async-ify fdm slicing layer diffs for ~3x speedup

src/kiri/mode/fdm/work/slice.js

@@ -672,14 +672,22 @@ export function sliceOne(settings, widget, onupdate, ondone) {
     async function processLayerDiffs(plo, phi) {
         let div = divide(plo, phi, [ 0.9, 0.05, 0.05 ]);
         // boolean diff layers to detect bridges and flats
+        let promises = [];
         profileStart("delta");
         forSlices(div[0].lo, div[1].hi, slice => {
             let params = slice.params || process;
             let solidMinArea = params.sliceSolidMinArea;
             let sliceMinThick = params.sliceSolidMinThick;
             let sliceFillGrow = params.sliceFillGrow;
-            layerDiff(slice, { area: solidMinArea, grow: sliceFillGrow, thick: sliceMinThick });
+            let p = layerDiff(slice, {
+                area: solidMinArea,
+                grow: sliceFillGrow,
+                thick: sliceMinThick,
+                async: true
+            });
+            promises.push(p);
         }, "layer deltas");
+        await Promise.all(promises);
         profileEnd();
         // project bridges and flats up and down into part
         profileStart("delta-project");
@@ -1443,9 +1451,26 @@ export function layerDiff(slice, options = {}) {
     let newBridges = [];
     let newFlats = [];
 
-    POLY.subtract(topInner, downInner, newBridges, newFlats, slice.z, area, {
-        wasm: true
-    });
+    if (options.async) {
+        return self.kiri_worker.minions
+            .subtract({
+                a: topInner, b: downInner,
+                outA: newBridges, outB: newFlats,
+                area, wasm: true, z: slice.z,
+            })
+            .then(() => {
+                layerDiffDone({ slice, bridges, flats, newBridges, newFlats, options });
+            });
+    } else {
+        POLY.subtract(topInner, downInner, newBridges, newFlats, slice.z, area, {
+            wasm: true
+        });
+        layerDiffDone({ slice, bridges, flats, newBridges, newFlats, options });
+    }
+}
+
+function layerDiffDone({ slice, bridges, flats, newBridges, newFlats, options }) {
+    const { sla, grow, area, thick } = options;
 
     // console.log(slice.z, { newBridges, newFlats });
     newBridges = newBridges.filter(p => p.areaDeep() >= area && p.thickness(true) >= thick);

src/kiri/run/minion.js

@@ -78,6 +78,20 @@ const funcs = self.minion = {
         }
     },
 
+    subtract(data, seq) {
+        let { arg, opt } = data;
+        let { area, wasm, z } = opt;
+        let a = codec.decode(arg.a);
+        let b = codec.decode(arg.b);
+        let outA = [], outB = [];
+        POLY.subtract(a, b, outA, outB, z, area, { wasm });
+        reply({
+            seq,
+            outA: codec.encode(outA),
+            outB: codec.encode(outB)
+        });
+    },
+
     union(data, seq) {
         if (!(data.polys && data.polys.length)) {
             reply({ seq, union: codec.encode([]) });

src/kiri/run/worker.js

@@ -101,6 +101,9 @@ function minhandler(msg) {
 
 // for concurrent operations
 const minwork = {
+
+    // core functions
+
     get concurrent() {
         return concurrent
     },
@@ -137,6 +140,66 @@ const minwork = {
         minions.length = 0;
     },
 
+    queue(work, ondone, direct) {
+        minionq.push({work, ondone, direct});
+        minwork.kick();
+    },
+
+    queueAsync(work, direct) {
+        return new Promise(resolve => {
+            minwork.queue(work, resolve, direct);
+        });
+    },
+
+    kick() {
+        if (minions.length && minionq.length) {
+            let qrec = minionq.shift();
+            let minion = minions.shift();
+            let seq = miniseq++;
+            qrec.work.seq = seq;
+            minifns[seq] = (data) => {
+                qrec.ondone(data);
+                minions.push(minion);
+                minwork.kick();
+            };
+            minion.postMessage(qrec.work, qrec.direct);
+        }
+    },
+
+    broadcast(cmd, data, direct) {
+        for (let minion of minions) {
+            minion.postMessage({
+                cmd, ...data
+            }, direct);
+        }
+    },
+
+    // added functions (should be namespaced)
+
+    subtract({ a, b, outA, outB, z, area, wasm }) {
+        return new Promise((resolve, reject) => {
+            if (concurrent < 2 || a.length + b.length < concurrent * 2 || POLY.points([...a,...b]) < concurrent * 50) {
+                POLY.subtract(a, b, outA, outB, z, area, { wasm });
+                resolve();
+                return;
+            }
+            minwork.queue({
+                cmd: "subtract",
+                opt: { area, wasm, z },
+                arg: {
+                    a: codec.encode(a),
+                    b: codec.encode(b),
+                    outA: outA ? 1 : 0,
+                    outB: outB ? 1 : 0,
+                }
+            }, result => {
+                if (outA) outA.push(...codec.decode(result.outA));
+                if (outB) outB.push(...codec.decode(result.outB));
+                resolve();
+            });
+        });
+    },
+
     union(polys, minarea) {
         return new Promise((resolve, reject) => {
             if (concurrent < 2 || polys.length < concurrent * 2 || POLY.points(polys) < concurrent * 50) {
@@ -245,40 +308,6 @@ const minwork = {
             }, [ floatP.buffer ]);
         });
     },
-
-    queue(work, ondone, direct) {
-        minionq.push({work, ondone, direct});
-        minwork.kick();
-    },
-
-    queueAsync(work, direct) {
-        return new Promise(resolve => {
-            minwork.queue(work, resolve, direct);
-        });
-    },
-
-    kick() {
-        if (minions.length && minionq.length) {
-            let qrec = minionq.shift();
-            let minion = minions.shift();
-            let seq = miniseq++;
-            qrec.work.seq = seq;
-            minifns[seq] = (data) => {
-                qrec.ondone(data);
-                minions.push(minion);
-                minwork.kick();
-            };
-            minion.postMessage(qrec.work, qrec.direct);
-        }
-    },
-
-    broadcast(cmd, data, direct) {
-        for (let minion of minions) {
-            minion.postMessage({
-                cmd, ...data
-            }, direct);
-        }
-    }
 };
 
 console.log(`kiri | init work | ${version || "rogue"}`);