mirror of https://github.com/tidwall/tile38.git
54 lines
1.2 KiB
Go
54 lines
1.2 KiB
Go
package poly
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// Inside returns true if point is inside of exterior and not in a hole.
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// The validity of the exterior and holes must be done elsewhere and are assumed valid.
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// A valid exterior is a near-linear ring.
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// A valid hole is one that is full contained inside the exterior.
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// A valid hole may not share the same segment line as the exterior.
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func (p Point) Inside(exterior Polygon, holes []Polygon) bool {
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if !insideshpext(p, exterior, true) {
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return false
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}
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for i := 0; i < len(holes); i++ {
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if insideshpext(p, holes[i], false) {
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return false
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}
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}
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return true
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}
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// Inside returns true if shape is inside of exterior and not in a hole.
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func (shape Polygon) Inside(exterior Polygon, holes []Polygon) bool {
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var ok bool
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for _, p := range shape {
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ok = p.Inside(exterior, holes)
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if !ok {
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return false
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}
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}
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ok = true
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for _, hole := range holes {
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if hole.Inside(shape, nil) {
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return false
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}
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}
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return ok
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}
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func insideshpext(p Point, shape Polygon, exterior bool) bool {
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// if len(shape) < 3 {
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// return false
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// }
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in := false
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for i := 0; i < len(shape); i++ {
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res := raycast(p, shape[i], shape[(i+1)%len(shape)])
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if res.on {
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return exterior
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}
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if res.in {
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in = !in
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}
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}
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return in
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}
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