FA-10691 / Rendering state / Open access

Depth write independent test · case 01

Passing depth testing overrides a disabled depth write mask.

Verified by executionVariant 1 · 4 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Passing depth testing overrides a disabled depth write mask.

THE FAILURE

Passing depth testing overrides a disabled depth write mask.

Unsuccessful approach: Enabled writes incorrectly commit depth for rejected fragments.

Case contract

Update a scalar depth buffer only if fragment depth testing passed and depth writes are enabled.

Why this case matters

A deterministic software graphics stage with explicit channel and coordinate conventions; no hardware, device profile or API behavior is inferred.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(old, incoming, test_passed, write_enabled):
    return incoming if test_passed else old
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve(*(0.5, 0.25, True, False)), 0.5)
check('fixture 2', solve(*(0.5, 0.25, False, True)), 0.5)
check('fixture 3', solve(*(0.5, 0.25, True, True)), 0.25)
check('fixture 4', solve(*(0.5, 0.25, False, False)), 0.5)
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 fixture	Actual	Expected	Outcome
fixture 1	`0.25`	`0.5`	Failed
fixture 2	`0.5`	`0.5`	Passed
fixture 3	`0.25`	`0.25`	Passed
fixture 4	`0.5`	`0.5`	Passed

SHA-256 / a77bf9c25e518f8b269ad3e915611baf0c19e34bf3c0d3c3ab1aeb4371a780be

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(old, incoming, test_passed, write_enabled):
    return incoming if write_enabled else old
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve(*(0.5, 0.25, True, False)), 0.5)
check('fixture 2', solve(*(0.5, 0.25, False, True)), 0.5)
check('fixture 3', solve(*(0.5, 0.25, True, True)), 0.25)
check('fixture 4', solve(*(0.5, 0.25, False, False)), 0.5)
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 fixture	Actual	Expected	Outcome
fixture 1	`0.5`	`0.5`	Passed
fixture 2	`0.25`	`0.5`	Failed
fixture 3	`0.25`	`0.25`	Passed
fixture 4	`0.5`	`0.5`	Passed

SHA-256 / 76369ec80fa0c55ce033c4b367726197c09de63fffc66416d1a6e989de685a6a

HELD IN THE MEMBER ARCHIVE

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

This mechanism has 4 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.

Verification & scope

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 2026-09-29T14:38:41.247362+00:00.

Case digest / bd595c17d94c0ed74a96a9a61b0edd6f25310adc7418d45c17de6fd36eae0245