Merge pull request #46 from pierre-dejoue/testbed-autozoom

QoL: Add auto-zoom feature to the testbed app

README.md

@@ -74,14 +74,19 @@ Load data points from a file:
 ```
 build/testbed/p2t <filename> <center_x> <center_y> <zoom>
 ```
+Load data points from a file and automatically fit the geometry to the window:
+```
+build/testbed/p2t <filename>
+```
 Random distribution of points inside a constrained box:
 ```
 build/testbed/p2t random <num_points> <box_radius> <zoom>
 ```
 Examples:
 ```
-build/testbed/p2t testbed/data/dude.dat 300 500 2
+build/testbed/p2t testbed/data/dude.dat 350 500 3
-build/testbed/p2t testbed/data/nazca_monkey.dat 0 0 9
+
+build/testbed/p2t testbed/data/nazca_monkey.dat
 
 build/testbed/p2t random 10 100 5.0
 build/testbed/p2t random 1000 20000 0.025

testbed/main.cc

@@ -1,5 +1,5 @@
 /*
- * Poly2Tri Copyright (c) 2009-2018, Poly2Tri Contributors
+ * Poly2Tri Copyright (c) 2009-2022, Poly2Tri Contributors
  * https://github.com/jhasse/poly2tri
  *
  * All rights reserved.
@@ -40,10 +40,12 @@
 #include <fstream>
 #include <iostream>
 #include <iterator>
+#include <limits>
 #include <list>
 #include <numeric>
 #include <sstream>
 #include <string>
+#include <utility>
 #include <vector>
 
 using namespace std;
@@ -51,11 +53,12 @@ using namespace p2t;
 
 bool ParseFile(string filename, vector<Point*>& out_polyline, vector<vector<Point*>>& out_holes,
                vector<Point*>& out_steiner);
+std::pair<Point, Point> BoundingBox(const std::vector<Point*>& polyline);
 void GenerateRandomPointDistribution(size_t num_points, double min, double max,
                                      vector<Point*>& out_polyline,
                                      vector<vector<Point*>>& out_holes,
                                      vector<Point*>& out_steiner);
-void Init();
+void Init(int window_width, int window_height);
 void ShutDown(int return_code);
 void MainLoop(const double zoom);
 void Draw(const double zoom);
@@ -69,6 +72,13 @@ double rotate_y = 0.0,
        rotate_z = 0.0;
 const double rotations_per_tick = 0.2;
 
+/// Default window size
+constexpr int default_window_width = 800;
+constexpr int default_window_height = 600;
+
+/// Autozoom border (percentage)
+const double autozoom_border = 0.05;
+
 /// Screen center x
 double cx = 0.0;
 /// Screen center y
@@ -105,14 +115,21 @@ int main(int argc, char* argv[])
   double max, min;
   double zoom;
 
-  if (argc != 5) {
+  if (argc != 2 && argc != 5) {
     cout << "-== USAGE ==-" << endl;
-    cout << "Load Data File: p2t filename center_x center_y zoom" << endl;
+    cout << "Load Data File: p2t <filename> <center_x> <center_y> <zoom>" << endl;
-    cout << "Example: ./build/p2t testbed/data/dude.dat 500 500 1" << endl;
+    cout << "  Example: build/testbed/p2t testbed/data/dude.dat 350 500 3" << endl;
+    cout << "Load Data File with Auto-Zoom: p2t <filename>" << endl;
+    cout << "  Example: build/testbed/p2t testbed/data/nazca_monkey.dat" << endl;
+    cout << "Generate Random Polygon: p2t random <num_points> <box_radius> <zoom>" << endl;
+    cout << "  Example: build/testbed/p2t random 100 1 500" << endl;
     return 1;
   }
 
-  if (string(argv[1]) == "random") {
+  // If true, adjust the zoom settings to fit the input geometry to the window
+  const bool autozoom = (argc == 2);
+
+  if (!autozoom && string(argv[1]) == "random") {
     num_points = atoi(argv[2]);
     random_distribution = true;
     char* pEnd;
@@ -122,9 +139,11 @@ int main(int argc, char* argv[])
     zoom = atof(argv[4]);
   } else {
     filename = string(argv[1]);
-    cx = atof(argv[2]);
+    if (!autozoom) {
-    cy = atof(argv[3]);
+      cx = atof(argv[2]);
-    zoom = atof(argv[4]);
+      cy = atof(argv[3]);
+      zoom = atof(argv[4]);
+    }
   }
 
   if (random_distribution) {
@@ -136,7 +155,21 @@ int main(int argc, char* argv[])
     }
   }
 
-  Init();
+  if (autozoom) {
+    assert(0.0 <= autozoom_border && autozoom_border < 1.0);
+    const auto bbox = BoundingBox(polyline);
+    Point center = bbox.first + bbox.second;
+    center *= 0.5;
+    cx = center.x;
+    cy = center.y;
+    Point sides = bbox.second - bbox.first;
+    zoom = 2.0 * (1.0 - autozoom_border) * std::min((double)default_window_width / sides.x, (double)default_window_height / sides.y);
+    std::cout << "center_x = " << cx << std::endl;
+    std::cout << "center_y = " << cy << std::endl;
+    std::cout << "zoom = " << zoom << std::endl;
+  }
+
+  Init(default_window_width, default_window_height);
 
   /*
    * Perform triangulation!
@@ -182,6 +215,7 @@ int main(int argc, char* argv[])
   cout << "Total number of points = " << (polyline.size() + points_in_holes + steiner.size())
        << endl;
   cout << "Number of triangles = " << triangles.size() << endl;
+  cout << "Is Delaunay = " << (IsDelaunay(triangles) ? "true" : "false") << endl;
   cout << "Elapsed time (ms) = " << dt * 1000.0 << endl;
 
   MainLoop(zoom);
@@ -262,6 +296,21 @@ bool ParseFile(string filename, vector<Point*>& out_polyline, vector<vector<Poin
   return true;
 }
 
+std::pair<Point, Point> BoundingBox(const std::vector<Point*>& polyline)
+{
+  assert(polyline.size() > 0);
+  using Scalar = decltype(p2t::Point::x);
+  Point min(std::numeric_limits<Scalar>::max(), std::numeric_limits<Scalar>::max());
+  Point max(std::numeric_limits<Scalar>::min(), std::numeric_limits<Scalar>::min());
+  for (const Point* point : polyline) {
+    min.x = std::min(min.x, point->x);
+    min.y = std::min(min.y, point->y);
+    max.x = std::max(max.x, point->x);
+    max.y = std::max(max.y, point->y);
+  }
+  return std::make_pair(min, max);
+}
+
 void GenerateRandomPointDistribution(size_t num_points, double min, double max,
                                      vector<Point*>& out_polyline,
                                      vector<vector<Point*>>& out_holes, vector<Point*>& out_steiner)
@@ -280,14 +329,11 @@ void GenerateRandomPointDistribution(size_t num_points, double min, double max,
   }
 }
 
-void Init()
+void Init(int window_width, int window_height)
 {
-  const int window_width = 800,
-            window_height = 600;
-
   if (glfwInit() != GL_TRUE)
     ShutDown(1);
-  // 800 x 600, 16 bit color, no depth, alpha or stencil buffers, windowed
+  // width x height, 16 bit color, no depth, alpha or stencil buffers, windowed
   window = glfwCreateWindow(window_width, window_height, "Poly2Tri - C++", NULL, NULL);
   if (!window)
     ShutDown(1);
@@ -373,7 +419,7 @@ void Draw(const double zoom)
   // reset zoom
   Point center = Point(cx, cy);
 
-  ResetZoom(zoom, center.x, center.y, 800, 600);
+  ResetZoom(zoom, center.x, center.y, (double)default_window_width, (double)default_window_height);
 
   for (int i = 0; i < triangles.size(); i++) {
     Triangle& t = *triangles[i];
@@ -414,7 +460,7 @@ void DrawMap(const double zoom)
   // reset zoom
   Point center = Point(cx, cy);
 
-  ResetZoom(zoom, center.x, center.y, 800, 600);
+  ResetZoom(zoom, center.x, center.y, (double)default_window_width, (double)default_window_height);
 
   list<Triangle*>::iterator it;
   for (it = map.begin(); it != map.end(); it++) {
@@ -454,8 +500,6 @@ void ConstrainedColor(bool constrain)
   }
 }
 
-
-
 double StringToDouble(const std::string& s)
 {
   std::istringstream i(s);