Move point writes to WASM, already a lot faster!!!!

client/speed.js

@@ -52,7 +52,6 @@ function do_lod_wasm(state, context) {
     const segments_from = state.wasm.exports.alloc((context.clipped_indices.size + 1) * 4); 
     const segments = state.wasm.exports.alloc(state.segments.capacity * 4); 
     const coordinates = state.wasm.exports.alloc(state.coordinates.size * 4);
-
     const mem = new Uint8Array(state.wasm.exports.memory.buffer);
 
     mem.set(tv_bytes(context.clipped_indices), clipped_indices);
@@ -71,6 +70,8 @@ function do_lod_wasm(state, context) {
     // copy result back
     const wasm_segments = new Uint32Array(state.wasm.exports.memory.buffer, segments, segment_count);
     const wasm_segments_from = new Uint32Array(state.wasm.exports.memory.buffer, segments_from, context.clipped_indices.size + 1);
+    const wasm_points = new Float32Array(state.wasm.exports.memory.buffer, coordinates + state.coordinates.size * 4, segment_count * 2);
+    const wasm_ids = new Uint32Array(state.wasm.exports.memory.buffer, coordinates + (state.coordinates.size + segment_count * 2) * 4, segment_count);
 
     state.segments.data.set(wasm_segments);
     state.segments.size = segment_count;
@@ -78,8 +79,16 @@ function do_lod_wasm(state, context) {
     state.segments_from.data.set(wasm_segments_from);
     state.segments_from.size = context.clipped_indices.size + 1;
 
-    state.wasm.exports.total_free();
+    tv_ensure(context.instance_data_points, segment_count * 2);
+    tv_ensure(context.instance_data_ids, segment_count);
 
+    context.instance_data_points.data.set(wasm_points);
+    context.instance_data_points.size = segment_count * 2;
+
+    context.instance_data_ids.data.set(wasm_ids);
+    context.instance_data_ids.size = segment_count;
+
+    state.wasm.exports.total_free();
 
     return segment_count;
 }
@@ -164,5 +173,47 @@ function do_lod(state, context) {
     state.segments_from.size = context.clipped_indices.size + 1;
     state.segments.size = segments_head;
 
+    write_coordinates(state, context); 
+
     return segments_head;
 }
+
+function write_coordinates(state, context) {
+    tv_ensure(context.instance_data_points, state.segments.size * 2);
+    tv_ensure(context.instance_data_ids, state.segments.size);
+
+    tv_clear(context.instance_data_points);
+    tv_clear(context.instance_data_ids);
+
+    const clipped = context.clipped_indices.data;
+    const segments_from = state.segments_from.data;
+    const segments = state.segments.data;
+    const coords = state.coordinates.data;
+    const events = state.events;
+    
+    // TODO: move this loop to WASM
+    for (let i = 0; i < state.segments_from.size - 1; ++i) {
+        const stroke_index = clipped[i];
+        const coords_from = state.events[stroke_index].coords_from;
+        const from = segments_from[i];
+        const to = segments_from[i + 1];
+
+        for (let j = from; j < to; ++j) {
+            const base_this = segments[j];
+
+            const ax = coords[coords_from + base_this * 2 + 0];
+            const ay = coords[coords_from + base_this * 2 + 1];
+           
+            tv_add(context.instance_data_points, ax);
+            tv_add(context.instance_data_points, ay);
+
+            // Pack 1 into highest bit of stroke_index if we should not draw a segemtn from this
+            // point to the next one
+            if (j != to - 1) {
+                tv_add(context.instance_data_ids, stroke_index);
+            } else {
+                tv_add(context.instance_data_ids, stroke_index | (1 << 31));
+            }
+        }
+    }
+}

client/wasm/lod.c

@@ -130,6 +130,37 @@ do_lod(int *clipped_indices, int clipped_count, float zoom,
     }
 
     segments_from[clipped_count] = segments_head;
+
+    // Write actual coordinates (points) and stroke ids
+    float *points = alloc(segments_head * 2 * 4);
+    int *ids = alloc(segments_head * 4);
+
+    int phead = 0;
+    int ihead = 0;
+
+    for (int i = 0; i < clipped_count; ++i) {
+        int stroke_index = clipped_indices[i];
+        
+        // TODO: convert to a proper CSR, save half the memory
+        int base_stroke = stroke_coords_from[stroke_index];
+        int from = segments_from[i];
+        int to = segments_from[i + 1];
+
+        for (int j = from; j < to; ++j) {
+            int point_index = segments[j];
+            float x = coordinates[base_stroke + point_index * 2 + 0];
+            float y = coordinates[base_stroke + point_index * 2 + 1];
+
+            points[phead++] = x;
+            points[phead++] = y;
+
+            if (j != to - 1) {
+                ids[ihead++] = stroke_index;
+            } else {
+                ids[ihead++] = stroke_index | (1 << 31);
+            }
+        }
+    }
     
     return(segments_head);
 }

client/webgl_geometry.js

@@ -49,47 +49,9 @@ function geometry_write_instances(state, context) {
 
     const segment_count = do_lod(state, context);
 
-    tv_ensure(context.instance_data_points, state.segments.size * 2);
-    tv_ensure(context.instance_data_ids, state.segments.size);
-
-    tv_clear(context.instance_data_points);
-    tv_clear(context.instance_data_ids);
-
-    const clipped = context.clipped_indices.data;
-    const segments_from = state.segments_from.data;
-    const segments = state.segments.data;
-    const coords = state.coordinates.data;
-    const events = state.events;
-    
-    // TODO: move this loop to WASM
-    for (let i = 0; i < state.segments_from.size - 1; ++i) {
-        const stroke_index = clipped[i];
-        const coords_from = state.events[stroke_index].coords_from;
-        const from = segments_from[i];
-        const to = segments_from[i + 1];
-
-        for (let j = from; j < to; ++j) {
-            const base_this = segments[j];
-
-            const ax = coords[coords_from + base_this * 2 + 0];
-            const ay = coords[coords_from + base_this * 2 + 1];
-           
-            tv_add(context.instance_data_points, ax);
-            tv_add(context.instance_data_points, ay);
-
-            // Pack 1 into highest bit of stroke_index if we should not draw a segemtn from this
-            // point to the next one
-            if (j != to - 1) {
-                tv_add(context.instance_data_ids, stroke_index);
-            } else {
-                tv_add(context.instance_data_ids, stroke_index | (1 << 31));
-            }
-        }
-    }
-
     if (config.debug_print) console.debug('instances:', state.segments.count, 'rdp max:', state.stats.rdp_max_count, 'rdp segments:', state.stats.rdp_segments);
 
-    return state.segments.size;
+    return segment_count;
 }
 
 function geometry_add_stroke(state, context, stroke, stroke_index, skip_bvh = false) {