Update node struct to know about noodle connected to it

connection logic to the application level

.gitignore

@@ -1,3 +1,4 @@
 .cache
 compile_commands.json
 main
+*.dSYM

.gitmodules

@@ -1,3 +1,3 @@
-[submodule "intern/aliases"]
-	path = intern/aliases
-	url = https://git.thewizardapprentice.com/abdelrahman/c-cpp-aliases.git
+[submodule "intern/wizapp"]
+	path = intern/wizapp
+	url = https://git.thewizardapprentice.com/abdelrahman/wizapp-stdlib.git

compile

@@ -1,9 +1,21 @@
 #!/bin/bash
 
 CC=clang
-CFLAGS="-g -Wall -Iinclude -Iintern $(pkg-config --cflags sdl2)"
+CFLAGS="-g -Wall $(pkg-config --cflags sdl2)"
 LIBS="$(pkg-config --libs sdl2) -lm"
-SRC=src/*.c
+INCLUDE="\
+	-Iinclude \
+	-Iintern/wizapp/aliases \
+	-Iintern/wizapp/cpath/include \
+	-Iintern/wizapp/dstr/include \
+	$(find intern/wizapp/mem/include -type d | xargs -I{} echo -n "-I{} ") \
+"
+SRC="\
+	intern/wizapp/cpath/src/*.c \
+	intern/wizapp/dstr/src/*.c \
+	intern/wizapp/mem/src/*/*.c \
+	src/*.c \
+"
 OUT=main
 
-(set -x ; $CC $CFLAGS $LIBS $SRC -o $OUT)
+(set -x ; $CC $CFLAGS $INCLUDE $LIBS $SRC -o $OUT)

include/compositor.h

@@ -1,7 +1,7 @@
 #ifndef COMPOSITOR_H
 #define COMPOSITOR_H
 
-#include "aliases/aliases.h"
+#include "aliases.h"
 
 i32 run_main_loop(void);
 

include/math_utils.h

@@ -1,7 +1,7 @@
 #ifndef MATH_UTILS_H
 #define MATH_UTILS_H
 
-#include "aliases/aliases.h"
+#include "aliases.h"
 
 #define square(x) (x * x)
 #define absolute(x) (x < 0.0 ? x * -1.0 : x)

include/nodes.h

@@ -1,21 +1,27 @@
 #ifndef NODES_H
 #define NODES_H
 
-#include "aliases/aliases.h"
+#include "aliases.h"
 #include "ui.h"
 
 #define MAX_NODES 1024
+#define IO_INPUT_COUNT 0
+#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;
 typedef union node_data node_data;
 typedef struct node node;
+typedef struct noodle noodle;
 
 enum node_type {
-  NODEYPE_IO,
-  NODEYPE_OP,
+  NODE_TYPE_IO,
+  NODE_TYPE_OP,
 
-  COUNT_NODEYPES,
+  COUNT_NODE_TYPES,
 };
 
 union node_data {
@@ -23,11 +29,21 @@ union node_data {
   node_func func;
 };
 
+struct noodle {
+  line ln;
+  u64 connected_node;
+  u64 connection_idx;
+};
+
 struct node {
-  ui_node_elem node;
+  rect rec;
   ui_elem_colours colours;
   node_type type;
   node_data data;
+  u64 inputs;
+  u64 connected;
+  noodle *noodles;
+  noodle **connected_noodles;
 };
 
 #endif // !NODES_H

include/ops.h

@@ -1,7 +1,7 @@
 #ifndef COMP_OPS_H
 #define COMP_OPS_H
 
-#include "aliases/aliases.h"
+#include "aliases.h"
 #include "nodes.h"
 
 enum comp_ops {
@@ -18,7 +18,7 @@ i32 comp_sub(i32 a, i32 b);
 i32 comp_mul(i32 a, i32 b);
 i32 comp_div(i32 a, i32 b);
 
-INTERNAL node_func ops[COUNT_COMP_OPS] = {
+internal node_func ops[COUNT_COMP_OPS] = {
     [COMP_OP_ADD] = comp_add,
     [COMP_OP_SUB] = comp_sub,
     [COMP_OP_MUL] = comp_mul,

include/ui.h

@@ -2,7 +2,7 @@
 #define UI_H
 
 #include "SDL_events.h"
-#include "aliases/aliases.h"
+#include "aliases.h"
 #include "window.h"
 #include <stdbool.h>
 
@@ -14,12 +14,17 @@
 #define NODE_WIDTH 70
 #define NODE_HEIGHT 20
 
+#define DEFAULT_NOODLE_LENGTH 60
+
 typedef enum ui_elem_type ui_elem_type;
 typedef struct ui_elem ui_elem;
 typedef struct ui_ctx ui_ctx;
+typedef struct ui_elem_colours ui_elem_colours;
+typedef enum noodle_action noodle_action;
 
 enum ui_elem_type {
   UI_ELEM_NODE,
+  UI_ELEM_NOODLE,
   UI_ELEM_BUTTON,
 
   COUNT_UI_ELEM,
@@ -27,20 +32,22 @@ enum ui_elem_type {
 
 struct ui_elem {
   u64 id;
-  rect rect;
+  union {
+    rect rec;
+    line ln;
+  };
   ui_elem_type type;
 };
 
-typedef struct ui_elem_colours ui_elem_colours;
 struct ui_elem_colours {
   colour fill;
   colour border;
 };
 
-typedef struct ui_node_elem ui_node_elem;
-struct ui_node_elem {
-  line noodle;
-  rect rec;
+enum noodle_action {
+  NOODLE_ACTION_NONE,
+  NOODLE_ACTION_DRAGGING,
+  NOODLE_ACTION_RELEASED,
 };
 
 struct ui_ctx {
@@ -54,6 +61,7 @@ struct ui_ctx {
   bool mouse_down;
   bool mouse_up;
   const window *wnd;
+  ui_elem elements[MAX_UI_ELEMENTS];
 };
 
 void init_ui_ctx(ui_ctx *ctx);
@@ -61,7 +69,9 @@ void reset_ui_ctx(ui_ctx *ctx);
 void handle_ui_events(const window *wnd, ui_ctx *ctx, const SDL_Event *event);
 bool ui_button(const window *wnd, ui_ctx *ctx, rect rect,
                ui_elem_colours colours);
-ui_node_elem ui_node(const window *wnd, ui_ctx *ctx, ui_node_elem node,
-                     ui_elem_colours colours);
+bool ui_node(const window *wnd, ui_ctx *ctx, rect rect,
+             ui_elem_colours colours);
+noodle_action ui_noodle(const window *wnd, ui_ctx *ctx, line ln,
+                        ui_elem_colours colours, rect parent_node);
 
 #endif // !UI_H

include/window.h

@@ -1,7 +1,7 @@
 #ifndef WINDOW_H
 #define WINDOW_H
 
-#include "aliases/aliases.h"
+#include "aliases.h"
 #include <SDL2/SDL_pixels.h>
 #include <SDL2/SDL_render.h>
 #include <SDL2/SDL_video.h>
@@ -80,5 +80,7 @@ void draw_rect(const window *wnd, rect rec, colour colour);
 void fill_triangle(const window *wnd, triangle triangle, colour colour);
 void fill_quad(const window *wnd, quad qd, colour colour);
 void fill_rect(const window *wnd, rect rec, colour colour);
+line line_from_origin(point origin, f64 angle, i32 line_length);
+bool aabb(rect rec, i32 x, i32 y);
 
 #endif // !WINDOW_H

src/compositor.c

@@ -1,4 +1,5 @@
-#include "aliases/aliases.h"
+#include "aliases.h"
+#include "mem_arena.h"
 #include "nodes.h"
 #include "ops.h"
 #include "ui.h"
@@ -15,21 +16,25 @@
 #define WINDOW_WIDTH 1280
 #define WINDOW_HEIGHT 720
 
+#define ARENA_CAPACITY 1 * 1024 * 1024
+
 typedef struct compositor compositor;
 struct compositor {
+  Arena *arena;
   window windows[MAX_WINDOWS];
   u32 active_window;
   SDL_Event event;
   bool running;
-  i64 node_hovered;
   u64 count;
   node *nodes;
-  bool move_node;
+  node *back_nodes;
   ui_ctx ctx;
 };
 
-void add_node(compositor *comp, node_type type, node_data data, i32 x, i32 y,
-              ui_elem_colours colours);
+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) {
   if (SDL_Init(SDL_INIT_EVERYTHING) != 0) {
@@ -39,8 +44,11 @@ i32 run_main_loop(void) {
   compositor comp = {0};
 
   init_ui_ctx(&(comp.ctx));
+  mem_arena_init(&comp.arena, ARENA_CAPACITY);
 
-  comp.nodes = (node *)malloc(sizeof(node) * MAX_NODES);
+  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]);
@@ -81,16 +89,16 @@ i32 run_main_loop(void) {
       handle_ui_events(&(comp.windows[comp.active_window - 1]), &(comp.ctx),
                        &(comp.event));
 
-      switch (comp.event.type) {
-      case SDL_QUIT:
+      if (comp.event.type == SDL_QUIT) {
         comp.running = false;
-        break;
-      case SDL_WINDOWEVENT:
-        switch (comp.event.window.event) {
-        case SDL_WINDOWEVENT_CLOSE:
+      }
+
+      if (comp.event.type == SDL_WINDOWEVENT) {
+        if (comp.event.window.event == SDL_WINDOWEVENT_CLOSE) {
           comp.running = false;
-          break;
-        case SDL_WINDOWEVENT_ENTER: {
+        }
+
+        if (comp.event.window.event == SDL_WINDOWEVENT_ENTER) {
           u32 id = comp.event.window.windowID;
           window *wnd = NULL;
 
@@ -104,29 +112,24 @@ i32 run_main_loop(void) {
             }
           }
 
-          if (!wnd) {
-            break;
+          if (wnd) {
+            SDL_RaiseWindow(wnd->window);
           }
-
-          SDL_RaiseWindow(wnd->window);
-
-          break;
-        }
         }
+      }
 
-        break;
-      case SDL_DROPFILE:
+      if (comp.event.type == SDL_DROPFILE) {
         if (comp.event.drop.windowID == main_window->id) {
           node_data data = (node_data){.path = comp.event.drop.file};
 
-          add_node(&comp, NODEYPE_IO, data, comp.ctx.mouse_x, comp.ctx.mouse_y,
-                   io_node_colours);
-
-          break;
+          add_node(&comp, NODE_TYPE_IO, data, IO_INPUT_COUNT, comp.ctx.mouse_x,
+                   comp.ctx.mouse_y, io_node_colours);
         }
       }
     }
 
+    update_node_graph(&comp, main_window);
+
     for (u64 i = 0; i < MAX_WINDOWS; ++i) {
       clear_window(&(comp.windows[i]), bg_colour);
     }
@@ -142,15 +145,12 @@ i32 run_main_loop(void) {
       if (ui_button(toolbox, &(comp.ctx), rect, button_colours)) {
         node_data data = (node_data){.func = ops[i]};
 
-        add_node(&comp, NODEYPE_OP, data, comp.ctx.mouse_x, comp.ctx.mouse_y,
-                 op_node_colours);
+        add_node(&comp, NODE_TYPE_OP, data, OP_INPUT_COUNT, comp.ctx.mouse_x,
+                 comp.ctx.mouse_y, op_node_colours);
       }
     }
 
-    for (u64 i = 0; i < comp.count; ++i) {
-      comp.nodes[i].node = ui_node(main_window, &(comp.ctx), comp.nodes[i].node,
-                                   comp.nodes[i].colours);
-    }
+    draw_node_graph(&comp, main_window);
 
     for (u64 i = 0; i < MAX_WINDOWS; ++i) {
       swap_buffers(&(comp.windows[i]));
@@ -165,29 +165,208 @@ i32 run_main_loop(void) {
 
   SDL_Quit();
 
+  mem_arena_free(&comp.arena);
+
   return EXIT_SUCCESS;
 }
 
-void add_node(compositor *comp, node_type type, node_data data, i32 x, i32 y,
-              ui_elem_colours colours) {
+internal void add_node(compositor *comp, node_type type, node_data data,
+                       u64 inputs, i32 x, i32 y, ui_elem_colours colours) {
   if (comp->count + 1 >= MAX_NODES) {
     return;
   }
 
-  comp->nodes[(comp->count)++] = (node){
-      .node =
-          (ui_node_elem){
-              .rec =
-                  (rect){
-                      .topleft.x = x,
-                      .topleft.y = y,
-                      .w = NODE_WIDTH,
-                      .h = NODE_HEIGHT,
-                  },
-              .noodle = (line){0},
-          },
+  u64 alloc_size = inputs * sizeof(noodle);
+  noodle *noodles = mem_arena_alloc(comp->arena, alloc_size);
+  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;
+  }
+
+  rect rec = (rect){
+      .topleft.x = x,
+      .topleft.y = y,
+      .w = NODE_WIDTH,
+      .h = NODE_HEIGHT,
+  };
+
+  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 < 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};
+
+        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:
+        back_ndl->ln.p0.x += comp->ctx.rel_x;
+        back_ndl->ln.p0.y += comp->ctx.rel_y;
+        break;
+      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};
+
+            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 {
+            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;
+      }
+
+      if (delta_multiplier > 0) {
+        angle = new_angle;
+      }
+
+      if (delta_multiplier == 0) {
+        delta_multiplier = -1;
+      } else {
+        delta_multiplier *= -1;
+      }
+    }
+
+    if (ui_node(wnd, &(comp->ctx), node_elem->rec, node_elem->colours)) {
+      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) {
+          back_ndl->ln.p0.x += comp->ctx.rel_x;
+          back_ndl->ln.p0.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 = CONNECTION_START; j <= back_node->connected; ++j) {
+        noodle *ndl = back_node->connected_noodles[j];
+
+        ndl->ln.p0.x += comp->ctx.rel_x;
+        ndl->ln.p0.y += comp->ctx.rel_y;
+      }
+    }
+  }
 }

src/main.c

@@ -1,4 +1,4 @@
-#include "aliases/aliases.h"
+#include "aliases.h"
 #include "compositor.h"
 
 i32 main(void) { return run_main_loop(); }

src/ops.c

@@ -1,5 +1,5 @@
 #include "ops.h"
-#include "aliases/aliases.h"
+#include "aliases.h"
 
 i32 comp_add(i32 a, i32 b) { return a + b; }
 

src/ui.c

@@ -1,6 +1,6 @@
 #include "ui.h"
 #include "SDL_events.h"
-#include "aliases/aliases.h"
+#include "aliases.h"
 #include "math_utils.h"
 #include "window.h"
 #include <math.h>
@@ -8,12 +8,8 @@
 #include <stdlib.h>
 
 #define NOODLE_HALF_WIDTH 2
-#define DEFAULT_NOODLE_LENGTH 60
 
-line ui_noodle(const window *wnd, ui_ctx *ctx, line ln,
-               ui_elem_colours colours);
-INTERNAL bool aabb(rect rec, i32 x, i32 y);
-INTERNAL line line_from_origin(point origin, f64 angle, i32 line_length);
+internal u64 get_id(ui_ctx *ctx);
 
 void init_ui_ctx(ui_ctx *ctx) {
   *ctx = (ui_ctx){0};
@@ -30,34 +26,31 @@ void reset_ui_ctx(ui_ctx *ctx) {
 }
 
 void handle_ui_events(const window *wnd, ui_ctx *ctx, const SDL_Event *event) {
-  switch (event->type) {
-  case SDL_MOUSEMOTION:
+  if (event->type == SDL_MOUSEMOTION) {
     if (wnd->id == event->motion.windowID) {
       ctx->mouse_x = event->motion.x;
       ctx->mouse_y = event->motion.y;
       ctx->rel_x += event->motion.xrel;
       ctx->rel_y += event->motion.yrel;
       ctx->wnd = wnd;
-
-      break;
     }
-  case SDL_MOUSEBUTTONDOWN:
+  }
+
+  if (event->type == SDL_MOUSEBUTTONDOWN) {
     if (wnd->id == event->button.windowID) {
       ctx->mouse_x = event->button.x;
       ctx->mouse_y = event->button.y;
       ctx->mouse_down = true;
       ctx->wnd = wnd;
-
-      break;
     }
-  case SDL_MOUSEBUTTONUP:
+  }
+
+  if (event->type == SDL_MOUSEBUTTONUP) {
     if (wnd->id == event->button.windowID) {
       ctx->mouse_x = event->button.x;
       ctx->mouse_y = event->button.y;
       ctx->mouse_up = true;
       ctx->wnd = wnd;
-
-      break;
     }
   }
 }
@@ -68,7 +61,12 @@ bool ui_button(const window *wnd, ui_ctx *ctx, rect rec,
     return false;
   }
 
-  u64 id = (ctx->count)++;
+  u64 id = get_id(ctx);
+  ctx->elements[id] = (ui_elem){
+      .id = id,
+      .rec = rec,
+      .type = UI_ELEM_BUTTON,
+  };
 
   fill_rect(wnd, rec, colours.fill);
   draw_rect(wnd, rec, colours.border);
@@ -95,52 +93,40 @@ bool ui_button(const window *wnd, ui_ctx *ctx, rect rec,
   return false;
 }
 
-ui_node_elem ui_node(const window *wnd, ui_ctx *ctx, ui_node_elem node,
-                     ui_elem_colours colours) {
+bool ui_node(const window *wnd, ui_ctx *ctx, rect rect,
+             ui_elem_colours colours) {
   if (ctx->count + 1 >= MAX_UI_ELEMENTS) {
-    return (ui_node_elem){0};
+    return false;
   }
 
-  u64 id = (ctx->count)++;
+  u64 id = get_id(ctx);
+  ctx->elements[id] = (ui_elem){
+      .id = id,
+      .rec = rect,
+      .type = UI_ELEM_NODE,
+  };
 
-  line ln;
-  if (node.noodle.p0.x == node.noodle.p1.x &&
-      node.noodle.p0.y == node.noodle.p1.y) {
-    ln = line_from_origin((point){node.rec.topleft.x + node.rec.w / 2,
-                                  node.rec.topleft.y + node.rec.h / 2},
-                          90.0, DEFAULT_NOODLE_LENGTH);
-  } else {
-    ln = node.noodle;
-  }
-
-  node.noodle = ui_noodle(wnd, ctx, ln, colours);
-
-  fill_rect(wnd, node.rec, colours.fill);
-  draw_rect(wnd, node.rec, colours.border);
+  fill_rect(wnd, rect, colours.fill);
+  draw_rect(wnd, rect, colours.border);
 
   if (wnd != ctx->wnd || (ctx->active >= 0 && ctx->active != id)) {
-    return node;
+    return false;
   }
 
   if (ctx->mouse_up) {
-    ctx->hovered = ctx->active = -1;
-    ctx->rel_x = ctx->rel_y = 0;
-    return node;
+    if (ctx->hovered == ctx->active && ctx->hovered == id) {
+      ctx->hovered = ctx->active = -1;
+    }
+
+    return false;
   }
 
   if (ctx->hovered == id && ctx->active == id) {
-    node.rec.topleft.x += ctx->rel_x;
-    node.rec.topleft.y += ctx->rel_y;
-    node.noodle.p0.x += ctx->rel_x;
-    node.noodle.p0.y += ctx->rel_y;
-    node.noodle.p1.x += ctx->rel_x;
-    node.noodle.p1.y += ctx->rel_y;
-
-    return node;
+    return true;
   }
 
-  if (!aabb(node.rec, ctx->mouse_x, ctx->mouse_y)) {
-    return node;
+  if (!aabb(rect, ctx->mouse_x, ctx->mouse_y)) {
+    return false;
   }
 
   ctx->hovered = id;
@@ -149,16 +135,21 @@ ui_node_elem ui_node(const window *wnd, ui_ctx *ctx, ui_node_elem node,
     ctx->active = id;
   }
 
-  return node;
+  return false;
 }
 
-line ui_noodle(const window *wnd, ui_ctx *ctx, line ln,
-               ui_elem_colours colours) {
+noodle_action ui_noodle(const window *wnd, ui_ctx *ctx, line ln,
+                        ui_elem_colours colours, rect parent_node) {
   if (ctx->count + 1 >= MAX_UI_ELEMENTS) {
-    return (line){0};
+    return NOODLE_ACTION_NONE;
   }
 
-  u64 id = (ctx->count)++;
+  u64 id = get_id(ctx);
+  ctx->elements[id] = (ui_elem){
+      .id = id,
+      .ln = ln,
+      .type = UI_ELEM_NOODLE,
+  };
 
   bool horizontal = ln.p0.y == ln.p1.y;
 
@@ -226,24 +217,25 @@ line ui_noodle(const window *wnd, ui_ctx *ctx, line ln,
   }
 
   if (wnd != ctx->wnd || (ctx->active >= 0 && ctx->active != id)) {
-    return ln;
+    return NOODLE_ACTION_NONE;
   }
 
   if (ctx->mouse_up) {
-    ctx->hovered = ctx->active = -1;
-    ctx->rel_x = ctx->rel_y = 0;
-    return ln;
+    if (ctx->hovered == ctx->active && ctx->hovered == id) {
+      ctx->hovered = ctx->active = -1;
+      return NOODLE_ACTION_RELEASED;
+    }
+
+    return NOODLE_ACTION_NONE;
   }
 
   if (ctx->hovered == id && ctx->active == id) {
-    ln.p0.x += ctx->rel_x;
-    ln.p0.y += ctx->rel_y;
-
-    return ln;
+    return NOODLE_ACTION_DRAGGING;
   }
 
-  if (!aabb(bounding_box, ctx->mouse_x, ctx->mouse_y)) {
-    return ln;
+  if (!aabb(bounding_box, ctx->mouse_x, ctx->mouse_y) ||
+      aabb(parent_node, ctx->mouse_x, ctx->mouse_y)) {
+    return NOODLE_ACTION_NONE;
   }
 
   ctx->hovered = id;
@@ -252,23 +244,10 @@ line ui_noodle(const window *wnd, ui_ctx *ctx, line ln,
     ctx->active = id;
   }
 
-  return ln;
+  return NOODLE_ACTION_NONE;
 }
 
-INTERNAL bool aabb(rect rec, i32 x, i32 y) {
-  return x > rec.topleft.x && x <= rec.topleft.x + rec.w && y > rec.topleft.y &&
-         y <= rec.topleft.y + rec.h;
-}
-
-INTERNAL line line_from_origin(point origin, f64 angle, i32 line_length) {
-  f64 rad = radians(angle);
-  f64 direction = angle / absolute(angle) * -1;
-
-  i32 adjacent = line_length * cos(rad) * direction; // dx
-  i32 opposite = line_length * sin(rad) * direction; // dy
-
-  return (line){
-      (point){origin.x + adjacent, origin.y + opposite},
-      origin,
-  };
+internal u64 get_id(ui_ctx *ctx) {
+  // This will always keep the 0 slot empty
+  return ++(ctx->count);
 }

src/window.c

@@ -1,12 +1,12 @@
 #include "window.h"
-#include "aliases/aliases.h"
+#include "aliases.h"
 #include "math_utils.h"
 #include <SDL2/SDL_rect.h>
 #include <SDL2/SDL_render.h>
 #include <SDL2/SDL_video.h>
 #include <stdbool.h>
 
-INTERNAL inline bool inside_triangle(triangle tri, point p);
+internal inline bool inside_triangle(triangle tri, point p);
 
 bool init_window(window *wnd, const char *title, u32 width, u32 height, i32 x,
                  i32 y) {
@@ -162,7 +162,25 @@ void fill_quad(const window *wnd, quad qd, colour colour) {
   fill_triangle(wnd, t1, colour);
 }
 
-INTERNAL inline bool inside_triangle(triangle tri, point p) {
+line line_from_origin(point origin, f64 angle, i32 line_length) {
+  f64 rad = radians(angle);
+  f64 direction = angle / absolute(angle) * -1;
+
+  i32 adjacent = line_length * cos(rad) * direction; // dx
+  i32 opposite = line_length * sin(rad) * direction; // dy
+
+  return (line){
+      (point){origin.x + adjacent, origin.y + opposite},
+      origin,
+  };
+}
+
+bool aabb(rect rec, i32 x, i32 y) {
+  return x > rec.topleft.x && x <= rec.topleft.x + rec.w && y > rec.topleft.y &&
+         y <= rec.topleft.y + rec.h;
+}
+
+internal inline bool inside_triangle(triangle tri, point p) {
   // Based on the following video:
   // https://www.youtube.com/watch?v=HYAgJN3x4GA
   f32 cy_min_ay = tri.p2.y - tri.p0.y;