Optimisation possible for rendering. Only evaluate expressions for items which are in viewport.

[nzjony]

Hi! 👋

Firstly, thanks for your work on this project! 🙂

Today I used patch-package to patch @here/harp-mapview@0.27.1 for the project I'm working on.

Here is the diff that solved my problem:

diff --git a/node_modules/@here/harp-mapview/lib/MapView.js b/node_modules/@here/harp-mapview/lib/MapView.js
index dd4d22a..7507d21 100644
--- a/node_modules/@here/harp-mapview/lib/MapView.js
+++ b/node_modules/@here/harp-mapview/lib/MapView.js
@@ -2308,11 +2308,18 @@ class MapView extends EventDispatcher_1.EventDispatcher {
         if (gatherStatistics) {
             cullTime = harp_utils_1.PerformanceTimer.now();
         }
+        const frustum = new THREE.Frustum();
+        const projScreenMatrix = new THREE.Matrix4();
+        this.m_camera.updateMatrixWorld();
+        this.m_camera.updateProjectionMatrix();
+        projScreenMatrix.multiplyMatrices(this.m_camera.projectionMatrix, this.m_camera.matrixWorldInverse);
+        frustum.setFromProjectionMatrix(projScreenMatrix);
+
         const renderList = this.m_visibleTiles.dataSourceTileList;
         // no need to check everything if we're not going to create text renderer.
         renderList.forEach(({ zoomLevel, renderedTiles }) => {
             renderedTiles.forEach(tile => {
-                this.m_tileObjectRenderer.render(tile, zoomLevel, this.zoomLevel, this.m_camera.position, this.m_sceneRoot);
+                this.m_tileObjectRenderer.render(tile, zoomLevel, this.zoomLevel, this.m_camera.position, this.m_sceneRoot, frustum);
                 //We know that rendered tiles are visible (in the view frustum), so we update the
                 //frame number, note we don't do this for the visibleTiles because some may still be
                 //loading (and therefore aren't visible in the sense of being seen on the screen).
diff --git a/node_modules/@here/harp-mapview/lib/TileObjectsRenderer.js b/node_modules/@here/harp-mapview/lib/TileObjectsRenderer.js
index afd9f31..9cb2981 100644
--- a/node_modules/@here/harp-mapview/lib/TileObjectsRenderer.js
+++ b/node_modules/@here/harp-mapview/lib/TileObjectsRenderer.js
@@ -19,21 +19,44 @@ class TileObjectRenderer {
         // Valid values start at 1, because the screen is cleared to zero
         this.m_stencilValue = DEFAULT_STENCIL_VALUE;
     }
-    render(tile, storageLevel, zoomLevel, cameraPosition, rootNode) {
+    render(tile, storageLevel, zoomLevel, cameraPosition, rootNode, frustum) {
         const worldOffsetX = tile.computeWorldOffsetX();
         if (tile.willRender(storageLevel)) {
             for (const object of tile.objects) {
-                const mapObjectAdapter = MapObjectAdapter_1.MapObjectAdapter.get(object);
-                if (!this.processTileObject(tile, storageLevel, zoomLevel, object, mapObjectAdapter)) {
-                    continue;
-                }
-                this.updateStencilRef(object);
+
+                // Set object in world space
                 object.position.copy(tile.center);
                 if (object.displacement !== undefined) {
                     object.position.add(object.displacement);
                 }
                 object.position.x += worldOffsetX;
+
+                // Optimization to not process objects which are outside the camera.
+                let visible = false;
+                if (object.geometry) {
+                    if (!object.geometry.boundingSphere) {
+                        object.geometry.computeBoundingSphere();
+                    }
+                    const s = object.geometry.boundingSphere;
+                    // Temporarily transform the sphere to world space
+                    s.center.add(tile.center);
+                    visible = frustum.intersectsSphere(s);
+                    // Transform it back, perhaps it is used elsewhere?
+                    s.center.sub(tile.center);
+                }
+
+                if (!visible) {
+                    continue;
+                }
+
+                // Move object relative to camera
                 object.position.sub(cameraPosition);
+
+                const mapObjectAdapter = MapObjectAdapter_1.MapObjectAdapter.get(object);
+                if (!this.processTileObject(tile, storageLevel, zoomLevel, object, mapObjectAdapter)) {
+                    continue;
+                }
+                this.updateStencilRef(object);
                 if (tile.localTangentSpace) {
                     object.setRotationFromMatrix(tile.boundingBox.getRotationMatrix());
                 }

This issue body was partially generated by patch-package.

[stale]

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