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FA-51681 / Raster clipping / Open access

Scanline polygon span clip: vertex double crossing · case 01

Closed edge ranges count a pass-through vertex on the sample row twice, flipping even-odd parity for the rest of the row.

Verified by executionVariant 1 · 13 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Closed edge ranges count a pass-through vertex on the sample row twice, flipping even-odd parity for the rest of the row.

THE FAILURE

Closed edge ranges count a pass-through vertex on the sample row twice, flipping even-odd parity for the rest of the row.

Unsuccessful approach: Opening both ends avoids the double count but loses pass-through vertices entirely.

Case contract

Each command is [polygon,scissor]. Rows y in the scissor rows [top,bottom) intersected with [0,size) are sampled at y+1/2. Each polygon edge is oriented bottom to top and contributes a crossing when top<=yc<bottom (half-open in y), interpolated exactly. Crossings are sorted and paired even-odd. A pair covers pixels whose centers x+1/2 satisfy xa<=x+1/2<xb, i.e. [ceil(xa-1/2),ceil(xb-1/2)), then clipped to the scissor columns [left,right) intersected with [0,size). Non-empty spans are returned as [row,start,end].

Why this case matters

Raster clipping decides which pixels a primitive may touch; a single wrong clip decision writes outside the target or scissor, or silently drops visible coverage.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
from fractions import Fraction
N = 1
observations = []
def solve(commands, size):
    out=[]
    for poly,clip in commands:
        l,t,r,b=max(clip[0],0),max(clip[1],0),min(clip[2],size),min(clip[3],size)
        pts=[(Fraction(x),Fraction(y)) for x,y in poly]
        spans=[]
        for y in range(t,b):
            yc=y+Fraction(1,2)
            xs=[]
            for i in range(len(pts)):
                (ax,ay),(bx,by)=pts[i-1],pts[i]
                if ay>by: ax,ay,bx,by=bx,by,ax,ay
                if ay<=yc<=by:
                    xs.append(ax+(bx-ax)*(yc-ay)/(by-ay))
            xs.sort()
            for j in range(0,len(xs)-1,2):
                start=math.ceil(xs[j]-Fraction(1,2))
                end=math.ceil(xs[j+1]-Fraction(1,2))
                start,end=max(start,l),min(end,r)
                if start<end: spans.append([y,start,end])
        out.append(spans)
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
if N == 1:
    check('explicit case 0', solve([[[[1, 1], [5, 1], [5, 5], [1, 5]], [0, 0, 6, 6]]], 6), [[[1, 1, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]])
    check('explicit case 1', solve([[[[1, 0], [3, '5/2'], [5, 0], [5, 5], [1, 5]], [0, 0, 6, 6]]], 6), [[[1, 1, 2], [1, 4, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]])
    check('explicit case 2', solve([[[[0, '1/2'], [4, '5/2'], [0, '9/2']], [0, 0, 6, 6]]], 6), [[[1, 0, 2], [2, 0, 4], [3, 0, 2]]])
    check('explicit case 3', solve([[[['1/2', 0], ['7/2', 0], ['7/2', 3], ['1/2', 3]], [0, 0, 6, 6]]], 6), [[[0, 0, 3], [1, 0, 3], [2, 0, 3]]])
    check('explicit case 4', solve([[[['3/2', 0], ['9/2', 0], ['9/2', 2], ['3/2', 2]], [0, 0, 6, 6]]], 6), [[[0, 1, 4], [1, 1, 4]]])
    check('explicit case 5', solve([[[[0, 0], [6, 0], [6, 6], [0, 6]], [2, 1, 4, 3]]], 6), [[[1, 2, 4], [2, 2, 4]]])
    check('explicit case 6', solve([[[[0, 0], [1, 4], [2, 0], [3, 4], [4, 0], [4, 5], [0, 5]], [0, 0, 6, 6]]], 6), [[[2, 0, 1], [2, 1, 3], [2, 3, 4], [3, 0, 1], [3, 1, 3], [3, 3, 4], [4, 0, 4]]])
    check('explicit case 7', solve([[[[-2, 0], [8, 0], [8, 2], [-2, 2]], [0, 0, 6, 6]]], 6), [[[0, 0, 6], [1, 0, 6]]])
    check('explicit case 8', solve([[[[0, 0], [2, 0], [2, 2], [0, 2]], [3, 0, 6, 6]]], 6), [[]])
    check('explicit case 9', solve([[[[1, 0], [5, 4], [1, 4]], [0, 0, 6, 6]]], 6), [[[1, 1, 2], [2, 1, 3], [3, 1, 4]]])
    check('explicit case 10', solve([[[['1/4', 0], ['5/2', 0], ['5/2', 2], ['1/4', 2]], [1, 0, 6, 6]]], 6), [[[0, 1, 2], [1, 1, 2]]])
    check('explicit case 11', solve([[[[4, 1], [4, 4], [1, 4], [1, 1]], [0, 0, 6, 6]]], 6), [[[1, 1, 4], [2, 1, 4], [3, 1, 4]]])
    check('explicit case 12', solve([[[[0, 0], [5, 0], [5, 4], [3, '3/2'], [1, 4], [0, 4]], [0, 0, 6, 6]]], 6), [[[0, 0, 5], [1, 0, 3], [1, 3, 5], [2, 0, 2], [2, 4, 5], [3, 0, 1]]])
if N == 2:
    check('explicit case 0', solve([[[[1, 1], [6, 1], [6, 6], [1, 6]], [0, 0, 7, 7]]], 7), [[[1, 1, 6], [2, 1, 6], [3, 1, 6], [4, 1, 6], [5, 1, 6]]])
    check('explicit case 1', solve([[[[1, 0], [3, '5/2'], [5, 0], [5, 5], [1, 5]], [0, 0, 7, 7]]], 7), [[[1, 1, 2], [1, 4, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]])
    check('explicit case 2', solve([[[[0, '1/2'], [4, '5/2'], [0, '9/2']], [0, 0, 7, 7]]], 7), [[[1, 0, 2], [2, 0, 4], [3, 0, 2]]])
    check('explicit case 3', solve([[[['1/2', 0], ['7/2', 0], ['7/2', 3], ['1/2', 3]], [0, 0, 7, 7]]], 7), [[[0, 0, 3], [1, 0, 3], [2, 0, 3]]])
    check('explicit case 4', solve([[[['3/2', 0], ['9/2', 0], ['9/2', 2], ['3/2', 2]], [0, 0, 7, 7]]], 7), [[[0, 1, 4], [1, 1, 4]]])
    check('explicit case 5', solve([[[[0, 0], [7, 0], [7, 7], [0, 7]], [2, 1, 4, 3]]], 7), [[[1, 2, 4], [2, 2, 4]]])
    check('explicit case 6', solve([[[[0, 0], [1, 4], [2, 0], [3, 4], [4, 0], [4, 5], [0, 5]], [0, 0, 7, 7]]], 7), [[[2, 0, 1], [2, 1, 3], [2, 3, 4], [3, 0, 1], [3, 1, 3], [3, 3, 4], [4, 0, 4]]])
    check('explicit case 7', solve([[[[-2, 0], [9, 0], [9, 2], [-2, 2]], [0, 0, 7, 7]]], 7), [[[0, 0, 7], [1, 0, 7]]])
    check('explicit case 8', solve([[[[0, 0], [2, 0], [2, 2], [0, 2]], [3, 0, 7, 7]]], 7), [[]])
    check('explicit case 9', solve([[[[1, 0], [5, 4], [1, 4]], [0, 0, 7, 7]]], 7), [[[1, 1, 2], [2, 1, 3], [3, 1, 4]]])
    check('explicit case 10', solve([[[['1/4', 0], ['5/2', 0], ['5/2', 2], ['1/4', 2]], [1, 0, 7, 7]]], 7), [[[0, 1, 2], [1, 1, 2]]])
    check('explicit case 11', solve([[[[4, 1], [4, 4], [1, 4], [1, 1]], [0, 0, 7, 7]]], 7), [[[1, 1, 4], [2, 1, 4], [3, 1, 4]]])
    check('explicit case 12', solve([[[[0, 0], [5, 0], [5, 4], [3, '3/2'], [1, 4], [0, 4]], [0, 0, 7, 7]]], 7), [[[0, 0, 5], [1, 0, 3], [1, 3, 5], [2, 0, 2], [2, 4, 5], [3, 0, 1]]])
if N == 3:
    check('explicit case 0', solve([[[[1, 1], [7, 1], [7, 7], [1, 7]], [0, 0, 8, 8]]], 8), [[[1, 1, 7], [2, 1, 7], [3, 1, 7], [4, 1, 7], [5, 1, 7], [6, 1, 7]]])
    check('explicit case 1', solve([[[[1, 0], [3, '5/2'], [5, 0], [5, 5], [1, 5]], [0, 0, 8, 8]]], 8), [[[1, 1, 2], [1, 4, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]])
    check('explicit case 2', solve([[[[0, '1/2'], [4, '5/2'], [0, '9/2']], [0, 0, 8, 8]]], 8), [[[1, 0, 2], [2, 0, 4], [3, 0, 2]]])
    check('explicit case 3', solve([[[['1/2', 0], ['7/2', 0], ['7/2', 3], ['1/2', 3]], [0, 0, 8, 8]]], 8), [[[0, 0, 3], [1, 0, 3], [2, 0, 3]]])
    check('explicit case 4', solve([[[['3/2', 0], ['9/2', 0], ['9/2', 2], ['3/2', 2]], [0, 0, 8, 8]]], 8), [[[0, 1, 4], [1, 1, 4]]])
    check('explicit case 5', solve([[[[0, 0], [8, 0], [8, 8], [0, 8]], [2, 1, 4, 3]]], 8), [[[1, 2, 4], [2, 2, 4]]])
    check('explicit case 6', solve([[[[0, 0], [1, 4], [2, 0], [3, 4], [4, 0], [4, 5], [0, 5]], [0, 0, 8, 8]]], 8), [[[2, 0, 1], [2, 1, 3], [2, 3, 4], [3, 0, 1], [3, 1, 3], [3, 3, 4], [4, 0, 4]]])
    check('explicit case 7', solve([[[[-2, 0], [10, 0], [10, 2], [-2, 2]], [0, 0, 8, 8]]], 8), [[[0, 0, 8], [1, 0, 8]]])
    check('explicit case 8', solve([[[[0, 0], [2, 0], [2, 2], [0, 2]], [3, 0, 8, 8]]], 8), [[]])
    check('explicit case 9', solve([[[[1, 0], [5, 4], [1, 4]], [0, 0, 8, 8]]], 8), [[[1, 1, 2], [2, 1, 3], [3, 1, 4]]])
    check('explicit case 10', solve([[[['1/4', 0], ['5/2', 0], ['5/2', 2], ['1/4', 2]], [1, 0, 8, 8]]], 8), [[[0, 1, 2], [1, 1, 2]]])
    check('explicit case 11', solve([[[[4, 1], [4, 4], [1, 4], [1, 1]], [0, 0, 8, 8]]], 8), [[[1, 1, 4], [2, 1, 4], [3, 1, 4]]])
    check('explicit case 12', solve([[[[0, 0], [5, 0], [5, 4], [3, '3/2'], [1, 4], [0, 4]], [0, 0, 8, 8]]], 8), [[[0, 0, 5], [1, 0, 3], [1, 3, 5], [2, 0, 2], [2, 4, 5], [3, 0, 1]]])
if N == 4:
    check('explicit case 0', solve([[[[1, 1], [8, 1], [8, 8], [1, 8]], [0, 0, 9, 9]]], 9), [[[1, 1, 8], [2, 1, 8], [3, 1, 8], [4, 1, 8], [5, 1, 8], [6, 1, 8], [7, 1, 8]]])
    check('explicit case 1', solve([[[[1, 0], [3, '5/2'], [5, 0], [5, 5], [1, 5]], [0, 0, 9, 9]]], 9), [[[1, 1, 2], [1, 4, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]])
    check('explicit case 2', solve([[[[0, '1/2'], [4, '5/2'], [0, '9/2']], [0, 0, 9, 9]]], 9), [[[1, 0, 2], [2, 0, 4], [3, 0, 2]]])
    check('explicit case 3', solve([[[['1/2', 0], ['7/2', 0], ['7/2', 3], ['1/2', 3]], [0, 0, 9, 9]]], 9), [[[0, 0, 3], [1, 0, 3], [2, 0, 3]]])
    check('explicit case 4', solve([[[['3/2', 0], ['9/2', 0], ['9/2', 2], ['3/2', 2]], [0, 0, 9, 9]]], 9), [[[0, 1, 4], [1, 1, 4]]])
    check('explicit case 5', solve([[[[0, 0], [9, 0], [9, 9], [0, 9]], [2, 1, 4, 3]]], 9), [[[1, 2, 4], [2, 2, 4]]])
    check('explicit case 6', solve([[[[0, 0], [1, 4], [2, 0], [3, 4], [4, 0], [4, 5], [0, 5]], [0, 0, 9, 9]]], 9), [[[2, 0, 1], [2, 1, 3], [2, 3, 4], [3, 0, 1], [3, 1, 3], [3, 3, 4], [4, 0, 4]]])
    check('explicit case 7', solve([[[[-2, 0], [11, 0], [11, 2], [-2, 2]], [0, 0, 9, 9]]], 9), [[[0, 0, 9], [1, 0, 9]]])
    check('explicit case 8', solve([[[[0, 0], [2, 0], [2, 2], [0, 2]], [3, 0, 9, 9]]], 9), [[]])
    check('explicit case 9', solve([[[[1, 0], [5, 4], [1, 4]], [0, 0, 9, 9]]], 9), [[[1, 1, 2], [2, 1, 3], [3, 1, 4]]])
    check('explicit case 10', solve([[[['1/4', 0], ['5/2', 0], ['5/2', 2], ['1/4', 2]], [1, 0, 9, 9]]], 9), [[[0, 1, 2], [1, 1, 2]]])
    check('explicit case 11', solve([[[[4, 1], [4, 4], [1, 4], [1, 1]], [0, 0, 9, 9]]], 9), [[[1, 1, 4], [2, 1, 4], [3, 1, 4]]])
    check('explicit case 12', solve([[[[0, 0], [5, 0], [5, 4], [3, '3/2'], [1, 4], [0, 4]], [0, 0, 9, 9]]], 9), [[[0, 0, 5], [1, 0, 3], [1, 3, 5], [2, 0, 2], [2, 4, 5], [3, 0, 1]]])
if N == 5:
    check('explicit case 0', solve([[[[1, 1], [9, 1], [9, 9], [1, 9]], [0, 0, 10, 10]]], 10), [[[1, 1, 9], [2, 1, 9], [3, 1, 9], [4, 1, 9], [5, 1, 9], [6, 1, 9], [7, 1, 9], [8, 1, 9]]])
    check('explicit case 1', solve([[[[1, 0], [3, '5/2'], [5, 0], [5, 5], [1, 5]], [0, 0, 10, 10]]], 10), [[[1, 1, 2], [1, 4, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]])
    check('explicit case 2', solve([[[[0, '1/2'], [4, '5/2'], [0, '9/2']], [0, 0, 10, 10]]], 10), [[[1, 0, 2], [2, 0, 4], [3, 0, 2]]])
    check('explicit case 3', solve([[[['1/2', 0], ['7/2', 0], ['7/2', 3], ['1/2', 3]], [0, 0, 10, 10]]], 10), [[[0, 0, 3], [1, 0, 3], [2, 0, 3]]])
    check('explicit case 4', solve([[[['3/2', 0], ['9/2', 0], ['9/2', 2], ['3/2', 2]], [0, 0, 10, 10]]], 10), [[[0, 1, 4], [1, 1, 4]]])
    check('explicit case 5', solve([[[[0, 0], [10, 0], [10, 10], [0, 10]], [2, 1, 4, 3]]], 10), [[[1, 2, 4], [2, 2, 4]]])
    check('explicit case 6', solve([[[[0, 0], [1, 4], [2, 0], [3, 4], [4, 0], [4, 5], [0, 5]], [0, 0, 10, 10]]], 10), [[[2, 0, 1], [2, 1, 3], [2, 3, 4], [3, 0, 1], [3, 1, 3], [3, 3, 4], [4, 0, 4]]])
    check('explicit case 7', solve([[[[-2, 0], [12, 0], [12, 2], [-2, 2]], [0, 0, 10, 10]]], 10), [[[0, 0, 10], [1, 0, 10]]])
    check('explicit case 8', solve([[[[0, 0], [2, 0], [2, 2], [0, 2]], [3, 0, 10, 10]]], 10), [[]])
    check('explicit case 9', solve([[[[1, 0], [5, 4], [1, 4]], [0, 0, 10, 10]]], 10), [[[1, 1, 2], [2, 1, 3], [3, 1, 4]]])
    check('explicit case 10', solve([[[['1/4', 0], ['5/2', 0], ['5/2', 2], ['1/4', 2]], [1, 0, 10, 10]]], 10), [[[0, 1, 2], [1, 1, 2]]])
    check('explicit case 11', solve([[[[4, 1], [4, 4], [1, 4], [1, 1]], [0, 0, 10, 10]]], 10), [[[1, 1, 4], [2, 1, 4], [3, 1, 4]]])
    check('explicit case 12', solve([[[[0, 0], [5, 0], [5, 4], [3, '3/2'], [1, 4], [0, 4]], [0, 0, 10, 10]]], 10), [[[0, 0, 5], [1, 0, 3], [1, 3, 5], [2, 0, 2], [2, 4, 5], [3, 0, 1]]])
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 case 0[[[1, 1, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]][[[1, 1, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]]Passed
explicit case 1[[[1, 1, 2], [1, 4, 5], [2, 1, 3], [2, 3, 5], [3, 1, 5], [4, 1, 5]]][[[1, 1, 2], [1, 4, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]]Failed
explicit case 2[[[1, 0, 2], [2, 0, 4], [3, 0, 2]]][[[1, 0, 2], [2, 0, 4], [3, 0, 2]]]Passed
explicit case 3[[[0, 0, 3], [1, 0, 3], [2, 0, 3]]][[[0, 0, 3], [1, 0, 3], [2, 0, 3]]]Passed
explicit case 4[[[0, 1, 4], [1, 1, 4]]][[[0, 1, 4], [1, 1, 4]]]Passed
explicit case 5[[[1, 2, 4], [2, 2, 4]]][[[1, 2, 4], [2, 2, 4]]]Passed
explicit case 6[[[2, 0, 1], [2, 1, 3], [2, 3, 4], [3, 0, 1], [3, 1, 3], [3, 3, 4], [4, 0, 4]]][[[2, 0, 1], [2, 1, 3], [2, 3, 4], [3, 0, 1], [3, 1, 3], [3, 3, 4], [4, 0, 4]]]Passed
explicit case 7[[[0, 0, 6], [1, 0, 6]]][[[0, 0, 6], [1, 0, 6]]]Passed
explicit case 8[[]][[]]Passed
explicit case 9[[[1, 1, 2], [2, 1, 3], [3, 1, 4]]][[[1, 1, 2], [2, 1, 3], [3, 1, 4]]]Passed
explicit case 10[[[0, 1, 2], [1, 1, 2]]][[[0, 1, 2], [1, 1, 2]]]Passed
explicit case 11[[[1, 1, 4], [2, 1, 4], [3, 1, 4]]][[[1, 1, 4], [2, 1, 4], [3, 1, 4]]]Passed
explicit case 12[[[0, 0, 5], [1, 0, 3], [1, 3, 5], [2, 0, 2], [2, 4, 5], [3, 0, 1]]][[[0, 0, 5], [1, 0, 3], [1, 3, 5], [2, 0, 2], [2, 4, 5], [3, 0, 1]]]Passed

SHA-256 / 4007c130e70bebfdd22e090ddd0b6622e40192830919261c665d0202892890ec

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
from fractions import Fraction
N = 1
observations = []
def solve(commands, size):
    out=[]
    for poly,clip in commands:
        l,t,r,b=max(clip[0],0),max(clip[1],0),min(clip[2],size),min(clip[3],size)
        pts=[(Fraction(x),Fraction(y)) for x,y in poly]
        spans=[]
        for y in range(t,b):
            yc=y+Fraction(1,2)
            xs=[]
            for i in range(len(pts)):
                (ax,ay),(bx,by)=pts[i-1],pts[i]
                if ay>by: ax,ay,bx,by=bx,by,ax,ay
                if ay<yc<by:
                    xs.append(ax+(bx-ax)*(yc-ay)/(by-ay))
            xs.sort()
            for j in range(0,len(xs)-1,2):
                start=math.ceil(xs[j]-Fraction(1,2))
                end=math.ceil(xs[j+1]-Fraction(1,2))
                start,end=max(start,l),min(end,r)
                if start<end: spans.append([y,start,end])
        out.append(spans)
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
if N == 1:
    check('explicit case 0', solve([[[[1, 1], [5, 1], [5, 5], [1, 5]], [0, 0, 6, 6]]], 6), [[[1, 1, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]])
    check('explicit case 1', solve([[[[1, 0], [3, '5/2'], [5, 0], [5, 5], [1, 5]], [0, 0, 6, 6]]], 6), [[[1, 1, 2], [1, 4, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]])
    check('explicit case 2', solve([[[[0, '1/2'], [4, '5/2'], [0, '9/2']], [0, 0, 6, 6]]], 6), [[[1, 0, 2], [2, 0, 4], [3, 0, 2]]])
    check('explicit case 3', solve([[[['1/2', 0], ['7/2', 0], ['7/2', 3], ['1/2', 3]], [0, 0, 6, 6]]], 6), [[[0, 0, 3], [1, 0, 3], [2, 0, 3]]])
    check('explicit case 4', solve([[[['3/2', 0], ['9/2', 0], ['9/2', 2], ['3/2', 2]], [0, 0, 6, 6]]], 6), [[[0, 1, 4], [1, 1, 4]]])
    check('explicit case 5', solve([[[[0, 0], [6, 0], [6, 6], [0, 6]], [2, 1, 4, 3]]], 6), [[[1, 2, 4], [2, 2, 4]]])
    check('explicit case 6', solve([[[[0, 0], [1, 4], [2, 0], [3, 4], [4, 0], [4, 5], [0, 5]], [0, 0, 6, 6]]], 6), [[[2, 0, 1], [2, 1, 3], [2, 3, 4], [3, 0, 1], [3, 1, 3], [3, 3, 4], [4, 0, 4]]])
    check('explicit case 7', solve([[[[-2, 0], [8, 0], [8, 2], [-2, 2]], [0, 0, 6, 6]]], 6), [[[0, 0, 6], [1, 0, 6]]])
    check('explicit case 8', solve([[[[0, 0], [2, 0], [2, 2], [0, 2]], [3, 0, 6, 6]]], 6), [[]])
    check('explicit case 9', solve([[[[1, 0], [5, 4], [1, 4]], [0, 0, 6, 6]]], 6), [[[1, 1, 2], [2, 1, 3], [3, 1, 4]]])
    check('explicit case 10', solve([[[['1/4', 0], ['5/2', 0], ['5/2', 2], ['1/4', 2]], [1, 0, 6, 6]]], 6), [[[0, 1, 2], [1, 1, 2]]])
    check('explicit case 11', solve([[[[4, 1], [4, 4], [1, 4], [1, 1]], [0, 0, 6, 6]]], 6), [[[1, 1, 4], [2, 1, 4], [3, 1, 4]]])
    check('explicit case 12', solve([[[[0, 0], [5, 0], [5, 4], [3, '3/2'], [1, 4], [0, 4]], [0, 0, 6, 6]]], 6), [[[0, 0, 5], [1, 0, 3], [1, 3, 5], [2, 0, 2], [2, 4, 5], [3, 0, 1]]])
if N == 2:
    check('explicit case 0', solve([[[[1, 1], [6, 1], [6, 6], [1, 6]], [0, 0, 7, 7]]], 7), [[[1, 1, 6], [2, 1, 6], [3, 1, 6], [4, 1, 6], [5, 1, 6]]])
    check('explicit case 1', solve([[[[1, 0], [3, '5/2'], [5, 0], [5, 5], [1, 5]], [0, 0, 7, 7]]], 7), [[[1, 1, 2], [1, 4, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]])
    check('explicit case 2', solve([[[[0, '1/2'], [4, '5/2'], [0, '9/2']], [0, 0, 7, 7]]], 7), [[[1, 0, 2], [2, 0, 4], [3, 0, 2]]])
    check('explicit case 3', solve([[[['1/2', 0], ['7/2', 0], ['7/2', 3], ['1/2', 3]], [0, 0, 7, 7]]], 7), [[[0, 0, 3], [1, 0, 3], [2, 0, 3]]])
    check('explicit case 4', solve([[[['3/2', 0], ['9/2', 0], ['9/2', 2], ['3/2', 2]], [0, 0, 7, 7]]], 7), [[[0, 1, 4], [1, 1, 4]]])
    check('explicit case 5', solve([[[[0, 0], [7, 0], [7, 7], [0, 7]], [2, 1, 4, 3]]], 7), [[[1, 2, 4], [2, 2, 4]]])
    check('explicit case 6', solve([[[[0, 0], [1, 4], [2, 0], [3, 4], [4, 0], [4, 5], [0, 5]], [0, 0, 7, 7]]], 7), [[[2, 0, 1], [2, 1, 3], [2, 3, 4], [3, 0, 1], [3, 1, 3], [3, 3, 4], [4, 0, 4]]])
    check('explicit case 7', solve([[[[-2, 0], [9, 0], [9, 2], [-2, 2]], [0, 0, 7, 7]]], 7), [[[0, 0, 7], [1, 0, 7]]])
    check('explicit case 8', solve([[[[0, 0], [2, 0], [2, 2], [0, 2]], [3, 0, 7, 7]]], 7), [[]])
    check('explicit case 9', solve([[[[1, 0], [5, 4], [1, 4]], [0, 0, 7, 7]]], 7), [[[1, 1, 2], [2, 1, 3], [3, 1, 4]]])
    check('explicit case 10', solve([[[['1/4', 0], ['5/2', 0], ['5/2', 2], ['1/4', 2]], [1, 0, 7, 7]]], 7), [[[0, 1, 2], [1, 1, 2]]])
    check('explicit case 11', solve([[[[4, 1], [4, 4], [1, 4], [1, 1]], [0, 0, 7, 7]]], 7), [[[1, 1, 4], [2, 1, 4], [3, 1, 4]]])
    check('explicit case 12', solve([[[[0, 0], [5, 0], [5, 4], [3, '3/2'], [1, 4], [0, 4]], [0, 0, 7, 7]]], 7), [[[0, 0, 5], [1, 0, 3], [1, 3, 5], [2, 0, 2], [2, 4, 5], [3, 0, 1]]])
if N == 3:
    check('explicit case 0', solve([[[[1, 1], [7, 1], [7, 7], [1, 7]], [0, 0, 8, 8]]], 8), [[[1, 1, 7], [2, 1, 7], [3, 1, 7], [4, 1, 7], [5, 1, 7], [6, 1, 7]]])
    check('explicit case 1', solve([[[[1, 0], [3, '5/2'], [5, 0], [5, 5], [1, 5]], [0, 0, 8, 8]]], 8), [[[1, 1, 2], [1, 4, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]])
    check('explicit case 2', solve([[[[0, '1/2'], [4, '5/2'], [0, '9/2']], [0, 0, 8, 8]]], 8), [[[1, 0, 2], [2, 0, 4], [3, 0, 2]]])
    check('explicit case 3', solve([[[['1/2', 0], ['7/2', 0], ['7/2', 3], ['1/2', 3]], [0, 0, 8, 8]]], 8), [[[0, 0, 3], [1, 0, 3], [2, 0, 3]]])
    check('explicit case 4', solve([[[['3/2', 0], ['9/2', 0], ['9/2', 2], ['3/2', 2]], [0, 0, 8, 8]]], 8), [[[0, 1, 4], [1, 1, 4]]])
    check('explicit case 5', solve([[[[0, 0], [8, 0], [8, 8], [0, 8]], [2, 1, 4, 3]]], 8), [[[1, 2, 4], [2, 2, 4]]])
    check('explicit case 6', solve([[[[0, 0], [1, 4], [2, 0], [3, 4], [4, 0], [4, 5], [0, 5]], [0, 0, 8, 8]]], 8), [[[2, 0, 1], [2, 1, 3], [2, 3, 4], [3, 0, 1], [3, 1, 3], [3, 3, 4], [4, 0, 4]]])
    check('explicit case 7', solve([[[[-2, 0], [10, 0], [10, 2], [-2, 2]], [0, 0, 8, 8]]], 8), [[[0, 0, 8], [1, 0, 8]]])
    check('explicit case 8', solve([[[[0, 0], [2, 0], [2, 2], [0, 2]], [3, 0, 8, 8]]], 8), [[]])
    check('explicit case 9', solve([[[[1, 0], [5, 4], [1, 4]], [0, 0, 8, 8]]], 8), [[[1, 1, 2], [2, 1, 3], [3, 1, 4]]])
    check('explicit case 10', solve([[[['1/4', 0], ['5/2', 0], ['5/2', 2], ['1/4', 2]], [1, 0, 8, 8]]], 8), [[[0, 1, 2], [1, 1, 2]]])
    check('explicit case 11', solve([[[[4, 1], [4, 4], [1, 4], [1, 1]], [0, 0, 8, 8]]], 8), [[[1, 1, 4], [2, 1, 4], [3, 1, 4]]])
    check('explicit case 12', solve([[[[0, 0], [5, 0], [5, 4], [3, '3/2'], [1, 4], [0, 4]], [0, 0, 8, 8]]], 8), [[[0, 0, 5], [1, 0, 3], [1, 3, 5], [2, 0, 2], [2, 4, 5], [3, 0, 1]]])
if N == 4:
    check('explicit case 0', solve([[[[1, 1], [8, 1], [8, 8], [1, 8]], [0, 0, 9, 9]]], 9), [[[1, 1, 8], [2, 1, 8], [3, 1, 8], [4, 1, 8], [5, 1, 8], [6, 1, 8], [7, 1, 8]]])
    check('explicit case 1', solve([[[[1, 0], [3, '5/2'], [5, 0], [5, 5], [1, 5]], [0, 0, 9, 9]]], 9), [[[1, 1, 2], [1, 4, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]])
    check('explicit case 2', solve([[[[0, '1/2'], [4, '5/2'], [0, '9/2']], [0, 0, 9, 9]]], 9), [[[1, 0, 2], [2, 0, 4], [3, 0, 2]]])
    check('explicit case 3', solve([[[['1/2', 0], ['7/2', 0], ['7/2', 3], ['1/2', 3]], [0, 0, 9, 9]]], 9), [[[0, 0, 3], [1, 0, 3], [2, 0, 3]]])
    check('explicit case 4', solve([[[['3/2', 0], ['9/2', 0], ['9/2', 2], ['3/2', 2]], [0, 0, 9, 9]]], 9), [[[0, 1, 4], [1, 1, 4]]])
    check('explicit case 5', solve([[[[0, 0], [9, 0], [9, 9], [0, 9]], [2, 1, 4, 3]]], 9), [[[1, 2, 4], [2, 2, 4]]])
    check('explicit case 6', solve([[[[0, 0], [1, 4], [2, 0], [3, 4], [4, 0], [4, 5], [0, 5]], [0, 0, 9, 9]]], 9), [[[2, 0, 1], [2, 1, 3], [2, 3, 4], [3, 0, 1], [3, 1, 3], [3, 3, 4], [4, 0, 4]]])
    check('explicit case 7', solve([[[[-2, 0], [11, 0], [11, 2], [-2, 2]], [0, 0, 9, 9]]], 9), [[[0, 0, 9], [1, 0, 9]]])
    check('explicit case 8', solve([[[[0, 0], [2, 0], [2, 2], [0, 2]], [3, 0, 9, 9]]], 9), [[]])
    check('explicit case 9', solve([[[[1, 0], [5, 4], [1, 4]], [0, 0, 9, 9]]], 9), [[[1, 1, 2], [2, 1, 3], [3, 1, 4]]])
    check('explicit case 10', solve([[[['1/4', 0], ['5/2', 0], ['5/2', 2], ['1/4', 2]], [1, 0, 9, 9]]], 9), [[[0, 1, 2], [1, 1, 2]]])
    check('explicit case 11', solve([[[[4, 1], [4, 4], [1, 4], [1, 1]], [0, 0, 9, 9]]], 9), [[[1, 1, 4], [2, 1, 4], [3, 1, 4]]])
    check('explicit case 12', solve([[[[0, 0], [5, 0], [5, 4], [3, '3/2'], [1, 4], [0, 4]], [0, 0, 9, 9]]], 9), [[[0, 0, 5], [1, 0, 3], [1, 3, 5], [2, 0, 2], [2, 4, 5], [3, 0, 1]]])
if N == 5:
    check('explicit case 0', solve([[[[1, 1], [9, 1], [9, 9], [1, 9]], [0, 0, 10, 10]]], 10), [[[1, 1, 9], [2, 1, 9], [3, 1, 9], [4, 1, 9], [5, 1, 9], [6, 1, 9], [7, 1, 9], [8, 1, 9]]])
    check('explicit case 1', solve([[[[1, 0], [3, '5/2'], [5, 0], [5, 5], [1, 5]], [0, 0, 10, 10]]], 10), [[[1, 1, 2], [1, 4, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]])
    check('explicit case 2', solve([[[[0, '1/2'], [4, '5/2'], [0, '9/2']], [0, 0, 10, 10]]], 10), [[[1, 0, 2], [2, 0, 4], [3, 0, 2]]])
    check('explicit case 3', solve([[[['1/2', 0], ['7/2', 0], ['7/2', 3], ['1/2', 3]], [0, 0, 10, 10]]], 10), [[[0, 0, 3], [1, 0, 3], [2, 0, 3]]])
    check('explicit case 4', solve([[[['3/2', 0], ['9/2', 0], ['9/2', 2], ['3/2', 2]], [0, 0, 10, 10]]], 10), [[[0, 1, 4], [1, 1, 4]]])
    check('explicit case 5', solve([[[[0, 0], [10, 0], [10, 10], [0, 10]], [2, 1, 4, 3]]], 10), [[[1, 2, 4], [2, 2, 4]]])
    check('explicit case 6', solve([[[[0, 0], [1, 4], [2, 0], [3, 4], [4, 0], [4, 5], [0, 5]], [0, 0, 10, 10]]], 10), [[[2, 0, 1], [2, 1, 3], [2, 3, 4], [3, 0, 1], [3, 1, 3], [3, 3, 4], [4, 0, 4]]])
    check('explicit case 7', solve([[[[-2, 0], [12, 0], [12, 2], [-2, 2]], [0, 0, 10, 10]]], 10), [[[0, 0, 10], [1, 0, 10]]])
    check('explicit case 8', solve([[[[0, 0], [2, 0], [2, 2], [0, 2]], [3, 0, 10, 10]]], 10), [[]])
    check('explicit case 9', solve([[[[1, 0], [5, 4], [1, 4]], [0, 0, 10, 10]]], 10), [[[1, 1, 2], [2, 1, 3], [3, 1, 4]]])
    check('explicit case 10', solve([[[['1/4', 0], ['5/2', 0], ['5/2', 2], ['1/4', 2]], [1, 0, 10, 10]]], 10), [[[0, 1, 2], [1, 1, 2]]])
    check('explicit case 11', solve([[[[4, 1], [4, 4], [1, 4], [1, 1]], [0, 0, 10, 10]]], 10), [[[1, 1, 4], [2, 1, 4], [3, 1, 4]]])
    check('explicit case 12', solve([[[[0, 0], [5, 0], [5, 4], [3, '3/2'], [1, 4], [0, 4]], [0, 0, 10, 10]]], 10), [[[0, 0, 5], [1, 0, 3], [1, 3, 5], [2, 0, 2], [2, 4, 5], [3, 0, 1]]])
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 case 0[[[1, 1, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]][[[1, 1, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]]Passed
explicit case 1[[[1, 1, 2], [1, 4, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]][[[1, 1, 2], [1, 4, 5], [2, 1, 5], [3, 1, 5], [4, 1, 5]]]Passed
explicit case 2[[[1, 0, 2], [3, 0, 2]]][[[1, 0, 2], [2, 0, 4], [3, 0, 2]]]Failed
explicit case 3[[[0, 0, 3], [1, 0, 3], [2, 0, 3]]][[[0, 0, 3], [1, 0, 3], [2, 0, 3]]]Passed
explicit case 4[[[0, 1, 4], [1, 1, 4]]][[[0, 1, 4], [1, 1, 4]]]Passed
explicit case 5[[[1, 2, 4], [2, 2, 4]]][[[1, 2, 4], [2, 2, 4]]]Passed
explicit case 6[[[2, 0, 1], [2, 1, 3], [2, 3, 4], [3, 0, 1], [3, 1, 3], [3, 3, 4], [4, 0, 4]]][[[2, 0, 1], [2, 1, 3], [2, 3, 4], [3, 0, 1], [3, 1, 3], [3, 3, 4], [4, 0, 4]]]Passed
explicit case 7[[[0, 0, 6], [1, 0, 6]]][[[0, 0, 6], [1, 0, 6]]]Passed
explicit case 8[[]][[]]Passed
explicit case 9[[[1, 1, 2], [2, 1, 3], [3, 1, 4]]][[[1, 1, 2], [2, 1, 3], [3, 1, 4]]]Passed
explicit case 10[[[0, 1, 2], [1, 1, 2]]][[[0, 1, 2], [1, 1, 2]]]Passed
explicit case 11[[[1, 1, 4], [2, 1, 4], [3, 1, 4]]][[[1, 1, 4], [2, 1, 4], [3, 1, 4]]]Passed
explicit case 12[[[0, 0, 5], [1, 0, 5], [2, 0, 2], [2, 4, 5], [3, 0, 1]]][[[0, 0, 5], [1, 0, 3], [1, 3, 5], [2, 0, 2], [2, 4, 5], [3, 0, 1]]]Failed

SHA-256 / 4fddc20a1ba282288dba21614a9615641409b823f4a9fb8815322dfc0aafd639

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 13 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

Exact integer/rational arithmetic on small stipulated fixtures models the clipping decision only; no memory layout, GPU pipeline, graphics API or standards 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 2026-09-29T14:45:21.609173+00:00.

Case digest / dd4e5a6c5629924a470a53124d1782ba03b8c83ef0c912408c10052334dbd9d9