Update node struct to know about noodle connected to it

include/nodes.h

@@ -9,6 +9,7 @@
 #define OP_INPUT_COUNT 2
 #define EMPTY_NODE 0
 #define NODE_START 1
+#define CONNECTION_START 1
 
 typedef i32 (*node_func)(i32 a, i32 b);
 typedef enum node_type node_type;
@@ -31,6 +32,7 @@ union node_data {
 struct noodle {
   line ln;
   u64 connected_node;
+  u64 connection_idx;
 };
 
 struct node {
@@ -39,7 +41,9 @@ struct node {
   node_type type;
   node_data data;
   u64 inputs;
+  u64 connected;
   noodle *noodles;
+  noodle **connected_noodles;
 };
 
 #endif // !NODES_H

src/compositor.c

@@ -25,15 +25,15 @@ struct compositor {
   u32 active_window;
   SDL_Event event;
   bool running;
-  i64 node_hovered;
   u64 count;
   node *nodes;
-  bool move_node;
+  node *back_nodes;
   ui_ctx ctx;
 };
 
 internal void add_node(compositor *comp, node_type type, node_data data,
                        u64 inputs, i32 x, i32 y, ui_elem_colours colours);
+internal void update_node_graph(compositor *comp, const window *wnd);
 internal void draw_node_graph(compositor *comp, const window *wnd);
 
 i32 run_main_loop(void) {
@@ -47,6 +47,8 @@ i32 run_main_loop(void) {
   mem_arena_init(&comp.arena, ARENA_CAPACITY);
 
   comp.nodes = (node *)mem_arena_alloc(comp.arena, sizeof(node) * MAX_NODES);
+  comp.back_nodes =
+      (node *)mem_arena_alloc(comp.arena, sizeof(node) * MAX_NODES);
 
   window *main_window = &(comp.windows[0]);
   window *toolbox = &(comp.windows[1]);
@@ -126,6 +128,8 @@ i32 run_main_loop(void) {
       }
     }
 
+    update_node_graph(&comp, main_window);
+
     for (u64 i = 0; i < MAX_WINDOWS; ++i) {
       clear_window(&(comp.windows[i]), bg_colour);
     }
@@ -174,7 +178,17 @@ internal void add_node(compositor *comp, node_type type, node_data data,
 
   u64 alloc_size = inputs * sizeof(noodle);
   noodle *noodles = mem_arena_alloc(comp->arena, alloc_size);
-  if (!noodles) {
+  noodle *back_noodles = mem_arena_alloc(comp->arena, alloc_size);
+  if (!noodles || !back_noodles) {
+    return;
+  }
+
+  u64 connected_alloc_size = MAX_NODES * sizeof(noodle *);
+  noodle **connected_noodles =
+      mem_arena_alloc(comp->arena, connected_alloc_size);
+  noodle **connected_back_noodles =
+      mem_arena_alloc(comp->arena, connected_alloc_size);
+  if (!connected_noodles || !connected_back_noodles) {
     return;
   }
 
@@ -185,61 +199,136 @@ internal void add_node(compositor *comp, node_type type, node_data data,
       .h = NODE_HEIGHT,
   };
 
-  comp->nodes[++(comp->count)] = (node){
+  u64 idx = ++(comp->count);
+
+  comp->nodes[idx] = comp->back_nodes[idx] = (node){
       .rec = rec,
       .colours = colours,
       .type = type,
       .data.path = data.path,
       .inputs = inputs,
+      .connected = 0,
       .noodles = noodles,
+      .connected_noodles = connected_noodles,
   };
+
+  comp->back_nodes[idx].noodles = back_noodles;
+  comp->back_nodes[idx].connected_noodles = connected_back_noodles;
+}
+
+internal void update_node_graph(compositor *comp, const window *wnd) {
+  for (u64 i = NODE_START; i <= comp->count; ++i) {
+    node *node_elem = &(comp->nodes[i]);
+    const node *back_node = &(comp->back_nodes[i]);
+
+    node_elem->rec = back_node->rec;
+    node_elem->connected = back_node->connected;
+
+    for (u64 j = 0; j < node_elem->inputs; ++j) {
+      noodle *ndl = &(node_elem->noodles[j]);
+      const noodle *back_ndl = &(back_node->noodles[j]);
+
+      *ndl = *back_ndl;
+    }
+
+    for (u64 j = CONNECTION_START; j <= back_node->connected; ++j) {
+      node_elem->connected_noodles[j] = back_node->connected_noodles[j];
+    }
+  }
 }
 
 internal void draw_node_graph(compositor *comp, const window *wnd) {
   for (u64 i = NODE_START; i <= comp->count; ++i) {
     node *node_elem = &(comp->nodes[i]);
+    node *back_node = &(comp->back_nodes[i]);
 
     f64 angle = 90.0;
     f64 angle_delta = 25.0;
     i64 delta_multiplier = node_elem->inputs % 2 == 0 ? -1 : 0;
 
-    for (u64 j = 0; j < comp->nodes[i].inputs; ++j) {
+    for (u64 j = 0; j < node_elem->inputs; ++j) {
       f64 new_angle = angle + angle_delta * delta_multiplier;
       noodle *ndl = &(node_elem->noodles[j]);
+      noodle *back_ndl = &(back_node->noodles[j]);
 
       if (ndl->ln.p0.x == ndl->ln.p1.x && ndl->ln.p0.y == ndl->ln.p1.y) {
         point origin = {node_elem->rec.topleft.x + node_elem->rec.w / 2,
                         node_elem->rec.topleft.y + node_elem->rec.h / 2};
 
-        ndl->ln = line_from_origin(origin, new_angle, DEFAULT_NOODLE_LENGTH);
+        back_ndl->ln =
+            line_from_origin(origin, new_angle, DEFAULT_NOODLE_LENGTH);
       }
 
       switch (ui_noodle(wnd, &(comp->ctx), ndl->ln, node_elem->colours,
                         node_elem->rec)) {
       case NOODLE_ACTION_DRAGGING:
-        ndl->ln.p0.x += comp->ctx.rel_x;
-        ndl->ln.p0.y += comp->ctx.rel_y;
+        back_ndl->ln.p0.x += comp->ctx.rel_x;
+        back_ndl->ln.p0.y += comp->ctx.rel_y;
         break;
-      case NOODLE_ACTION_RELEASED:
+      case NOODLE_ACTION_RELEASED: {
+        bool connected = false;
+        bool disconnect = false;
+
         for (u64 k = NODE_START; k <= comp->count; ++k) {
           if (k == i) {
             continue;
           }
 
           const node *nd = &(comp->nodes[k]);
+          node *back_node = &(comp->back_nodes[k]);
 
           if (aabb(nd->rec, comp->ctx.mouse_x, comp->ctx.mouse_y)) {
             point p0 = {nd->rec.topleft.x + nd->rec.w / 2,
                         nd->rec.topleft.y + nd->rec.h / 2};
 
-            ndl->ln.p0 = p0;
-            ndl->connected_node = k;
+            back_ndl->ln.p0 = p0;
+
+            connected = true;
+            disconnect = back_ndl->connected_node != EMPTY_NODE &&
+                         back_ndl->connected_node != k;
+
+            if (back_ndl->connected_node != k) {
+              back_ndl->connected_node = k;
+              u64 idx = ++(back_node->connected);
+              back_ndl->connection_idx = idx;
+              back_node->connected_noodles[idx] = back_ndl;
+            }
+
+            break;
           } else {
-            ndl->ln.p0 = ndl->ln.p1;
-            ndl->connected_node = EMPTY_NODE;
+            if (back_ndl->connected_node != EMPTY_NODE) {
+              disconnect = true;
+            }
           }
         }
+
+        if (disconnect) {
+          u64 conntection_idx = back_ndl->connection_idx;
+          u64 node_idx = back_ndl->connected_node;
+
+          node *connected_node = &(comp->back_nodes[node_idx]);
+
+          if (conntection_idx == connected_node->connected) {
+            connected_node->connected_noodles[conntection_idx] = NULL;
+          } else {
+            connected_node->connected_noodles[conntection_idx] =
+                connected_node->connected_noodles[connected_node->connected];
+            connected_node->connected_noodles[connected_node->connected] = NULL;
+
+            connected_node->connected_noodles[conntection_idx]->connection_idx =
+                conntection_idx;
+          }
+
+          connected_node->connected -= 1;
+        }
+
+        if (!connected) {
+          back_ndl->ln.p0 = ndl->ln.p1;
+          back_ndl->connected_node = EMPTY_NODE;
+        }
+
         break;
+      }
       default:
         break;
       }
@@ -256,38 +345,27 @@ internal void draw_node_graph(compositor *comp, const window *wnd) {
     }
 
     if (ui_node(wnd, &(comp->ctx), node_elem->rec, node_elem->colours)) {
-      node_elem->rec.topleft.x += comp->ctx.rel_x;
-      node_elem->rec.topleft.y += comp->ctx.rel_y;
+      back_node->rec.topleft.x += comp->ctx.rel_x;
+      back_node->rec.topleft.y += comp->ctx.rel_y;
 
       for (u64 j = 0; j < node_elem->inputs; ++j) {
         noodle *ndl = &(node_elem->noodles[j]);
+        noodle *back_ndl = &(back_node->noodles[j]);
 
         if (ndl->connected_node == EMPTY_NODE) {
-          ndl->ln.p0.x += comp->ctx.rel_x;
-          ndl->ln.p0.y += comp->ctx.rel_y;
+          back_ndl->ln.p0.x += comp->ctx.rel_x;
+          back_ndl->ln.p0.y += comp->ctx.rel_y;
         }
 
-        ndl->ln.p1.x += comp->ctx.rel_x;
-        ndl->ln.p1.y += comp->ctx.rel_y;
+        back_ndl->ln.p1.x += comp->ctx.rel_x;
+        back_ndl->ln.p1.y += comp->ctx.rel_y;
       }
 
-      for (u64 j = NODE_START; j <= comp->count; ++j) {
-        if (j == i) {
-          continue;
-        }
+      for (u64 j = CONNECTION_START; j <= back_node->connected; ++j) {
+        noodle *ndl = back_node->connected_noodles[j];
 
-        node *nd = &(comp->nodes[j]);
-        if (nd->inputs == 0) {
-          continue;
-        }
-
-        for (u64 k = 0; k < nd->inputs; ++k) {
-          noodle *ndl = &(nd->noodles[k]);
-          if (ndl->connected_node == i) {
-            ndl->ln.p0.x += comp->ctx.rel_x;
-            ndl->ln.p0.y += comp->ctx.rel_y;
-          }
-        }
+        ndl->ln.p0.x += comp->ctx.rel_x;
+        ndl->ln.p0.y += comp->ctx.rel_y;
       }
     }
   }