From cd3b222467ff1c3a6d47db9b7353c8ccf24f5a7d Mon Sep 17 00:00:00 2001
From: Olivier Guyot <olivier.guyot@camptocamp.com>
Date: Fri, 25 Oct 2019 16:56:16 +0200
Subject: [PATCH] Specify an actual extent when loading features in the Webgl
 points renderer

This means any specified loading strategy will be taken into account.

Also added some tests to make sure the interaction with the source is
correct.
---
 src/ol/renderer/webgl/PointsLayer.js          | 29 +++++++++--------
 .../ol/renderer/webgl/pointslayer.test.js     | 32 ++++++++++++++++++-
 2 files changed, 47 insertions(+), 14 deletions(-)

diff --git a/src/ol/renderer/webgl/PointsLayer.js b/src/ol/renderer/webgl/PointsLayer.js
index 71788a373c..7d415b525f 100644
--- a/src/ol/renderer/webgl/PointsLayer.js
+++ b/src/ol/renderer/webgl/PointsLayer.js
@@ -7,7 +7,7 @@ import {AttributeType, DefaultUniform} from '../../webgl/Helper.js';
 import GeometryType from '../../geom/GeometryType.js';
 import WebGLLayerRenderer, {colorDecodeId, colorEncodeId, WebGLWorkerMessageType} from './Layer.js';
 import ViewHint from '../../ViewHint.js';
-import {createEmpty, equals} from '../../extent.js';
+import {buffer, createEmpty, equals} from '../../extent.js';
 import {
   apply as applyTransform,
   create as createTransform,
@@ -18,6 +18,7 @@ import {create as createWebGLWorker} from '../../worker/webgl.js';
 import {getUid} from '../../util.js';
 import WebGLRenderTarget from '../../webgl/RenderTarget.js';
 import {assert} from '../../asserts.js';
+import BaseVector from '../../layer/BaseVector.js';
 
 /**
  * @typedef {Object} CustomAttribute A description of a custom attribute to be passed on to the GPU, with a value different
@@ -296,20 +297,22 @@ class WebGLPointsLayerRenderer extends WebGLLayerRenderer {
     const layer = this.getLayer();
     const vectorSource = layer.getSource();
     const viewState = frameState.viewState;
-
-    // the source has changed: clear the feature cache & reload features
-    const sourceChanged = this.sourceRevision_ < vectorSource.getRevision();
-    if (sourceChanged) {
-      this.sourceRevision_ = vectorSource.getRevision();
-
-      const projection = viewState.projection;
-      const resolution = viewState.resolution;
-      vectorSource.loadFeatures([-Infinity, -Infinity, Infinity, Infinity], resolution, projection);
-    }
-
     const viewNotMoving = !frameState.viewHints[ViewHint.ANIMATING] && !frameState.viewHints[ViewHint.INTERACTING];
     const extentChanged = !equals(this.previousExtent_, frameState.extent);
-    if ((sourceChanged || extentChanged) && viewNotMoving) {
+    const sourceChanged = this.sourceRevision_ < vectorSource.getRevision();
+
+    if (sourceChanged) {
+      this.sourceRevision_ = vectorSource.getRevision();
+    }
+
+    if (viewNotMoving && (extentChanged || sourceChanged)) {
+      const projection = viewState.projection;
+      const resolution = viewState.resolution;
+
+      const renderBuffer = layer instanceof BaseVector ? layer.getRenderBuffer() : 0;
+      const extent = buffer(frameState.extent, renderBuffer * resolution);
+      vectorSource.loadFeatures(extent, resolution, projection);
+
       this.rebuildBuffers_(frameState);
       this.previousExtent_ = frameState.extent.slice();
     }
diff --git a/test/spec/ol/renderer/webgl/pointslayer.test.js b/test/spec/ol/renderer/webgl/pointslayer.test.js
index bd41446491..25d6d230b9 100644
--- a/test/spec/ol/renderer/webgl/pointslayer.test.js
+++ b/test/spec/ol/renderer/webgl/pointslayer.test.js
@@ -104,7 +104,8 @@ describe('ol.renderer.webgl.PointsLayer', function() {
 
     beforeEach(function() {
       layer = new VectorLayer({
-        source: new VectorSource()
+        source: new VectorSource(),
+        renderBuffer: 10
       });
       renderer = new WebGLPointsLayerRenderer(layer, {
         vertexShader: simpleVertexShader,
@@ -233,6 +234,35 @@ describe('ol.renderer.webgl.PointsLayer', function() {
       renderer.prepareFrame(frameState);
       expect(spy.callCount).to.be(2);
     });
+
+    it('triggers source loading when the extent changes', function() {
+      const spy = sinon.spy(layer.getSource(), 'loadFeatures');
+
+      renderer.prepareFrame(frameState);
+      expect(spy.callCount).to.be(1);
+
+      renderer.prepareFrame(frameState);
+      expect(spy.callCount).to.be(1);
+
+      frameState.extent = [10, 20, 30, 40];
+      renderer.prepareFrame(frameState);
+      expect(spy.callCount).to.be(2);
+      expect(spy.getCall(1).args[0]).to.eql([0, 10, 40, 50]); // renderBuffer is 10
+    });
+
+    it('triggers source loading when the source revision changes', function() {
+      const spy = sinon.spy(layer.getSource(), 'loadFeatures');
+
+      renderer.prepareFrame(frameState);
+      expect(spy.callCount).to.be(1);
+
+      renderer.prepareFrame(frameState);
+      expect(spy.callCount).to.be(1);
+
+      layer.getSource().changed();
+      renderer.prepareFrame(frameState);
+      expect(spy.callCount).to.be(2);
+    });
   });
 
   describe('#forEachFeatureAtCoordinate', function() {