/*
* Copyright 2003-2006, 2009, 2017, United States Government, as represented by the Administrator of the
* National Aeronautics and Space Administration. All rights reserved.
*
* The NASAWorldWind/WebWorldWind platform is licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @exports Tessellator
*/
define(['../geom/Angle',
'../error/ArgumentError',
'../shaders/BasicProgram',
'../globe/Globe',
'../shaders/GpuProgram',
'../util/Level',
'../util/LevelSet',
'../geom/Location',
'../util/Logger',
'../geom/Matrix',
'../cache/MemoryCache',
'../error/NotYetImplementedError',
'../pick/PickedObject',
'../geom/Position',
'../geom/Rectangle',
'../geom/Sector',
'../globe/Terrain',
'../globe/TerrainTile',
'../globe/TerrainTileList',
'../util/Tile',
'../util/WWMath',
'../util/WWUtil'
],
function (Angle,
ArgumentError,
BasicProgram,
Globe,
GpuProgram,
Level,
LevelSet,
Location,
Logger,
Matrix,
MemoryCache,
NotYetImplementedError,
PickedObject,
Position,
Rectangle,
Sector,
Terrain,
TerrainTile,
TerrainTileList,
Tile,
WWMath,
WWUtil) {
"use strict";
/**
* Constructs a Tessellator.
* @alias Tessellator
* @constructor
* @classdesc Provides terrain tessellation for a globe.
*/
var Tessellator = function () {
// Parameterize top level subdivision in one place.
// TilesInTopLevel describes the most coarse tile structure.
this.numRowsTilesInTopLevel = 4; // baseline: 4
this.numColumnsTilesInTopLevel = 8; // baseline: 8
// The maximum number of levels that will ever be tessellated.
this.maximumSubdivisionDepth = 15; // baseline: 15
// tileWidth, tileHeight - the number of subdivisions a single tile has; this determines the sampling grid.
this.tileWidth = 32; // baseline: 32
this.tileHeight = 32; // baseline: 32
/**
* Controls the level of detail switching for this layer. The next highest resolution level is
* used when an elevation tile's cell size is greater than this number of pixels, up to the maximum
* resolution of the elevation model.
* @type {Number}
* @default 1.75
*/
this.detailControl = 40;
this.levels = new LevelSet(
Sector.FULL_SPHERE,
new Location(
180 / this.numRowsTilesInTopLevel,
360 / this.numColumnsTilesInTopLevel),
this.maximumSubdivisionDepth,
this.tileWidth,
this.tileHeight);
this.topLevelTiles = {};
this.currentTiles = new TerrainTileList(this);
this.tileCache = new MemoryCache(5000000, 4000000); // Holds 316 32x32 tiles.
this.elevationTimestamp = undefined;
this.lastModelViewProjection = Matrix.fromIdentity();
this.vertexPointLocation = -1;
this.vertexTexCoordLocation = -1;
this.texCoords = null;
this.texCoordVboCacheKey = 'global_tex_coords';
this.indices = null;
this.indicesVboCacheKey = 'global_indices';
this.baseIndices = null;
this.baseIndicesOffset = null;
this.numBaseIndices = null;
this.indicesNorth = null;
this.indicesNorthOffset = null;
this.numIndicesNorth = null;
this.indicesSouth = null;
this.indicesSouthOffset = null;
this.numIndicesSouth = null;
this.indicesWest = null;
this.indicesWestOffset = null;
this.numIndicesWest = null;
this.indicesEast = null;
this.indicesEastOffset = null;
this.numIndicesEast = null;
this.indicesLoresNorth = null;
this.indicesLoresNorthOffset = null;
this.numIndicesLoresNorth = null;
this.indicesLoresSouth = null;
this.indicesLoresSouthOffset = null;
this.numIndicesLoresSouth = null;
this.indicesLoresWest = null;
this.indicesLoresWestOffset = null;
this.numIndicesLoresWest = null;
this.indicesLoresEast = null;
this.indicesLoresEastOffset = null;
this.numIndicesLoresEast = null;
this.outlineIndicesOffset = null;
this.numOutlineIndices = null;
this.wireframeIndicesOffset = null;
this.numWireframeIndices = null;
this.scratchMatrix = Matrix.fromIdentity();
this.scratchElevations = null;
this.scratchPrevElevations = null;
this.corners = {};
this.tiles = [];
};
/**
* Creates the visible terrain of the globe associated with the current draw context.
* @param {DrawContext} dc The draw context.
* @returns {Terrain} The computed terrain, or null if terrain could not be computed.
* @throws {ArgumentError} If the dc is null or undefined.
*/
Tessellator.prototype.tessellate = function (dc) {
if (!dc) {
throw new ArgumentError(
Logger.logMessage(Logger.LEVEL_SEVERE, "Tessellator", "tessellate", "missingDC"));
}
var lastElevationsChange = dc.globe.elevationTimestamp();
if (this.lastGlobeStateKey === dc.globeStateKey
&& this.lastVerticalExaggeration === dc.verticalExaggeration
&& this.elevationTimestamp === lastElevationsChange
&& dc.modelviewProjection.equals(this.lastModelViewProjection)) {
return this.lastTerrain;
}
this.lastModelViewProjection.copy(dc.modelviewProjection);
this.lastGlobeStateKey = dc.globeStateKey;
this.elevationTimestamp = lastElevationsChange;
this.lastVerticalExaggeration = dc.verticalExaggeration;
this.currentTiles.removeAllTiles();
if (!this.topLevelTiles[dc.globeStateKey] || this.topLevelTiles[dc.globeStateKey].length == 0) {
this.createTopLevelTiles(dc);
}
this.corners = {};
this.tiles = [];
for (var index = 0, len = this.topLevelTiles[dc.globeStateKey].length; index < len; index += 1) {
var tile = this.topLevelTiles[dc.globeStateKey][index];
tile.update(dc);
if (this.isTileVisible(dc, tile)) {
this.addTileOrDescendants(dc, tile);
}
}
this.refineNeighbors(dc);
this.finishTessellating(dc);
this.lastTerrain = this.currentTiles.length === 0 ? null
: new Terrain(dc.globe, this, this.currentTiles, dc.verticalExaggeration);
return this.lastTerrain;
};
Tessellator.prototype.createTile = function (tileSector, level, row, column) {
if (!tileSector) {
throw new ArgumentError(
Logger.logMessage(Logger.LEVEL_SEVERE, "Tile", "constructor", "missingSector"));
}
if (!level) {
throw new ArgumentError(
Logger.logMessage(Logger.LEVEL_SEVERE, "Tile", "constructor",
"The specified level is null or undefined."));
}
if (row < 0 || column < 0) {
throw new ArgumentError(
Logger.logMessage(Logger.LEVEL_SEVERE, "Tile", "constructor",
"The specified row or column is less than zero."));
}
return new TerrainTile(tileSector, level, row, column);
};
/**
* Initializes rendering state to draw a succession of terrain tiles.
* @param {DrawContext} dc The draw context.
*/
Tessellator.prototype.beginRendering = function (dc) {
var program = dc.currentProgram; // use the current program; the caller configures other program state
if (!program) {
Logger.logMessage(Logger.LEVEL_INFO, "Tessellator", "beginRendering", "Current Program is empty");
return;
}
this.buildSharedGeometry();
this.cacheSharedGeometryVBOs(dc);
var gl = dc.currentGlContext,
gpuResourceCache = dc.gpuResourceCache;
// Keep track of the program's attribute locations. The tessellator does not know which program the caller has
// bound, and therefore must look up the location of attributes by name.
this.vertexPointLocation = program.attributeLocation(gl, "vertexPoint");
this.vertexTexCoordLocation = program.attributeLocation(gl, "vertexTexCoord");
gl.enableVertexAttribArray(this.vertexPointLocation);
if (this.vertexTexCoordLocation >= 0) { // location of vertexTexCoord attribute is -1 when the basic program is bound
var texCoordVbo = gpuResourceCache.resourceForKey(this.texCoordVboCacheKey);
gl.bindBuffer(gl.ARRAY_BUFFER, texCoordVbo);
gl.vertexAttribPointer(this.vertexTexCoordLocation, 2, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(this.vertexTexCoordLocation);
}
var indicesVbo = gpuResourceCache.resourceForKey(this.indicesVboCacheKey);
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indicesVbo);
};
/**
* Restores rendering state after drawing a succession of terrain tiles.
* @param {DrawContext} dc The draw context.
*/
Tessellator.prototype.endRendering = function (dc) {
var gl = dc.currentGlContext;
gl.bindBuffer(gl.ARRAY_BUFFER, null);
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, null);
// Restore the global OpenGL vertex attribute array state.
if (this.vertexPointLocation >= 0) {
gl.disableVertexAttribArray(this.vertexPointLocation);
}
if (this.vertexTexCoordLocation >= 0) { // location of vertexTexCoord attribute is -1 when the basic program is bound
gl.disableVertexAttribArray(this.vertexTexCoordLocation);
}
};
/**
* Initializes rendering state for drawing a specified terrain tile.
* @param {DrawContext} dc The draw context.
* @param {TerrainTile} terrainTile The terrain tile subsequently drawn via this tessellator's render function.
* @throws {ArgumentError} If the specified tile is null or undefined.
*/
Tessellator.prototype.beginRenderingTile = function (dc, terrainTile) {
if (!terrainTile) {
throw new ArgumentError(
Logger.logMessage(Logger.LEVEL_SEVERE, "Tessellator", "beginRenderingTile", "missingTile"));
}
var gl = dc.currentGlContext,
gpuResourceCache = dc.gpuResourceCache;
this.scratchMatrix.setToMultiply(dc.modelviewProjection, terrainTile.transformationMatrix);
dc.currentProgram.loadModelviewProjection(gl, this.scratchMatrix);
var vboCacheKey = dc.globeStateKey + terrainTile.tileKey,
vbo = gpuResourceCache.resourceForKey(vboCacheKey);
if (!vbo) {
vbo = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, vbo);
gl.bufferData(gl.ARRAY_BUFFER, terrainTile.points, gl.STATIC_DRAW);
dc.frameStatistics.incrementVboLoadCount(1);
gpuResourceCache.putResource(vboCacheKey, vbo, terrainTile.points.length * 4);
terrainTile.pointsVboStateKey = terrainTile.pointsStateKey;
}
else if (terrainTile.pointsVboStateKey != terrainTile.pointsStateKey) {
gl.bindBuffer(gl.ARRAY_BUFFER, vbo);
gl.bufferSubData(gl.ARRAY_BUFFER, 0, terrainTile.points);
terrainTile.pointsVboStateKey = terrainTile.pointsStateKey;
}
else {
dc.currentGlContext.bindBuffer(gl.ARRAY_BUFFER, vbo);
}
gl.vertexAttribPointer(this.vertexPointLocation, 3, gl.FLOAT, false, 0, 0);
};
/**
* Restores rendering state after drawing the most recent tile specified to
* [beginRenderingTile]{@link Tessellator#beginRenderingTile}.
* @param {DrawContext} dc The draw context.
* @param {TerrainTile} terrainTile The terrain tile most recently rendered.
* @throws {ArgumentError} If the specified tile is null or undefined.
*/
Tessellator.prototype.endRenderingTile = function (dc, terrainTile) {
// Intentionally empty until there's some reason to add code here.
};
/**
* Renders a specified terrain tile.
* @param {DrawContext} dc The draw context.
* @param {TerrainTile} terrainTile The terrain tile to render.
* @throws {ArgumentError} If the specified tile is null or undefined.
*/
Tessellator.prototype.renderTile = function (dc, terrainTile) {
if (!terrainTile) {
throw new ArgumentError(
Logger.logMessage(Logger.LEVEL_SEVERE, "Tessellator", "renderTile", "missingTile"));
}
var gl = dc.currentGlContext,
prim = gl.TRIANGLE_STRIP; // replace TRIANGLE_STRIP with LINE_STRIP to debug borders
/*
* Indices order in the buffer:
*
* base indices
*
* north border
* south border
* west border
* east border
*
* north lores
* south lores
* west lores
* east lores
*
* wireframe
* outline
*/
gl.drawElements(
prim,
this.numBaseIndices,
gl.UNSIGNED_SHORT,
this.baseIndicesOffset * 2);
var level = terrainTile.level,
neighborLevel;
neighborLevel = terrainTile.neighborLevel(WorldWind.NORTH);
if (neighborLevel && neighborLevel.compare(level) < 0) {
gl.drawElements(
prim,
this.numIndicesLoresNorth,
gl.UNSIGNED_SHORT,
this.indicesLoresNorthOffset * 2);
}
else {
gl.drawElements(
prim,
this.numIndicesNorth,
gl.UNSIGNED_SHORT,
this.indicesNorthOffset * 2);
}
neighborLevel = terrainTile.neighborLevel(WorldWind.SOUTH);
if (neighborLevel && neighborLevel.compare(level) < 0) {
gl.drawElements(
prim,
this.numIndicesLoresSouth,
gl.UNSIGNED_SHORT,
this.indicesLoresSouthOffset * 2);
}
else {
gl.drawElements(
prim,
this.numIndicesSouth,
gl.UNSIGNED_SHORT,
this.indicesSouthOffset * 2);
}
neighborLevel = terrainTile.neighborLevel(WorldWind.WEST);
if (neighborLevel && neighborLevel.compare(level) < 0) {
gl.drawElements(
prim,
this.numIndicesLoresWest,
gl.UNSIGNED_SHORT,
this.indicesLoresWestOffset * 2);
}
else {
gl.drawElements(
prim,
this.numIndicesWest,
gl.UNSIGNED_SHORT,
this.indicesWestOffset * 2);
}
neighborLevel = terrainTile.neighborLevel(WorldWind.EAST);
if (neighborLevel && neighborLevel.compare(level) < 0) {
gl.drawElements(
prim,
this.numIndicesLoresEast,
gl.UNSIGNED_SHORT,
this.indicesLoresEastOffset * 2);
}
else {
gl.drawElements(
prim,
this.numIndicesEast,
gl.UNSIGNED_SHORT,
this.indicesEastOffset * 2);
}
};
/**
* Draws outlines of the triangles composing the tile.
* @param {DrawContext} dc The current draw context.
* @param {TerrainTile} terrainTile The tile to draw.
* @throws {ArgumentError} If the specified tile is null or undefined.
*/
Tessellator.prototype.renderWireframeTile = function (dc, terrainTile) {
if (!terrainTile) {
throw new ArgumentError(
Logger.logMessage(Logger.LEVEL_SEVERE, "Tessellator", "renderWireframeTile", "missingTile"));
}
var gl = dc.currentGlContext;
// Must turn off texture coordinates, which were turned on in beginRendering.
if (this.vertexTexCoordLocation >= 0) {
gl.disableVertexAttribArray(this.vertexTexCoordLocation);
}
gl.drawElements(
gl.LINES,
this.numWireframeIndices,
gl.UNSIGNED_SHORT,
this.wireframeIndicesOffset * 2);
};
/**
* Draws the outer boundary of a specified terrain tile.
* @param {DrawContext} dc The current draw context.
* @param {TerrainTile} terrainTile The tile whose outer boundary to draw.
* @throws {ArgumentError} If the specified tile is null or undefined.
*/
Tessellator.prototype.renderTileOutline = function (dc, terrainTile) {
if (!terrainTile) {
throw new ArgumentError(
Logger.logMessage(Logger.LEVEL_SEVERE, "Tessellator", "renderTileOutline", "missingTile"));
}
var gl = dc.currentGlContext;
// Must turn off texture coordinates, which were turned on in beginRendering.
if (this.vertexTexCoordLocation >= 0) {
gl.disableVertexAttribArray(this.vertexTexCoordLocation);
}
gl.drawElements(
gl.LINE_LOOP,
this.numOutlineIndices,
gl.UNSIGNED_SHORT,
this.outlineIndicesOffset * 2);
};
/**
* Causes this terrain to perform the picking operations on the specified tiles, as appropriate for the draw
* context's pick settings. Normally, this draws the terrain in a unique pick color and computes the picked
* terrain position. When the draw context is set to region picking mode, this omits the computation of a picked
* terrain position.
* @param {DrawContext} dc The current draw context.
* @param {Array} tileList The list of tiles to pick.
* @param {Object} pickDelegate Indicates the object to use as the picked object's <code>userObject</code>.
* If null, then this tessellator is used as the <code>userObject</code>.
* @throws {ArgumentError} If either the draw context or the tile list are null or undefined.
*/
Tessellator.prototype.pick = function (dc, tileList, pickDelegate) {
if (!dc) {
throw new ArgumentError(
Logger.logMessage(Logger.LEVEL_SEVERE, "Tessellator", "pick", "missingDc"));
}
if (!tileList) {
throw new ArgumentError(
Logger.logMessage(Logger.LEVEL_SEVERE, "Tessellator", "pick", "missingList"));
}
var color = null,
userObject = pickDelegate || this,
position = new Position(0, 0, 0),
pickableTiles = [];
// Assemble a list of tiles that intersect the pick frustum. This eliminates unnecessary work for tiles that
// do not contribute to the pick result.
for (var i = 0, len = tileList.length; i < len; i++) {
var tile = tileList[i];
if (tile.extent.intersectsFrustum(dc.pickFrustum)) {
pickableTiles.push(tile);
}
}
// Draw the pickable tiles in a unique pick color. Suppress this step when picking the terrain only. In this
// case drawing to the pick framebuffer is unnecessary.
if (!dc.pickTerrainOnly) {
color = dc.uniquePickColor();
this.drawPickTiles(dc, pickableTiles, color);
}
// Determine the terrain position at the pick point. If the terrain is picked, add a corresponding picked
// object to the draw context. Suppress this step in region picking mode.
if (!dc.regionPicking) {
var ray = dc.pickRay.clone(), // Cloning the pick ray is necessary here due to the fact that Tesselator.computeIntersections modifies ray
point = this.computeNearestIntersection(ray, pickableTiles);
if (point) {
dc.globe.computePositionFromPoint(point[0], point[1], point[2], position);
position.altitude = dc.globe.elevationAtLocation(position.latitude, position.longitude);
dc.addPickedObject(new PickedObject(color, userObject, position, null, true));
}
}
};
// Internal function. Intentionally not documented.
Tessellator.prototype.drawPickTiles = function (dc, tileList, color) {
var gl = dc.currentGlContext;
try {
dc.findAndBindProgram(BasicProgram);
dc.currentProgram.loadColor(gl, color);
this.beginRendering(dc);
for (var i = 0, len = tileList.length; i < len; i++) {
var tile = tileList[i];
this.beginRenderingTile(dc, tile);
this.renderTile(dc, tile);
this.endRenderingTile(dc, tile);
}
} finally {
this.endRendering(dc);
}
};
// Internal function. Intentionally not documented.
Tessellator.prototype.computeNearestIntersection = function (line, tileList) {
// Compute all intersections between the specified line and tile list.
var results = [];
for (var i = 0, len = tileList.length; i < len; i++) {
this.computeIntersections(line, tileList[i], results);
}
if (results.length == 0) {
return null; // no intersection
} else {
// Find and return the intersection nearest to the line's origin.
var minDistance = Number.POSITIVE_INFINITY,
minIndex;
for (i = 0, len = results.length; i < len; i++) {
var distance = line.origin.distanceToSquared(results[i]);
if (minDistance > distance) {
minDistance = distance;
minIndex = i;
}
}
return results[minIndex];
}
};
// Internal function. Intentionally not documented.
Tessellator.prototype.computeIntersections = function (line, tile, results) {
var level = tile.level,
neighborLevel,
points = tile.points,
elements,
firstResult = results.length;
// Translate the line from model coordinates to tile local coordinates.
line.origin.subtract(tile.referencePoint);
// Assemble the shared tile index geometry. This initializes the index properties used below.
this.buildSharedGeometry(tile);
// Compute any intersections with the tile's interior triangles..
elements = this.baseIndices;
WWMath.computeTriStripIntersections(line, points, elements, results);
// Compute any intersections with the tile's south border triangles.
neighborLevel = tile.neighborLevel(WorldWind.SOUTH);
elements = neighborLevel && neighborLevel.compare(level) < 0 ? this.indicesLoresSouth : this.indicesSouth;
WWMath.computeTriStripIntersections(line, points, elements, results);
// Compute any intersections with the tile's west border triangles.
neighborLevel = tile.neighborLevel(WorldWind.WEST);
elements = neighborLevel && neighborLevel.compare(level) < 0 ? this.indicesLoresWest : this.indicesWest;
WWMath.computeTriStripIntersections(line, points, elements, results);
// Compute any intersections with the tile's east border triangles.
neighborLevel = tile.neighborLevel(WorldWind.EAST);
elements = neighborLevel && neighborLevel.compare(level) < 0 ? this.indicesLoresEast : this.indicesEast;
WWMath.computeTriStripIntersections(line, points, elements, results);
// Compute any intersections with the tile's north border triangles.
neighborLevel = tile.neighborLevel(WorldWind.NORTH);
elements = neighborLevel && neighborLevel.compare(level) < 0 ? this.indicesLoresNorth : this.indicesNorth;
WWMath.computeTriStripIntersections(line, points, elements, results);
// Translate the line and the intersection results from tile local coordinates to model coordinates.
line.origin.add(tile.referencePoint);
for (var i = firstResult, len = results.length; i < len; i++) {
results[i].add(tile.referencePoint);
}
};
/***********************************************************************
* Internal methods - assume that arguments have been validated already.
***********************************************************************/
Tessellator.prototype.createTopLevelTiles = function (dc) {
this.topLevelTiles[dc.globeStateKey] = [];
Tile.createTilesForLevel(this.levels.firstLevel(), this, this.topLevelTiles[dc.globeStateKey]);
};
Tessellator.prototype.addTileOrDescendants = function (dc, tile) {
if (this.tileMeetsRenderCriteria(dc, tile)) {
this.addTile(dc, tile);
return;
}
this.addTileDescendants(dc, tile);
};
Tessellator.prototype.addTileDescendants = function (dc, tile) {
var nextLevel = tile.level.nextLevel();
var subTiles = tile.subdivideToCache(nextLevel, this, this.tileCache);
for (var index = 0; index < subTiles.length; index += 1) {
var child = subTiles[index];
child.update(dc);
if (this.levels.sector.intersects(child.sector) && this.isTileVisible(dc, child)) {
this.addTileOrDescendants(dc, child);
}
}
};
Tessellator.prototype.addTile = function (dc, tile) {
// Insert tile at index idx.
var idx = this.tiles.length;
this.tiles.push(tile);
// Insert tile into corner data collection for later LOD neighbor analysis.
var sector = tile.sector;
// Corners of the tile.
var neTileCorner = [sector.maxLatitude, sector.maxLongitude].toString(),
seTileCorner = [sector.minLatitude, sector.maxLongitude].toString(),
nwTileCorner = [sector.maxLatitude, sector.minLongitude].toString(),
swTileCorner = [sector.minLatitude, sector.minLongitude].toString(),
corner;
corner = this.corners[swTileCorner];
if (!corner) {
this.corners[swTileCorner] = {'sw': idx}; //corner;
}
else {
// assert(!corner.sw, "sw already defined");
corner.sw = idx;
}
corner = this.corners[nwTileCorner];
if (!corner) {
this.corners[nwTileCorner] = {'nw': idx};
}
else {
// assert(!corner.nw, "nw already defined");
corner.nw = idx;
}
corner = this.corners[seTileCorner];
if (!corner) {
this.corners[seTileCorner] = {'se': idx};
}
else {
// assert(!corver.se, "se already defined");
corner.se = idx;
}
corner = this.corners[neTileCorner];
if (!corner) {
this.corners[neTileCorner] = {'ne': idx};
}
else {
//assert(!corner.ne, "ne already defined");
corner.ne = idx;
}
};
Tessellator.prototype.refineNeighbors = function (dc) {
var tileRefinementSet = {};
for (var idx = 0, len = this.tiles.length; idx < len; idx += 1) {
var tile = this.tiles[idx],
levelNumber = tile.level.levelNumber,
sector = tile.sector,
corner,
neighbor,
idx,
len;
// Corners of the tile.
var neTileCorner = [sector.maxLatitude, sector.maxLongitude].toString(),
seTileCorner = [sector.minLatitude, sector.maxLongitude].toString(),
nwTileCorner = [sector.maxLatitude, sector.minLongitude].toString(),
swTileCorner = [sector.minLatitude, sector.minLongitude].toString();
corner = this.corners[neTileCorner];
// assert(corner, "northeast corner not found");
if (corner.hasOwnProperty('se')) {
neighbor = corner.se;
if (this.tiles[neighbor].level.levelNumber < levelNumber - 1) {
if (!tileRefinementSet[neighbor]) {
tileRefinementSet[neighbor] = true;
}
}
}
if (corner.hasOwnProperty('nw')) {
neighbor = corner.nw;
if (this.tiles[neighbor].level.levelNumber < levelNumber - 1) {
if (!tileRefinementSet[neighbor]) {
tileRefinementSet[neighbor] = true;
}
}
}
corner = this.corners[seTileCorner];
// assert(corner, "southeast corner not found");
if (corner.hasOwnProperty('ne')) {
neighbor = corner.ne;
if (this.tiles[neighbor].level.levelNumber < levelNumber - 1) {
if (!tileRefinementSet[neighbor]) {
tileRefinementSet[neighbor] = true;
}
}
}
if (corner.hasOwnProperty('sw')) {
neighbor = corner.sw;
if (this.tiles[neighbor].level.levelNumber < levelNumber - 1) {
if (!tileRefinementSet[neighbor]) {
tileRefinementSet[neighbor] = true;
}
}
}
corner = this.corners[nwTileCorner];
// assert(corner, "northwest corner not found");
if (corner.hasOwnProperty('ne')) {
neighbor = corner.ne;
if (this.tiles[neighbor].level.levelNumber < levelNumber - 1) {
if (!tileRefinementSet[neighbor]) {
tileRefinementSet[neighbor] = true;
}
}
}
if (corner.hasOwnProperty('sw')) {
neighbor = corner.sw;
if (this.tiles[neighbor].level.levelNumber < levelNumber - 1) {
if (!tileRefinementSet[neighbor]) {
tileRefinementSet[neighbor] = true;
}
}
}
corner = this.corners[swTileCorner];
// assert(corner, "southwest corner not found");
if (corner.hasOwnProperty('se')) {
neighbor = corner.se;
if (this.tiles[neighbor].level.levelNumber < levelNumber - 1) {
if (!tileRefinementSet[neighbor]) {
tileRefinementSet[neighbor] = true;
}
}
}
if (corner.hasOwnProperty('nw')) {
neighbor = corner.nw;
if (this.tiles[neighbor].level.levelNumber < levelNumber - 1) {
if (!tileRefinementSet[neighbor]) {
tileRefinementSet[neighbor] = true;
}
}
}
}
// Partition tiles into those requiring refinement and those that don't need refinement.
var tilesNeedingRefinement = [],
tilesNotNeedingRefinement = [];
for (idx = 0, len = this.tiles.length; idx < len; idx += 1) {
tile = this.tiles[idx];
if (tileRefinementSet[idx]) {
tilesNeedingRefinement.push(tile);
}
else {
tilesNotNeedingRefinement.push(tile);
}
}
// When tiles need refinement, recur.
if (tilesNeedingRefinement.length > 0) {
// Reset refinement state.
this.tiles = [];
this.corners = {};
// For tiles that don't need refinement, simply add the tile.
for (idx = 0, len = tilesNotNeedingRefinement.length; idx < len; idx += 1) {
tile = tilesNotNeedingRefinement[idx];
this.addTile(dc, tile);
}
// For tiles that do need refinement, subdivide the tile and add its descendants.
for (idx = 0, len = tilesNeedingRefinement.length; idx < len; idx += 1) {
var tile = tilesNeedingRefinement[idx];
this.addTileDescendants(dc, tile);
}
// Recur.
this.refineNeighbors(dc);
}
};
Tessellator.prototype.finishTessellating = function (dc) {
for (var idx = 0, len = this.tiles.length; idx < len; idx += 1) {
var tile = this.tiles[idx];
this.setNeighbors(tile);
this.regenerateTileGeometryIfNeeded(dc, tile);
this.currentTiles.addTile(tile);
}
};
Tessellator.prototype.setNeighbors = function (tile) {
var sector = tile.sector;
// Corners of the tile.
var neTileCorner = [sector.maxLatitude, sector.maxLongitude].toString(),
seTileCorner = [sector.minLatitude, sector.maxLongitude].toString(),
nwTileCorner = [sector.maxLatitude, sector.minLongitude].toString(),
swTileCorner = [sector.minLatitude, sector.minLongitude].toString();
var neCorner = this.corners[neTileCorner],
seCorner = this.corners[seTileCorner],
nwCorner = this.corners[nwTileCorner],
swCorner = this.corners[swTileCorner];
var northIdx = -1, // neCorner.hasOwnProperty('se') ? neCorner.se : nwCorner.hasOwnProperty('sw') ? nwCorner.sw : -1,
southIdx = -1, // seCorner.hasOwnProperty('ne') ? seCorner.ne : swCorner.hasOwnProperty('nw') ? swCorner.nw : -1,
eastIdx = -1, // neCorner.hasOwnProperty('nw') ? neCorner.nw : seCorner.hasOwnProperty('sw') ? seCorner.sw : -1,
westIdx = -1; //nwCorner.hasOwnProperty('ne') ? nwCorner.ne : swCorner.hasOwnProperty('se') ? swCorner.se : -1;
if (neCorner.hasOwnProperty('se')) {
northIdx = neCorner.se;
}
else if (nwCorner.hasOwnProperty('sw')) {
northIdx = nwCorner.sw;
}
if (seCorner.hasOwnProperty('ne')) {
southIdx = seCorner.ne;
}
else if (swCorner.hasOwnProperty('nw')) {
southIdx = swCorner.nw;
}
if (neCorner.hasOwnProperty('nw')) {
eastIdx = neCorner.nw;
}
else if (seCorner.hasOwnProperty('sw')) {
eastIdx = seCorner.sw;
}
if (nwCorner.hasOwnProperty('ne')) {
westIdx = nwCorner.ne;
}
else if (swCorner.hasOwnProperty('se')) {
westIdx = swCorner.se;
}
tile.setNeighborLevel(WorldWind.NORTH, (northIdx >= 0) ? this.tiles[northIdx].level : null);
tile.setNeighborLevel(WorldWind.SOUTH, (southIdx >= 0) ? this.tiles[southIdx].level : null);
tile.setNeighborLevel(WorldWind.EAST, (eastIdx >= 0) ? this.tiles[eastIdx].level : null);
tile.setNeighborLevel(WorldWind.WEST, (westIdx >= 0) ? this.tiles[westIdx].level : null);
};
Tessellator.prototype.isTileVisible = function (dc, tile) {
if (dc.globe.projectionLimits && !tile.sector.overlaps(dc.globe.projectionLimits)) {
return false;
}
return tile.extent.intersectsFrustum(dc.frustumInModelCoordinates);
};
Tessellator.prototype.tileMeetsRenderCriteria = function (dc, tile) {
var s = this.detailControl;
if (tile.sector.minLatitude >= 75 || tile.sector.maxLatitude <= -75) {
s *= 2;
}
return tile.level.isLastLevel() || !tile.mustSubdivide(dc, s);
};
Tessellator.prototype.regenerateTileGeometryIfNeeded = function (dc, tile) {
var stateKey = dc.globeStateKey + tile.stateKey + dc.verticalExaggeration;
if (!tile.points || tile.pointsStateKey != stateKey) {
this.regenerateTileGeometry(dc, tile);
tile.pointsStateKey = stateKey;
}
};
/**
* Internal use only.
* TODO: Remove this function when Tessellator and ElevationModel are refactored
* Artificially calculates an adjusted target resolution for the given texel size to more
* optimally select elevation coverages until later refactoring.
* @returns {Number} An adjusted target resolution in degrees.
* @ignore
*/
Tessellator.prototype.coverageTargetResolution = function (texelSize) {
return (texelSize / 8) * Angle.RADIANS_TO_DEGREES;
};
Tessellator.prototype.regenerateTileGeometry = function (dc, tile) {
var numLat = tile.tileHeight + 1, // num points in each dimension is 1 more than the number of tile cells
numLon = tile.tileWidth + 1,
refPoint = tile.referencePoint,
elevations = this.scratchElevations;
// Allocate space for the tile's elevations.
if (!elevations) {
elevations = new Float64Array(numLat * numLon);
this.scratchElevations = elevations;
}
// Allocate space for the tile's Cartesian coordinates.
if (!tile.points) {
tile.points = new Float32Array(numLat * numLon * 3);
}
// Retrieve the elevations for all points in the tile.
WWUtil.fillArray(elevations, 0);
dc.globe.elevationsForGrid(tile.sector, numLat, numLon, this.coverageTargetResolution(tile.texelSize), elevations);
// Modify the elevations around the tile's border to match neighbors of lower resolution, if any.
if (this.mustAlignNeighborElevations(dc, tile)) {
this.alignNeighborElevations(dc, tile, elevations);
}
// Compute the tile's Cartesian coordinates relative to a local origin, called the reference point.
WWUtil.multiplyArray(elevations, dc.verticalExaggeration);
dc.globe.computePointsForGrid(tile.sector, numLat, numLon, elevations, refPoint, tile.points);
// Establish a transform that is used later to move the tile coordinates into place relative to the globe.
tile.transformationMatrix.setTranslation(refPoint[0], refPoint[1], refPoint[2]);
};
Tessellator.prototype.mustAlignNeighborElevations = function (dc, tile) {
var level = tile.level,
northLevel = tile.neighborLevel(WorldWind.NORTH),
southLevel = tile.neighborLevel(WorldWind.SOUTH),
eastLevel = tile.neighborLevel(WorldWind.EAST),
westLevel = tile.neighborLevel(WorldWind.WEST);
return (northLevel && northLevel.compare(level) < 0) ||
(southLevel && southLevel.compare(level) < 0) ||
(eastLevel && eastLevel.compare(level) < 0) ||
(westLevel && westLevel.compare(level) < 0);
};
Tessellator.prototype.alignNeighborElevations = function (dc, tile, elevations) {
var numLat = tile.tileHeight + 1, // num points in each dimension is 1 more than the number of tile cells
numLon = tile.tileWidth + 1,
level = tile.level,
prevNumLat = Math.floor(numLat / 2) + 1, // num prev level points is 1 more than 1/2 the number of cells
prevNumLon = Math.floor(numLon / 2) + 1,
prevLevel = level.previousLevel(),
prevElevations = this.scratchPrevElevations,
neighborLevel,
i, index, prevIndex;
// Allocate space for the previous level elevations.
if (!prevElevations) {
prevElevations = new Float64Array(prevNumLat * prevNumLon);
this.scratchPrevElevations = prevElevations;
}
// Retrieve the previous level elevations, using 1/2 the number of tile cells.
WWUtil.fillArray(prevElevations, 0);
dc.globe.elevationsForGrid(tile.sector, prevNumLat, prevNumLon, this.coverageTargetResolution(prevLevel.texelSize), prevElevations);
// Use previous level elevations along the north edge when the northern neighbor is lower resolution.
neighborLevel = tile.neighborLevel(WorldWind.NORTH);
if (neighborLevel && neighborLevel.compare(level) < 0) {
index = (numLat - 1) * numLon;
prevIndex = (prevNumLat - 1) * prevNumLon;
for (i = 0; i < prevNumLon; i++, index += 2, prevIndex += 1) {
elevations[index] = prevElevations[prevIndex];
if (i < prevNumLon - 1) {
elevations[index + 1] = 0.5 * (prevElevations[prevIndex] + prevElevations[prevIndex + 1]);
}
}
}
// Use previous level elevations along the south edge when the southern neighbor is lower resolution.
neighborLevel = tile.neighborLevel(WorldWind.SOUTH);
if (neighborLevel && neighborLevel.compare(level) < 0) {
index = 0;
prevIndex = 0;
for (i = 0; i < prevNumLon; i++, index += 2, prevIndex += 1) {
elevations[index] = prevElevations[prevIndex];
if (i < prevNumLon - 1) {
elevations[index + 1] = 0.5 * (prevElevations[prevIndex] + prevElevations[prevIndex + 1]);
}
}
}
// Use previous level elevations along the east edge when the eastern neighbor is lower resolution.
neighborLevel = tile.neighborLevel(WorldWind.EAST);
if (neighborLevel && neighborLevel.compare(level) < 0) {
index = numLon - 1;
prevIndex = prevNumLon - 1;
for (i = 0; i < prevNumLat; i++, index += 2 * numLon, prevIndex += prevNumLon) {
elevations[index] = prevElevations[prevIndex];
if (i < prevNumLat - 1) {
elevations[index + numLon] = 0.5 * (prevElevations[prevIndex] + prevElevations[prevIndex + prevNumLon]);
}
}
}
// Use previous level elevations along the west edge when the western neighbor is lower resolution.
neighborLevel = tile.neighborLevel(WorldWind.WEST);
if (neighborLevel && neighborLevel.compare(level) < 0) {
index = 0;
prevIndex = 0;
for (i = 0; i < prevNumLat; i++, index += 2 * numLon, prevIndex += prevNumLon) {
elevations[index] = prevElevations[prevIndex];
if (i < prevNumLat - 1) {
elevations[index + numLon] = 0.5 * (prevElevations[prevIndex] + prevElevations[prevIndex + prevNumLon]);
}
}
}
};
Tessellator.prototype.buildSharedGeometry = function () {
// TODO: put all indices into a single buffer
var tileWidth = this.levels.tileWidth,
tileHeight = this.levels.tileHeight;
if (!this.texCoords) {
this.buildTexCoords(tileWidth, tileHeight);
}
if (!this.indices) {
this.buildIndices(tileWidth, tileHeight);
}
};
Tessellator.prototype.buildTexCoords = function (tileWidth, tileHeight) {
var numCols = tileWidth + 1,
numRows = tileHeight + 1,
colDelta = 1 / tileWidth,
rowDelta = 1 / tileHeight,
buffer = new Float32Array(numCols * numRows * 2),
index = 0;
for (var row = 0, t = 0; row < numRows; row++, t += rowDelta) {
if (row == numRows - 1) {
t = 1; // explicitly set the last row coordinate to ensure alignment
}
for (var col = 0, s = 0; col < numCols; col++, s += colDelta) {
if (col == numCols - 1) {
s = 1; // explicitly set the last column coordinate to ensure alignment
}
buffer[index++] = s;
buffer[index++] = t;
}
}
this.texCoords = buffer;
};
Tessellator.prototype.buildIndices = function (tileWidth, tileHeight) {
var vertexIndex; // The index of the vertex in the sample grid.
// The number of vertices in each dimension is 1 more than the number of cells.
var numLatVertices = tileHeight + 1,
numLonVertices = tileWidth + 1,
latIndexMid = tileHeight / 2, // Assumption: tileHeight is even, so that there is a midpoint!
lonIndexMid = tileWidth / 2; // Assumption: tileWidth is even, so that there is a midpoint!
// Each vertex has two indices associated with it: the current vertex index and the index of the row.
// There are tileHeight rows.
// There are tileHeight + 2 columns
var numIndices = 2 * (numLatVertices - 3) * (numLonVertices - 2) + 2 * (numLatVertices - 3);
var indices = [];
// Inset core by one round of sub-tiles. Full grid is numLatVertices x numLonVertices. This must be used
// to address vertices in the core as well.
var index = 0;
for (var lonIndex = 1; lonIndex < numLonVertices - 2; lonIndex += 1) {
for (var latIndex = 1; latIndex < numLatVertices - 1; latIndex += 1) {
vertexIndex = lonIndex + latIndex * numLonVertices;
// Create a triangle strip joining each adjacent column of vertices, starting in the top left corner and
// proceeding to the right. The first vertex starts with the left row of vertices and moves right to create a
// counterclockwise winding order.
indices[index++] = vertexIndex;
indices[index++] = vertexIndex + 1;
}
// Insert indices to create 2 degenerate triangles:
// one for the end of the current row, and
// one for the beginning of the next row.
indices[index++] = vertexIndex + 1;
vertexIndex = (lonIndex + 1) + 1 * numLonVertices;
indices[index++] = vertexIndex;
}
this.baseIndicesOffset = indices.length - numIndices;
this.baseIndices = new Uint16Array(indices.slice(this.baseIndicesOffset));
this.numBaseIndices = numIndices;
// TODO: parameterize and refactor!!!!!
// Software engineering notes: There are patterns being used in the following code that should be abstracted.
// However, I suspect that the process of abstracting the patterns will result in as much code created
// as gets removed. YMMV. If JavaScript had a meta-programming (a.k.a., macro) facility, that code would be
// processed at "compile" time rather than "runtime". But it doesn't have such a facility that I know of.
//
// Patterns used:
// 0) Each tile has four borders: north, south, east, and west.
// 1) Counter-clockwise traversal around the outside results in clockwise meshes amendable to back-face elimination.
// 2) For each vertex on the exterior, there corresponds a vertex on the interior that creates a diagonal.
// 3) Each border construction is broken into three phases:
// a) The starting phase to generate the first half of the border,
// b) The middle phase, where a single vertex reference gets created, and
// c) The ending phase to complete the generation of the border.
// 4) Each border is generated in two variants:
// a) one variant that mates with a tile at the same level of detail, and
// b) another variant that mates with a tile at the next lower level of detail.
// 5) Borders that mate with the next lower level of detail are constrained to lie on even indices.
// 6) Evenness is generated by ANDing the index with a mask that has 1's in all bits except for the LSB,
// which results in clearing the LSB os the index, making it even.
// 7) The section that generates lower level LOD borders gives up any attempt to be optimal because of the
// complexity. Instead, correctness was preferred. That said, any performance lost is in the noise,
// since this code only gets run once.
/*
* The following section of code generates full resolution boundary meshes. These are used to mate
* with neighboring tiles that are at the same level of detail.
*/
// North border.
numIndices = 2 * numLonVertices - 2;
latIndex = numLatVertices - 1;
// Corner vertex.
lonIndex = numLonVertices - 1;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
for (lonIndex = numLonVertices - 2; lonIndex > 0; lonIndex -= 1) {
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
indices[index++] = vertexIndex - numLonVertices;
}
// Corner vertex.
lonIndex = 0;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
this.indicesNorthOffset = indices.length - numIndices;
this.indicesNorth = new Uint16Array(indices.slice(this.indicesNorthOffset));
this.numIndicesNorth = numIndices;
// South border.
numIndices = 2 * numLonVertices - 2;
latIndex = 0;
// Corner vertex.
lonIndex = 0;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
for (lonIndex = 1; lonIndex < numLonVertices - 1; lonIndex += 1) {
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
indices[index++] = vertexIndex + numLonVertices;
}
// Corner vertex.
lonIndex = numLonVertices - 1;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
this.indicesSouthOffset = indices.length - numIndices;
this.indicesSouth = new Uint16Array(indices.slice(this.indicesSouthOffset));
this.numIndicesSouth = numIndices;
// West border.
numIndices = 2 * numLatVertices - 2;
lonIndex = 0;
// Corner vertex.
latIndex = numLatVertices - 1;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
for (latIndex = numLatVertices - 2; latIndex > 0; latIndex -= 1) {
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
indices[index++] = vertexIndex + 1;
}
// Corner vertex.
latIndex = 0;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
this.indicesWestOffset = indices.length - numIndices;
this.indicesWest = new Uint16Array(indices.slice(this.indicesWestOffset));
this.numIndicesWest = numIndices;
// East border.
numIndices = 2 * numLatVertices - 2;
lonIndex = numLonVertices - 1;
// Corner vertex.
latIndex = 0;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
for (latIndex = 1; latIndex < numLatVertices - 1; latIndex += 1) {
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
indices[index++] = vertexIndex - 1;
}
// Corner vertex.
latIndex = numLatVertices - 1;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
this.indicesEastOffset = indices.length - numIndices;
this.indicesEast = new Uint16Array(indices.slice(this.indicesEastOffset));
this.numIndicesEast = numIndices;
/*
* The following section of code generates "lores" low resolution boundary meshes. These are used to mate
* with neighboring tiles that are at a lower level of detail. The property of these lower level meshes is that
* they have half the number of vertices.
*
* To generate the boundary meshes, force the use of only even boundary vertex indices.
*/
// North border.
numIndices = 2 * numLonVertices - 2;
latIndex = numLatVertices - 1;
// Corner vertex.
lonIndex = numLonVertices - 1;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
for (lonIndex = numLonVertices - 2; lonIndex > 0; lonIndex -= 1) {
// Exterior vertex rounded up to even index.
vertexIndex = ((lonIndex + 1) & ~1) + latIndex * numLonVertices;
indices[index++] = vertexIndex;
// Interior vertex.
vertexIndex = lonIndex + (latIndex - 1) * numLonVertices;
indices[index++] = vertexIndex;
}
// Corner vertex.
lonIndex = 0;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
this.indicesLoresNorthOffset = indices.length - numIndices;
this.indicesLoresNorth = new Uint16Array(indices.slice(this.indicesLoresNorthOffset));
this.numIndicesLoresNorth = numIndices;
// South border.
numIndices = 2 * numLonVertices - 2;
latIndex = 0;
// Corner vertex.
lonIndex = 0;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
for (lonIndex = 1; lonIndex < numLonVertices - 1; lonIndex += 1) {
// Exterior Vertex rounded down to even index.
vertexIndex = (lonIndex & ~1) + latIndex * numLonVertices;
indices[index++] = vertexIndex;
// Interior vertex.
vertexIndex = lonIndex + (latIndex + 1) * numLonVertices;
indices[index++] = vertexIndex;
}
// Corner vertex.
lonIndex = numLonVertices - 1;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
this.indicesLoresSouthOffset = indices.length - numIndices;
this.indicesLoresSouth = new Uint16Array(indices.slice(this.indicesLoresSouthOffset));
this.numIndicesLoresSouth = numIndices;
// West border.
numIndices = 2 * numLatVertices - 2;
lonIndex = 0;
// Corner vertex.
latIndex = numLatVertices - 1;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
for (latIndex = numLatVertices - 2; latIndex > 0; latIndex -= 1) {
// Exterior Vertex rounded up to even index.
vertexIndex = lonIndex + ((latIndex + 1) & ~1) * numLonVertices;
indices[index++] = vertexIndex;
// Interior vertex.
vertexIndex = (lonIndex + 1) + latIndex * numLonVertices;
indices[index++] = vertexIndex;
}
// Corner vertex.
latIndex = 0;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
this.indicesLoresWestOffset = indices.length - numIndices;
this.indicesLoresWest = new Uint16Array(indices.slice(this.indicesLoresWestOffset));
this.numIndicesLoresWest = numIndices;
// East border.
numIndices = 2 * numLatVertices - 2;
lonIndex = numLonVertices - 1;
// Corner vertex.
latIndex = 0;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
for (latIndex = 1; latIndex < numLatVertices - 1; latIndex += 1) {
// Exterior vertex rounded down to even index.
vertexIndex = lonIndex + (latIndex & ~1) * numLonVertices;
indices[index++] = vertexIndex;
// Interior vertex.
vertexIndex = (lonIndex - 1) + latIndex * numLonVertices;
indices[index++] = vertexIndex;
}
// Corner vertex.
latIndex = numLatVertices - 1;
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index++] = vertexIndex;
this.indicesLoresEastOffset = indices.length - numIndices;
this.indicesLoresEast = new Uint16Array(indices.slice(this.indicesLoresEastOffset));
this.numIndicesLoresEast = numIndices;
var wireframeIndices = this.buildWireframeIndices(tileWidth, tileHeight);
var outlineIndices = this.buildOutlineIndices(tileWidth, tileHeight);
indices = indices.concat(wireframeIndices);
this.wireframeIndicesOffset = indices.length - this.numWireframeIndices;
indices = indices.concat(outlineIndices);
this.outlineIndicesOffset = indices.length - this.numOutlineIndices;
this.indices = new Uint16Array(indices);
};
Tessellator.prototype.buildWireframeIndices = function (tileWidth, tileHeight) {
// The wireframe representation draws the vertices that appear on the surface.
// The number of vertices in each dimension is 1 more than the number of cells.
var numLatVertices = tileHeight + 1;
var numLonVertices = tileWidth + 1;
// Allocate an array to hold the computed indices.
var numIndices = 2 * tileWidth * numLatVertices + 2 * tileHeight * numLonVertices;
var indices = [];
var rowStride = numLonVertices;
var index = 0,
lonIndex,
latIndex,
vertexIndex;
// Add a line between each row to define the horizontal cell outlines.
for (latIndex = 0; latIndex < numLatVertices; latIndex += 1) {
for (lonIndex = 0; lonIndex < tileWidth; lonIndex += 1) {
vertexIndex = lonIndex + latIndex * rowStride;
indices[index] = vertexIndex;
indices[index + 1] = (vertexIndex + 1);
index += 2
}
}
// Add a line between each column to define the vertical cell outlines.
for (lonIndex = 0; lonIndex < numLonVertices; lonIndex += 1) {
for (latIndex = 0; latIndex < tileHeight; latIndex += 1) {
vertexIndex = lonIndex + latIndex * rowStride;
indices[index] = vertexIndex;
indices[index + 1] = (vertexIndex + rowStride);
index += 2;
}
}
this.numWireframeIndices = numIndices;
return indices;
};
Tessellator.prototype.buildOutlineIndices = function (tileWidth, tileHeight) {
// The outline representation traces the tile's outer edge on the surface.
// The number of vertices in each dimension is 1 more than the number of cells.
var numLatVertices = tileHeight + 1;
var numLonVertices = tileWidth + 1;
// Allocate an array to hold the computed indices.
var numIndices = 2 * (numLatVertices - 2) + 2 * numLonVertices + 1;
var indices = [];
var rowStride = numLatVertices;
var index = 0,
lonIndex,
latIndex,
vertexIndex;
// Bottom row, starting at the left and going right.
latIndex = 0;
for (lonIndex = 0; lonIndex < numLonVertices; lonIndex += 1) {
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index] = vertexIndex;
index += 1;
}
// Right column, starting at the bottom and going up.
lonIndex = numLonVertices - 1;
for (latIndex = 1; latIndex < numLatVertices; latIndex += 1) {
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index] = vertexIndex;
index += 1
}
// Top row, starting on the right and going to the left.
latIndex = numLatVertices - 1;
for (lonIndex = numLonVertices - 1; lonIndex >= 0; lonIndex -= 1) {
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index] = vertexIndex;
index += 1
}
// Leftmost column, starting at the top and going down.
lonIndex = 0;
for (latIndex = numLatVertices - 1; latIndex >= 0; latIndex -= 1) {
vertexIndex = lonIndex + latIndex * numLonVertices;
indices[index] = vertexIndex;
index += 1
}
this.numOutlineIndices = numIndices;
return indices;
};
Tessellator.prototype.cacheSharedGeometryVBOs = function (dc) {
var gl = dc.currentGlContext,
gpuResourceCache = dc.gpuResourceCache;
var texCoordVbo = gpuResourceCache.resourceForKey(this.texCoordVboCacheKey);
if (!texCoordVbo) {
texCoordVbo = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, texCoordVbo);
gl.bufferData(gl.ARRAY_BUFFER, this.texCoords, gl.STATIC_DRAW);
dc.frameStatistics.incrementVboLoadCount(1);
gpuResourceCache.putResource(this.texCoordVboCacheKey, texCoordVbo, this.texCoords.length * 4 / 2);
}
var indicesVbo = gpuResourceCache.resourceForKey(this.indicesVboCacheKey);
if (!indicesVbo) {
indicesVbo = gl.createBuffer();
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indicesVbo);
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, this.indices, gl.STATIC_DRAW);
dc.frameStatistics.incrementVboLoadCount(1);
gpuResourceCache.putResource(this.indicesVboCacheKey, indicesVbo, this.indices.length * 2);
}
};
return Tessellator;
});