Fix point cloud voxel size issues for additive refinement pnts (#5407)

Co-authored-by: Paul Connelly <22944042+pmconne@users.noreply.github.com>

common/api/core-frontend.api.md

@@ -8693,7 +8693,7 @@ export class ReadonlyTileUserSet extends ReadonlySortedArray<TileUser> {
 }
 
 // @internal
-export function readPointCloudTileContent(stream: ByteStream, iModel: IModelConnection, modelId: Id64String, _is3d: boolean, range: ElementAlignedBox3d, system: RenderSystem): Promise<{
+export function readPointCloudTileContent(stream: ByteStream, iModel: IModelConnection, modelId: Id64String, _is3d: boolean, tile: RealityTile, system: RenderSystem): Promise<{
     graphic: RenderGraphic | undefined;
     rtcCenter: Point3d | undefined;
 }>;

common/changes/@itwin/core-frontend/djs-fix-add-refine-voxel-size_2023-04-18-18-06.json

@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@itwin/core-frontend",
+      "comment": "Fixed inconsistent point sizes for additive point cloud tiles.",
+      "type": "none"
+    }
+  ],
+  "packageName": "@itwin/core-frontend"
+}

core/frontend/src/tile/PntsReader.ts

@@ -8,12 +8,13 @@
 
 import { ByteStream, Id64String, Logger, utf8ToString } from "@itwin/core-bentley";
 import { Point3d, Range3d } from "@itwin/core-geometry";
-import { BatchType, ElementAlignedBox3d, Feature, FeatureTable, PackedFeatureTable, PntsHeader, QParams3d, QPoint3d, Quantization } from "@itwin/core-common";
+import { BatchType, Feature, FeatureTable, PackedFeatureTable, PntsHeader, QParams3d, QPoint3d, Quantization } from "@itwin/core-common";
 import { FrontendLoggerCategory } from "../FrontendLoggerCategory";
 import { IModelConnection } from "../IModelConnection";
 import { Mesh } from "../render/primitives/mesh/MeshPrimitives";
 import { RenderGraphic } from "../render/RenderGraphic";
 import { RenderSystem } from "../render/RenderSystem";
+import { RealityTile } from "./internal";
 
 /** Schema for the [3DTILES_draco_point_compression](https://github.com/CesiumGS/3d-tiles/tree/main/extensions/3DTILES_draco_point_compression) extension. */
 interface DracoPointCloud {
@@ -201,13 +202,14 @@ async function decodeDracoPointCloud(buf: Uint8Array): Promise<PointCloudProps |
 /** Deserialize a point cloud tile and return it as a RenderGraphic.
  * @internal
  */
-export async function readPointCloudTileContent(stream: ByteStream, iModel: IModelConnection, modelId: Id64String, _is3d: boolean, range: ElementAlignedBox3d, system: RenderSystem): Promise<{ graphic: RenderGraphic | undefined, rtcCenter: Point3d | undefined }> {
+export async function readPointCloudTileContent(stream: ByteStream, iModel: IModelConnection, modelId: Id64String, _is3d: boolean, tile: RealityTile, system: RenderSystem): Promise<{ graphic: RenderGraphic | undefined, rtcCenter: Point3d | undefined }> {
   let graphic;
   let rtcCenter;
   const header = new PntsHeader(stream);
   if (!header.isValid)
     return { graphic, rtcCenter };
 
+  const range = tile.contentRange;
   const featureTableJsonOffset = stream.curPos;
   const featureStrData = stream.nextBytes(header.featureTableJsonLength);
   const featureStr = utf8ToString(featureStrData);
@@ -269,7 +271,14 @@ export async function readPointCloudTileContent(stream: ByteStream, iModel: IMod
       rng.extendXYZ(props.points[i], props.points[i + 1], props.points[i + 2]);
     params = QParams3d.fromRange(rng);
   }
-  const voxelSize = params.rangeDiagonal.maxAbs() / 256;
+  // 256 here is tile.maximumSize (on non-additive refinement tiles)
+  // If additiveRefinement, set voxelSize to 0 which will cause it draw to with minPixelsPerVoxel, which defaults to 2
+  // That way, it will draw as if in pixel mode, and voxelScale will still function
+  // Checking across a variety of 10 point clouds, 2 to 4 seems to work well for pixel settings (depending on the
+  // cloud), so 2 is a decent default
+  // (If voxelSize is used normally in this case, it draws different size pixels for different tiles, and since
+  // they can overlap ranges, no good way found to calculate a voxelSize)
+  const voxelSize = tile.additiveRefinement ? 0 : params.rangeDiagonal.maxAbs() / 256;
 
   graphic = system.createPointCloud({
     positions: props.points,

core/frontend/src/tile/RealityTileLoader.ts

@@ -110,7 +110,7 @@ export abstract class RealityTileLoader {
         break;
       case TileFormat.Pnts:
         this._containsPointClouds = true;
-        const res = await readPointCloudTileContent(streamBuffer, iModel, modelId, is3d, tile.contentRange, system);
+        const res = await readPointCloudTileContent(streamBuffer, iModel, modelId, is3d, tile, system);
         let graphic = res.graphic;
         const rtcCenter = res.rtcCenter;
         if (graphic && (rtcCenter || tile.transformToRoot && !tile.transformToRoot.isIdentity)) {