feat(文件拆分): 拆分几何三维基础能力

internal/base/geom/contain.go

@@ -0,0 +1,87 @@
+// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package geom
+
+import (
+	"math"
+)
+
+// ConvexContains 判断单个非退化凸直线区域是否包含另一闭合直线区域
+// 入参: outer 外部区域, inner 内部区域
+// 返回: bool 是否完全包含，曲线及多轮廓返回false
+func ConvexContains(outer, inner Path) bool {
+	a, b := geometryPolygonPoints(outer), geometryPolygonPoints(inner)
+	if len(a) < 3 || len(b) < 3 {
+		return false
+	}
+	nondegenerate := false
+	for i, start := range a {
+		end := a[(i+1)%len(a)]
+		dx, dy := end.X-start.X, end.Y-start.Y
+		length := math.Hypot(dx, dy)
+		if !finite(length) {
+			return false
+		}
+		if length == 0 {
+			continue
+		}
+		dx, dy = dx/length, dy/length
+		distance := func(point Point) float64 {
+			x, y := point.X-start.X, point.Y-start.Y
+			value := math.FMA(dx, y, -dy*x)
+			bound := (math.Abs(dx*y) + math.Abs(dy*x) + math.Abs(dx)*(math.Abs(point.Y)+math.Abs(start.Y)) + math.Abs(dy)*(math.Abs(point.X)+math.Abs(start.X))) * 0x1p-49
+			if finite(bound) && math.Abs(value) <= bound {
+				return 0
+			}
+			return value
+		}
+		sign := 0.0
+		for _, point := range a {
+			value := distance(point)
+			if !finite(value) || sign*value < 0 {
+				return false
+			}
+			if value != 0 {
+				sign, nondegenerate = math.Copysign(1, value), true
+			}
+		}
+		for _, point := range b {
+			value := distance(point)
+			if !finite(value) || sign*value < 0 {
+				return false
+			}
+		}
+	}
+	return nondegenerate
+}
+
+// geometryPolygonPoints 读取单个显式闭合直线轮廓的顶点，不修改原路径
+// 入参: path 直线轮廓
+// 返回: []Point 独立顶点，其他路径返回nil
+func geometryPolygonPoints(path Path) []Point {
+	if len(path) < 4 || path[0].Verb != Move || path[len(path)-1].Verb != ClosePath {
+		return nil
+	}
+	for i, segment := range path[:len(path)-1] {
+		if i > 0 && segment.Verb != Line || !finite(segment.End.X) || !finite(segment.End.Y) {
+			return nil
+		}
+	}
+	points := make([]Point, len(path)-1)
+	for i := range points {
+		points[i] = path[i].End
+	}
+	return points
+}