ZQlib都能幹些什麼之十一：形狀插值（Shape Interpolation）

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本文形狀插值是指：給定拓撲結構相同的兩個形狀，插值得到中間的漸變形狀。

參考自論文：As-Rigid-As-Possible Shape Interpolation, 2000.

上圖

輸入如下兩個形狀

插值結果

介面函數

https://github.com/zuoqing1988/ZQlib/blob/master/ZQlib/ZQ_ShapeInterpolation.h

template<class T>class ZQ_ShapeInterpolation{public: /*indices, verts1, verts2 will be copied in this function*/ bool BuildMatrix(int nTri, const int* indices, int nPts, const T* verts1, const T* verts2, bool symmetric = true, int pivot_id = 0); /*make sure out_verts has the same size as verts1, verts2*/ bool Interpolation(float t, T* out_verts, int max_iter = 100);};

使用示例

https://github.com/zuoqing1988/ZQlib/blob/master/SampleShapeInterpolation/SampleShapeInterpolation.cpp

#include "ZQ_ShapeInterpolation.h"#include "opencv2opencv.hpp"using namespace ZQ;template<class T>void _show(const char* winName, int nTri, int nPts, const int* indices, const T* vert);template<class T>void test(){ int triangle_num = 20; int pts_num = 12; int indices[60] = { 0, 1, 6, 1, 7, 6, 0,1, 7, 0, 6, 7, 1, 2, 7, 2, 8, 7, 1,2, 8, 1, 7, 8, 2, 3, 8, 3, 9, 8, 2,3, 9, 2, 8, 9, 3, 4, 9, 4,10, 9, 3,4,10, 3, 9,10, 4, 5,10, 5,11,10, 4,5,11, 4,10,11 }; T p[24] = { 100,100,200,100,300,100,400,100,500,100,600,100, 100,200,200,200,300,200,400,200,500,200,600,200 }; T q[24] = { 100,100,200,100,320,120,450,250,500,450,500,550, 100,200,200,200,300,220,370,350,400,450,400,550}; T out1[24],out2[24]; ZQ_ShapeInterpolation<T> deform1,deform2; if (!deform1.BuildMatrix(triangle_num, indices, pts_num, p, q, false, 0) || !deform2.BuildMatrix(triangle_num, indices, pts_num, p, q, true, 0)) { printf("failed to set source
"); return; } const char* winName1 = "show1"; const char* winName2 = "show2"; cv::namedWindow(winName1); cv::namedWindow(winName2); float ori_step = 0.01f; float step = ori_step; for (float t = 0; ; t += step) { printf("t = %.2f
", t); if (!deform1.Interpolation(t, out1) || !deform2.Interpolation(t,out2)) { printf("failed to deform ARAP
"); return; } _show(winName1, triangle_num, pts_num, indices, out1); _show(winName2, triangle_num, pts_num, indices, out2); int key = cvWaitKey(20); if (key == q) break; if (t > 1) step = -ori_step; if (t < 0) step = ori_step; } return;}template<class T>void _show(const char* winName, int nTri, int nPts, const int* indices, const T* vert){ cv::Mat img = cv::Mat(600, 800, CV_MAKETYPE(8, 3), cv::Scalar(0)); cv::Scalar color(0, 0, 255); for (int tr = 0; tr < nTri; tr++) { int id0 = indices[tr * 3 + 0]; int id1 = indices[tr * 3 + 1]; int id2 = indices[tr * 3 + 2]; cv::line(img, cv::Point(vert[id0 * 2 + 0], vert[id0 * 2 + 1]), cv::Point(vert[id1 * 2 + 0], vert[id1 * 2 + 1]), color, 2); cv::line(img, cv::Point(vert[id1 * 2 + 0], vert[id1 * 2 + 1]), cv::Point(vert[id2 * 2 + 0], vert[id2 * 2 + 1]), color, 2); cv::line(img, cv::Point(vert[id2 * 2 + 0], vert[id2 * 2 + 1]), cv::Point(vert[id0 * 2 + 0], vert[id0 * 2 + 1]), color, 2); } cv::imshow(winName, img);}int main(){ test<float>(); //test<double>(); return EXIT_SUCCESS;}

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