From: Francois Fleuret <francois@fleuret.org>
Date: Wed, 1 Mar 2017 08:28:50 +0000 (+0100)
Subject: Seems to work quite well.
X-Git-Url: https://fleuret.org/cgi-bin/gitweb/gitweb.cgi?p=flatland.git;a=commitdiff_plain;h=2cd32038873961c8ff3861efb218fad75fbcbf69

Seems to work quite well.
---

diff --git a/flatland.cc b/flatland.cc
index e41e565..abfc644 100644
--- a/flatland.cc
+++ b/flatland.cc
@@ -222,7 +222,7 @@ extern "C" void fl_generate_sequences(int nb_sequences,
             scalar_t xf = grabbed_polygon->absolute_x(grab_relative_x, grab_relative_y);
             scalar_t yf = grabbed_polygon->absolute_y(grab_relative_x, grab_relative_y);
             grabbed_polygon->apply_force(dt, xf, yf, 0.0, -1.0);
-            universe->update(dt);
+            universe->update(dt, 1.0 / scaling);
           }
         }
       }
@@ -238,17 +238,6 @@ extern "C" void fl_generate_sequences(int nb_sequences,
           }
         }
       }
-
-      /*
-      {
-        cout << canvases[0]->_actual_width << " "<< canvases[1]->_actual_height << endl;
-        cout << "Writing /tmp/sanity.png" << endl;
-        CanvasCairo main_canvas(scaling, nb_images_per_sequence, 1, canvases);
-        FILE *file = safe_fopen("/tmp/sanity.png", "w");
-        main_canvas.write_png(file);
-        fclose(file);
-      }
-      */
     }
 
     for(int t = 0; t < 2 * nb_saved_frames; t++) {
diff --git a/mylib.c b/mylib.c
index 61a461d..6d62c24 100644
--- a/mylib.c
+++ b/mylib.c
@@ -19,8 +19,7 @@
 
 #include "flatland.h"
 
-int generate_sequence(THByteTensor *output) {
-  long nb_sequences = 1;
+int generate_sequence(long nb_sequences, THByteTensor *output) {
   long nb_images_per_sequence = 5;
   long depth = 3;
   long width = 64;
diff --git a/mylib.h b/mylib.h
index 9c9208b..a0a255f 100644
--- a/mylib.h
+++ b/mylib.h
@@ -1,2 +1,2 @@
 
-int generate_sequence(THByteTensor *output);
+int generate_sequence(long nb_sequences, THByteTensor *output);
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];
diff --git a/polygon.h b/polygon.h
index 8e23a70..557fdd6 100644
--- a/polygon.h
+++ b/polygon.h
@@ -119,7 +119,7 @@ public:
   scalar_t absolute_y(scalar_t rx, scalar_t ry);
 
   void apply_force(scalar_t dt, scalar_t x, scalar_t y, scalar_t fx, scalar_t fy);
-  void apply_border_forces(scalar_t dt, scalar_t xmax, scalar_t ymax);
+  void apply_border_forces(scalar_t dt, scalar_t xmin, scalar_t ymin, scalar_t xmax, scalar_t ymax);
   void apply_collision_forces(scalar_t dt, int n_polygon, Polygon *p);
 
   bool collide(Polygon *p);
diff --git a/test.py b/test.py
index d6d2df1..de408aa 100755
--- a/test.py
+++ b/test.py
@@ -10,10 +10,11 @@ x = torch.ByteTensor(4, 5).fill_(0)
 
 print(x.size())
 
-mylib.generate_sequence(x)
+mylib.generate_sequence(8, x)
 
 print(x.size())
 
 x = x.float().sub_(128).div_(128)
 
-torchvision.utils.save_image(x[0], 'example.png')
+for s in range(0, x.size(0)):
+    torchvision.utils.save_image(x[s], 'example_' + str(s) + '.png')
diff --git a/universe.cc b/universe.cc
index 2b1383d..b897d0c 100644
--- a/universe.cc
+++ b/universe.cc
@@ -122,11 +122,13 @@ void Universe::compute_pseudo_collisions(int nb_axis, int *nb_colliding_axis) {
   }
 }
 
-bool Universe::update(scalar_t dt) {
+bool Universe::update(scalar_t dt, scalar_t padding) {
   bool result = false;
   apply_collision_forces(dt);
   for(int n = 0; n < _nb_polygons; n++) if(_polygons[n]) {
-    _polygons[n]->apply_border_forces(dt, _width, _height);
+      _polygons[n]->apply_border_forces(dt,
+                                        padding, padding,
+                                        _width - padding, _height - padding);
     result |= _polygons[n]->update(dt);
   }
   return result;
diff --git a/universe.h b/universe.h
index 11dacc7..c80bf2c 100644
--- a/universe.h
+++ b/universe.h
@@ -56,7 +56,7 @@ public:
   // axis to speed up the computation
   void compute_pseudo_collisions(int nb_axis, int *nb_colliding_axis);
   void apply_collision_forces(scalar_t dt);
-  bool update(scalar_t dt);
+  bool update(scalar_t dt, scalar_t padding);
 
   Polygon *pick_polygon(scalar_t x, scalar_t y);