cesium
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CesiumJS is a JavaScript library for creating 3D globes and 2D maps in a web browser without a plugin.
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JavaScript
import PixelDatatype from '../Renderer/PixelDatatype.js';
import WebGLConstants from './WebGLConstants.js';
/**
* The format of a pixel, i.e., the number of components it has and what they represent.
*
* @exports PixelFormat
*/
var PixelFormat = {
/**
* A pixel format containing a depth value.
*
* @type {Number}
* @constant
*/
DEPTH_COMPONENT : WebGLConstants.DEPTH_COMPONENT,
/**
* A pixel format containing a depth and stencil value, most often used with {@link PixelDatatype.UNSIGNED_INT_24_8}.
*
* @type {Number}
* @constant
*/
DEPTH_STENCIL : WebGLConstants.DEPTH_STENCIL,
/**
* A pixel format containing an alpha channel.
*
* @type {Number}
* @constant
*/
ALPHA : WebGLConstants.ALPHA,
/**
* A pixel format containing red, green, and blue channels.
*
* @type {Number}
* @constant
*/
RGB : WebGLConstants.RGB,
/**
* A pixel format containing red, green, blue, and alpha channels.
*
* @type {Number}
* @constant
*/
RGBA : WebGLConstants.RGBA,
/**
* A pixel format containing a luminance (intensity) channel.
*
* @type {Number}
* @constant
*/
LUMINANCE : WebGLConstants.LUMINANCE,
/**
* A pixel format containing luminance (intensity) and alpha channels.
*
* @type {Number}
* @constant
*/
LUMINANCE_ALPHA : WebGLConstants.LUMINANCE_ALPHA,
/**
* A pixel format containing red, green, and blue channels that is DXT1 compressed.
*
* @type {Number}
* @constant
*/
RGB_DXT1 : WebGLConstants.COMPRESSED_RGB_S3TC_DXT1_EXT,
/**
* A pixel format containing red, green, blue, and alpha channels that is DXT1 compressed.
*
* @type {Number}
* @constant
*/
RGBA_DXT1 : WebGLConstants.COMPRESSED_RGBA_S3TC_DXT1_EXT,
/**
* A pixel format containing red, green, blue, and alpha channels that is DXT3 compressed.
*
* @type {Number}
* @constant
*/
RGBA_DXT3 : WebGLConstants.COMPRESSED_RGBA_S3TC_DXT3_EXT,
/**
* A pixel format containing red, green, blue, and alpha channels that is DXT5 compressed.
*
* @type {Number}
* @constant
*/
RGBA_DXT5 : WebGLConstants.COMPRESSED_RGBA_S3TC_DXT5_EXT,
/**
* A pixel format containing red, green, and blue channels that is PVR 4bpp compressed.
*
* @type {Number}
* @constant
*/
RGB_PVRTC_4BPPV1 : WebGLConstants.COMPRESSED_RGB_PVRTC_4BPPV1_IMG,
/**
* A pixel format containing red, green, and blue channels that is PVR 2bpp compressed.
*
* @type {Number}
* @constant
*/
RGB_PVRTC_2BPPV1 : WebGLConstants.COMPRESSED_RGB_PVRTC_2BPPV1_IMG,
/**
* A pixel format containing red, green, blue, and alpha channels that is PVR 4bpp compressed.
*
* @type {Number}
* @constant
*/
RGBA_PVRTC_4BPPV1 : WebGLConstants.COMPRESSED_RGBA_PVRTC_4BPPV1_IMG,
/**
* A pixel format containing red, green, blue, and alpha channels that is PVR 2bpp compressed.
*
* @type {Number}
* @constant
*/
RGBA_PVRTC_2BPPV1 : WebGLConstants.COMPRESSED_RGBA_PVRTC_2BPPV1_IMG,
/**
* A pixel format containing red, green, and blue channels that is ETC1 compressed.
*
* @type {Number}
* @constant
*/
RGB_ETC1 : WebGLConstants.COMPRESSED_RGB_ETC1_WEBGL,
/**
* @private
*/
componentsLength : function(pixelFormat) {
switch (pixelFormat) {
case PixelFormat.RGB:
return 3;
case PixelFormat.RGBA:
return 4;
case PixelFormat.LUMINANCE_ALPHA:
return 2;
case PixelFormat.ALPHA:
case PixelFormat.LUMINANCE:
return 1;
default:
return 1;
}
},
/**
* @private
*/
validate : function(pixelFormat) {
return pixelFormat === PixelFormat.DEPTH_COMPONENT ||
pixelFormat === PixelFormat.DEPTH_STENCIL ||
pixelFormat === PixelFormat.ALPHA ||
pixelFormat === PixelFormat.RGB ||
pixelFormat === PixelFormat.RGBA ||
pixelFormat === PixelFormat.LUMINANCE ||
pixelFormat === PixelFormat.LUMINANCE_ALPHA ||
pixelFormat === PixelFormat.RGB_DXT1 ||
pixelFormat === PixelFormat.RGBA_DXT1 ||
pixelFormat === PixelFormat.RGBA_DXT3 ||
pixelFormat === PixelFormat.RGBA_DXT5 ||
pixelFormat === PixelFormat.RGB_PVRTC_4BPPV1 ||
pixelFormat === PixelFormat.RGB_PVRTC_2BPPV1 ||
pixelFormat === PixelFormat.RGBA_PVRTC_4BPPV1 ||
pixelFormat === PixelFormat.RGBA_PVRTC_2BPPV1 ||
pixelFormat === PixelFormat.RGB_ETC1;
},
/**
* @private
*/
isColorFormat : function(pixelFormat) {
return pixelFormat === PixelFormat.ALPHA ||
pixelFormat === PixelFormat.RGB ||
pixelFormat === PixelFormat.RGBA ||
pixelFormat === PixelFormat.LUMINANCE ||
pixelFormat === PixelFormat.LUMINANCE_ALPHA;
},
/**
* @private
*/
isDepthFormat : function(pixelFormat) {
return pixelFormat === PixelFormat.DEPTH_COMPONENT ||
pixelFormat === PixelFormat.DEPTH_STENCIL;
},
/**
* @private
*/
isCompressedFormat : function(pixelFormat) {
return pixelFormat === PixelFormat.RGB_DXT1 ||
pixelFormat === PixelFormat.RGBA_DXT1 ||
pixelFormat === PixelFormat.RGBA_DXT3 ||
pixelFormat === PixelFormat.RGBA_DXT5 ||
pixelFormat === PixelFormat.RGB_PVRTC_4BPPV1 ||
pixelFormat === PixelFormat.RGB_PVRTC_2BPPV1 ||
pixelFormat === PixelFormat.RGBA_PVRTC_4BPPV1 ||
pixelFormat === PixelFormat.RGBA_PVRTC_2BPPV1 ||
pixelFormat === PixelFormat.RGB_ETC1;
},
/**
* @private
*/
isDXTFormat : function(pixelFormat) {
return pixelFormat === PixelFormat.RGB_DXT1 ||
pixelFormat === PixelFormat.RGBA_DXT1 ||
pixelFormat === PixelFormat.RGBA_DXT3 ||
pixelFormat === PixelFormat.RGBA_DXT5;
},
/**
* @private
*/
isPVRTCFormat : function(pixelFormat) {
return pixelFormat === PixelFormat.RGB_PVRTC_4BPPV1 ||
pixelFormat === PixelFormat.RGB_PVRTC_2BPPV1 ||
pixelFormat === PixelFormat.RGBA_PVRTC_4BPPV1 ||
pixelFormat === PixelFormat.RGBA_PVRTC_2BPPV1;
},
/**
* @private
*/
isETC1Format : function(pixelFormat) {
return pixelFormat === PixelFormat.RGB_ETC1;
},
/**
* @private
*/
compressedTextureSizeInBytes : function(pixelFormat, width, height) {
switch (pixelFormat) {
case PixelFormat.RGB_DXT1:
case PixelFormat.RGBA_DXT1:
case PixelFormat.RGB_ETC1:
return Math.floor((width + 3) / 4) * Math.floor((height + 3) / 4) * 8;
case PixelFormat.RGBA_DXT3:
case PixelFormat.RGBA_DXT5:
return Math.floor((width + 3) / 4) * Math.floor((height + 3) / 4) * 16;
case PixelFormat.RGB_PVRTC_4BPPV1:
case PixelFormat.RGBA_PVRTC_4BPPV1:
return Math.floor((Math.max(width, 8) * Math.max(height, 8) * 4 + 7) / 8);
case PixelFormat.RGB_PVRTC_2BPPV1:
case PixelFormat.RGBA_PVRTC_2BPPV1:
return Math.floor((Math.max(width, 16) * Math.max(height, 8) * 2 + 7) / 8);
default:
return 0;
}
},
/**
* @private
*/
textureSizeInBytes : function(pixelFormat, pixelDatatype, width, height) {
var componentsLength = PixelFormat.componentsLength(pixelFormat);
if (PixelDatatype.isPacked(pixelDatatype)) {
componentsLength = 1;
}
return componentsLength * PixelDatatype.sizeInBytes(pixelDatatype) * width * height;
},
/**
* @private
*/
alignmentInBytes : function(pixelFormat, pixelDatatype, width) {
var mod = PixelFormat.textureSizeInBytes(pixelFormat, pixelDatatype, width, 1) % 4;
return mod === 0 ? 4 : (mod === 2 ? 2 : 1);
},
/**
* @private
*/
createTypedArray : function(pixelFormat, pixelDatatype, width, height) {
var constructor;
var sizeInBytes = PixelDatatype.sizeInBytes(pixelDatatype);
if (sizeInBytes === Uint8Array.BYTES_PER_ELEMENT) {
constructor = Uint8Array;
} else if (sizeInBytes === Uint16Array.BYTES_PER_ELEMENT) {
constructor = Uint16Array;
} else if (sizeInBytes === Float32Array.BYTES_PER_ELEMENT && pixelDatatype === PixelDatatype.FLOAT) {
constructor = Float32Array;
} else {
constructor = Uint32Array;
}
var size = PixelFormat.componentsLength(pixelFormat) * width * height;
return new constructor(size);
},
/**
* @private
*/
flipY : function(bufferView, pixelFormat, pixelDatatype, width, height) {
if (height === 1) {
return bufferView;
}
var flipped = PixelFormat.createTypedArray(pixelFormat, pixelDatatype, width, height);
var numberOfComponents = PixelFormat.componentsLength(pixelFormat);
var textureWidth = width * numberOfComponents;
for (var i = 0; i < height; ++i) {
var row = i * height * numberOfComponents;
var flippedRow = (height - i - 1) * height * numberOfComponents;
for (var j = 0; j < textureWidth; ++j) {
flipped[flippedRow + j] = bufferView[row + j];
}
}
return flipped;
}
};
export default Object.freeze(PixelFormat);