Update graph example

1 files changed, 89 insertions, 32 deletions

diff --git a/examples/graph.c b/examples/graph.c
index 36c110f..a224a5b 100755
--- a/examples/graph.c
+++ b/examples/graph.c
@@ -180,7 +180,22 @@ void remove_node(i64 node_index) {
   world.nodes[node_index].enabled = 0;
 }
 
+f64 distance_between(f64 x0, f64 y0, f64 x1, f64 y1) {
+  f64 dx = x1 - x0;
+  f64 dy = y1 - y0;
+
+  return sqrt(dx * dx + dy * dy);
+}
+
 void add_node(f64 x, f64 y) {
+  f64 radius = 50;
+
+  for (i64 i = 0; i < MAX_NUM_NODES; ++i) {
+    Node n = world.nodes[i];
+    if (n.enabled && distance_between(n.x, n.y, x, y) < radius + n.radius)
+      return;
+  }
+
   i64 node_index = 0;
 
   while (node_index < MAX_NUM_NODES && world.nodes[node_index].enabled)
@@ -192,7 +207,7 @@ void add_node(f64 x, f64 y) {
     .enabled = 1,
     .x       = x,
     .y       = y,
-    .radius  = 50,
+    .radius  = radius,
   };
 }
 
@@ -203,9 +218,12 @@ void add_edge(i64 src, i64 dst) {
   if (src == dst)
     return;
 
-  for (i64 i = 0; i < MAX_NUM_EDGES; ++i)
-    if (world.edges[i].enabled && world.edges[i].src == src && world.edges[i].dst == dst)
-      return;
+  for (i64 i = 0; i < MAX_NUM_EDGES; ++i) {
+    Edge e = world.edges[i];
+    if (!e.enabled) continue;
+    if (e.src == src && e.dst == dst) return;
+    if (e.dst == src && e.src == dst) return;
+  }
 
   i64 edge_index = 0;
 
@@ -222,17 +240,7 @@ void add_edge(i64 src, i64 dst) {
   };
 }
 
-f64 distance_between(f64 x0, f64 y0, f64 x1, f64 y1) {
-  f64 dx = x1 - x0;
-  f64 dy = y1 - y0;
-
-  return sqrt(dx * dx + dy * dy);
-}
-
 void highlight_path(i64 src, i64 dst) {
-  if (!check_node_index(src)) return;
-  if (!check_node_index(dst)) return;
-
   for (i64 i = 0; i < MAX_NUM_NODES; ++i) {
     world.nodes[i].highlight = 0;
     world.nodes[i].distance  = -1;
@@ -241,6 +249,9 @@ void highlight_path(i64 src, i64 dst) {
   for (i64 i = 0; i < MAX_NUM_EDGES; ++i)
     world.edges[i].highlight = 0;
 
+  if (!check_node_index(src)) return;
+  if (!check_node_index(dst)) return;
+
   world.nodes[src].highlight = 1;
   world.nodes[dst].highlight = 1;
 
@@ -290,11 +301,8 @@ void highlight_path(i64 src, i64 dst) {
 
     world.nodes[min_index].distance = min_distance;
 
-    //  Repeat until we got the destination node
+    //  Repeat until there's no connected nodes left
     //
-
-    if (min_index == dst)
-      break;
   }
 
   //  If path not found, stop
@@ -308,14 +316,13 @@ void highlight_path(i64 src, i64 dst) {
   //  Reconstruct the path
   //
 
-  f64 min_distance = world.nodes[dst].distance;
-
   for (i64 node_index = dst; node_index != src;) {
     //  Repeat until we got the source node
 
     //  Find neighbor node with minimal path distance
     //
 
+    f64 min_distance   = -1;
     i64 min_node_index = -1;
     i64 min_edge_index = -1;
 
@@ -325,19 +332,23 @@ void highlight_path(i64 src, i64 dst) {
         Node n0 = world.nodes[e.src];
         Node n1 = world.nodes[e.dst];
 
+        f64 l = distance_between(n0.x, n0.y, n1.x, n1.y);
+
         //  Assume bi-directional graph
 
-        if (e.src == node_index && n1.distance >= 0 && n1.distance < min_distance) {
-          min_node_index = e.dst;
-          min_edge_index = i;
-          min_distance   = n1.distance;
-        }
+        if (e.src == node_index && n1.distance >= 0)
+          if (min_distance < 0 || l + n1.distance < min_distance) {
+            min_node_index = e.dst;
+            min_edge_index = i;
+            min_distance   = l + n1.distance;
+          }
 
-        if (e.dst == node_index && n0.distance >= 0 && n0.distance < min_distance) {
-          min_node_index = e.src;
-          min_edge_index = i;
-          min_distance   = n0.distance;
-        }
+        if (e.dst == node_index && n0.distance >= 0)
+          if (min_distance < 0 || l + n0.distance < min_distance) {
+            min_node_index = e.src;
+            min_edge_index = i;
+            min_distance   = l + n0.distance;
+          }
       }
 
     //  If not found, stop
@@ -369,6 +380,11 @@ b8  path_changed = 0;
 i64 path_src     = -1;
 i64 path_dst     = -1;
 
+b8  drag_on   = 0;
+i64 drag_node = -1;
+i64 drag_x0   = 0;
+i64 drag_y0   = 0;
+
 void update_and_render_frame(void) {
   p_wait_events();
 
@@ -399,6 +415,8 @@ void update_and_render_frame(void) {
     for (i64 i = 0; i < MAX_NUM_NODES; ++i)
       if (world.nodes[i].enabled && world.nodes[i].hover)
         remove_node(i);
+
+    path_changed = 1;
   }
 
   if (platform.key_pressed['1']) {
@@ -423,8 +441,19 @@ void update_and_render_frame(void) {
     path_changed = 0;
   }
 
-  if (platform.key_pressed[BUTTON_LEFT])
-    add_node(platform.cursor_x, platform.cursor_y);
+  if (platform.key_pressed[BUTTON_LEFT]) {
+    for (i64 i = 0; i < MAX_NUM_NODES; ++i)
+      if (world.nodes[i].enabled && world.nodes[i].hover) {
+        drag_on   = 1;
+        drag_node = i;
+        drag_x0   = world.nodes[i].x - platform.cursor_x;
+        drag_y0   = world.nodes[i].y - platform.cursor_y;
+        break;
+      }
+
+    if (!drag_on)
+      add_node(platform.cursor_x, platform.cursor_y);
+  }
 
   if (platform.key_pressed[BUTTON_RIGHT])
     for (i64 i = 0; i < MAX_NUM_NODES; ++i)
@@ -445,6 +474,34 @@ void update_and_render_frame(void) {
   if (adding_edge && !platform.key_down[BUTTON_RIGHT]) {
     adding_edge = 0;
     add_edge(adding_src, adding_dst);
+    path_changed = 1;
+  }
+
+  if (drag_on) {
+    if (check_node_index(drag_node)) {
+      f64 r = world.nodes[drag_node].radius;
+      f64 x = drag_x0 + platform.cursor_x;
+      f64 y = drag_y0 + platform.cursor_y;
+
+      b8 collision = 0;
+
+      for (i64 i = 0; i < MAX_NUM_NODES; ++i) {
+        Node n = world.nodes[i];
+        if (i != drag_node && n.enabled && distance_between(n.x, n.y, x, y) < n.radius + r) {
+          collision = 1;
+          break;
+        }
+      }
+
+      if (!collision) {
+        world.nodes[drag_node].x = x;
+        world.nodes[drag_node].y = y;
+        path_changed             = 1;
+      }
+    }
+
+    if (!platform.key_down[BUTTON_LEFT])
+      drag_on = 0;
   }
 
   //  Render