{"abstract":"Draw first-index is ignored when selecting index-buffer elements.","category":"Rendering state","checks":4,"contract":"Given a valid index subrange, apply first/count to index-buffer positions and base to fetched vertex indices.","evaluation_group":"xg-draw-range-base-vertex","failed_approach":"The first-index offset is added to vertex IDs instead of the independent base-vertex offset.","family":"xg-draw-range-base-vertex","id":"FA-10726","implementations":{"attempt":{"sha256":"0fd6b2dfb08b1f26491c387c784a96e2a7ee779a3d4d7dfe24e1e5153191e931","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(indices, first, count, base):\n    return [x+first for x in indices[first:first+count]]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*([0, 2, 4, 6], 1, 2, 10)), [12, 14])\ncheck('fixture 2', solve(*([1, 3], 0, 2, -1)), [0, 2])\ncheck('fixture 3', solve(*([0, 1], 1, 0, 7)), [])\ncheck('fixture 4', solve(*([5], 0, 1, 0)), [5])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"6cc88648a85bd1e05c3ed6cb12db5e196db81865c6e55921f8357506b2c0cde0","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(indices, first, count, base):\n    return [x+base for x in indices[:count]]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*([0, 2, 4, 6], 1, 2, 10)), [12, 14])\ncheck('fixture 2', solve(*([1, 3], 0, 2, -1)), [0, 2])\ncheck('fixture 3', solve(*([0, 1], 1, 0, 7)), [])\ncheck('fixture 4', solve(*([5], 0, 1, 0)), [5])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"fixed":{"sha256":"1dd0ec3b2570c5ab13b888afa0f2af93182549339da066d07dd9dff2a912eb13","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport math\nN = 1\nobservations = []\ndef solve(indices, first, count, base):\n    return [x+base for x in indices[first:first+count]]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\ncheck('fixture 1', solve(*([0, 2, 4, 6], 1, 2, 10)), [12, 14])\ncheck('fixture 2', solve(*([1, 3], 0, 2, -1)), [0, 2])\ncheck('fixture 3', solve(*([0, 1], 1, 0, 7)), [])\ncheck('fixture 4', solve(*([5], 0, 1, 0)), [5])\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":" 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.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"xg-draw-range-base-vertex","generated_at":"2026-09-29T14:38:41.686116+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"A deterministic software graphics stage with explicit channel and coordinate conventions; no hardware, device profile or API behavior is inferred.","repair":"Use the stage contract: Given a valid index subrange, apply first/count to index-buffer positions and base to fetched vertex indices.","root_cause":"Draw first-index is ignored when selecting index-buffer elements.","sha256":"644ffab8ab6908029df4697bee169bad7b81ed9cfb99c1b2e6dc1047c787a62c","title":"Draw range base vertex · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":38.709,"exit_code":1,"observations":[{"actual":[3,5],"check":"fixture 1","expected":[12,14],"passed":false},{"actual":[1,3],"check":"fixture 2","expected":[0,2],"passed":false},{"actual":[],"check":"fixture 3","expected":[],"passed":true},{"actual":[5],"check":"fixture 4","expected":[5],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [3, 5], \"expected\": [12, 14], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [1, 3], \"expected\": [0, 2], \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [5], \"expected\": [5], \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":36.494,"exit_code":1,"observations":[{"actual":[10,12],"check":"fixture 1","expected":[12,14],"passed":false},{"actual":[0,2],"check":"fixture 2","expected":[0,2],"passed":true},{"actual":[],"check":"fixture 3","expected":[],"passed":true},{"actual":[5],"check":"fixture 4","expected":[5],"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [10, 12], \"expected\": [12, 14], \"passed\": false}, {\"check\": \"fixture 2\", \"actual\": [0, 2], \"expected\": [0, 2], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [5], \"expected\": [5], \"passed\": true}], \"passed\": false}\n"},"fixed":{"elapsed_ms":38.059,"exit_code":0,"observations":[{"actual":[12,14],"check":"fixture 1","expected":[12,14],"passed":true},{"actual":[0,2],"check":"fixture 2","expected":[0,2],"passed":true},{"actual":[],"check":"fixture 3","expected":[],"passed":true},{"actual":[5],"check":"fixture 4","expected":[5],"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 1\", \"actual\": [12, 14], \"expected\": [12, 14], \"passed\": true}, {\"check\": \"fixture 2\", \"actual\": [0, 2], \"expected\": [0, 2], \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": [], \"expected\": [], \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": [5], \"expected\": [5], \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}