1]])
    check('explicit sequence 1', solve([[[[-3, 1], [2, -1]], 'nonzero', False]], 4), [[0, 1]])
    check('explicit sequence 2', solve([[[[0, 1], [2, -1]], 'nonzero', False]], 4), [[0, 1]])
    check('explicit sequence 3', solve([[[[0, -1], [2, 1]], 'nonzero', False]], 4), [[0, 1]])
    check('explicit sequence 4', solve([[[[0, 3], [2, -3]], 'odd', False]], 4), [[0, 1]])
    check('explicit sequence 5', solve([[[[0, 2], [2, -2]], 'positive', False]], 4), [[0, 1]])
    check('explicit sequence 6', solve([[[[0, -2], [2, 2]], 'negative', False]], 4), [[0, 1]])
    check('explicit sequence 7', solve([[[[0, -3], [2, 3]], 'double', False]], 4), [[0, 1]])
    check('explicit sequence 8', solve([[[[0, 1], [2, -1]], 'nonzero', True]], 4), [[2, 3]])
    check('explicit sequence 9', solve([[[[0, 1], [1, 1], [3, -2]], 'nonzero', False]], 4), [[0, 1, 2]])
    check('explicit sequence 10', solve([[[[0, 1], [0, -1]], 'nonzero', False]], 4), [[]])
    check('explicit sequence 11', solve([[[], 'odd', False]], 4), [[]])
if N == 2:
    check('explicit sequence 0', solve([[[[0, 1], [0, 1], [2, -2]], 'nonzero', False]], 5), [[0, 1]])
    check('explicit sequence 1', solve([[[[-3, 1], [2, -1]], 'nonzero', False]], 5), [[0, 1]])
    check('explicit sequence 2', solve([[[[0, 1], [2, -1]], 'nonzero', False]], 5), [[0, 1]])
    check('explicit sequence 3', solve([[[[0, -1], [2, 1]], 'nonzero', False]], 5), [[0, 1]])
    check('explicit sequence 4', solve([[[[0, 3], [2, -3]], 'odd', False]], 5), [[0, 1]])
    check('explicit sequence 5', solve([[[[0, 2], [2, -2]], 'positive', False]], 5), [[0, 1]])
    check('explicit sequence 6', solve([[[[0, -2], [2, 2]], 'negative', False]], 5), [[0, 1]])
    check('explicit sequence 7', solve([[[[0, -3], [2, 3]], 'double', False]], 5), [[0, 1]])
    check('explicit sequence 8', solve([[[[0, 1], [2, -1]], 'nonzero', True]], 5), [[2, 3, 4]])
    check('explicit sequence 9', solve([[[[0, 1], [1, 1], [3, -2]], 'nonzero', False]], 5), [[0, 1, 2]])
    check('explicit sequence 10', solve([[[[0, 1], [0, -1]], 'nonzero', False]], 5), [[]])
    check('explicit sequence 11', solve([[[], 'odd', False]], 5), [[]])
if N == 3:
    check('explicit sequence 0', solve([[[[0, 1], [0, 1], [2, -2]], 'nonzero', False]], 6), [[0, 1]])
    check('explicit sequence 1', solve([[[[-3, 1], [2, -1]], 'nonzero', False]], 6), [[0, 1]])
    check('explicit sequence 2', solve([[[[0, 1], [2, -1]], 'nonzero', False]], 6), [[0, 1]])
    check('explicit sequence 3', solve([[[[0, -1], [2, 1]], 'nonzero', False]], 6), [[0, 1]])
    check('explicit sequence 4', solve([[[[0, 3], [2, -3]], 'odd', False]], 6), [[0, 1]])
    check('explicit sequence 5', solve([[[[0, 2], [2, -2]], 'positive', False]], 6), [[0, 1]])
    check('explicit sequence 6', solve([[[[0, -2], [2, 2]], 'negative', False]], 6), [[0, 1]])
    check('explicit sequence 7', solve([[[[0, -3], [2, 3]], 'double', False]], 6), [[0, 1]])
    check('explicit sequence 8', solve([[[[0, 1], [2, -1]], 'nonzero', True]], 6), [[2, 3, 4, 5]])
    check('explicit sequence 9', solve([[[[0, 1], [1, 1], [3, -2]], 'nonzero', False]], 6), [[0, 1, 2]])
    check('explicit sequence 10', solve([[[[0, 1], [0, -1]], 'nonzero', False]], 6), [[]])
    check('explicit sequence 11', solve([[[], 'odd', False]], 6), [[]])
if N == 4:
    check('explicit sequence 0', solve([[[[0, 1], [0, 1], [2, -2]], 'nonzero', False]], 7), [[0, 1]])
    check('explicit sequence 1', solve([[[[-3, 1], [2, -1]], 'nonzero', False]], 7), [[0, 1]])
    check('explicit sequence 2', solve([[[[0, 1], [2, -1]], 'nonzero', False]], 7), [[0, 1]])
    check('explicit sequence 3', solve([[[[0, -1], [2, 1]], 'nonzero', False]], 7), [[0, 1]])
    check('explicit sequence 4', solve([[[[0, 3], [2, -3]], 'odd', False]], 7), [[0, 1]])
    check('explicit sequence 5', solve([[[[0, 2], [2, -2]], 'positive', False]], 7), [[0, 1]])
    check('explicit sequence 6', solve([[[[0, -2], [2, 2]], 'negative', False]], 7), [[0, 1]])
    check('explicit sequence 7', solve([[[[0, -3], [2, 3]], 'double', False]], 7), [[0, 1]])
    check('explicit sequence 8', solve([[[[0, 1], [2, -1]], 'nonzero', True]], 7), [[2, 3, 4, 5, 6]])
    check('explicit sequence 9', solve([[[[0, 1], [1, 1], [3, -2]], 'nonzero', False]], 7), [[0, 1, 2]])
    check('explicit sequence 10', solve([[[[0, 1], [0, -1]], 'nonzero', False]], 7), [[]])
    check('explicit sequence 11', solve([[[], 'odd', False]], 7), [[]])
if N == 5:
    check('explicit sequence 0', solve([[[[0, 1], [0, 1], [2, -2]], 'nonzero', False]], 8), [[0, 1]])
    check('explicit sequence 1', solve([[[[-3, 1], [2, -1]], 'nonzero', False]], 8), [[0, 1]])
    check('explicit sequence 2', solve([[[[0, 1], [2, -1]], 'nonzero', False]], 8), [[0, 1]])
    check('explicit sequence 3', solve([[[[0, -1], [2, 1]], 'nonzero', False]], 8), [[0, 1]])
    check('explicit sequence 4', solve([[[[0, 3], [2, -3]], 'odd', False]], 8), [[0, 1]])
    check('explicit sequence 5', solve([[[[0, 2], [2, -2]], 'positive', False]], 8), [[0, 1]])
    check('explicit sequence 6', solve([[[[0, -2], [2, 2]], 'negative', False]], 8), [[0, 1]])
    check('explicit sequence 7', solve([[[[0, -3], [2, 3]], 'double', False]], 8), [[0, 1]])
    check('explicit sequence 8', solve([[[[0, 1], [2, -1]], 'nonzero', True]], 8), [[2, 3, 4, 5, 6, 7]])
    check('explicit sequence 9', solve([[[[0, 1], [1, 1], [3, -2]], 'nonzero', False]], 8), [[0, 1, 2]])
    check('explicit sequence 10', solve([[[[0, 1], [0, -1]], 'nonzero', False]], 8), [[]])
    check('explicit sequence 11', solve([[[], 'odd', False]], 8), [[]])
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
explicit sequence 0[[0, 1]][[0, 1]]Passed
explicit sequence 1[[0, 1]][[0, 1]]Passed
explicit sequence 2[[0, 1]][[0, 1]]Passed
explicit sequence 3[[0, 1]][[0, 1]]Passed
explicit sequence 4[[0, 1]][[0, 1]]Passed
explicit sequence 5[[0, 1]][[0, 1]]Passed
explicit sequence 6[[0, 1]][[0, 1]]Passed
explicit sequence 7[[]][[0, 1]]Failed
explicit sequence 8[[2, 3]][[2, 3]]Passed
explicit sequence 9[[0, 1, 2]][[0, 1, 2]]Passed
explicit sequence 10[[]][[]]Passed
explicit sequence 11[[]][[]]Passed

SHA-256 / 58b086dddf4c7ea2145c173c7dd4beda321b723f1e1ac09bb5ee6beca1e31ac3

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 12 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

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Verification & scope

Finite one-dimensional integer sample sets model coverage state only; no geometric intersection, memory layout, GPU or graphics-standard conformance is claimed. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:45:14.259562+00:00.

Case digest / 82ee32e0e682beb8aa749cc4f360521f1e0cbb105d89305ffaa19ddf8f33f854