fix(B06): 옹벽 물빼기 파이프 끝을 벽 면에서 자름(73-2)

- B07 수확은 화면 밖 SVG 라 clip 이 안 먹음 — 벽 밖 0.5 m 가 실려 그림 범위가 바뀌던 것
- 파이프 가운데 = 그 높이의 벽 두께 중심 · 시험에 벽 밖 판정 추가

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013rJwJMVL4EE31y77TB11AP

B06_Section/B06_Section_UI_Cross_Wall_Hatch.ts

@@ -17,7 +17,7 @@
  * ========================================================================== */
 
 import { REVET_THICKNESS_M } from "./B06_Section_UI_Cross_Culvert_Const";
-import type { WallLayout } from "./B06_Section_UI_Cross_Culvert_Types";
+import type { OffsetPoint, WallLayout } from "./B06_Section_UI_Cross_Culvert_Types";
 
 const SVG_NS = "http://www.w3.org/2000/svg";
 const HATCH_CLASS = "b06-chart__culvert-stone";
@@ -159,9 +159,32 @@ const DRAIN_DIAMETER_M = 0.15;
 const DRAIN_FALL = 0.1;
 const DRAIN_CLASS = "b06-chart__wall-drain";
 
+/** 직선 a→b 가 볼록 벽 단면 안을 지나는 구간 — clip 이 없는 곳(B07 오프스크린 수확)도 벽 밖으로 안 샘. */
+function insideRun(a: OffsetPoint, b: OffsetPoint, polygon: OffsetPoint[]): OffsetPoint[] | null {
+  const dx = b.offset - a.offset;
+  const dy = b.elevation - a.elevation;
+  const hits: number[] = [];
+  polygon.forEach((p, i) => {
+    const q = polygon[(i + 1) % polygon.length];
+    const ex = q.offset - p.offset;
+    const ey = q.elevation - p.elevation;
+    const denominator = dx * ey - dy * ex;
+    if (Math.abs(denominator) < 1e-12) return;
+    const t = ((p.offset - a.offset) * ey - (p.elevation - a.elevation) * ex) / denominator;
+    const u = ((p.offset - a.offset) * dy - (p.elevation - a.elevation) * dx) / denominator;
+    if (u >= -1e-9 && u <= 1 + 1e-9) hits.push(t);
+  });
+  if (hits.length < 2) return null;
+  const at = (t: number): OffsetPoint => ({
+    offset: a.offset + dx * t,
+    elevation: a.elevation + dy * t,
+  });
+  return [at(Math.min(...hits)), at(Math.max(...hits))];
+}
+
 /**
  * 옹벽 물빼기 — 높이(바닥~상단)를 반올림(높이 / 1.5)개(최소 1) 띠로 고르게 나눠 띠마다
- * 가운데 하나. 배면 → 전면으로 꿰는 두 줄 평행선(앞쪽 조금 낮게) · 끝은 벽 clip 이 자름.
+ * 가운데 하나. 배면 → 전면으로 꿰는 두 줄 평행선(앞쪽 조금 낮게) · 벽 두께만큼.
  */
 function drawDrains(
   group: SVGElement,
@@ -172,20 +195,31 @@ function drawDrains(
   const bottom = wall.bottomBack.elevation;
   const height = wall.topBack.elevation - bottom;
   const count = Math.max(1, Math.round(height / DRAIN_BAND_M));
+  const back = wall.backOffset;
+  const [, , topFront, bottomFront] = wall.points;
   for (let i = 0; i < count; i += 1) {
     const center = bottom + (height * (i + 0.5)) / count;
+    // 그 높이의 전면 — 전면은 기울어 위로 갈수록 배면에 가까움.
+    const front =
+      bottomFront.offset + (topFront.offset - bottomFront.offset) * ((center - bottom) / height);
+    const fall = (DRAIN_FALL * Math.abs(front - back)) / 2;
     const pipe = document.createElementNS(SVG_NS, "g");
     pipe.setAttribute("class", DRAIN_CLASS);
     const title = document.createElementNS(SVG_NS, "title");
     title.textContent = "물빼기(보기용)";
     pipe.append(title);
-    // 배면 바깥 0.5m ~ 전면 발끝 바깥 0.5m — 기울기를 유지한 채 벽 clip 이 두께만큼 남김.
-    const back = wall.backOffset - wall.outward * 0.5;
-    const front = wall.bottomFront.offset + wall.outward * 0.5;
-    const fall = (DRAIN_FALL * Math.abs(front - back)) / 2;
     for (const side of [-0.5, 0.5]) {
       const level = center + side * DRAIN_DIAMETER_M;
-      const el = line([x(back), y(level + fall)], [x(front), y(level - fall)]);
+      const run = insideRun(
+        { offset: back, elevation: level + fall },
+        { offset: front, elevation: level - fall },
+        wall.points,
+      );
+      if (!run) continue;
+      const el = line(
+        [x(run[0].offset), y(run[0].elevation)],
+        [x(run[1].offset), y(run[1].elevation)],
+      );
       el.removeAttribute("class"); // 색은 묶음(`.b06-chart__wall-drain line`)이 정함
       pipe.append(el);
     }

resources/tester/test_b06_wall_drain_pipe.py

@@ -45,6 +45,8 @@ const drains = (heightM, form, retaining, outward = 1) => {
   const layer = make("svg");
   appendWallHatch(layer, wall, (o) => o, (e) => -e, "t");
   const bottom = wall.bottomBack.elevation;
+  const xs = wall.points.map((p) => p.offset);
+  const [lo, hi] = [Math.min(...xs) - 1e-6, Math.max(...xs) + 1e-6];
   return walk(layer).map((pipe) => {
     const lines = pipe.children.filter((c) => c.tag === "line");
     const mid = lines.map((l) => -(Number(l.attrs.y1) + Number(l.attrs.y2)) / 2);
@@ -53,6 +55,7 @@ const drains = (heightM, form, retaining, outward = 1) => {
       lines: lines.length,
       center: (mid[0] + mid[1]) / 2 - bottom,
       frontLower: drop.every((d) => d > 0),
+      inside: lines.every((l) => [l.attrs.x1, l.attrs.x2].every((v) => lo <= +v && +v <= hi)),
       title: pipe.children.find((c) => c.tag === "title")?.text,
       cls: lines.map((l) => l.attrs.class ?? null),
     };
@@ -104,14 +107,15 @@ def test_옹벽만_높이_15m_띠마다_파이프_하나(tmp_path: Path) -> None
     )
     got = json.loads(result.read_text(encoding="utf-8"))
 
-    assert [p["center"] for p in got["h15"]] == pytest.approx([0.75])
-    assert [p["center"] for p in got["h30"]] == pytest.approx([0.75, 2.25])
-    assert [p["center"] for p in got["h30right"]] == pytest.approx([0.75, 2.25])
+    assert [p["center"] for p in got["h15"]] == pytest.approx([0.75], abs=0.01)
+    assert [p["center"] for p in got["h30"]] == pytest.approx([0.75, 2.25], abs=0.01)
+    assert [p["center"] for p in got["h30right"]] == pytest.approx([0.75, 2.25], abs=0.01)
     assert len(got["low"]) == 1, "낮은 옹벽도 최소 1개"
     assert got["wet"] == [] and got["concrete"] == [], "흙막이(찰쌓기 · 콘크리트)에 파이프가 섬"
     for pipe in got["h15"] + got["h30"] + got["h30right"]:
         assert pipe["lines"] == 2, "두 줄 평행선이 아님"
         assert pipe["frontLower"], "앞쪽이 낮지 않음"
+        assert pipe["inside"], "파이프가 벽 밖으로 나감(B07 수확은 clip 이 없음)"
         assert pipe["title"] == "물빼기(보기용)"
         assert pipe["cls"] == [None, None], "선 색은 묶음 토큰이 정함"