X-Git-Url: https://fleuret.org/cgi-bin/gitweb/gitweb.cgi?p=flatland.git;a=blobdiff_plain;f=polygon.cc;fp=polygon.cc;h=b64fbe4ab3d570038ff491f82e823f315aedc05a;hp=69b125eb789e86e3ec798b0edbd139d1f1e5d081;hb=2cd32038873961c8ff3861efb218fad75fbcbf69;hpb=546ec5453243e2efbf8c3caefdc04394ca87676d

diff --git a/polygon.cc b/polygon.cc
index 69b125e..b64fbe4 100644
--- a/polygon.cc
+++ b/polygon.cc
@@ -356,7 +356,9 @@ void Polygon::apply_force(scalar_t dt, scalar_t x, scalar_t y, scalar_t fx, scal
   _dtheta -= prod_vect(x - _center_x, y - _center_y, fx, fy) / (_mass * _moment_of_inertia) * dt;
 }
 
-void Polygon::apply_border_forces(scalar_t dt, scalar_t xmax, scalar_t ymax) {
+void Polygon::apply_border_forces(scalar_t dt,
+                                  scalar_t xmin, scalar_t ymin,
+                                  scalar_t xmax, scalar_t ymax) {
   for(int v = 0; v < _nb_vertices; v++) {
     int vp = (v+1)%_nb_vertices;
     for(int d = 0; d < _nb_dots[v]; d++) {
@@ -364,9 +366,9 @@ void Polygon::apply_border_forces(scalar_t dt, scalar_t xmax, scalar_t ymax) {
       scalar_t x = _x[v] * (1 - s) + _x[vp] * s;
       scalar_t y = _y[v] * (1 - s) + _y[vp] * s;
       scalar_t vx = 0, vy = 0;
-      if(x < 0) vx = x;
+      if(x < xmin) vx = xmin - x;
       else if(x > xmax) vx = x - xmax;
-      if(y < 0) vy = y;
+      if(y < ymin) vy = ymin - y;
       else if(y > ymax) vy = y - ymax;
       apply_force(dt, x, y, - dl * vx * repulsion_constant, - dl * vy * repulsion_constant);
     }
@@ -390,9 +392,10 @@ void Polygon::apply_collision_forces(scalar_t dt, int n_polygon, Polygon *p) {
       distance[d] = FLT_MAX;
     }
 
-    // First, we tag the dots located inside the polygon p
+    // First, we tag the dots located inside the polygon p by looping
+    // through the _nb_vertices - 2 triangles from the decomposition
 
-    for(int t = 0; t < p->_nb_vertices-2; t++) {
+    for(int t = 0; t < p->_nb_vertices - 2; t++) {
       scalar_t min = 0, max = 1;
       scalar_t xa = p->_x[p->_triangles[t].a], ya = p->_y[p->_triangles[t].a];
       scalar_t xb = p->_x[p->_triangles[t].b], yb = p->_y[p->_triangles[t].b];