3D Tiles - Dynamic Screen Space Error #4307

lilleyse · 2016-09-09T18:05:23Z

Like terrain fog, this enables a dynamic screen space error for rendering lower detail tiles based on distance. I mainly tested this with replacement refinement tilesets and I see about 20% reduction in the number of visited tiles for street-level views for city-like tilesets and anywhere from 50% to 70% improvement for more terrain-like datasets without too much loss in visual quality. These percentages fluctuate depending on the maximumScreenSpaceError that is applied, and is more favorable for lower values.

The settings can be tweaked by changing tileset.usesDynamicScreenSpaceError, tileset.dynamicScreenSpaceErrorDensity, and tileset.dynamicScreenSpaceErrorFactor.

lilleyse · 2016-09-09T18:13:33Z

Source/Scene/Fog.js

@@ -131,7 +131,7 @@ define([

        // Fade fog in as the camera tilts toward the horizon.
        var positionNormal = Cartesian3.normalize(camera.positionWC, scratchPositionNormal);
-        var dot = CesiumMath.clamp(Cartesian3.dot(camera.directionWC, positionNormal), 0.0, 1.0);
+        var dot = Math.abs(Cartesian3.dot(camera.directionWC, positionNormal));


I changed this because I noticed that any views that are looking from horizon-view to birds-eye-view would result in a negative dot product. So all views between horizon and birds-eye are considered to be in complete fog, but really it should adjust.

By the way, this does not really affect anything in practice, so if anything we could just remove this code.

Up to you and @bagnell

You probably want to revert this. You can look up at terrain (try at Everest, it's pretty easy) in which case we want to clamp at zero.

Actually, after talking offline. This will be fine. @lilleyse is going to update the tests.

pjcozzi · 2016-09-09T19:55:21Z

@bagnell can you also take a quick look at this?

pjcozzi · 2016-09-09T20:42:33Z

Source/Scene/Cesium3DTileset.js

@@ -70,6 +72,7 @@ define([
     * @param {Matrix4} [options.modelMatrix=Matrix4.IDENTITY] A 4x4 transformation matrix that transforms the tileset's root tile.
     * @param {Number} [options.maximumScreenSpaceError=16] The maximum screen-space error used to drive level-of-detail refinement.
     * @param {Boolean} [options.refineToVisible=false] Whether replacement refinement should refine when all visible children are ready. An experimental optimization.
+     * @param {Boolean} [options.useDynamicScreenSpaceError=false] Reduce the screen space error for tiles that are further away from the camera.


We generally don't start variables with use, e.g., above is just refineToVisible, not useRefineToVisible, so this could just be dynamicScreenSpaceError or scaleScreenSpaceErrorByDistance.

pjcozzi · 2016-09-09T20:49:27Z

Just those comments. Will also test this with some datasets once the Sandcastle example has more options.

pjcozzi · 2016-09-10T18:05:45Z

When fog is used with a dynamic SSE for terrain, we also stop requesting tiles that are completely in fog.

It is worth doing something similar here with a max distance?

lilleyse · 2016-09-12T15:34:13Z

When fog is used with a dynamic SSE for terrain, we also stop requesting tiles that are completely in fog. It is worth doing something similar here with a max distance?

We could do that, but also the tiles in the distance should be pretty low res to begin with so there won't be that many requests saved.

EDIT: it does depend on the dataset though.

pjcozzi · 2016-09-12T15:44:20Z

We could do that, but also the tiles in the distance should be pretty low res to begin with so there won't be that many requests saved.

This widely depends on the tileset. Consider a root tile with 300 children, or just a uniform grid.

pjcozzi · 2016-09-12T15:45:12Z

Any concerns if I merge this into 3d-tiles-temp for testing?

lilleyse · 2016-09-12T16:04:40Z

Any concerns if I merge this into 3d-tiles-temp for testing?

Nope, go ahead.

pjcozzi · 2016-09-12T16:33:07Z

My testing and the code look good. I still don't think the doc for dynamicScreenSpaceErrorDensity and dynamicScreenSpaceErrorFactor make it obvious how to use them, e.g., explain-ish how they are non-linear. Perhaps the terrain doc also should be improved.

I'll also hold off on merging until the local coordinate system change we discussed offline.

lilleyse · 2016-09-13T18:20:40Z

Updated.

When fog is used with a dynamic SSE for terrain, we also stop requesting tiles that are completely in fog.

It is worth doing something similar here with a max distance?

I could be wrong, but I think it's just doing the same thing as here, requesting less because it refines less. But the uniform grid type scenario for 3d tiles is definitely worth handling. Is it ok if I handle this in another PR? I also want to clean up some of the checks we do (check sse, check visibility, compute distance, sort by distance, check request volume) that we do in multiple places.

pjcozzi · 2016-09-19T00:44:12Z

Source/Scene/Cesium3DTileset.js

+         *
+         * @see Fog.density
+         */
+        this.dynamicScreenSpaceErrorDensity = 0.00278;


Any reason this and dynamicScreenSpaceErrorFactor should not also be constructor arguments?

pjcozzi · 2016-09-19T00:45:15Z

Source/Scene/Cesium3DTileset.js

+        var root = tileset._root;
+        var tileBoundingVolume = root.contentBoundingVolume;
+
+        if (tileBoundingVolume instanceof TileBoundingRegion) {


Do you know how fast instanceof is? If it isn't basically free we should not use it here.

Ah, this is only for the root tile. Probably not an issue, but we should still research.

Yeah it's only once per update. According to jsPerf on my machine instanceof can be done in 224,000 operations per second.

That is actual kind of slow I bet compared to, for example, === with numbers. Regardless, it is fine here, of course.

@lilleyse which test did you use? There's no way that's correct. I get 146,620,901 on this one https://jsperf.com/instanceof-vs-method?

The performance of instanceof depends on a lot of factors (the most significant of which is how far up the prototype chain you need to look.). But I wouldn't worry about it's usage unless you already identified a given function as a hotspot.

I used this test: https://jsperf.com/instanceof-performance/2.

The code is not much of a hotspot, it is called once per frame.

pjcozzi · 2016-09-19T00:47:15Z

Source/Scene/Cesium3DTileset.js

+            }
+        }
+
+        // The range where the density starts to lessen. Start at the quarter height of the tileset.


Shouldn't this be a user option?

pjcozzi · 2016-09-19T00:48:35Z

Source/Scene/Cesium3DTileset.js

+    var scratchPosition = new Cartesian3();
+    var scratchDirection = new Cartesian3();
+
+    function updateDynamicScreenSpaceError(tileset, frameState) {


How is test coverage? Does the new test cover all the paths in this function?

lilleyse · 2016-10-19T18:16:12Z

I'll look at this

lilleyse · 2016-10-19T21:13:49Z

Updated. I addressed the remaining points. I just have to add one more bounding volume test, and will update this issue when its ready (should be later today).

pjcozzi · 2016-10-19T21:34:25Z

CC @pmconne

pjcozzi · 2016-10-19T21:43:33Z

Looks good, let me know when the tests are finished.

lilleyse · 2016-10-20T14:00:06Z

The last test is done now.

pjcozzi · 2016-10-20T14:08:54Z

Do these tests fail for you?

Scene/GlobeSurfaceTileProvider fog culls tiles in full fog
Expected [ 255, 0, 0, 255 ] to equal [ 0, 0, 0, 255 ].
Error: Expected [ 255, 0, 0, 255 ] to equal [ 0, 0, 0, 255 ].
    at stack (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:1475:17)
    at buildExpectationResult (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:1445:14)
    at Spec.expectationResultFactory (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:584:18)
    at Spec.addExpectationResult (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:332:34)
    at Expectation.addExpectationResult (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:528:21)
    at Expectation.toEqual (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:1399:12)
    at http://localhost:8080/Specs/Scene/GlobeSurfaceTileProviderSpec.js:391:48
    at Promise.then (http://localhost:8080/Source/ThirdParty/when.js:196:34)
    at http://localhost:8080/Source/ThirdParty/when.js:297:13
    at processQueue (http://localhost:8080/Source/ThirdParty/when.js:647:4)
Scene/GlobeSurfaceTileProvider fog culls tiles because of increased SSE
Expected [ 255, 0, 0, 255 ] not to equal [ 255, 0, 0, 255 ].
Error: Expected [ 255, 0, 0, 255 ] not to equal [ 255, 0, 0, 255 ].
    at stack (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:1475:17)
    at buildExpectationResult (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:1445:14)
    at Spec.expectationResultFactory (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:584:18)
    at Spec.addExpectationResult (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:332:34)
    at Expectation.addExpectationResult (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:528:21)
    at Expectation.toEqual (http://localhost:8080/ThirdParty/jasmine-2.2.0/jasmine.js:1399:12)
    at http://localhost:8080/Specs/Scene/GlobeSurfaceTileProviderSpec.js:417:52
    at Promise.then (http://localhost:8080/Source/ThirdParty/when.js:196:34)
    at http://localhost:8080/Source/ThirdParty/when.js:297:13
    at processQueue (http://localhost:8080/Source/ThirdParty/when.js:647:4)

lilleyse · 2016-10-20T15:21:06Z

Ah those are caused by this change: #4307 (comment)

Because of the old math, fog would be applied in bird's eye view, which is the view these tests use. But my change prevents fog from happening for those views. @bagnell can you check that my code change makes sense?

pjcozzi · 2016-10-20T18:59:01Z

@bagnell thoughts here? We want to merge this soon.

lilleyse · 2016-10-20T19:44:11Z

Updated. Those tests pass now.

pjcozzi · 2016-10-21T13:47:28Z

👍

lilleyse added 4 commits September 9, 2016 13:40

Dynamic sse for 3d tiles

73064bd

Merge branch '3d-tiles' into dynamic-sse

368a8f4

Make useDynamicScreenSpaceError public

50271a7

Wording

6aa67da

lilleyse reviewed Sep 9, 2016
View reviewed changes

lilleyse added 3 commits September 9, 2016 14:15

Reword comment

527b14a

Add button to Sandcastle

aa4da55

Typo

94c140c

pjcozzi mentioned this pull request Sep 9, 2016

3D Tiles Roadmap #3241

Open

pjcozzi reviewed Sep 9, 2016
View reviewed changes

Renaming and deriving density falloff from the bounding volume

746537b

lilleyse closed this Sep 12, 2016

lilleyse reopened this Sep 12, 2016

Fix typo

6865298

lilleyse added 2 commits September 13, 2016 13:01

Find minimum and maximum height of bounding volume

3c6c909

Fix up description

2dd4df9

pjcozzi reviewed Sep 19, 2016

View reviewed changes

lilleyse added 2 commits October 19, 2016 15:52

Merge branch '3d-tiles' into dynamic-sse

e9e921d

Round out documentation and tests

c44e384

Added last test

603e14b

Fix fog tests

9343bd5

pjcozzi merged commit 4cb21ad into 3d-tiles Oct 21, 2016

pjcozzi deleted the dynamic-sse branch October 21, 2016 13:47

pjcozzi added the bug bash label Oct 21, 2016

lilleyse mentioned this pull request May 1, 2017

Misc changes and helpers from 3d-tiles #5249

Merged

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

3D Tiles - Dynamic Screen Space Error #4307

3D Tiles - Dynamic Screen Space Error #4307

lilleyse commented Sep 9, 2016 •

edited

Loading

lilleyse Sep 9, 2016

lilleyse Sep 9, 2016

pjcozzi Sep 19, 2016

bagnell Oct 20, 2016

bagnell Oct 20, 2016

pjcozzi commented Sep 9, 2016

pjcozzi Sep 9, 2016

pjcozzi commented Sep 9, 2016

pjcozzi commented Sep 10, 2016

lilleyse commented Sep 12, 2016 •

edited

Loading

pjcozzi commented Sep 12, 2016

pjcozzi commented Sep 12, 2016

lilleyse commented Sep 12, 2016

pjcozzi commented Sep 12, 2016

lilleyse commented Sep 13, 2016

pjcozzi Sep 19, 2016

pjcozzi Sep 19, 2016

pjcozzi Sep 19, 2016

lilleyse Oct 19, 2016

pjcozzi Oct 19, 2016

mramato Oct 19, 2016

lilleyse Oct 19, 2016

pjcozzi Sep 19, 2016

pjcozzi Sep 19, 2016

lilleyse commented Oct 19, 2016

lilleyse commented Oct 19, 2016

pjcozzi commented Oct 19, 2016

pjcozzi commented Oct 19, 2016

lilleyse commented Oct 20, 2016

pjcozzi commented Oct 20, 2016

lilleyse commented Oct 20, 2016

pjcozzi commented Oct 20, 2016

lilleyse commented Oct 20, 2016

pjcozzi commented Oct 21, 2016

3D Tiles - Dynamic Screen Space Error #4307

3D Tiles - Dynamic Screen Space Error #4307

Conversation

lilleyse commented Sep 9, 2016 • edited Loading

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

pjcozzi commented Sep 9, 2016

Choose a reason for hiding this comment

pjcozzi commented Sep 9, 2016

pjcozzi commented Sep 10, 2016

lilleyse commented Sep 12, 2016 • edited Loading

pjcozzi commented Sep 12, 2016

pjcozzi commented Sep 12, 2016

lilleyse commented Sep 12, 2016

pjcozzi commented Sep 12, 2016

lilleyse commented Sep 13, 2016

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

lilleyse commented Oct 19, 2016

lilleyse commented Oct 19, 2016

pjcozzi commented Oct 19, 2016

pjcozzi commented Oct 19, 2016

lilleyse commented Oct 20, 2016

pjcozzi commented Oct 20, 2016

lilleyse commented Oct 20, 2016

pjcozzi commented Oct 20, 2016

lilleyse commented Oct 20, 2016

pjcozzi commented Oct 21, 2016

lilleyse commented Sep 9, 2016 •

edited

Loading

lilleyse commented Sep 12, 2016 •

edited

Loading