70 lines
1.6 KiB
C++
70 lines
1.6 KiB
C++
/*
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* © Copyright 2014 – Urheberrechtshinweis
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* Alle Rechte vorbehalten / All Rights Reserved
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*
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* Programmcode ist urheberrechtlich geschuetzt.
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* Das Urheberrecht liegt, soweit nicht ausdruecklich anders gekennzeichnet, bei Frank Ebner.
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* Keine Verwendung ohne explizite Genehmigung.
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* (vgl. § 106 ff UrhG / § 97 UrhG)
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*/
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#ifndef TRIANGLESTRIP3_H
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#define TRIANGLESTRIP3_H
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#include <vector>
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#include "Point3.h"
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#include "Triangle3.h"
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class TriangleStrip3 {
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private:
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std::vector<Point3> pts;
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public:
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void add(const Point3 p) {
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pts.push_back(p);
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}
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void set(const std::vector<Point3>& pts) {
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this->pts = pts;
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}
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void toTriangles(std::vector<Triangle3>& trias) const {
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// https://en.wikipedia.org/wiki/Triangle_strip
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// GL_TRIANGLE_STRIP
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// Draws a series of triangles (three-sided polygons) using vertices v0, v1, v2, then v2, v1, v3 (note the order), then v2, v3, v4, and so on. The ordering is to ensure that the triangles are all drawn with the same orientation so that the strip can correctly form part of a surface.
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// For odd n, vertices n, n+1, and n+2 define triangle n. For even n, vertices n+1, n, and n+2 define triangle n. N-2 triangles are drawn.
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for (size_t j = 2; j < pts.size(); ++j) {
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if (j % 2 == 0) {
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Triangle3 tria(
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pts[j-2],
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pts[j-1],
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pts[j]
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);
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trias.push_back(tria);
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} else {
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Triangle3 tria(
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pts[j-1],
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pts[j-2],
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pts[j]
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);
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trias.push_back(tria);
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}
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}
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}
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std::vector<Triangle3> toTriangles() const {
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std::vector<Triangle3> trias;
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toTriangles(trias);
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return trias;
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}
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};
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#endif // TRIANGLESTRIP3_H
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