Mercurial > gemma

comparison pkg/mesh/vertex.go @ 5710:37c8feeecb4d

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Merged branch sr-v2 into default.
author Sascha L. Teichmann <sascha.teichmann@intevation.de>
date Tue, 20 Feb 2024 21:28:56 +0100
parents 148abae1fcd0
children 61eff98a40ae
comparison
equal deleted inserted replaced
5672:b1a10654bf0f 5710:37c8feeecb4d
86 // the three points of the triangles are in. 86 // the three points of the triangles are in.
87 func (t *Triangle) Plane3D() Plane3D { 87 func (t *Triangle) Plane3D() Plane3D {
88 88
89 v0 := t[1].Sub(t[0]) 89 v0 := t[1].Sub(t[0])
90 v1 := t[2].Sub(t[0]) 90 v1 := t[2].Sub(t[0])
91 n := v0.Cross(v1).Normalize() 91 n := v0.Cross(v1)
92
93 // If the length of normal is near zero assume we have
94 // a plane constant in z with an average z value of
95 // the three vertices.
96 // This should protect us from the effects of collinear
97 // geometries.
98 l := n.Length()
99 if l < 1e-7 {
100 sum := t[0].Z + t[1].Z + t[2].Z
101 return Plane3D{
102 A: 0,
103 B: 0,
104 C: 1,
105 D: -sum / 3,
106 }
107 }
108 n = n.Scale(1 / l)
92 109
93 // x*nx+ y*ny+ z*nz + d = 0 110 // x*nx+ y*ny+ z*nz + d = 0
94 // d = - (x*nx+ y*ny + z*nz) 111 // d = - (x*nx+ y*ny + z*nz)
95 d := -t[0].Dot(n) 112 d := -t[0].Dot(n)
96 return Plane3D{ 113 return Plane3D{
1142 } 1159 }
1143 1160
1144 return out 1161 return out
1145 } 1162 }
1146 1163
1164 // QuantizeXY quantize the X/Y values to scale and
1165 // removes duplicates in place. The z value of
1166 // duplicates will be averaged pairwise.
1167 func (mpz MultiPointZ) QuantizeXY(scale float64) MultiPointZ {
1168 type qpoint struct {
1169 x int64
1170 y int64
1171 }
1172 m := make(map[qpoint]float64, len(mpz))
1173 for _, p := range mpz {
1174 k := qpoint{
1175 x: int64(math.Round(p.X * scale)),
1176 y: int64(math.Round(p.Y * scale)),
1177 }
1178 if z, ok := m[k]; ok {
1179 m[k] = (z + p.Z) * 0.5
1180 } else {
1181 m[k] = p.Z
1182 }
1183 }
1184 i := 0
1185 invScale := 1 / scale
1186 for k, z := range m {
1187 mpz[i] = Vertex{
1188 X: float64(k.x) * invScale,
1189 Y: float64(k.y) * invScale,
1190 Z: z,
1191 }
1192 i++
1193 }
1194 return mpz[:i]
1195 }
1196
1147 // Filter returns a copy removed the vertices which 1197 // Filter returns a copy removed the vertices which
1148 // don't pass the filter test. 1198 // don't pass the filter test.
1149 func (mpz MultiPointZ) Filter(filter func(Vertex) bool) MultiPointZ { 1199 func (mpz MultiPointZ) Filter(filter func(Vertex) bool) MultiPointZ {
1150 n := make(MultiPointZ, 0, len(mpz)) 1200 n := make(MultiPointZ, 0, len(mpz))
1151 for _, v := range mpz { 1201 for _, v := range mpz {