cesium
Version:
CesiumJS is a JavaScript library for creating 3D globes and 2D maps in a web browser without a plugin.
1,036 lines (921 loc) • 59 kB
JavaScript
define([
'../Core/Cartesian2',
'../Core/Cartesian4',
'../Core/defaultValue',
'../Core/defined',
'../Core/defineProperties',
'../Core/destroyObject',
'../Core/DeveloperError',
'../Core/FeatureDetection',
'../Core/GeographicTilingScheme',
'../Core/IndexDatatype',
'../Core/Math',
'../Core/PixelFormat',
'../Core/Rectangle',
'../Core/Request',
'../Core/RequestState',
'../Core/RequestType',
'../Core/TerrainProvider',
'../Core/TileProviderError',
'../Core/WebMercatorProjection',
'../Core/WebMercatorTilingScheme',
'../Renderer/Buffer',
'../Renderer/BufferUsage',
'../Renderer/ComputeCommand',
'../Renderer/ContextLimits',
'../Renderer/MipmapHint',
'../Renderer/Sampler',
'../Renderer/ShaderProgram',
'../Renderer/ShaderSource',
'../Renderer/Texture',
'../Renderer/TextureMagnificationFilter',
'../Renderer/TextureMinificationFilter',
'../Renderer/TextureWrap',
'../Renderer/VertexArray',
'../Shaders/ReprojectWebMercatorFS',
'../Shaders/ReprojectWebMercatorVS',
'../ThirdParty/when',
'./Imagery',
'./ImagerySplitDirection',
'./ImageryState',
'./TileImagery'
], function(
Cartesian2,
Cartesian4,
defaultValue,
defined,
defineProperties,
destroyObject,
DeveloperError,
FeatureDetection,
GeographicTilingScheme,
IndexDatatype,
CesiumMath,
PixelFormat,
Rectangle,
Request,
RequestState,
RequestType,
TerrainProvider,
TileProviderError,
WebMercatorProjection,
WebMercatorTilingScheme,
Buffer,
BufferUsage,
ComputeCommand,
ContextLimits,
MipmapHint,
Sampler,
ShaderProgram,
ShaderSource,
Texture,
TextureMagnificationFilter,
TextureMinificationFilter,
TextureWrap,
VertexArray,
ReprojectWebMercatorFS,
ReprojectWebMercatorVS,
when,
Imagery,
ImagerySplitDirection,
ImageryState,
TileImagery) {
'use strict';
/**
* An imagery layer that displays tiled image data from a single imagery provider
* on a {@link Globe}.
*
* @alias ImageryLayer
* @constructor
*
* @param {ImageryProvider} imageryProvider The imagery provider to use.
* @param {Object} [options] Object with the following properties:
* @param {Rectangle} [options.rectangle=imageryProvider.rectangle] The rectangle of the layer. This rectangle
* can limit the visible portion of the imagery provider.
* @param {Number|Function} [options.alpha=1.0] The alpha blending value of this layer, from 0.0 to 1.0.
* This can either be a simple number or a function with the signature
* <code>function(frameState, layer, x, y, level)</code>. The function is passed the
* current frame state, this layer, and the x, y, and level coordinates of the
* imagery tile for which the alpha is required, and it is expected to return
* the alpha value to use for the tile.
* @param {Number|Function} [options.brightness=1.0] The brightness of this layer. 1.0 uses the unmodified imagery
* color. Less than 1.0 makes the imagery darker while greater than 1.0 makes it brighter.
* This can either be a simple number or a function with the signature
* <code>function(frameState, layer, x, y, level)</code>. The function is passed the
* current frame state, this layer, and the x, y, and level coordinates of the
* imagery tile for which the brightness is required, and it is expected to return
* the brightness value to use for the tile. The function is executed for every
* frame and for every tile, so it must be fast.
* @param {Number|Function} [options.contrast=1.0] The contrast of this layer. 1.0 uses the unmodified imagery color.
* Less than 1.0 reduces the contrast while greater than 1.0 increases it.
* This can either be a simple number or a function with the signature
* <code>function(frameState, layer, x, y, level)</code>. The function is passed the
* current frame state, this layer, and the x, y, and level coordinates of the
* imagery tile for which the contrast is required, and it is expected to return
* the contrast value to use for the tile. The function is executed for every
* frame and for every tile, so it must be fast.
* @param {Number|Function} [options.hue=0.0] The hue of this layer. 0.0 uses the unmodified imagery color.
* This can either be a simple number or a function with the signature
* <code>function(frameState, layer, x, y, level)</code>. The function is passed the
* current frame state, this layer, and the x, y, and level coordinates
* of the imagery tile for which the hue is required, and it is expected to return
* the contrast value to use for the tile. The function is executed for every
* frame and for every tile, so it must be fast.
* @param {Number|Function} [options.saturation=1.0] The saturation of this layer. 1.0 uses the unmodified imagery color.
* Less than 1.0 reduces the saturation while greater than 1.0 increases it.
* This can either be a simple number or a function with the signature
* <code>function(frameState, layer, x, y, level)</code>. The function is passed the
* current frame state, this layer, and the x, y, and level coordinates
* of the imagery tile for which the saturation is required, and it is expected to return
* the contrast value to use for the tile. The function is executed for every
* frame and for every tile, so it must be fast.
* @param {Number|Function} [options.gamma=1.0] The gamma correction to apply to this layer. 1.0 uses the unmodified imagery color.
* This can either be a simple number or a function with the signature
* <code>function(frameState, layer, x, y, level)</code>. The function is passed the
* current frame state, this layer, and the x, y, and level coordinates of the
* imagery tile for which the gamma is required, and it is expected to return
* the gamma value to use for the tile. The function is executed for every
* frame and for every tile, so it must be fast.
* @param {ImagerySplitDirection|Function} [options.splitDirection=ImagerySplitDirection.NONE] The {@link ImagerySplitDirection} split to apply to this layer.
* @param {TextureMinificationFilter} [options.minificationFilter=TextureMinificationFilter.LINEAR] The
* texture minification filter to apply to this layer. Possible values
* are <code>TextureMinificationFilter.LINEAR</code> and
* <code>TextureMinificationFilter.NEAREST</code>.
* @param {TextureMagnificationFilter} [options.magnificationFilter=TextureMagnificationFilter.LINEAR] The
* texture minification filter to apply to this layer. Possible values
* are <code>TextureMagnificationFilter.LINEAR</code> and
* <code>TextureMagnificationFilter.NEAREST</code>.
* @param {Boolean} [options.show=true] True if the layer is shown; otherwise, false.
* @param {Number} [options.maximumAnisotropy=maximum supported] The maximum anisotropy level to use
* for texture filtering. If this parameter is not specified, the maximum anisotropy supported
* by the WebGL stack will be used. Larger values make the imagery look better in horizon
* views.
* @param {Number} [options.minimumTerrainLevel] The minimum terrain level-of-detail at which to show this imagery layer,
* or undefined to show it at all levels. Level zero is the least-detailed level.
* @param {Number} [options.maximumTerrainLevel] The maximum terrain level-of-detail at which to show this imagery layer,
* or undefined to show it at all levels. Level zero is the least-detailed level.
*/
function ImageryLayer(imageryProvider, options) {
this._imageryProvider = imageryProvider;
options = defaultValue(options, {});
/**
* The alpha blending value of this layer, with 0.0 representing fully transparent and
* 1.0 representing fully opaque.
*
* @type {Number}
* @default 1.0
*/
this.alpha = defaultValue(options.alpha, defaultValue(imageryProvider.defaultAlpha, 1.0));
/**
* The brightness of this layer. 1.0 uses the unmodified imagery color. Less than 1.0
* makes the imagery darker while greater than 1.0 makes it brighter.
*
* @type {Number}
* @default {@link ImageryLayer.DEFAULT_BRIGHTNESS}
*/
this.brightness = defaultValue(options.brightness, defaultValue(imageryProvider.defaultBrightness, ImageryLayer.DEFAULT_BRIGHTNESS));
/**
* The contrast of this layer. 1.0 uses the unmodified imagery color. Less than 1.0 reduces
* the contrast while greater than 1.0 increases it.
*
* @type {Number}
* @default {@link ImageryLayer.DEFAULT_CONTRAST}
*/
this.contrast = defaultValue(options.contrast, defaultValue(imageryProvider.defaultContrast, ImageryLayer.DEFAULT_CONTRAST));
/**
* The hue of this layer in radians. 0.0 uses the unmodified imagery color.
*
* @type {Number}
* @default {@link ImageryLayer.DEFAULT_HUE}
*/
this.hue = defaultValue(options.hue, defaultValue(imageryProvider.defaultHue, ImageryLayer.DEFAULT_HUE));
/**
* The saturation of this layer. 1.0 uses the unmodified imagery color. Less than 1.0 reduces the
* saturation while greater than 1.0 increases it.
*
* @type {Number}
* @default {@link ImageryLayer.DEFAULT_SATURATION}
*/
this.saturation = defaultValue(options.saturation, defaultValue(imageryProvider.defaultSaturation, ImageryLayer.DEFAULT_SATURATION));
/**
* The gamma correction to apply to this layer. 1.0 uses the unmodified imagery color.
*
* @type {Number}
* @default {@link ImageryLayer.DEFAULT_GAMMA}
*/
this.gamma = defaultValue(options.gamma, defaultValue(imageryProvider.defaultGamma, ImageryLayer.DEFAULT_GAMMA));
/**
* The {@link ImagerySplitDirection} to apply to this layer.
*
* @type {ImagerySplitDirection}
* @default {@link ImageryLayer.DEFAULT_SPLIT}
*/
this.splitDirection = defaultValue(options.splitDirection, defaultValue(imageryProvider.defaultSplit, ImageryLayer.DEFAULT_SPLIT));
/**
* The {@link TextureMinificationFilter} to apply to this layer.
* Possible values are {@link TextureMinificationFilter.LINEAR} (the default)
* and {@link TextureMinificationFilter.NEAREST}.
*
* To take effect, this property must be set immediately after adding the imagery layer.
* Once a texture is loaded it won't be possible to change the texture filter used.
*
* @type {TextureMinificationFilter}
* @default {@link ImageryLayer.DEFAULT_MINIFICATION_FILTER}
*/
this.minificationFilter = defaultValue(options.minificationFilter, defaultValue(imageryProvider.defaultMinificationFilter, ImageryLayer.DEFAULT_MINIFICATION_FILTER));
/**
* The {@link TextureMagnificationFilter} to apply to this layer.
* Possible values are {@link TextureMagnificationFilter.LINEAR} (the default)
* and {@link TextureMagnificationFilter.NEAREST}.
*
* To take effect, this property must be set immediately after adding the imagery layer.
* Once a texture is loaded it won't be possible to change the texture filter used.
*
* @type {TextureMagnificationFilter}
* @default {@link ImageryLayer.DEFAULT_MAGNIFICATION_FILTER}
*/
this.magnificationFilter = defaultValue(options.magnificationFilter, defaultValue(imageryProvider.defaultMagnificationFilter, ImageryLayer.DEFAULT_MAGNIFICATION_FILTER));
/**
* Determines if this layer is shown.
*
* @type {Boolean}
* @default true
*/
this.show = defaultValue(options.show, true);
this._minimumTerrainLevel = options.minimumTerrainLevel;
this._maximumTerrainLevel = options.maximumTerrainLevel;
this._rectangle = defaultValue(options.rectangle, Rectangle.MAX_VALUE);
this._maximumAnisotropy = options.maximumAnisotropy;
this._imageryCache = {};
this._skeletonPlaceholder = new TileImagery(Imagery.createPlaceholder(this));
// The value of the show property on the last update.
this._show = true;
// The index of this layer in the ImageryLayerCollection.
this._layerIndex = -1;
// true if this is the base (lowest shown) layer.
this._isBaseLayer = false;
this._requestImageError = undefined;
this._reprojectComputeCommands = [];
}
defineProperties(ImageryLayer.prototype, {
/**
* Gets the imagery provider for this layer.
* @memberof ImageryLayer.prototype
* @type {ImageryProvider}
* @readonly
*/
imageryProvider : {
get: function() {
return this._imageryProvider;
}
},
/**
* Gets the rectangle of this layer. If this rectangle is smaller than the rectangle of the
* {@link ImageryProvider}, only a portion of the imagery provider is shown.
* @memberof ImageryLayer.prototype
* @type {Rectangle}
* @readonly
*/
rectangle: {
get: function() {
return this._rectangle;
}
}
});
/**
* This value is used as the default brightness for the imagery layer if one is not provided during construction
* or by the imagery provider. This value does not modify the brightness of the imagery.
* @type {Number}
* @default 1.0
*/
ImageryLayer.DEFAULT_BRIGHTNESS = 1.0;
/**
* This value is used as the default contrast for the imagery layer if one is not provided during construction
* or by the imagery provider. This value does not modify the contrast of the imagery.
* @type {Number}
* @default 1.0
*/
ImageryLayer.DEFAULT_CONTRAST = 1.0;
/**
* This value is used as the default hue for the imagery layer if one is not provided during construction
* or by the imagery provider. This value does not modify the hue of the imagery.
* @type {Number}
* @default 0.0
*/
ImageryLayer.DEFAULT_HUE = 0.0;
/**
* This value is used as the default saturation for the imagery layer if one is not provided during construction
* or by the imagery provider. This value does not modify the saturation of the imagery.
* @type {Number}
* @default 1.0
*/
ImageryLayer.DEFAULT_SATURATION = 1.0;
/**
* This value is used as the default gamma for the imagery layer if one is not provided during construction
* or by the imagery provider. This value does not modify the gamma of the imagery.
* @type {Number}
* @default 1.0
*/
ImageryLayer.DEFAULT_GAMMA = 1.0;
/**
* This value is used as the default split for the imagery layer if one is not provided during construction
* or by the imagery provider.
* @type {ImagerySplitDirection}
* @default ImagerySplitDirection.NONE
*/
ImageryLayer.DEFAULT_SPLIT = ImagerySplitDirection.NONE;
/**
* This value is used as the default texture minification filter for the imagery layer if one is not provided
* during construction or by the imagery provider.
* @type {TextureMinificationFilter}
* @default TextureMinificationFilter.LINEAR
*/
ImageryLayer.DEFAULT_MINIFICATION_FILTER = TextureMinificationFilter.LINEAR;
/**
* This value is used as the default texture magnification filter for the imagery layer if one is not provided
* during construction or by the imagery provider.
* @type {TextureMagnificationFilter}
* @default TextureMagnificationFilter.LINEAR
*/
ImageryLayer.DEFAULT_MAGNIFICATION_FILTER = TextureMagnificationFilter.LINEAR;
/**
* Gets a value indicating whether this layer is the base layer in the
* {@link ImageryLayerCollection}. The base layer is the one that underlies all
* others. It is special in that it is treated as if it has global rectangle, even if
* it actually does not, by stretching the texels at the edges over the entire
* globe.
*
* @returns {Boolean} true if this is the base layer; otherwise, false.
*/
ImageryLayer.prototype.isBaseLayer = function() {
return this._isBaseLayer;
};
/**
* Returns true if this object was destroyed; otherwise, false.
* <br /><br />
* If this object was destroyed, it should not be used; calling any function other than
* <code>isDestroyed</code> will result in a {@link DeveloperError} exception.
*
* @returns {Boolean} True if this object was destroyed; otherwise, false.
*
* @see ImageryLayer#destroy
*/
ImageryLayer.prototype.isDestroyed = function() {
return false;
};
/**
* Destroys the WebGL resources held by this object. Destroying an object allows for deterministic
* release of WebGL resources, instead of relying on the garbage collector to destroy this object.
* <br /><br />
* Once an object is destroyed, it should not be used; calling any function other than
* <code>isDestroyed</code> will result in a {@link DeveloperError} exception. Therefore,
* assign the return value (<code>undefined</code>) to the object as done in the example.
*
* @exception {DeveloperError} This object was destroyed, i.e., destroy() was called.
*
*
* @example
* imageryLayer = imageryLayer && imageryLayer.destroy();
*
* @see ImageryLayer#isDestroyed
*/
ImageryLayer.prototype.destroy = function() {
return destroyObject(this);
};
var imageryBoundsScratch = new Rectangle();
var tileImageryBoundsScratch = new Rectangle();
var clippedRectangleScratch = new Rectangle();
var terrainRectangleScratch = new Rectangle();
/**
* Computes the intersection of this layer's rectangle with the imagery provider's availability rectangle,
* producing the overall bounds of imagery that can be produced by this layer.
*
* @returns {Promise.<Rectangle>} A promise to a rectangle which defines the overall bounds of imagery that can be produced by this layer.
*
* @example
* // Zoom to an imagery layer.
* imageryLayer.getViewableRectangle().then(function (rectangle) {
* return camera.flyTo({
* destination: rectangle
* });
* });
*/
ImageryLayer.prototype.getViewableRectangle = function() {
var imageryProvider = this._imageryProvider;
var rectangle = this._rectangle;
return imageryProvider.readyPromise.then(function() {
return Rectangle.intersection(imageryProvider.rectangle, rectangle);
});
};
/**
* Create skeletons for the imagery tiles that partially or completely overlap a given terrain
* tile.
*
* @private
*
* @param {Tile} tile The terrain tile.
* @param {TerrainProvider} terrainProvider The terrain provider associated with the terrain tile.
* @param {Number} insertionPoint The position to insert new skeletons before in the tile's imagery list.
* @returns {Boolean} true if this layer overlaps any portion of the terrain tile; otherwise, false.
*/
ImageryLayer.prototype._createTileImagerySkeletons = function(tile, terrainProvider, insertionPoint) {
var surfaceTile = tile.data;
if (defined(this._minimumTerrainLevel) && tile.level < this._minimumTerrainLevel) {
return false;
}
if (defined(this._maximumTerrainLevel) && tile.level > this._maximumTerrainLevel) {
return false;
}
var imageryProvider = this._imageryProvider;
if (!defined(insertionPoint)) {
insertionPoint = surfaceTile.imagery.length;
}
if (!imageryProvider.ready) {
// The imagery provider is not ready, so we can't create skeletons, yet.
// Instead, add a placeholder so that we'll know to create
// the skeletons once the provider is ready.
this._skeletonPlaceholder.loadingImagery.addReference();
surfaceTile.imagery.splice(insertionPoint, 0, this._skeletonPlaceholder);
return true;
}
// Use Web Mercator for our texture coordinate computations if this imagery layer uses
// that projection and the terrain tile falls entirely inside the valid bounds of the
// projection.
var useWebMercatorT = imageryProvider.tilingScheme instanceof WebMercatorTilingScheme &&
tile.rectangle.north < WebMercatorProjection.MaximumLatitude &&
tile.rectangle.south > -WebMercatorProjection.MaximumLatitude;
// Compute the rectangle of the imagery from this imageryProvider that overlaps
// the geometry tile. The ImageryProvider and ImageryLayer both have the
// opportunity to constrain the rectangle. The imagery TilingScheme's rectangle
// always fully contains the ImageryProvider's rectangle.
var imageryBounds = Rectangle.intersection(imageryProvider.rectangle, this._rectangle, imageryBoundsScratch);
var rectangle = Rectangle.intersection(tile.rectangle, imageryBounds, tileImageryBoundsScratch);
if (!defined(rectangle)) {
// There is no overlap between this terrain tile and this imagery
// provider. Unless this is the base layer, no skeletons need to be created.
// We stretch texels at the edge of the base layer over the entire globe.
if (!this.isBaseLayer()) {
return false;
}
var baseImageryRectangle = imageryBounds;
var baseTerrainRectangle = tile.rectangle;
rectangle = tileImageryBoundsScratch;
if (baseTerrainRectangle.south >= baseImageryRectangle.north) {
rectangle.north = rectangle.south = baseImageryRectangle.north;
} else if (baseTerrainRectangle.north <= baseImageryRectangle.south) {
rectangle.north = rectangle.south = baseImageryRectangle.south;
} else {
rectangle.south = Math.max(baseTerrainRectangle.south, baseImageryRectangle.south);
rectangle.north = Math.min(baseTerrainRectangle.north, baseImageryRectangle.north);
}
if (baseTerrainRectangle.west >= baseImageryRectangle.east) {
rectangle.west = rectangle.east = baseImageryRectangle.east;
} else if (baseTerrainRectangle.east <= baseImageryRectangle.west) {
rectangle.west = rectangle.east = baseImageryRectangle.west;
} else {
rectangle.west = Math.max(baseTerrainRectangle.west, baseImageryRectangle.west);
rectangle.east = Math.min(baseTerrainRectangle.east, baseImageryRectangle.east);
}
}
var latitudeClosestToEquator = 0.0;
if (rectangle.south > 0.0) {
latitudeClosestToEquator = rectangle.south;
} else if (rectangle.north < 0.0) {
latitudeClosestToEquator = rectangle.north;
}
// Compute the required level in the imagery tiling scheme.
// The errorRatio should really be imagerySSE / terrainSSE rather than this hard-coded value.
// But first we need configurable imagery SSE and we need the rendering to be able to handle more
// images attached to a terrain tile than there are available texture units. So that's for the future.
var errorRatio = 1.0;
var targetGeometricError = errorRatio * terrainProvider.getLevelMaximumGeometricError(tile.level);
var imageryLevel = getLevelWithMaximumTexelSpacing(this, targetGeometricError, latitudeClosestToEquator);
imageryLevel = Math.max(0, imageryLevel);
var maximumLevel = imageryProvider.maximumLevel;
if (imageryLevel > maximumLevel) {
imageryLevel = maximumLevel;
}
if (defined(imageryProvider.minimumLevel)) {
var minimumLevel = imageryProvider.minimumLevel;
if (imageryLevel < minimumLevel) {
imageryLevel = minimumLevel;
}
}
var imageryTilingScheme = imageryProvider.tilingScheme;
var northwestTileCoordinates = imageryTilingScheme.positionToTileXY(Rectangle.northwest(rectangle), imageryLevel);
var southeastTileCoordinates = imageryTilingScheme.positionToTileXY(Rectangle.southeast(rectangle), imageryLevel);
// If the southeast corner of the rectangle lies very close to the north or west side
// of the southeast tile, we don't actually need the southernmost or easternmost
// tiles.
// Similarly, if the northwest corner of the rectangle lies very close to the south or east side
// of the northwest tile, we don't actually need the northernmost or westernmost tiles.
// We define "very close" as being within 1/512 of the width of the tile.
var veryCloseX = tile.rectangle.width / 512.0;
var veryCloseY = tile.rectangle.height / 512.0;
var northwestTileRectangle = imageryTilingScheme.tileXYToRectangle(northwestTileCoordinates.x, northwestTileCoordinates.y, imageryLevel);
if (Math.abs(northwestTileRectangle.south - tile.rectangle.north) < veryCloseY && northwestTileCoordinates.y < southeastTileCoordinates.y) {
++northwestTileCoordinates.y;
}
if (Math.abs(northwestTileRectangle.east - tile.rectangle.west) < veryCloseX && northwestTileCoordinates.x < southeastTileCoordinates.x) {
++northwestTileCoordinates.x;
}
var southeastTileRectangle = imageryTilingScheme.tileXYToRectangle(southeastTileCoordinates.x, southeastTileCoordinates.y, imageryLevel);
if (Math.abs(southeastTileRectangle.north - tile.rectangle.south) < veryCloseY && southeastTileCoordinates.y > northwestTileCoordinates.y) {
--southeastTileCoordinates.y;
}
if (Math.abs(southeastTileRectangle.west - tile.rectangle.east) < veryCloseX && southeastTileCoordinates.x > northwestTileCoordinates.x) {
--southeastTileCoordinates.x;
}
// Create TileImagery instances for each imagery tile overlapping this terrain tile.
// We need to do all texture coordinate computations in the imagery tile's tiling scheme.
var terrainRectangle = Rectangle.clone(tile.rectangle, terrainRectangleScratch);
var imageryRectangle = imageryTilingScheme.tileXYToRectangle(northwestTileCoordinates.x, northwestTileCoordinates.y, imageryLevel);
var clippedImageryRectangle = Rectangle.intersection(imageryRectangle, imageryBounds, clippedRectangleScratch);
var imageryTileXYToRectangle;
if (useWebMercatorT) {
imageryTilingScheme.rectangleToNativeRectangle(terrainRectangle, terrainRectangle);
imageryTilingScheme.rectangleToNativeRectangle(imageryRectangle, imageryRectangle);
imageryTilingScheme.rectangleToNativeRectangle(clippedImageryRectangle, clippedImageryRectangle);
imageryTilingScheme.rectangleToNativeRectangle(imageryBounds, imageryBounds);
imageryTileXYToRectangle = imageryTilingScheme.tileXYToNativeRectangle.bind(imageryTilingScheme);
veryCloseX = terrainRectangle.width / 512.0;
veryCloseY = terrainRectangle.height / 512.0;
} else {
imageryTileXYToRectangle = imageryTilingScheme.tileXYToRectangle.bind(imageryTilingScheme);
}
var minU;
var maxU = 0.0;
var minV = 1.0;
var maxV;
// If this is the northern-most or western-most tile in the imagery tiling scheme,
// it may not start at the northern or western edge of the terrain tile.
// Calculate where it does start.
if (!this.isBaseLayer() && Math.abs(clippedImageryRectangle.west - terrainRectangle.west) >= veryCloseX) {
maxU = Math.min(1.0, (clippedImageryRectangle.west - terrainRectangle.west) / terrainRectangle.width);
}
if (!this.isBaseLayer() && Math.abs(clippedImageryRectangle.north - terrainRectangle.north) >= veryCloseY) {
minV = Math.max(0.0, (clippedImageryRectangle.north - terrainRectangle.south) / terrainRectangle.height);
}
var initialMinV = minV;
for ( var i = northwestTileCoordinates.x; i <= southeastTileCoordinates.x; i++) {
minU = maxU;
imageryRectangle = imageryTileXYToRectangle(i, northwestTileCoordinates.y, imageryLevel);
clippedImageryRectangle = Rectangle.simpleIntersection(imageryRectangle, imageryBounds, clippedRectangleScratch);
if (!defined(clippedImageryRectangle)) {
continue;
}
maxU = Math.min(1.0, (clippedImageryRectangle.east - terrainRectangle.west) / terrainRectangle.width);
// If this is the eastern-most imagery tile mapped to this terrain tile,
// and there are more imagery tiles to the east of this one, the maxU
// should be 1.0 to make sure rounding errors don't make the last
// image fall shy of the edge of the terrain tile.
if (i === southeastTileCoordinates.x && (this.isBaseLayer() || Math.abs(clippedImageryRectangle.east - terrainRectangle.east) < veryCloseX)) {
maxU = 1.0;
}
minV = initialMinV;
for ( var j = northwestTileCoordinates.y; j <= southeastTileCoordinates.y; j++) {
maxV = minV;
imageryRectangle = imageryTileXYToRectangle(i, j, imageryLevel);
clippedImageryRectangle = Rectangle.simpleIntersection(imageryRectangle, imageryBounds, clippedRectangleScratch);
if (!defined(clippedImageryRectangle)) {
continue;
}
minV = Math.max(0.0, (clippedImageryRectangle.south - terrainRectangle.south) / terrainRectangle.height);
// If this is the southern-most imagery tile mapped to this terrain tile,
// and there are more imagery tiles to the south of this one, the minV
// should be 0.0 to make sure rounding errors don't make the last
// image fall shy of the edge of the terrain tile.
if (j === southeastTileCoordinates.y && (this.isBaseLayer() || Math.abs(clippedImageryRectangle.south - terrainRectangle.south) < veryCloseY)) {
minV = 0.0;
}
var texCoordsRectangle = new Cartesian4(minU, minV, maxU, maxV);
var imagery = this.getImageryFromCache(i, j, imageryLevel);
surfaceTile.imagery.splice(insertionPoint, 0, new TileImagery(imagery, texCoordsRectangle, useWebMercatorT));
++insertionPoint;
}
}
return true;
};
/**
* Calculate the translation and scale for a particular {@link TileImagery} attached to a
* particular terrain tile.
*
* @private
*
* @param {Tile} tile The terrain tile.
* @param {TileImagery} tileImagery The imagery tile mapping.
* @returns {Cartesian4} The translation and scale where X and Y are the translation and Z and W
* are the scale.
*/
ImageryLayer.prototype._calculateTextureTranslationAndScale = function(tile, tileImagery) {
var imageryRectangle = tileImagery.readyImagery.rectangle;
var terrainRectangle = tile.rectangle;
if (tileImagery.useWebMercatorT) {
var tilingScheme = tileImagery.readyImagery.imageryLayer.imageryProvider.tilingScheme;
imageryRectangle = tilingScheme.rectangleToNativeRectangle(imageryRectangle, imageryBoundsScratch);
terrainRectangle = tilingScheme.rectangleToNativeRectangle(terrainRectangle, terrainRectangleScratch);
}
var terrainWidth = terrainRectangle.width;
var terrainHeight = terrainRectangle.height;
var scaleX = terrainWidth / imageryRectangle.width;
var scaleY = terrainHeight / imageryRectangle.height;
return new Cartesian4(
scaleX * (terrainRectangle.west - imageryRectangle.west) / terrainWidth,
scaleY * (terrainRectangle.south - imageryRectangle.south) / terrainHeight,
scaleX,
scaleY);
};
/**
* Request a particular piece of imagery from the imagery provider. This method handles raising an
* error event if the request fails, and retrying the request if necessary.
*
* @private
*
* @param {Imagery} imagery The imagery to request.
* @param {Function} [priorityFunction] The priority function used for sorting the imagery request.
*/
ImageryLayer.prototype._requestImagery = function(imagery, priorityFunction) {
var imageryProvider = this._imageryProvider;
var that = this;
function success(image) {
if (!defined(image)) {
return failure();
}
imagery.image = image;
imagery.state = ImageryState.RECEIVED;
imagery.request = undefined;
TileProviderError.handleSuccess(that._requestImageError);
}
function failure(e) {
if (imagery.request.state === RequestState.CANCELLED) {
// Cancelled due to low priority - try again later.
imagery.state = ImageryState.UNLOADED;
imagery.request = undefined;
return;
}
// Initially assume failure. handleError may retry, in which case the state will
// change to TRANSITIONING.
imagery.state = ImageryState.FAILED;
imagery.request = undefined;
var message = 'Failed to obtain image tile X: ' + imagery.x + ' Y: ' + imagery.y + ' Level: ' + imagery.level + '.';
that._requestImageError = TileProviderError.handleError(
that._requestImageError,
imageryProvider,
imageryProvider.errorEvent,
message,
imagery.x, imagery.y, imagery.level,
doRequest,
e);
}
function doRequest() {
var request = new Request({
throttle : true,
throttleByServer : true,
type : RequestType.IMAGERY,
priorityFunction : priorityFunction
});
imagery.request = request;
imagery.state = ImageryState.TRANSITIONING;
var imagePromise = imageryProvider.requestImage(imagery.x, imagery.y, imagery.level, request);
if (!defined(imagePromise)) {
// Too many parallel requests, so postpone loading tile.
imagery.state = ImageryState.UNLOADED;
imagery.request = undefined;
return;
}
if (defined(imageryProvider.getTileCredits)) {
imagery.credits = imageryProvider.getTileCredits(imagery.x, imagery.y, imagery.level);
}
when(imagePromise, success, failure);
}
doRequest();
};
/**
* Create a WebGL texture for a given {@link Imagery} instance.
*
* @private
*
* @param {Context} context The rendered context to use to create textures.
* @param {Imagery} imagery The imagery for which to create a texture.
*/
ImageryLayer.prototype._createTexture = function(context, imagery) {
var imageryProvider = this._imageryProvider;
var image = imagery.image;
// If this imagery provider has a discard policy, use it to check if this
// image should be discarded.
if (defined(imageryProvider.tileDiscardPolicy)) {
var discardPolicy = imageryProvider.tileDiscardPolicy;
if (defined(discardPolicy)) {
// If the discard policy is not ready yet, transition back to the
// RECEIVED state and we'll try again next time.
if (!discardPolicy.isReady()) {
imagery.state = ImageryState.RECEIVED;
return;
}
// Mark discarded imagery tiles invalid. Parent imagery will be used instead.
if (discardPolicy.shouldDiscardImage(image)) {
imagery.state = ImageryState.INVALID;
return;
}
}
}
//>>includeStart('debug', pragmas.debug);
if (this.minificationFilter !== TextureMinificationFilter.NEAREST &&
this.minificationFilter !== TextureMinificationFilter.LINEAR) {
throw new DeveloperError('ImageryLayer minification filter must be NEAREST or LINEAR');
}
//>>includeEnd('debug');
var sampler = new Sampler({
minificationFilter : this.minificationFilter,
magnificationFilter : this.magnificationFilter
});
// Imagery does not need to be discarded, so upload it to WebGL.
var texture;
if (defined(image.internalFormat)) {
texture = new Texture({
context : context,
pixelFormat : image.internalFormat,
width : image.width,
height : image.height,
source : {
arrayBufferView : image.bufferView
},
sampler : sampler
});
} else {
texture = new Texture({
context : context,
source : image,
pixelFormat : imageryProvider.hasAlphaChannel ? PixelFormat.RGBA : PixelFormat.RGB,
sampler : sampler
});
}
if (imageryProvider.tilingScheme instanceof WebMercatorTilingScheme) {
imagery.textureWebMercator = texture;
} else {
imagery.texture = texture;
}
imagery.image = undefined;
imagery.state = ImageryState.TEXTURE_LOADED;
};
function getSamplerKey(minificationFilter, magnificationFilter, maximumAnisotropy) {
return minificationFilter + ':' + magnificationFilter + ':' + maximumAnisotropy;
}
function finalizeReprojectTexture(imageryLayer, context, imagery, texture) {
var minificationFilter = imageryLayer.minificationFilter;
var magnificationFilter = imageryLayer.magnificationFilter;
var usesLinearTextureFilter = minificationFilter === TextureMinificationFilter.LINEAR && magnificationFilter === TextureMagnificationFilter.LINEAR;
// Use mipmaps if this texture has power-of-two dimensions.
// In addition, mipmaps are only generated if the texture filters are both LINEAR.
if (usesLinearTextureFilter && !PixelFormat.isCompressedFormat(texture.pixelFormat) && CesiumMath.isPowerOfTwo(texture.width) && CesiumMath.isPowerOfTwo(texture.height)) {
minificationFilter = TextureMinificationFilter.LINEAR_MIPMAP_LINEAR;
var maximumSupportedAnisotropy = ContextLimits.maximumTextureFilterAnisotropy;
var maximumAnisotropy = Math.min(maximumSupportedAnisotropy, defaultValue(imageryLayer._maximumAnisotropy, maximumSupportedAnisotropy));
var mipmapSamplerKey = getSamplerKey(minificationFilter, magnificationFilter, maximumAnisotropy);
var mipmapSamplers = context.cache.imageryLayerMipmapSamplers;
if (!defined(mipmapSamplers)) {
mipmapSamplers = {};
context.cache.imageryLayerMipmapSamplers = mipmapSamplers;
}
var mipmapSampler = mipmapSamplers[mipmapSamplerKey];
if (!defined(mipmapSampler)) {
mipmapSampler = mipmapSamplers[mipmapSamplerKey] = new Sampler({
wrapS : TextureWrap.CLAMP_TO_EDGE,
wrapT : TextureWrap.CLAMP_TO_EDGE,
minificationFilter : minificationFilter,
magnificationFilter : magnificationFilter,
maximumAnisotropy : maximumAnisotropy
});
}
texture.generateMipmap(MipmapHint.NICEST);
texture.sampler = mipmapSampler;
} else {
var nonMipmapSamplerKey = getSamplerKey(minificationFilter, magnificationFilter, 0);
var nonMipmapSamplers = context.cache.imageryLayerNonMipmapSamplers;
if (!defined(nonMipmapSamplers)) {
nonMipmapSamplers = {};
context.cache.imageryLayerNonMipmapSamplers = nonMipmapSamplers;
}
var nonMipmapSampler = nonMipmapSamplers[nonMipmapSamplerKey];
if (!defined(nonMipmapSampler)) {
nonMipmapSampler = nonMipmapSamplers[nonMipmapSamplerKey] = new Sampler({
wrapS : TextureWrap.CLAMP_TO_EDGE,
wrapT : TextureWrap.CLAMP_TO_EDGE,
minificationFilter : minificationFilter,
magnificationFilter : magnificationFilter
});
}
texture.sampler = nonMipmapSampler;
}
imagery.state = ImageryState.READY;
}
/**
* Enqueues a command re-projecting a texture to a {@link GeographicProjection} on the next update, if necessary, and generate
* mipmaps for the geographic texture.
*
* @private
*
* @param {FrameState} frameState The frameState.
* @param {Imagery} imagery The imagery instance to reproject.
* @param {Boolean} [needGeographicProjection=true] True to reproject to geographic, or false if Web Mercator is fine.
*/
ImageryLayer.prototype._reprojectTexture = function(frameState, imagery, needGeographicProjection) {
var texture = imagery.textureWebMercator || imagery.texture;
var rectangle = imagery.rectangle;
var context = frameState.context;
needGeographicProjection = defaultValue(needGeographicProjection, true);
// Reproject this texture if it is not already in a geographic projection and
// the pixels are more than 1e-5 radians apart. The pixel spacing cutoff
// avoids precision problems in the reprojection transformation while making
// no noticeable difference in the georeferencing of the image.
if (needGeographicProjection &&
!(this._imageryProvider.tilingScheme instanceof GeographicTilingScheme) &&
rectangle.width / texture.width > 1e-5) {
var that = this;
imagery.addReference();
var computeCommand = new ComputeCommand({
persists : true,
owner : this,
// Update render resources right before execution instead of now.
// This allows different ImageryLayers to share the same vao and buffers.
preExecute : function(command) {
reprojectToGeographic(command, context, texture, imagery.rectangle);
},
postExecute : function(outputTexture) {
imagery.texture = outputTexture;
finalizeReprojectTexture(that, context, imagery, outputTexture);
imagery.releaseReference();
}
});
this._reprojectComputeCommands.push(computeCommand);
} else {
if (needGeographicProjection) {
imagery.texture = texture;
}
finalizeReprojectTexture(this, context, imagery, texture);
}
};
/**
* Updates frame state to execute any queued texture re-projections.
*
* @private
*
* @param {FrameState} frameState The frameState.
*/
ImageryLayer.prototype.queueReprojectionCommands = function(frameState) {
var computeCommands = this._reprojectComputeCommands;
var length = computeCommands.length;
for (var i = 0; i < length; ++i) {
frameState.commandList.push(computeCommands[i]);
}
computeCommands.length = 0;
};
/**
* Cancels re-projection commands queued for the next frame.
*
* @private
*/
ImageryLayer.prototype.cancelReprojections = function() {
this._reprojectComputeCommands.length = 0;
};
ImageryLayer.prototype.getImageryFromCache = function(x, y, level, imageryRectangle) {
var cacheKey = getImageryCacheKey(x, y, level);
var imagery = this._imageryCache[cacheKey];
if (!defined(imagery)) {
imagery = new Imagery(this, x, y, level, imageryRectangle);
this._imageryCache[cacheKey] = imagery;
}
imagery.addReference();
return imagery;
};
ImageryLayer.prototype.removeImageryFromCache = function(imagery) {
var cacheKey = getImageryCacheKey(imagery.x, imagery.y, imagery.level);
delete this._imageryCache[cacheKey];
};
function getImageryCacheKey(x, y, level) {
return JSON.stringify([x, y, level]);
}
var uniformMap = {
u_textureDimensions : function() {
return this.textureDimensions;
},
u_texture : function() {
return this.texture;
},
textureDimensions : new Cartesian2(),
texture : undefined
};
var float32ArrayScratch = FeatureDetection.supportsTypedArrays() ? new Float32Array(2 * 64) : undefined;
function reprojectToGeographic(command, context, texture, rectangle) {
// This function has gone through a number of iterations, because GPUs are awesome.
//
// Originally, we had a very simple vertex shader and computed the Web Mercator texture coordinates
// per-fragment in the fragment shader. That worked well, except on mobile devices, because
// fragment shaders have limited precision on many mobile devices. The result was smearing artifacts
// at medium zoom levels because different geographic texture coordinates would be reprojected to Web
// Mercator as the same value.
//
// Our solution was to reproject to Web Mercator in the vertex shader instead of the fragment shader.
// This required far more vertex data. With fragment shader reprojection, we only needed a single quad.
// But to achieve the same precision with vertex shader reprojection, we needed a vertex for each
// output pixel. So we used a grid of 256x256 vertices, because most of our imagery