Batching of the main instanced drawcall

client/webgl_draw.js

@@ -274,13 +274,21 @@ async function draw(state, context, animate, ts) {
     }
 
     // TODO: what do we do with this
-    const circle_lod = Math.ceil(Math.min(7, 1 + Math.sqrt(state.canvas.zoom)));
+    const circle_lod = Math.round(Math.min(7, 3 * Math.sqrt(state.canvas.zoom)));
     const circle_data = geometry_good_circle_and_dummy(circle_lod);
 
     // "Static" data upload
     if (segment_count > 0) {
         const pr = programs['main'];
 
+        const nbatches = 10;
+        const batches = [];
+
+        for (let i = 0; i < nbatches; ++i) {
+            batches.push(Math.floor(segment_count / nbatches * i));
+        }
+        batches.push(segment_count);
+
         gl.clear(gl.DEPTH_BUFFER_BIT); // draw strokes above the images 
         gl.useProgram(pr.program);
 
@@ -319,11 +327,6 @@ async function draw(state, context, animate, ts) {
         // Circle meshes (shared for all instances)
         gl.vertexAttribPointer(pr.locations['a_pos'],        2, gl.FLOAT,         false, 2 * 4, context.instance_data_points.size * 4 + context.instance_data_ids.size * 4 + round_to_pow2(context.instance_data_pressures.size, 4));
 
-        // Points (a, b) and stroke ids are stored in separate cpu buffers so that points can be reused (look at stride and offset values)
-        gl.vertexAttribPointer(pr.locations['a_a'],          2, gl.FLOAT,         false, 2 * 4, 0);
-        gl.vertexAttribPointer(pr.locations['a_b'],          2, gl.FLOAT,         false, 2 * 4, 2 * 4);
-        gl.vertexAttribIPointer(pr.locations['a_stroke_id'], 1, gl.INT,                  4, context.instance_data_points.size * 4);
-        gl.vertexAttribPointer(pr.locations['a_pressure'],   2, gl.UNSIGNED_BYTE, true,  1, context.instance_data_points.size * 4 + context.instance_data_ids.size * 4);
 
         gl.vertexAttribDivisor(pr.locations['a_pos'], 0);
         gl.vertexAttribDivisor(pr.locations['a_a'], 1);
@@ -331,8 +334,18 @@ async function draw(state, context, animate, ts) {
         gl.vertexAttribDivisor(pr.locations['a_stroke_id'], 1);
         gl.vertexAttribDivisor(pr.locations['a_pressure'], 1);
 
-        // Static draw (everything already bound)
+        for (let b = 0; b < batches.length - 1; ++b) {
-        gl.drawElementsInstanced(gl.TRIANGLES, circle_data.indices.size, gl.UNSIGNED_INT, 0, segment_count); 
+            const batch_from = batches[b];
+            const batch_size = batches[b + 1] - batch_from;
+
+            // Points (a, b) and stroke ids are stored in separate cpu buffers so that points can be reused (look at stride and offset values)
+            gl.vertexAttribPointer(pr.locations['a_a'], 2, gl.FLOAT, false, 2 * 4, batch_from * 2 * 4);
+            gl.vertexAttribPointer(pr.locations['a_b'], 2, gl.FLOAT, false, 2 * 4, batch_from * 2 * 4 + 2 * 4);
+            gl.vertexAttribIPointer(pr.locations['a_stroke_id'], 1, gl.INT, 4, context.instance_data_points.size * 4 + batch_from * 4);
+            gl.vertexAttribPointer(pr.locations['a_pressure'], 2, gl.UNSIGNED_BYTE, true, 1, context.instance_data_points.size * 4 + context.instance_data_ids.size * 4 + batch_from);
+
+            gl.drawElementsInstanced(gl.TRIANGLES, circle_data.indices.size, gl.UNSIGNED_INT, 0, batch_size); 
+        }
 
         // I don't really know why I need to do this, but it
         // makes background patter drawcall work properly
@@ -540,6 +553,8 @@ async function draw(state, context, animate, ts) {
     document.getElementById('debug-stats').innerHTML = `
     <span>Strokes onscreen: ${context.clipped_indices.size}</span>
     <span>Segments onscreen: ${segment_count}</span>
+    <span>Total vertices: ${segment_count * circle_data.indices.size}</span>
+    <span>Circle LOD: ${circle_lod}</span>
     <span>Canvas offset: (${Math.round(state.canvas.offset.x * 100) / 100}, ${Math.round(state.canvas.offset.y * 100) / 100})</span>
     <span>Canvas zoom level: ${state.canvas.zoom_level}</span>
     <span>Canvas zoom: ${Math.round(state.canvas.zoom * 100) / 100}</span>`;

client/webgl_geometry.js

@@ -549,7 +549,7 @@ function geometry_line_segments_with_two_circles(circle_segments) {
 }
 
 function geometry_good_circle_and_dummy(lod) {
-    const total_points = 3 * Math.pow(2, lod - 1) + 4; // 3, 6, 12, 24, ... + Dummy for line segment
+    const total_points = 3 * Math.pow(2, lod) + 4; // 3, 6, 12, 24, ... + Dummy for line segment
     const total_indices = 3 * (Math.pow(3, lod + 1) - 1) / 2 + 6; // 3, 3 + 9, 3 + 9 + 18, ... + Dummy for line segment
     const points = tv_create(Float32Array, total_points * 2);
     const indices = tv_create(Uint32Array, total_indices);
@@ -576,7 +576,7 @@ function geometry_good_circle_and_dummy(lod) {
     let last_base = 3;
     let last_offset = 0;
 
-    for (let i = 0; i < lod; ++i) {
+    for (let i = 0; i <= lod; ++i) {
         // generate 3 * Math.pow(2, i) points on a circle
         const npoints = 3 * Math.pow(2, i);
         const base = indices.size;

client/webgl_shaders.js

@@ -322,8 +322,10 @@ function init_webgl(state, context) {
     gl.enable(gl.BLEND);
     gl.blendFunc(gl.ONE, gl.ONE_MINUS_SRC_ALPHA);
 
+    /*
     gl.enable(gl.DEPTH_TEST);
     gl.depthFunc(gl.NOTEQUAL);
+    */
 
     context.gpu_timer_ext = gl.getExtension('EXT_disjoint_timer_query_webgl2');
     if (context.gpu_timer_ext === null) {