Add a geometry pool, shape hierarchy, addittion and deletion.

src/interact.h

@@ -0,0 +1,144 @@
+#ifndef INTERACT_H
+#define INTERACT_H
+
+#include "api.h"
+#include "types.h"
+
+static void selected_aabb(userdata_t *ud, float *min_x, float *min_y,
+                           float *max_x, float *max_y)
+{
+    bool first = true;
+    for (int i = 0; i < ud->shapes.count; i++) {
+        shape_t *s = (shape_t*) vec_get(&ud->shapes, i);
+        if (!s->selected) continue;
+        float sc = cosf(s->rotation), ss = sinf(s->rotation);
+        for (uint32_t v = 0; v < s->num_verts; v++) {
+            float lx = s->verts[v].x * s->sx;
+            float ly = s->verts[v].y * s->sy;
+            float wx = s->cx + lx * sc - ly * ss;
+            float wy = s->cy + lx * ss + ly * sc;
+            if (first) { *min_x = *max_x = wx; *min_y = *max_y = wy; first = false; }
+            else {
+                if (wx < *min_x) *min_x = wx;
+                if (wx > *max_x) *max_x = wx;
+                if (wy < *min_y) *min_y = wy;
+                if (wy > *max_y) *max_y = wy;
+            }
+        }
+    }
+}
+
+static void update_shape_states(userdata_t *ud)
+{
+    for (int i = 0; i < ud->shapes.count; i++) {
+        shape_t *s = (shape_t*) vec_get(&ud->shapes, i);
+        shape_set_state(s, s->hovered, s->selected);
+    }
+}
+
+static void select_group_recursive(userdata_t *ud, int gid)
+{
+    for (int i = 0; i < ud->shapes.count; i++) {
+        shape_t *s = (shape_t*) vec_get(&ud->shapes, i);
+        if (is_shape_in_group_hierarchy(s->group_id, gid, &ud->groups)) {
+            s->selected = true;
+            ud->interact.selected_count++;
+        }
+    }
+}
+
+static void deselect_and_select_group_recursive(userdata_t *ud, int gid)
+{
+    for (int i = 0; i < ud->shapes.count; i++)
+        ((shape_t*) vec_get(&ud->shapes, i))->selected = false;
+    ud->interact.selected_count = 0;
+    select_group_recursive(ud, gid);
+}
+
+static void toggle_group_recursive(userdata_t *ud, int gid)
+{
+    int total = 0, sel = 0;
+    for (int i = 0; i < ud->shapes.count; i++) {
+        shape_t *s = (shape_t*) vec_get(&ud->shapes, i);
+        if (is_shape_in_group_hierarchy(s->group_id, gid, &ud->groups)) {
+            total++;
+            if (s->selected) sel++;
+        }
+    }
+    bool all_sel = (sel == total && total > 0);
+    for (int i = 0; i < ud->shapes.count; i++) {
+        shape_t *s = (shape_t*) vec_get(&ud->shapes, i);
+        if (is_shape_in_group_hierarchy(s->group_id, gid, &ud->groups)) {
+            s->selected = !all_sel;
+            ud->interact.selected_count += s->selected ? 1 : -1;
+        }
+    }
+}
+
+static void rebuild_groups_from_shapes(vector_t *groups, vector_t *shapes)
+{
+    // Save existing parent relationships so nested groups survive rebuild
+    int old_count = groups->count;
+    int *saved = NULL;
+    if (old_count > 0) {
+        saved = (int*) ALLOC((size_t)old_count * 2 * sizeof(int));
+        for (int i = 0; i < old_count; i++) {
+            group_t *g = (group_t*) vec_get(groups, i);
+            saved[i * 2] = g->id;
+            saved[i * 2 + 1] = g->parent_id;
+        }
+    }
+
+    groups->count = 0;
+    for (int i = 0; i < shapes->count; i++) {
+        shape_t *s = (shape_t*) vec_get(shapes, i);
+        if (s->group_id == 0) continue;
+        bool found = false;
+        for (int g = 0; g < groups->count; g++) {
+            if (((group_t*) vec_get(groups, g))->id == s->group_id) { found = true; break; }
+        }
+        if (!found) {
+            group_t grp = { .id = s->group_id, .parent_id = 0 };
+            *((group_t*) vec_push(groups)) = grp;
+        }
+    }
+
+    // Restore parent relationships for groups that still exist
+    for (int i = 0; i < old_count; i++) {
+        int gid = saved[i * 2];
+        int pid = saved[i * 2 + 1];
+        if (pid == 0) continue;
+        group_t *g = find_group(groups, gid);
+        if (g) {
+            // Only restore if parent group still exists
+            if (find_group(groups, pid))
+                g->parent_id = pid;
+        }
+    }
+
+    if (saved) FREE(saved);
+}
+
+static int hit_test_resize_handles(userdata_t *ud, float wx, float wy, float tol)
+{
+    if (ud->interact.selected_count <= 0) return -1;
+    float omin[2], omax[2];
+    if (ud->interact.aabb_cached) {
+        omin[0] = ud->interact.cached_aabb[0]; omin[1] = ud->interact.cached_aabb[1];
+        omax[0] = ud->interact.cached_aabb[2]; omax[1] = ud->interact.cached_aabb[3];
+    } else {
+        selected_aabb(ud, &omin[0], &omin[1], &omax[0], &omax[1]);
+    }
+    float hs = CORNER_SIZE_PX / ud->camera.zoom * 0.5f + tol;
+    float mid_x = (omin[0] + omax[0]) * 0.5f;
+    float mid_y = (omin[1] + omax[1]) * 0.5f;
+    float hx[8] = {omin[0],    mid_x, omax[0], omax[0],    omax[0], mid_x, omin[0], omin[0]};
+    float hy[8] = {omin[1], omin[1], omin[1],    mid_y, omax[1], omax[1], omax[1],    mid_y};
+    for (int h = 0; h < 8; h++) {
+        if (fabsf(wx - hx[h]) <= hs && fabsf(wy - hy[h]) <= hs)
+            return h;
+    }
+    return -1;
+}
+
+#endif