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import AttributeCompression from "./AttributeCompression.js";
import Axis from "../Scene/Axis.js";
import AxisAlignedBoundingBox from "./AxisAlignedBoundingBox.js";
import binarySearch from "./binarySearch.js";
import BoundingSphere from "./BoundingSphere.js";
import Cartesian2 from "./Cartesian2.js";
import Cartesian3 from "./Cartesian3.js";
import Cartographic from "./Cartographic.js";
import CesiumMath from "./Math.js";
import Check from "./Check.js";
import ComponentDatatype from "./ComponentDatatype.js";
import Ellipsoid from "./Ellipsoid.js";
import EllipsoidalOccluder from "./EllipsoidalOccluder.js";
import Frozen from "./Frozen.js";
import Matrix4 from "./Matrix4.js";
import OrientedBoundingBox from "./OrientedBoundingBox.js";
import Rectangle from "./Rectangle.js";
import TerrainEncoding from "./TerrainEncoding.js";
import TerrainMesh from "./TerrainMesh.js";
import TerrainProvider from "./TerrainProvider.js";
import Transforms from "./Transforms.js";
import WebMercatorProjection from "./WebMercatorProjection.js";
/**
* Contains functions to create a mesh from 3D Tiles terrain data.
*
* @namespace Cesium3DTilesTerrainGeometryProcessor
*
* @private
*/
const Cesium3DTilesTerrainGeometryProcessor = {};
/**
* Contains information about geometry-related vertex arrays in a glTF asset.
* @private
* @typedef GltfInfo
*
* @property {Float32Array} positions The decoded position attributes.
* @property {Float32Array|undefined} normals The decoded normal attributes, or <code>undefined</code> if the glTF has no normals.
* @property {Uint16Array|Uint32Array} indices The decoded indices.
* @property {Uint16Array|Uint32Array} edgeIndicesWest The edge indices along the West side of the tile.
* @property {Uint16Array|Uint32Array} edgeIndicesSouth The edge indices along the South side of the tile.
* @property {Uint16Array|Uint32Array} edgeIndicesEast The edge indices along the East side of the tile.
* @property {Uint16Array|Uint32Array} edgeIndicesNorth The edge indices along the North side of the tile.
*/
const scratchGltfInfo = {
positions: undefined,
normals: undefined,
indices: undefined,
edgeIndicesWest: undefined,
edgeIndicesSouth: undefined,
edgeIndicesEast: undefined,
edgeIndicesNorth: undefined,
};
const scratchCenterCartographic = new Cartographic();
const scratchCenterCartesian = new Cartesian3();
const scratchEnuToEcef = new Matrix4();
const scratchEcefToEnu = new Matrix4();
const scratchTilesetTransform = new Matrix4();
const scratchMinimumPositionENU = new Cartesian3();
const scratchMaximumPositionENU = new Cartesian3();
const scratchPosLocal = new Cartesian3();
const scratchPosEcef = new Cartesian3();
const scratchCartographic = new Cartographic();
const scratchUV = new Cartesian2();
const scratchNormal = new Cartesian3();
const scratchNormalOct = new Cartesian2();
const scratchGeodeticSurfaceNormal = new Cartesian3();
const scratchPosEnu = new Cartesian3();
/**
* Compares two edge indices for sorting.
* @private
* @param {number} a The first edge index.
* @param {number} b The second edge index.
* @returns {number} A negative number if <code>a</code> is less than <code>b</code>, a positive number if <code>a</code> is greater than <code>b</code>, or zero if they are equal.
*/
const sortedEdgeCompare = function (a, b) {
return a - b;
};
/**
* @typedef {object} Cesium3DTilesTerrainGeometryProcessor.CreateMeshOptions
* @property {Ellipsoid} ellipsoid The ellipsoid.
* @property {Rectangle} rectangle The rectangle covered by the tile.
* @property {boolean} hasVertexNormals <code>true</code> if the tile has vertex normals.
* @property {boolean} hasWebMercatorT <code>true</code> if the tile has Web Mercator T coordinates.
* @property {Object.<string,*>} gltf The glTF JSON of the tile.
* @property {number} minimumHeight The minimum height of the tile.
* @property {number} maximumHeight The maximum height of the tile.
* @property {BoundingSphere} boundingSphere The bounding sphere of the tile.
* @property {OrientedBoundingBox} orientedBoundingBox The oriented bounding box of the tile.
* @property {Cartesian3} horizonOcclusionPoint The horizon occlusion point of the tile.
* @property {number} skirtHeight The height of the skirts.
* @property {number} [exaggeration=1.0] The scale used to exaggerate the terrain.
* @property {number} [exaggerationRelativeHeight=0.0] The height relative to which terrain is exaggerated.
*/
/**
* Creates a {@link TerrainMesh} from this terrain data.
* @function
*
* @private
*
* @param {Cesium3DTilesTerrainGeometryProcessor.CreateMeshOptions} options An object describing options for mesh creation.
* @returns {Promise.<TerrainMesh>} A promise to a terrain mesh.
*/
Cesium3DTilesTerrainGeometryProcessor.createMesh = async function (options) {
options = options ?? Frozen.EMPTY_OBJECT;
const {
exaggeration = 1.0,
exaggerationRelativeHeight = 0.0,
hasVertexNormals,
hasWebMercatorT,
gltf,
minimumHeight,
maximumHeight,
skirtHeight,
} = options;
//>>includeStart('debug', pragmas.debug);
Check.typeOf.object("options.ellipsoid", options.ellipsoid);
Check.typeOf.object("options.rectangle", options.rectangle);
Check.typeOf.bool("options.hasVertexNormals", hasVertexNormals);
Check.typeOf.bool("options.hasWebMercatorT", hasWebMercatorT);
Check.typeOf.object("options.gltf", gltf);
Check.typeOf.number("options.minimumHeight", minimumHeight);
Check.typeOf.number("options.maximumHeight", maximumHeight);
Check.typeOf.object("options.boundingSphere", options.boundingSphere);
Check.typeOf.object(
"options.orientedBoundingBox",
options.orientedBoundingBox,
);
Check.typeOf.object(
"options.horizonOcclusionPoint",
options.horizonOcclusionPoint,
);
Check.typeOf.number("options.skirtHeight", skirtHeight);
//>>includeEnd('debug');
const hasExaggeration = exaggeration !== 1.0;
const hasGeodeticSurfaceNormals = hasExaggeration;
const boundingSphere = BoundingSphere.clone(
options.boundingSphere,
new BoundingSphere(),
);
const orientedBoundingBox = OrientedBoundingBox.clone(
options.orientedBoundingBox,
new OrientedBoundingBox(),
);
const horizonOcclusionPoint = Cartesian3.clone(
options.horizonOcclusionPoint,
new Cartesian3(),
);
const ellipsoid = Ellipsoid.clone(options.ellipsoid, new Ellipsoid());
const rectangle = Rectangle.clone(options.rectangle, new Rectangle());
const hasMeshOptCompression =
gltf.extensionsRequired !== undefined &&
gltf.extensionsRequired.indexOf("EXT_meshopt_compression") !== -1;
const decoderPromise = hasMeshOptCompression
? MeshoptDecoder.ready
: Promise.resolve(undefined);
await decoderPromise;
const tileMinLongitude = rectangle.west;
const tileMinLatitude = rectangle.south;
const tileMaxLatitude = rectangle.north;
const tileLengthLongitude = rectangle.width;
const tileLengthLatitude = rectangle.height;
const approximateCenterCartographic = Rectangle.center(
rectangle,
scratchCenterCartographic,
);
approximateCenterCartographic.height = 0.5 * (minimumHeight + maximumHeight);
const approximateCenterPosition = Cartographic.toCartesian(
approximateCenterCartographic,
ellipsoid,
scratchCenterCartesian,
);
const enuToEcef = Transforms.eastNorthUpToFixedFrame(
approximateCenterPosition,
ellipsoid,
scratchEnuToEcef,
);
const ecefToEnu = Matrix4.inverseTransformation(enuToEcef, scratchEcefToEnu);
let tilesetTransform = Matrix4.unpack(
gltf.nodes[0].matrix,
0,
scratchTilesetTransform,
);
tilesetTransform = Matrix4.multiply(
Axis.Y_UP_TO_Z_UP,
tilesetTransform,
tilesetTransform,
);
const gltfInfo = decodeGltf(gltf, hasVertexNormals, scratchGltfInfo);
const skirtVertexCount = TerrainProvider.getSkirtVertexCount(
gltfInfo.edgeIndicesWest,
gltfInfo.edgeIndicesSouth,
gltfInfo.edgeIndicesEast,
gltfInfo.edgeIndicesNorth,
);
const positionsLocalWithoutSkirts = gltfInfo.positions;
const normalsWithoutSkirts = gltfInfo.normals;
const indicesWithoutSkirts = gltfInfo.indices;
const vertexCountWithoutSkirts = positionsLocalWithoutSkirts.length / 3;
const vertexCountWithSkirts = vertexCountWithoutSkirts + skirtVertexCount;
const indexCountWithoutSkirts = indicesWithoutSkirts.length;
const skirtIndexCount =
TerrainProvider.getSkirtIndexCountWithFilledCorners(skirtVertexCount);
// For consistency with glTF spec, 16 bit index buffer can't contain 65535
const SizedIndexTypeWithSkirts =
vertexCountWithSkirts <= 65535 ? Uint16Array : Uint32Array;
// Make the index buffer large enough that we can add in the skirt indices later
const indexBufferWithSkirts = new SizedIndexTypeWithSkirts(
indexCountWithoutSkirts + skirtIndexCount,
);
indexBufferWithSkirts.set(indicesWithoutSkirts);
const westIndices = new SizedIndexTypeWithSkirts(gltfInfo.edgeIndicesWest);
const southIndices = new SizedIndexTypeWithSkirts(gltfInfo.edgeIndicesSouth);
const eastIndices = new SizedIndexTypeWithSkirts(gltfInfo.edgeIndicesEast);
const northIndices = new SizedIndexTypeWithSkirts(gltfInfo.edgeIndicesNorth);
const sortedWestIndices = new SizedIndexTypeWithSkirts(westIndices).sort();
const sortedSouthIndices = new SizedIndexTypeWithSkirts(southIndices).sort();
const sortedEastIndices = new SizedIndexTypeWithSkirts(eastIndices).sort();
const sortedNorthIndices = new SizedIndexTypeWithSkirts(northIndices).sort();
const southMercatorAngle =
WebMercatorProjection.geodeticLatitudeToMercatorAngle(tileMinLatitude);
const northMercatorAngle =
WebMercatorProjection.geodeticLatitudeToMercatorAngle(tileMaxLatitude);
const oneOverMercatorHeight = 1.0 / (northMercatorAngle - southMercatorAngle);
// Use a terrain encoding without quantization.
// This is just an easier way to save intermediate state
let minPosEnu = Cartesian3.fromElements(
Number.POSITIVE_INFINITY,
Number.POSITIVE_INFINITY,
Number.POSITIVE_INFINITY,
scratchMinimumPositionENU,
);
let maxPosEnu = Cartesian3.fromElements(
Number.NEGATIVE_INFINITY,
Number.NEGATIVE_INFINITY,
Number.NEGATIVE_INFINITY,
scratchMaximumPositionENU,
);
const tempTerrainEncoding = new TerrainEncoding(
boundingSphere.center,
undefined,
undefined,
undefined,
undefined,
hasVertexNormals,
hasWebMercatorT,
hasGeodeticSurfaceNormals,
exaggeration,
exaggerationRelativeHeight,
);
const tempBufferStride = tempTerrainEncoding.stride;
const tempBuffer = new Float32Array(vertexCountWithSkirts * tempBufferStride);
let tempBufferOffset = 0;
for (let i = 0; i < vertexCountWithoutSkirts; i++) {
const posLocal = Cartesian3.unpack(
positionsLocalWithoutSkirts,
i * 3,
scratchPosLocal,
);
const posECEF = Matrix4.multiplyByPoint(
tilesetTransform,
posLocal,
scratchPosEcef,
);
const cartographic = Cartographic.fromCartesian(
posECEF,
ellipsoid,
scratchCartographic,
);
const { longitude, latitude, height } = cartographic;
// If a vertex is an edge vertex we already know its exact UV and don't need to derive it from the position (which can have accuracy issues).
let u = (longitude - tileMinLongitude) / tileLengthLongitude;
let v = (latitude - tileMinLatitude) / tileLengthLatitude;
// Clamp the UVs to the valid range
// This should only happen when the cartesian to cartographic conversion introduces error on a point that is already very close the edge
u = CesiumMath.clamp(u, 0.0, 1.0);
v = CesiumMath.clamp(v, 0.0, 1.0);
if (binarySearch(sortedWestIndices, i, sortedEdgeCompare) >= 0) {
u = 0.0;
} else if (binarySearch(sortedEastIndices, i, sortedEdgeCompare) >= 0) {
u = 1.0;
}
if (binarySearch(sortedSouthIndices, i, sortedEdgeCompare) >= 0) {
v = 0.0;
} else if (binarySearch(sortedNorthIndices, i, sortedEdgeCompare) >= 0) {
v = 1.0;
}
const uv = Cartesian2.fromElements(u, v, scratchUV);
let normalOct;
if (hasVertexNormals) {
let normal = Cartesian3.unpack(
normalsWithoutSkirts,
i * 3,
scratchNormal,
);
normal = Matrix4.multiplyByPointAsVector(
tilesetTransform,
normal,
scratchNormal,
);
normal = Cartesian3.normalize(normal, scratchNormal);
normalOct = AttributeCompression.octEncode(normal, scratchNormalOct);
}
let webMercatorT;
if (hasWebMercatorT) {
const mercatorAngle =
WebMercatorProjection.geodeticLatitudeToMercatorAngle(latitude);
webMercatorT =
(mercatorAngle - southMercatorAngle) * oneOverMercatorHeight;
}
let geodeticSurfaceNormal;
if (hasGeodeticSurfaceNormals) {
geodeticSurfaceNormal = ellipsoid.geodeticSurfaceNormal(
posECEF,
scratchGeodeticSurfaceNormal,
);
}
tempBufferOffset = tempTerrainEncoding.encode(
tempBuffer,
tempBufferOffset,
posECEF,
uv,
height,
normalOct,
webMercatorT,
geodeticSurfaceNormal,
);
const posEnu = Matrix4.multiplyByPoint(ecefToEnu, posECEF, scratchPosEnu);
minPosEnu = Cartesian3.minimumByComponent(posEnu, minPosEnu, minPosEnu);
maxPosEnu = Cartesian3.maximumByComponent(posEnu, maxPosEnu, maxPosEnu);
}
const mesh = new TerrainMesh(
Cartesian3.clone(tempTerrainEncoding.center, new Cartesian3()),
tempBuffer,
indexBufferWithSkirts,
indexCountWithoutSkirts,
vertexCountWithoutSkirts,
minimumHeight,
maximumHeight,
rectangle,
BoundingSphere.clone(boundingSphere, new BoundingSphere()),
Cartesian3.clone(horizonOcclusionPoint, new Cartesian3()),
tempBufferStride,
OrientedBoundingBox.clone(orientedBoundingBox, new OrientedBoundingBox()),
tempTerrainEncoding,
westIndices,
southIndices,
eastIndices,
northIndices,
);
addSkirtsToMesh(
mesh,
rectangle,
ellipsoid,
minPosEnu,
maxPosEnu,
enuToEcef,
ecefToEnu,
skirtHeight,
);
return Promise.resolve(mesh);
};
const scratchMinUV = new Cartesian2();
const scratchMaxUV = new Cartesian2();
const scratchPolygonIndices = new Array(6);
const scratchUvA = new Cartesian2();
const scratchUvB = new Cartesian2();
const scratchUvC = new Cartesian2();
const scratchNormalA = new Cartesian3();
const scratchNormalB = new Cartesian3();
const scratchNormalC = new Cartesian3();
const scratchCenterCartographicUpsample = new Cartographic();
const scratchCenterCartesianUpsample = new Cartesian3();
const scratchCartographicSkirt = new Cartographic();
const scratchCartographicUpsample = new Cartographic();
const scratchPosEcefSkirt = new Cartesian3();
const scratchPosEcefUpsample = new Cartesian3();
const scratchPosEnuSkirt = new Cartesian3();
const scratchPosEnuUpsample = new Cartesian3();
const scratchMinimumPositionENUSkirt = new Cartesian3();
const scratchMaximumPositionENUSkirt = new Cartesian3();
const scratchMinimumPositionENUUpsample = new Cartesian3();
const scratchMaximumPositionENUUpsample = new Cartesian3();
const scratchEnuToEcefUpsample = new Matrix4();
const scratchEcefToEnuUpsample = new Matrix4();
const scratchUVSkirt = new Cartesian2();
const scratchUVUpsample = new Cartesian2();
const scratchHorizonOcclusionPoint = new Cartesian3();
const scratchBoundingSphere = new BoundingSphere();
const scratchOrientedBoundingBox = new OrientedBoundingBox();
const scratchAABBEnuSkirt = new AxisAlignedBoundingBox();
const scratchNormalUpsample = new Cartesian3();
const scratchNormalOctSkirt = new Cartesian2();
const scratchNormalOctUpsample = new Cartesian2();
const scratchGeodeticSurfaceNormalSkirt = new Cartesian3();
const scratchGeodeticSurfaceNormalUpsample = new Cartesian3();
/**
* Decode the position attributes from a glTF object.
* @private
* @param {Object.<string,*>} gltf The glTF JSON.
* @returns {Float32Array} The decoded positions, as a flattened array of x, y, z values.
*/
function decodePositions(gltf) {
const primitive = gltf.meshes[0].primitives[0];
const accessor = gltf.accessors[primitive.attributes["POSITION"]];
const bufferView = gltf.bufferViews[accessor.bufferView];
const positionCount = accessor.count;
const bufferViewMeshOpt = bufferView.extensions
? bufferView.extensions["EXT_meshopt_compression"]
: undefined;
if (bufferViewMeshOpt === undefined) {
const buffer = gltf.buffers[bufferView.buffer].extras._pipeline.source;
return new Float32Array(
buffer.buffer,
buffer.byteOffset + // offset from the start of the glb
(bufferView.byteOffset ?? 0) +
(accessor.byteOffset ?? 0),
positionCount * 3,
);
}
const buffer = gltf.buffers[bufferViewMeshOpt.buffer].extras._pipeline.source;
const compressedBuffer = new Uint8Array(
buffer.buffer,
buffer.byteOffset + // offset from the start of the glb
(bufferViewMeshOpt.byteOffset ?? 0) +
(accessor.byteOffset ?? 0),
bufferViewMeshOpt.byteLength,
);
const positionByteLength = bufferViewMeshOpt.byteStride;
const PositionType = positionByteLength === 4 ? Uint8Array : Uint16Array;
const positionsResult = new PositionType(positionCount * 4);
MeshoptDecoder.decodeVertexBuffer(
new Uint8Array(positionsResult.buffer),
positionCount,
positionByteLength,
compressedBuffer,
);
const positionStorageValueMax =
(1 << (positionsResult.BYTES_PER_ELEMENT * 8)) - 1;
const positions = new Float32Array(positionCount * 3);
for (let p = 0; p < positionCount; p++) {
// only the first 3 components are used
positions[p * 3 + 0] = positionsResult[p * 4 + 0] / positionStorageValueMax;
positions[p * 3 + 1] = positionsResult[p * 4 + 1] / positionStorageValueMax;
positions[p * 3 + 2] = positionsResult[p * 4 + 2] / positionStorageValueMax;
// fourth component is not used
}
return positions;
}
/**
* Decode the normal attributes from a glTF object.
* @private
* @param {Object.<string,*>} gltf The glTF JSON.
* @returns {Float32Array} The decoded normals, as a flattened array of x, y, z values.
*/
function decodeNormals(gltf) {
const primitive = gltf.meshes[0].primitives[0];
const accessor = gltf.accessors[primitive.attributes["NORMAL"]];
const bufferView = gltf.bufferViews[accessor.bufferView];
const normalCount = accessor.count;
const bufferViewMeshOpt = bufferView.extensions
? bufferView.extensions["EXT_meshopt_compression"]
: undefined;
if (bufferViewMeshOpt === undefined) {
const buffer = gltf.buffers[bufferView.buffer].extras._pipeline.source;
return new Float32Array(
buffer.buffer,
buffer.byteOffset + // offset from the start of the glb
(bufferView.byteOffset ?? 0) +
(accessor.byteOffset ?? 0),
normalCount * 3,
);
}
const buffer = gltf.buffers[bufferViewMeshOpt.buffer].extras._pipeline.source;
const compressedBuffer = new Uint8Array(
buffer.buffer,
buffer.byteOffset + // offset from the start of the glb
(bufferViewMeshOpt.byteOffset ?? 0) +
(accessor.byteOffset ?? 0),
bufferViewMeshOpt.byteLength,
);
const normalByteLength = bufferViewMeshOpt.byteStride;
const normalsResult = new Int8Array(normalCount * normalByteLength);
MeshoptDecoder.decodeVertexBuffer(
new Uint8Array(normalsResult.buffer),
normalCount,
normalByteLength,
compressedBuffer,
);
const normals = new Float32Array(normalCount * 3);
for (let i = 0; i < normalCount; i++) {
// AttributeCompression.octDecodeInRange is not compatible with KHR_mesh_quantization, so do the oct decode manually
// The quantization puts values between -127 and +127, but clamp in case it has -128
// The third component is unused until normals support non-8-bit quantization
// The fourth component is always unused
let octX = Math.max(normalsResult[i * 4 + 0] / 127.0, -1.0);
let octY = Math.max(normalsResult[i * 4 + 1] / 127.0, -1.0);
const octZ = 1.0 - (Math.abs(octX) + Math.abs(octY));
if (octZ < 0.0) {
const oldX = octX;
const oldY = octY;
octX = (1.0 - Math.abs(oldY)) * CesiumMath.signNotZero(oldX);
octY = (1.0 - Math.abs(oldX)) * CesiumMath.signNotZero(oldY);
}
let normal = scratchNormal;
normal.x = octX;
normal.y = octY;
normal.z = octZ;
normal = Cartesian3.normalize(normal, scratchNormal);
normals[i * 3 + 0] = normal.x;
normals[i * 3 + 1] = normal.y;
normals[i * 3 + 2] = normal.z;
}
return normals;
}
/**
* Decode the index attributes from a glTF object.
* @private
* @param {Object.<string,*>} gltf The glTF JSON.
* @returns {Uint16Array|Uint32Array} An array of indices.
*/
function decodeIndices(gltf) {
const primitive = gltf.meshes[0].primitives[0];
const accessor = gltf.accessors[primitive.indices];
const bufferView = gltf.bufferViews[accessor.bufferView];
const indexCount = accessor.count;
const SizedIndexType =
accessor.componentType === ComponentDatatype.UNSIGNED_SHORT
? Uint16Array
: Uint32Array;
const bufferViewMeshOpt = bufferView.extensions
? bufferView.extensions["EXT_meshopt_compression"]
: undefined;
if (bufferViewMeshOpt === undefined) {
const buffer = gltf.buffers[bufferView.buffer].extras._pipeline.source;
return new SizedIndexType(
buffer.buffer,
buffer.byteOffset + // offset from the glb
(bufferView.byteOffset ?? 0) +
(accessor.byteOffset ?? 0),
indexCount,
);
}
const buffer = gltf.buffers[bufferViewMeshOpt.buffer].extras._pipeline.source;
const compressedBuffer = new Uint8Array(
buffer.buffer,
buffer.byteOffset + // offset from the start of the glb
(bufferViewMeshOpt.byteOffset ?? 0) +
(accessor.byteOffset ?? 0),
bufferViewMeshOpt.byteLength,
);
const indices = new SizedIndexType(indexCount);
MeshoptDecoder.decodeIndexBuffer(
new Uint8Array(indices.buffer),
indexCount,
bufferViewMeshOpt.byteStride,
compressedBuffer,
);
return indices;
}
/**
* Decode the edge index attributes from a glTF object.
* @private
* @param {Object.<string,*>} gltf The glTF JSON.
* @param {string} name The name of the edge indices to decode.
* @returns {Uint16Array|Uint32Array} An array of edge indices.
*/
function decodeEdgeIndices(gltf, name) {
const primitive = gltf.meshes[0].primitives[0];
const accessor = gltf.accessors[primitive.extensions.CESIUM_tile_edges[name]];
const bufferView = gltf.bufferViews[accessor.bufferView];
const indexCount = accessor.count;
const SizedIndexType =
accessor.componentType === ComponentDatatype.UNSIGNED_SHORT
? Uint16Array
: Uint32Array;
const bufferViewMeshOpt = bufferView.extensions
? bufferView.extensions["EXT_meshopt_compression"]
: undefined;
if (bufferViewMeshOpt === undefined) {
const buffer = gltf.buffers[bufferView.buffer].extras._pipeline.source;
return new SizedIndexType(
buffer.buffer,
buffer.byteOffset + // offset from the glb
(bufferView.byteOffset ?? 0) +
(accessor.byteOffset ?? 0),
indexCount,
);
}
const buffer = gltf.buffers[bufferViewMeshOpt.buffer].extras._pipeline.source;
const compressedBuffer = new Uint8Array(
buffer.buffer,
buffer.byteOffset + // offset from the start of the glb
(bufferViewMeshOpt.byteOffset ?? 0) +
(accessor.byteOffset ?? 0),
bufferViewMeshOpt.byteLength,
);
const indices = new SizedIndexType(indexCount);
const indexByteLength = bufferViewMeshOpt.byteStride;
MeshoptDecoder.decodeIndexSequence(
new Uint8Array(indices.buffer),
indexCount,
indexByteLength,
compressedBuffer,
);
return indices;
}
/**
* Decodes geometry-related vertex arrays from a glTF asset.
* @private
* @param {Object.<string,*>} gltf The glTF JSON.
* @param {boolean} hasNormals <code>true</code> if the glTF has normal attributes.
* @param {GltfInfo} result The object to store the decoded arrays.
* @returns {GltfInfo} The decoded geometry info.
*/
function decodeGltf(gltf, hasNormals, result) {
result.positions = decodePositions(gltf);
result.normals = hasNormals ? decodeNormals(gltf) : undefined;
result.indices = decodeIndices(gltf);
result.edgeIndicesWest = decodeEdgeIndices(gltf, "left");
result.edgeIndicesSouth = decodeEdgeIndices(gltf, "bottom");
result.edgeIndicesEast = decodeEdgeIndices(gltf, "right");
result.edgeIndicesNorth = decodeEdgeIndices(gltf, "top");
return result;
}
/**
* @typedef {object} Cesium3DTilesTerrainGeometryProcessor.UpsampleMeshOptions
* @property {boolean} isEastChild <code>true</code> if the tile is the east child of its parent.
* @property {boolean} isNorthChild <code>true</code> if the tile is the north child of its parent.
* @property {Rectangle} rectangle The rectangle covered by the tile.
* @property {Ellipsoid} ellipsoid The ellipsoid.
* @property {number} skirtHeight The height of the skirts.
* @property {Float32Array} parentVertices The parent tile's vertex buffer.
* @property {Uint8Array|Uint16Array|Uint32Array} parentIndices The parent tile's index buffer.
* @property {number} parentVertexCountWithoutSkirts The number of vertices in the parent tile excluding skirts.
* @property {number} parentIndexCountWithoutSkirts The number of indices in the parent tile excluding skirts.
* @property {number} parentMinimumHeight The minimum height of the parent tile.
* @property {number} parentMaximumHeight The maximum height of the parent tile.
* @property {TerrainEncoding} parentEncoding The parent tile's terrain encoding.
*/
/**
* Upsamples a parent tile's mesh to create a higher-detail child tile's mesh.
*
* Overview: Only include triangles that are inside the UV clipping region.
* If a triangle is partly outside, it will be clipped at the border.
* The clipping function returns a polygon where each point is a barycentric coordinate of the input triangle.
* Most of the time the triangle will not be clipped, so the polygon will be the three barycentric coordinates of the input triangle.
* If the triangle is completely outside the clipping region, the polygon will have no points and will be ignored.
* If the triangle is clipped, the polygon will have between four and six points and needs to be triangulated.
* Vertex data for points that fall inside the triangle will be interpolated using the barycentric coordinates.
* Each vertex in the polygon is added to the new vertex list, with some special handling to avoid duplicate points between triangles.
*
* @private
* @param {Cesium3DTilesTerrainGeometryProcessor.UpsampleMeshOptions} options An object describing options for mesh upsampling.
* @returns {TerrainMesh} The upsampled terrain mesh.
*/
Cesium3DTilesTerrainGeometryProcessor.upsampleMesh = function (options) {
options = options ?? Frozen.EMPTY_OBJECT;
const {
isEastChild,
isNorthChild,
parentMinimumHeight,
parentMaximumHeight,
skirtHeight,
} = options;
//>>includeStart('debug', pragmas.debug)
Check.typeOf.bool("options.isEastChild", isEastChild);
Check.typeOf.bool("options.isNorthChild", isNorthChild);
Check.typeOf.object("options.parentVertices", options.parentVertices);
Check.typeOf.object("options.parentIndices", options.parentIndices);
Check.typeOf.number(
"options.parentVertexCountWithoutSkirts",
options.parentVertexCountWithoutSkirts,
);
Check.typeOf.number(
"options.parentIndexCountWithoutSkirts",
options.parentIndexCountWithoutSkirts,
);
Check.typeOf.number("options.parentMinimumHeight", parentMinimumHeight);
Check.typeOf.number("options.parentMaximumHeight", parentMaximumHeight);
Check.typeOf.object("options.parentEncoding", options.parentEncoding);
Check.typeOf.object("options.rectangle", options.rectangle);
Check.typeOf.number("options.skirtHeight", skirtHeight);
Check.typeOf.object("options.ellipsoid", options.ellipsoid);
//>>includeEnd('debug');
const indexCount = options.parentIndexCountWithoutSkirts;
const indices = options.parentIndices;
const vertexCount = options.parentVertexCountWithoutSkirts;
const vertexBuffer = options.parentVertices;
const encoding = TerrainEncoding.clone(
options.parentEncoding,
new TerrainEncoding(),
);
const hasVertexNormals = encoding.hasVertexNormals;
const hasWebMercatorT = encoding.hasWebMercatorT;
const exaggeration = encoding.exaggeration;
const exaggerationRelativeHeight = encoding.exaggerationRelativeHeight;
const hasExaggeration = exaggeration !== 1.0;
const hasGeodeticSurfaceNormals = hasExaggeration;
const upsampleRectangle = Rectangle.clone(options.rectangle, new Rectangle());
const ellipsoid = Ellipsoid.clone(options.ellipsoid);
const upsampledTriIDs = [];
const upsampledUVs = [];
const upsampledBarys = [];
const upsampledIndices = [];
const upsampledWestIndices = [];
const upsampledSouthIndices = [];
const upsampledEastIndices = [];
const upsampledNorthIndices = [];
clipTileFromQuadrant(
isEastChild,
isNorthChild,
indexCount,
indices,
vertexCount,
vertexBuffer,
encoding,
upsampledIndices,
upsampledWestIndices,
upsampledSouthIndices,
upsampledEastIndices,
upsampledNorthIndices,
upsampledTriIDs,
upsampledBarys,
upsampledUVs,
);
// Don't know the min and max height of the upsampled positions yet,
// so calculate a center point from the parent's min and max height
const approximateCenterCartographic = Rectangle.center(
upsampleRectangle,
scratchCenterCartographicUpsample,
);
approximateCenterCartographic.height =
0.5 * (parentMinimumHeight + parentMaximumHeight);
const approximateCenterPosition = Cartographic.toCartesian(
approximateCenterCartographic,
ellipsoid,
scratchCenterCartesianUpsample,
);
const upsampledVertexCountWithoutSkirts = upsampledTriIDs.length;
const upsampledTerrainEncoding = new TerrainEncoding(
approximateCenterPosition,
undefined,
undefined,
undefined,
undefined,
hasVertexNormals,
hasWebMercatorT,
hasGeodeticSurfaceNormals,
exaggeration,
exaggerationRelativeHeight,
);
const upsampledVertexBufferStride = upsampledTerrainEncoding.stride;
const upsampledSkirtVertexCount = TerrainProvider.getSkirtVertexCount(
upsampledWestIndices,
upsampledSouthIndices,
upsampledEastIndices,
upsampledNorthIndices,
);
const upsampledVertexCountWithSkirts =
upsampledVertexCountWithoutSkirts + upsampledSkirtVertexCount;
const upsampledIndexCountWithoutSkirts = upsampledIndices.length;
const upsampledSkirtIndexCount =
TerrainProvider.getSkirtIndexCountWithFilledCorners(
upsampledSkirtVertexCount,
);
const upsampledIndexCountWithSkirts =
upsampledIndexCountWithoutSkirts + upsampledSkirtIndexCount;
// For consistency with glTF spec, 16 bit index buffer can't contain 65535
const SizedIndexTypeWithSkirts =
upsampledVertexCountWithSkirts <= 65535 ? Uint16Array : Uint32Array;
const upsampledIndexBuffer = new SizedIndexTypeWithSkirts(
upsampledIndexCountWithSkirts,
);
upsampledIndexBuffer.set(upsampledIndices);
const upsampledWestIndicesBuffer = new SizedIndexTypeWithSkirts(
upsampledWestIndices,
);
const upsampledSouthIndicesBuffer = new SizedIndexTypeWithSkirts(
upsampledSouthIndices,
);
const upsampledEastIndicesBuffer = new SizedIndexTypeWithSkirts(
upsampledEastIndices,
);
const upsampledNorthIndicesBuffer = new SizedIndexTypeWithSkirts(
upsampledNorthIndices,
);
const upsampledVertexBuffer = new Float32Array(
upsampledVertexCountWithSkirts * upsampledVertexBufferStride,
);
let upsampledVertexBufferOffset = 0;
const enuToEcef = Transforms.eastNorthUpToFixedFrame(
approximateCenterPosition,
ellipsoid,
scratchEnuToEcefUpsample,
);
const ecefToEnu = Matrix4.inverseTransformation(
enuToEcef,
scratchEcefToEnuUpsample,
);
const minimumLongitude = upsampleRectangle.west;
const maximumLongitude = upsampleRectangle.east;
const minimumLatitude = upsampleRectangle.south;
const maximumLatitude = upsampleRectangle.north;
const southMercatorAngle =
WebMercatorProjection.geodeticLatitudeToMercatorAngle(minimumLatitude);
const northMercatorAngle =
WebMercatorProjection.geodeticLatitudeToMercatorAngle(maximumLatitude);
const oneOverMercatorHeight = 1.0 / (northMercatorAngle - southMercatorAngle);
let minimumHeight = Number.POSITIVE_INFINITY;
let maximumHeight = Number.NEGATIVE_INFINITY;
let minPosEnu = Cartesian3.fromElements(
Number.POSITIVE_INFINITY,
Number.POSITIVE_INFINITY,
Number.POSITIVE_INFINITY,
scratchMinimumPositionENUUpsample,
);
let maxPosEnu = Cartesian3.fromElements(
Number.NEGATIVE_INFINITY,
Number.NEGATIVE_INFINITY,
Number.NEGATIVE_INFINITY,
scratchMaximumPositionENUUpsample,
);
for (let i = 0; i < upsampledVertexCountWithoutSkirts; i++) {
const triId = upsampledTriIDs[i];
const indexA = indices[triId * 3 + 0];
const indexB = indices[triId * 3 + 1];
const indexC = indices[triId * 3 + 2];
const uv = scratchUVUpsample;
uv.x = upsampledUVs[i * 2 + 0];
uv.y = upsampledUVs[i * 2 + 1];
const u = uv.x;
const v = uv.y;
const baryA = upsampledBarys[i * 2 + 0];
const baryB = upsampledBarys[i * 2 + 1];
const baryC = 1.0 - baryA - baryB;
const heightA = encoding.decodeHeight(vertexBuffer, indexA);
const heightB = encoding.decodeHeight(vertexBuffer, indexB);
const heightC = encoding.decodeHeight(vertexBuffer, indexC);
const height = heightA * baryA + heightB * baryB + heightC * baryC;
minimumHeight = Math.min(height, minimumHeight);
maximumHeight = Math.max(height, maximumHeight);
const lon = CesiumMath.lerp(minimumLongitude, maximumLongitude, u);
const lat = CesiumMath.lerp(minimumLatitude, maximumLatitude, v);
const carto = Cartographic.fromRadians(
lon,
lat,
height,
scratchCartographicUpsample,
);
const position = Cartographic.toCartesian(
carto,
ellipsoid,
scratchPosEcefUpsample,
);
const posEnu = Matrix4.multiplyByPoint(
ecefToEnu,
position,
scratchPosEnuUpsample,
);
minPosEnu = Cartesian3.minimumByComponent(posEnu, minPosEnu, minPosEnu);
maxPosEnu = Cartesian3.maximumByComponent(posEnu, maxPosEnu, maxPosEnu);
let normalOct;
if (hasVertexNormals) {
const normalA = encoding.decodeNormal(
vertexBuffer,
indexA,
scratchNormalA,
);
const normalB = encoding.decodeNormal(
vertexBuffer,
indexB,
scratchNormalB,
);
const normalC = encoding.decodeNormal(
vertexBuffer,
indexC,
scratchNormalC,
);
let normal = Cartesian3.fromElements(
normalA.x * baryA + normalB.x * baryB + normalC.x * baryC,
normalA.y * baryA + normalB.y * baryB + normalC.y * baryC,
normalA.z * baryA + normalB.z * baryB + normalC.z * baryC,
scratchNormalUpsample,
);
normal = Cartesian3.normalize(normal, scratchNormalUpsample);
normalOct = AttributeCompression.octEncode(
normal,
scratchNormalOctUpsample,
);
}
let webMercatorT;
if (hasWebMercatorT) {
const mercatorAngle =
WebMercatorProjection.geodeticLatitudeToMercatorAngle(lat);
webMercatorT =
(mercatorAngle - southMercatorAngle) * oneOverMercatorHeight;
}
let geodeticSurfaceNormal;
if (hasGeodeticSurfaceNormals) {
geodeticSurfaceNormal = ellipsoid.geodeticSurfaceNormal(
position,
scratchGeodeticSurfaceNormalUpsample,
);
}
upsampledVertexBufferOffset = upsampledTerrainEncoding.encode(
upsampledVertexBuffer,
upsampledVertexBufferOffset,
position,
uv,
height,
normalOct,
webMercatorT,
geodeticSurfaceNormal,
);
}
// Now generate the more tight-fitting bounding volumes that are used for culling and other things
const orientedBoundingBox = OrientedBoundingBox.fromRectangle(
upsampleRectangle,
minimumHeight,
maximumHeight,
ellipsoid,
scratchOrientedBoundingBox,
);
const boundingSphere = BoundingSphere.fromVertices(
upsampledVertexBuffer,
upsampledTerrainEncoding.center,
upsampledVertexBufferStride,
scratchBoundingSphere,
);
const occluder = new EllipsoidalOccluder(ellipsoid);
const horizonOcclusionPoint =
occluder.computeHorizonCullingPointFromVerticesPossiblyUnderEllipsoid(
upsampledTerrainEncoding.center, // vector from ellipsoid center to horizon occlusion point
upsampledVertexBuffer,
upsampledVertexBufferStride,
upsampledTerrainEncoding.center,
minimumHeight,
scratchHorizonOcclusionPoint,
);
const upsampledMesh = new TerrainMesh(
Cartesian3.clone(upsampledTerrainEncoding.center, new Cartesian3()),
upsampledVertexBuffer,
upsampledIndexBuffer,
upsampledIndexCountWithoutSkirts,
upsampledVertexCountWithoutSkirts,
minimumHeight,
maximumHeight,
upsampleRectangle,
BoundingSphere.clone(boundingSphere),
Cartesian3.clone(horizonOcclusionPoint),
upsampledVertexBufferStride,
OrientedBoundingBox.clone(orientedBoundingBox),
upsampledTerrainEncoding,
upsampledWestIndicesBuffer,
upsampledSouthIndicesBuffer,
upsampledEastIndicesBuffer,
upsampledNorthIndicesBuffer,
);
addSkirtsToMesh(
upsampledMesh,
upsampleRectangle,
ellipsoid,
minPosEnu,
maxPosEnu,
enuToEcef,
ecefToEnu,
skirtHeight,
);
return upsampledMesh;
};
/**
* Helper function that adds skirts to a TerrainMesh. The mesh's vertex and index
* buffers are expected to be pre-allocated to fit the skirts.
* The mesh's vertex buffer must have quantization disabled.
* If the final quantization changes, a new vertex buffer will be allocated using the new quantization.
* Currently skirts do not affect the tile's bounding volume.
* @private
* @param {TerrainMesh} mesh
* @param {Rectangle} rectangle
* @param {Ellipsoid} ellipsoid
* @param {Cartesian3} enuMinimum
* @param {Cartesian3} enuMaximum
* @param {Matrix4} enuToEcef
* @param {Matrix4} ecefToEnu
* @param {number} skirtHeight
*/
function addSkirtsToMesh(
mesh,
rectangle,
ellipsoid,
enuMinimum,
enuMaximum,
enuToEcef,
ecefToEnu,
skirtHeight,
) {
const { encoding } = mesh;
const vertexStride = encoding.stride;
const vertexBuffer = mesh.vertices;
const {
hasVertexNormals,
hasWebMercatorT,
exaggeration,
exaggerationRelativeHeight,
} = encoding;
const hasExaggeration = exaggeration !== 1.0;
const hasGeodeticSurfaceNormals = hasExaggeration;
const vertexCountWithoutSkirts = mesh.vertexCountWithoutSkirts;
let vertexBufferOffset = vertexCountWithoutSkirts * vertexStride;
const vertexCountWithSkirts = vertexBuffer.length / vertexStride;
const skirtVertexCount = vertexCountWithSkirts - vertexCountWithoutSkirts;
const indices = mesh.indices;
const indexCountWithoutSkirts = mesh.indexCountWithoutSkirts;
const westIndices = mesh.westIndicesSouthToNorth;
const southIndices = mesh.southIndicesEastToWest;
const eastIndices = mesh.eastIndicesNorthToSouth;
const northIndices = mesh.northIndicesWestToEast;
TerrainProvider.addSkirtIndicesWithFilledCorners(
westIndices,
southIndices,
eastIndices,
northIndices,
vertexCountWithoutSkirts,
indices,
indexCountWithoutSkirts,
);
const westOffset = 0;
const southOffset = westOffset + westIndices.length;
const eastOffset = southOffset + southIndices.length;
const northOffset = eastOffset + eastIndices.length;
const edges = [westIndices, southIndices, eastIndices, northIndices];
const edgeIndexOffset = [westOffset, southOffset, eastOffset, northOffset];
const edgeLongitudeSign = [-1.0, 0.0, +1.0, 0.0];
const edgeLatitudeSign = [0.0, -1.0, 0.0, +1.0];
const minimumPositionENUWithSkirts = Cartesian3.clone(
enuMinimum,
scratchMinimumPositionENUSkirt,
);
const maximumPositionENUWithSkirts = Cartesian3.clone(
enuMaximum,
scratchMaximumPositionENUSkirt,
);
const maximumHeight = mesh.maximumHeight;
const minimumHeightWithSkirts = mesh.minimumHeight - skirtHeight;
for (let skirtId = 0; skirtId < skirtVertexCount; skirtId++) {
let side = 0;
for (side = 0; side < 3; side++) {
if (skirtId < edgeIndexOffset[side + 1]) {
break;
}
}
const vertexIndex = edges[side][skirtId - edgeIndexOffset[side]];
const uv = encoding.decodeTextureCoordinates(
vertexBuffer,
vertexIndex,
scratchUVSkirt,
);
const skirtLonLatOffsetPercent = 0.0001;
const longitudeT =
uv.x + edgeLongitudeSign[side] * skirtLonLatOffsetPercent;
const latitudeT = uv.y + edgeLatitudeSign[side] * skirtLonLatOffsetPercent;
const longitude = CesiumMath.lerp(
rectangle.west,
rectangle.east,
longitudeT,
);
// Don't offset the skirt past the poles, it will screw up the cartographic -> cartesian
const latitude = CesiumMath.clamp(
CesiumMath.lerp(rectangle.south, rectangle.north, latitudeT),
-CesiumMath.PI_OVER_TWO,
+CesiumMath.PI_OVER_TWO,
);
const vertHeight = encoding.decodeHeight(vertexBuffer, vertexIndex);
const height = vertHeight - skirtHeight;
const cartographic = Cartographic.fromRadians(
longitude,
latitude,
height,
scratchCartographicSkirt,
);
const positionEcef = Cartographic.toCartesian(
cartographic,
ellipsoid,
scratchPosEcefSkirt,
);
let normalOct;
if (hasVertexNormals) {
normalOct = encoding.getOctEncodedNormal(
vertexBuffer,
vertexIndex,
scratchNormalOctSkirt,
);
}
let webMercatorT;
if (hasWebMercatorT) {
webMercatorT = encoding.decodeWebMercatorT(vertexBuffer, vertexIndex);
}
let geodeticSurfaceNormal;
if (hasGeodeticSurfaceNormals) {
geodeticSurfaceNormal = ellipsoid.geodeticSurfaceNormal(
positionEcef,
scratchGeodeticSurfaceNormalSkirt,
);
}
vertexBufferOffset = encoding.encode(
vertexBuffer,
vertexBufferOffset,
positionEcef,
uv,
height,
normalOct,
webMercatorT,
geodeticSurfaceNormal,
);
const positionENU = Matrix4.multiplyByPoint(
ecefToEnu,
positionEcef,
scratchPosEnuSkirt,
);
Cartesian3.minimumByComponent(
positionENU,
minimumPositionENUWithSkirts,
minimumPositionENUWithSkirts,
);
Cartesian3.maximumByComponent(
positionENU,
maximumPositionENUWithSkirts,
maximumPositionENUWithSkirts,
);
}
const aabbEnuWithSkirts = AxisAlignedBoundingBox.fromCorners(
minimumPositionENUWithSkirts,
maximumPositionENUWithSkirts,
scratchAABBEnuSkirt,
);
// Check if the final terrain encoding has a different quantization. If so,
// the vertices need to be re-encoded with the new quantization. Otherwise,
// use the vertex buffer as-is.
const encodingWithSkirts = new TerrainEncoding(
encoding.center,
aabbEnuWithSkirts,
minimumHeightWithSkirts,
maximumHeight,
enuToEcef,
encoding.hasVertexNormals,
encoding.hasWebMercatorT,
hasGeodeticSurfaceNormals,
exaggeration,
exaggerationRelativeHeight,
);
if (encoding.quantization !== encodingWithSkirts.quantization) {
const finalEncoding = encodingWithSkirts;
const finalVertexStride = finalEncoding.stride;
const finalVertexBuffer = new Float32Array(
vertexCountWithSkirts * finalVertexStride,
);
let finalVertexBufferOffset = 0;
for (let i = 0; i < vertexCountWithSkirts; i++) {
finalVertexBufferOffset = finalEncoding.encode(
finalVertexBuffer,
finalVertexBufferOffset,
encoding.decodePosition(vertexBuffer, i, scratchPosEcefSkirt),
encoding.decodeTextureCoordinates(vertexBuffer, i, scratchUVSkirt),
encoding.decodeHeight(vertexBuffer, i),
encoding.hasVertexNormals
? encoding.getOctEncodedNormal(vertexBuffer, i, scratchNormalOctSkirt)
: undefined,
encoding.hasWebMercatorT
? encoding.decodeWebMercatorT(vertexBuffer, i)
: undefined,
encoding.hasGeodeticSurfaceNormals
? encoding.decodeGeodeticSurfaceNormal(
vertexBuffer,
i,
scratchGeodeticSurfaceNormalSkirt,
)
: undefined,
);
}
mesh.vertices = finalVertexBuffer;
mesh.stride = finalVertexStride;
mesh.encoding = finalEncoding;
}
return mesh;
}
const EDGE_ID_LEFT = 0;
const EDGE_ID_TOP = 1;
const EDGE_ID_RIGHT = 2;
const EDGE_ID_BOTTOM = 3;
const EDGE_COUNT = 4;
const scratchIntersection = new Cartesian3();
const scratchInBarys = [
new Cartesian3(),
new Cartesian3(),
new Cartesian3(),
new Cartesian3(),
new Cartesian3(),
new Cartesian3(),
];
const scratchInPoints = [
new Cartesian2(),
new Cartesian2(),
new Cartesian2(),
new Cartesian2(),
new Cartesian2(),
new Cartesian2(),
];
const scratchOutBarys = [
new Cartesian3(),
new Cartesian3(),
new Cartesian3(),
new Cartesian3(),
new Cartesian3(),
new Cartesian3(),
];
const scratchOutPoints = [
new Cartesian2(),
new Cartesian2(),
new Cartesian2(),
new Cartesian2(),
new Cartesian2(),
new Cartesian2(),
];
/**
* Check if a given point is inside the limits of a box.
* @private
* @param {Cartesian2} boxMinimum The lower left corner of the box.
* @param {Cartesian2} boxMaximum The upper right corner of the box.
* @param {number} edgeId The ID of the edge to test against.
* @param {Cartesian2} p The point to test.
* @returns {number} Positive if inside, negative if outside, zero if on the edge.
*/
function inside(boxMinimum, boxMaximum, edgeId, p) {
switch (edgeId) {
case EDGE_ID_LEFT:
return CesiumMath.sign(p.x - boxMinimum.x);
case EDGE_ID_RIGHT:
return CesiumMath.sign(boxMaximum.x - p.x);
case EDGE_ID_BOTTOM:
return CesiumMath.sign(p.y - boxMinimum.y);
default:
// EDGE_ID_TOP
return CesiumMath.sign(boxMaximum.y - p.y);
}
}
/**
* Compute the intersection of a line segment against one edge of a box.
* @private
* @param {Cartesian2} boxMinimum The lower left corner of the box.
* @param {Cartesian2} boxMaximum The upper right corner of the box.
* @param {number} edgeId The ID of the edge to intersect against.
* @param {Cartesian2} a The beginning of the line segment.
* @param {Cartesian2} b The end of the line segment.
* @param {Cartesian3} result The object into which to copy the result.
* @returns {Cartesian3} The intersection point in 2D coordinates and the interpolation factor t as the third component.
*/
function intersect(boxMinimum, boxMaximum, edgeId, a, b, result) {
let t, intersectX, intersectY;
switch (edgeId) {
case EDGE_ID_LEFT:
t = (boxMinimum.x - a.x) / (b.x - a.x);
intersectX = boxMinimum.x;
intersectY = a.y + (b.y - a.y) * t;
break;
case EDGE_ID_RIGHT:
t = (boxMaximum.x - a.x) / (b.x - a.x);
intersectX = boxMaximum.x;
intersectY = a.y + (b.y - a.y) * t;
break;
case EDGE_ID_BOTTOM:
t = (boxMinimum.y - a.y) / (b.y - a.y);
intersectX = a.x + (b.x - a.x) * t;
intersectY = boxMinimum.y;
break;
default:
// EDGE_ID_TOP
t = (boxMaximum.y - a.y) / (b.y - a.y);
intersectX = a.x + (b.x - a.x) * t;
intersectY = boxMaximum.y;
break;
}
return Cartesian3.fromElements(intersectX, intersectY, t, result);
}
/**
* Coordinates of a quadrilateral resulting from clipping a triangle against a box.
* @private
* @typedef PolygonResult
*
* @property {number} length
* @property {Cartesian2[]} coordinates A pre-allocated array of six 2D coordinates.
* @property {Cartesian3[]} barycentricCoordinates A pre-allocated array of six barycentric coordinates.
*/
/**
* A scratch polygon result for use in clipping.
* @private
* @type {PolygonResult}
*/
const scratchPolygon = {
length: 0,
coordinates: [
new Cartesian2(),
new Cartesian2(),
new Cartesian2(),
new Cartesian2(),
new Cartesian2(),
new Cartesian2(),
],
barycentricCoordinates: [
new Cartesian3(),
new Cartesian3(),
new Cartesian3(),
new Cartesian3(),
new Cartesian3(),
new Cartesian3(),
],
};
/**
* Clips a 2D triangle against axis-aligned edges of a box using the Sutherland-Hodgman
* clipping algorithm. The resulting polygon will have between 0 and 6 vertices.
*
* @private
* @param {number} edgeStart The first edge to clip against.
* @param {number} edgeCount The number of edges to clip against, starting from edgeStart.
* @param {Cartesian2} boxMinimum The bottom-left corner of the axis-aligned box.
* @param {Cartesian2} boxMaximum The top-right corner of the axis-aligned box.
* @param {Cartesian2} p0 The coordinates of the first vertex in the triangle, in counter-clockwise order.
* @param {Cartesian2} p1 The coordinates of the second vertex in the triangle, in counter-clockwise order.
* @param {Cartesian2} p2 The coordinates of the third vertex in the triangle, in counter-clockwise order.
* @param {PolygonResult} result The object into which to copy the result.
* @returns {PolygonResult} The polygon that results after the clip, specified as a list of coordinates in counter-clockwise order.
*/
function clipTriangleAgainstBoxEdgeRange(
edgeStart,
edgeCount,
boxMinimum,
boxMaximum,
p0,
p1,
p2,
result,
) {
let inputLength = 0;
let inputPoints = scratchInPoints;
let inputBarys = scratchInBarys;
let outputLength = 3;
let outputPoints = scratchOutPoints;
Cartesian2.clone(p0, outputPoints[0]);
Cartesian2.clone(p1, outputPoints[1]);
Cartesian2.clone(p2, outputPoints[2]);
let outputBarys = scratchOutBarys;
Cartesian3.fromElements(1, 0, 0, outputBarys[0]);
Cartesian3.fromElements(0, 1, 0, outputBarys[1]);
Cartesian3.fromElements(0, 0, 1, outputBarys[2]);
// Loop over the clip window edges
for (let e = 0; e < edgeCount; e++) {
const edgeId = (edgeStart + e) % EDGE_COUNT;
// Swap the input and output arrays
const tempPoints = inputPoints;
const tempBarys = inputBarys;
inputPoints = outputPoints;
inputBarys = outputBarys;
inputLength = outputLength;
outputPoints = tempPoints;
outputBarys = tempBarys;
outputLength = 0;
// Check each polygon edge against each clip window edge
let prevIdx = inputLength - 1;
let prevPoint = inputPoints[prevIdx];
let prevBary = inputBarys[prevIdx];
let prevInside = inside(boxMinimum, boxMaximum, edgeId, prevPoint);
for (let currIdx = 0; currIdx < inputLength; currIdx++) {
const currPoint = inputPoints[currIdx];
const currBary = inputBarys[currIdx];
const currInside = inside(boxMinimum, boxMaximum, edgeId, currPoint);
// Check if the two points are on opposite sides of the edge.
// If so, there's an intersection, and a new point is created.
if (prevInside * currInside === -1) {
const intersection = intersect(
boxMinimum,
boxMaximum,
edgeId,
prevPoint,
currPoint,
scratchIntersection,
);
const { x, y, z: t } = intersection;
const tInv = 1.0 - t;
// Interpolate the barycentric coordinates
const baryA = prevBary.x * tInv + currBary.x * t;
const baryB = prevBary.y * tInv + currBary.y * t;
const baryC = prevBary.z * tInv + currBary.z * t;
Cartesian2.fromElements(x, y, outputPoints[outputLength]);
Cartesian3.fromElements(baryA, baryB, baryC, outputBarys[outputLength]);
outputLength++;
}
// If the second point is on or inside, add it
if (currInside >= 0) {
Cartesian2.clone(currPoint, outputPoints[outputLength]);
Cartesian3.clone(currBary, outputBarys[outputLength]);
outputLength++;
}
prevIdx = currIdx;
prevPoint = currPoint;
prevBary = currBary;
prevInside = currInside;
}
// All points were outside, so break early
if (outputLength === 0) {
break;
}
}
result.length = outputLength;
for (let i = 0; i < outputLength; i++) {
Cartesian2.clone(outputPoints[i], result.coordinates[i]);
Cartesian3.clone(outputBarys[i], result.barycentricCoordinates[i]);
}
return result;
}
/**
* Clips a 2D triangle against one quadrant of a box.
* @private
* @param {boolean} isEastChild <code>true</code> if the quadrant is on the east side of the box.
* @param {boolean} isNorthChild <code>true</code> if the quadrant is on the north side of the box.
* @param {Cartesian2} boxMinimum The lower left corner of the box.
* @param {Cartesian2} boxMaximum The upper right corner of the box.
* @param {Cartesian2} p0 The first vertex of the triangle.
* @param {Cartesian2} p1 The second vertex of the triangle.
* @param {Cartesian2} p2 The third vertex of the triangle.
* @param {PolygonResult} result The object into which to copy the result.
* @returns {PolygonResult} The polygon that results after the clip, specified as a list of coordinates in counter-clockwise order.
*/
function clipTriangleFromQuadrant(
isEastChild,
isNorthChild,
boxMinimum,
boxMaximum,
p0,
p1,
p2,
result,
) {
const edgeStart = isEastChild
? isNorthChild
? EDGE_ID_BOTTOM
: EDGE_ID_LEFT
: isNorthChild
? EDGE_ID_RIGHT
: EDGE_ID_TOP;
return clipTriangleAgainstBoxEdgeRange(
edgeStart,
2,
boxMinimum,
boxMaximum,
p0,
p1,
p2,
result,
);
}
const lookUpTableBaryToPrim = [
[], // 000
[0], // 001
[1], // 010
[0, 1], // 011
[2], // 100
[0, 2], // 101
[1, 2], // 110
[0, 1, 2], // 111
];
/**
* Returns triangles that are clipped against a quadrant of a tile.
* @private
* @param {boolean} isEastChild <code>true</code> if the quadrant is on the east side of the tile.
* @param {boolean} isNorthChild <code>true</code> if the quadrant is on the north side of the tile.
* @param {number} indexCount Number of indices in the original triangle list.
* @param {Uint8Array|Uint16Array|Uint32Array} indices Original triangle index list.
* @param {number} vertexCount Number of vertices in the original vertex list.
* @param {Float32Array} vertices Original vertex list.
* @param {TerrainEncoding} vertexEncoding Encoding of the original vertices.
* @param {number[]} resultIndices Indices of the clipped triangles.
* @param {number[]} resultWestIndices Indices on the west edge.
* @param {number[]} resultSouthIndices Indices on the south edge.
* @param {number[]} resultEastIndices Indices on the east edge.
* @param {number[]} resultNorthIndices Indices on the north edge.
* @param {number[]} resultTriIds Per-vertex index to the originating triangle in indices.
* @param {number[]} resultBary Per-vertex barycentric coordinate corresponding to the originating triangle.
* @param {number[]} resultUVs Per-vertex UV within the quadrant.
*/
function clipTileFromQuadrant(
isEastChild,
isNorthChild,
indexCount,
indices,
vertexCount,
vertices,
vertexEncoding,
resultIndices,
resultWestIndices,
resultSouthIndices,
resultEastIndices,
resultNorthIndices,
resultTriIds,
resultBary,
resultUVs,
) {
const upsampledVertexMap = {};
const minU = isEastChild ? 0.5 : 0.0;
const maxU = isEastChild ? 1.0 : 0.5;
const minV = isNorthChild ? 0.5 : 0.0;
const maxV = isNorthChild ? 1.0 : 0.5;
const minUV = scratchMinUV;
minUV.x = minU;
minUV.y = minV;
const maxUV = scratchMaxUV;
maxUV.x = maxU;
maxUV.y = maxV;
let upsampledVertexCount = 0;
// Loop over all the original triangles
for (let i = 0; i < indexCount; i += 3) {
const indexA = indices[i + 0];
const indexB = indices[i + 1];
const indexC = indices[i + 2];
const uvA = vertexEncoding.decodeTextureCoordinates(
vertices,
indexA,
scratchUvA,
);
const uvB = vertexEncoding.decodeTextureCoordinates(
vertices,
indexB,
scratchUvB,
);
const uvC = vertexEncoding.decodeTextureCoordinates(
vertices,
indexC,
scratchUvC,
);
const clippedPolygon = clipTriangleFromQuadrant(
isEastChild,
isNorthChild,
minUV,
maxUV,
uvA,
uvB,
uvC,
scratchPolygon,
);
const clippedPolygonLength = clippedPolygon.length;
if (clippedPolygonLength < 3) {
// Triangle is outside clipping window, so skip it
continue;
}
const polygonUpsampledIndices = scratchPolygonIndices;
for (let p = 0; p < clippedPolygonLength; p++) {
const polygonBary = clippedPolygon.barycentricCoordinates[p];
const bA = polygonBary.x;
const bB = polygonBary.y;
const bC = polygonBary.z;
// Convert the barycentric coords to a bitfield to find out which vertices are involved
const baryId =
Math.ceil(bA) | (Math.ceil(bB) << 1) | (Math.ceil(bC) << 2);
const primitiveIds = lookUpTableBaryToPrim[baryId];
let upsampledIndex;
let isNewVertex = false;
if (primitiveIds.length === 1) {
//-------------------------------------------------------
// Vertex: Only one barycentric coord is set, so it's on a vertex
//-------------------------------------------------------
const pointPrimitiveId = primitiveIds[0];
const pointIndex = indices[i + pointPrimitiveId];
// Add the vertex if it doesn't exist already
const pointKey = pointIndex;
upsampledIndex = upsampledVertexMap[pointKey];
if (upsampledIndex === undefined) {
isNewVertex = true;
upsampledIndex = upsampledVertexCount++;
upsampledVertexMap[pointKey] = upsampledIndex;
}
} else if (primitiveIds.length === 2) {
//-------------------------------------------------------
// Edge: Only two barycentric coords are set, so it's on an edge
//-------------------------------------------------------
const edgePrimitiveIdA = primitiveIds[0];
const edgePrimitiveIdB = primitiveIds[1];
const edgeIndexA = indices[i + edgePrimitiveIdA];
const edgeIndexB = indices[i + edgePrimitiveIdB];
// Detect if a clipped position was already added by a triangle that shares the same edge.
// The key is based on the two edge indices and whether it is the first or second clipped position on the edge (an edge can be clipped by a convex shape at most twice).
const prevBary =
clippedPolygon.barycentricCoordinates[
(p + clippedPolygonLength - 1) % clippedPolygonLength
];
const prevBaryId =
Math.ceil(prevBary.x) |
(Math.ceil(prevBary.y) << 1) |
(Math.ceil(prevBary.z) << 2);
const sameEdge = baryId === prevBaryId;
// The winding order of the edge will consty between triangles (i.e. A -> B vs B -> A), so take the min/max to make the key consistent.
const minIndex = Math.min(edgeIndexA, edgeIndexB);
const maxIndex = Math.max(edgeIndexA, edgeIndexB);
const baseKey = vertexCount + 2 * (minIndex * vertexCount + maxIndex);
const firstKey = baseKey + 0;
const secondKey = baseKey + 1;
const firstEntry = upsampledVertexMap[firstKey];
const secondEntry = upsampledVertexMap[secondKey];
// !firstEntry && !sameEdge -> firstEntry (undefined)
// !secondEntry && sameEdge -> secondEntry (undefined)
// firstEntry && !secondEntry && !sameEdge -> firstEntry (reverse solo)
// firstEntry && secondEntry && !sameEdge -> secondEntry (reverse first)
// firstEntry && secondEntry && sameEdge -> firstEntry (reverse second)
const useFirst =
!sameEdge === (firstEntry === undefined || secondEntry === undefined);
upsampledIndex = useFirst ? firstEntry : secondEntry;
// Add the vertex if it doesn't already exist
if (upsampledIndex === undefined) {
isNewVertex = true;
upsampledIndex = upsampledVertexCount++;
const edgeKey = useFirst ? firstKey : secondKey;
upsampledVertexMap[edgeKey] = upsampledIndex;
}
} else {
//-------------------------------------------------------
// Face: All three barycentric coords are set, so it's inside the triangle
//-------------------------------------------------------
isNewVertex = true;
upsampledIndex = upsampledVertexCount++;
}
// Store the index for this point in the polygon
polygonUpsampledIndices[p] = upsampledIndex;
if (isNewVertex) {
const triId = i / 3;
resultTriIds.push(triId);
const polygonUV = clippedPolygon.coordinates[p];
const u = (polygonUV.x - minU) / (maxU - minU);
const v = (polygonUV.y - minV) / (maxV - minV);
resultUVs.push(u, v);
resultBary.push(bA, bB);
if (u === 0.0) {
resultWestIndices.push(upsampledIndex);
} else if (u === 1.0) {
resultEastIndices.push(upsampledIndex);
}
if (v === 0.0) {
resultSouthIndices.push(upsampledIndex);
} else if (v === 1.0) {
resultNorthIndices.push(upsampledIndex);
}
}
}
// Triangulate the polygon by connecting vertices in a fan shape
const ui0 = polygonUpsampledIndices[0];
let ui1 = polygonUpsampledIndices[1];
let ui2 = polygonUpsampledIndices[2];
resultIndices.push(ui0, ui1, ui2);
for (let j = 3; j < clippedPolygonLength; j++) {
ui1 = ui2;
ui2 = polygonUpsampledIndices[j];
resultIndices.push(ui0, ui1, ui2);
}
}
resultWestIndices.sort(function (a, b) {
return resultUVs[a * 2 + 1] - resultUVs[b * 2 + 1];
});
resultSouthIndices.sort(function (a, b) {
return resultUVs[b * 2 + 0] - resultUVs[a * 2 + 0];
});
resultEastIndices.sort(function (a, b) {
return resultUVs[b * 2 + 1] - resultUVs[a * 2 + 1];
});
resultNorthIndices.sort(function (a, b) {
return resultUVs[a * 2 + 0] - resultUVs[b * 2 + 0];
});
}
export default Cesium3DTilesTerrainGeometryProcessor;
|