prune unused elements

src/ht.h

@@ -96,6 +96,20 @@ void *ht_get(ed_ht *ht, string key) {
     return NULL;
 }
 
+void ht_remove(ed_ht *ht, string key) {
+    ht_hash_t hash = ht_hash(key, ht->capacity);
+
+    for (size_t i=hash; i<ht->capacity; ++i) {
+        if (ht->key_slots[i].key.data == NULL) {
+            return;
+        }
+
+        if (string_eq(ht->key_slots[i].key, key)) {
+            ht->key_slots[i] = (ed_ht_slot) { 0 };
+        }
+    }
+}
+
 void ht_destroy(ed_ht *ht) {
     // TODO: destroy the hash table
     free(ht->key_slots);

src/main.c

@@ -307,36 +307,30 @@ void ed_init() {
         },
     });
 
-    // queue_text(_String("But what even is text! []!@#$%^&*()_=+"), (float[]){ 0, 0 });
-    // queue_text(_String("v0.1.0"), (float[]){ 32, 128 });
-    // queue_text(_String("an_editor - what even"), (float[]){ 32, 256 });
-
     state.ui_cx = ui_init_context();
 
 }
 void ed_frame() {
-    string label = _String("Number 1");
-    ui_element(&state.ui_cx, label);
+    state.ui_cx.frame_elements.data[0].size.computed_size[0] = sapp_width();
+    state.ui_cx.frame_elements.data[0].size.computed_size[1] = sapp_height();
+
+    ui_element(&state.ui_cx, _String("Number 1"));
     ui_element(&state.ui_cx, _String("ui element 2"));
     ui_element(&state.ui_cx, _String("ui element 3"));
 
     ui_compute_layout(&state.ui_cx, 0);
-    state.ui_cx.frame_elements.data[0].size.computed_size[0] = sapp_width();
-    state.ui_cx.frame_elements.data[0].size.computed_size[1] = sapp_height();
-    ui_update_cache(&state.ui_cx, 0);
 
     state.gpu_glyphs.size = 0;
-    for (size_t i = 0; i < state.ui_cx.cached_elements.capacity; ++i) {
-        if (state.ui_cx.cached_elements.key_slots[i].key.data != NULL) {
-            string text = state.ui_cx.cached_elements.key_slots[i].key;
+    for (size_t i = 0; i < state.ui_cx.frame_elements.size; ++i) {
+        string text = state.ui_cx.frame_elements.data[i].key;
+        ui_element_frame_data *elm = &state.ui_cx.frame_elements.data[i];
 
-            ui_element_cache_data *value = ht_get(&state.ui_cx.cached_elements, text);
-            if (value) {
-                queue_text(text, (float[]){ (float)value->size.computed_pos[0], (float)value->size.computed_pos[1] });
-            }
-        }
+        queue_text(text, (float[]){ (float)elm->size.computed_pos[0], (float)elm->size.computed_pos[1] });
     }
 
+    ui_update_cache(&state.ui_cx, 0);
+    ui_prune(&state.ui_cx);
+
     if (state.gpu_glyphs.size > 0) {
         sg_update_buffer(state.bind.vertex_buffers[1], &(sg_range) {
             .ptr = state.gpu_glyphs.data,
@@ -363,10 +357,12 @@ void ed_frame() {
     sg_end_pass();
     sg_commit();
 }
+
 void ed_cleanup() {
     sfetch_shutdown();
     sg_shutdown();
 }
+
 void ed_event(const sapp_event *event) {
     switch (event->type) {
         case SAPP_EVENTTYPE_MOUSE_DOWN:

src/ui.h

@@ -24,6 +24,7 @@
 #define _prev_ref(index) (_elm(_prev(index)))
 #define _parent_ref(index) (_elm(_parent(index)))
 
+#include <stdio.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdbool.h>
@@ -360,6 +361,13 @@ void ui_update_cache(ui_context *cx, size_t element_index) {
         do {
             __auto_type child = _elm(child_index);
 
+            size_t last_instantiated_index = cx->frame_index;
+
+            ui_element_cache_data *cache;
+            if ((cache = ht_get(&cx->cached_elements, child->key))) {
+                last_instantiated_index = cache->last_instantiated_index;
+            }
+
             ht_set(&cx->cached_elements, child->key, &(ui_element_cache_data) {
                 .label = child->label,
                 .size = {
@@ -367,8 +375,8 @@ void ui_update_cache(ui_context *cx, size_t element_index) {
                     .semantic_size = { child->size.semantic_size[0], child->size.semantic_size[1] },
                     .computed_size = { child->size.computed_size[0], child->size.computed_size[1] },
                     .computed_pos = { child->size.computed_pos[0], child->size.computed_pos[1] },
-                }
-                // FIXME: don't mangle last_instantiated_index
+                },
+                .last_instantiated_index = last_instantiated_index,
             });
 
             ui_update_cache(cx, child_index);
@@ -384,5 +392,23 @@ void ui_update_cache(ui_context *cx, size_t element_index) {
     cx->current_parent = 0;
 }
 
+void ui_prune(ui_context *cx) {
+    for (size_t i = 0; i < cx->cached_elements.capacity; ++i) {
+        if (cx->cached_elements.key_slots[i].key.data != NULL) {
+            string key = cx->cached_elements.key_slots[i].key;
+
+            // if this element hasn't been created in the past 5 frames, remove it
+            ui_element_cache_data *cached = ht_get(&cx->cached_elements, key);
+            if (cached && cached->last_instantiated_index < cx->frame_index-5) {
+                // fprintf(stderr, "removing %.*s from cache, cache index: %zu, frame index: %zu\n", (int)key.len, key.data, cached->last_instantiated_index, cx->frame_index);
+
+                ht_remove(&cx->cached_elements, key);
+            }
+        }
+    }
+
+    cx->frame_index += 1;
+}
+
 #endif
 #endif