Undo eraser

README.txt

@@ -8,7 +8,7 @@ Release:
         + Do not copy memory to wasm, instead use wasm memory to store data in the first place
         + SIMD for LOD?
         + Multithreading for LOD
-        + Textured quads (pictures, code already written in older version)
+        + Textured quads (pictures, code already written in older version
         + Resize and move pictures (draw handles)
         - Z-prepass fringe bug (also, when do we enable the prepass?)
     + Bugs
@@ -45,8 +45,8 @@ Release:
             - Live preview
             - Alignment (horizontal, vertical, diagonal, etc)
         + Undo
+            + Undo for eraser
             - Undo for images (add, move, scale)
-            - Undo for eraser
         - Redo
         + Snapping to grid
         - Snapping to other points?

client/bvh.js

@@ -176,6 +176,19 @@ function bvh_delete_stroke(state, stroke) {
     }
 }
 
+function bvh_undelete_stroke(state, stroke) {
+    let node = state.bvh.nodes[stroke.bvh_node];
+    
+    while (node.parent_index !== null) {
+        if (node.is_fullnode) {
+            tv_add2(node.stroke_indices, stroke.index);
+            break;
+        }
+
+        node = state.bvh.nodes[node.parent_index];
+    }
+}
+
 function bvh_intersect_quad(state, bvh, quad, result_buffer) {
     if (bvh.root === null) {
         return;

client/client_recv.js

@@ -366,17 +366,24 @@ function handle_event(state, context, event, options = {}) {
                         break;
                     } else if (other_event.type === EVENT.UNDO) {
                         // do not undo an undo, we are not Notepad
+                    } else if (other_event.type === EVENT.IMAGE) {
+                        console.log('TODO: undo image');
                     } else if (other_event.type === EVENT.IMAGE_MOVE) {
                         // TODO
-                        console.log('TODO: undo image scale');
+                        console.log('TODO: undo image move');
                         break;
                     } else if (other_event.type === EVENT.IMAGE_SCALE) {
                         // TODO 
                         console.log('TODO: undo image scale');
                         break;
                     } else if (other_event.type === EVENT.ERASER) {
-                        // TODO 
+                        const stroke = state.events[other_event.stroke_id];
-                        console.log('TODO: undo eraser');
+                        stroke.deleted = false;
+                        if (!options.skip_bvh) {
+                            bvh_undelete_stroke(state, stroke);
+                        }
+                        need_draw = true;
+                        other_event.deleted = true;
                         break;
                     } else {
                         console.error('cant undo event type', other_event.type);