three 基础库
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( function () {
class DDSLoader extends THREE.CompressedTextureLoader {
constructor( manager ) {
super( manager );
}
parse( buffer, loadMipmaps ) {
const dds = {
mipmaps: [],
width: 0,
height: 0,
format: null,
mipmapCount: 1
}; // Adapted from @toji's DDS utils
// https://github.com/toji/webgl-texture-utils/blob/master/texture-util/dds.js
// All values and structures referenced from:
// http://msdn.microsoft.com/en-us/library/bb943991.aspx/
const DDS_MAGIC = 0x20534444; // let DDSD_CAPS = 0x1;
// let DDSD_HEIGHT = 0x2;
// let DDSD_WIDTH = 0x4;
// let DDSD_PITCH = 0x8;
// let DDSD_PIXELFORMAT = 0x1000;
const DDSD_MIPMAPCOUNT = 0x20000; // let DDSD_LINEARSIZE = 0x80000;
// let DDSD_DEPTH = 0x800000;
// let DDSCAPS_COMPLEX = 0x8;
// let DDSCAPS_MIPMAP = 0x400000;
// let DDSCAPS_TEXTURE = 0x1000;
const DDSCAPS2_CUBEMAP = 0x200;
const DDSCAPS2_CUBEMAP_POSITIVEX = 0x400;
const DDSCAPS2_CUBEMAP_NEGATIVEX = 0x800;
const DDSCAPS2_CUBEMAP_POSITIVEY = 0x1000;
const DDSCAPS2_CUBEMAP_NEGATIVEY = 0x2000;
const DDSCAPS2_CUBEMAP_POSITIVEZ = 0x4000;
const DDSCAPS2_CUBEMAP_NEGATIVEZ = 0x8000; // let DDSCAPS2_VOLUME = 0x200000;
// let DDPF_ALPHAPIXELS = 0x1;
// let DDPF_ALPHA = 0x2;
const DDPF_FOURCC = 0x4; // let DDPF_RGB = 0x40;
// let DDPF_YUV = 0x200;
// let DDPF_LUMINANCE = 0x20000;
function fourCCToInt32( value ) {
return value.charCodeAt( 0 ) + ( value.charCodeAt( 1 ) << 8 ) + ( value.charCodeAt( 2 ) << 16 ) + ( value.charCodeAt( 3 ) << 24 );
}
function int32ToFourCC( value ) {
return String.fromCharCode( value & 0xff, value >> 8 & 0xff, value >> 16 & 0xff, value >> 24 & 0xff );
}
function loadARGBMip( buffer, dataOffset, width, height ) {
const dataLength = width * height * 4;
const srcBuffer = new Uint8Array( buffer, dataOffset, dataLength );
const byteArray = new Uint8Array( dataLength );
let dst = 0;
let src = 0;
for ( let y = 0; y < height; y ++ ) {
for ( let x = 0; x < width; x ++ ) {
const b = srcBuffer[ src ];
src ++;
const g = srcBuffer[ src ];
src ++;
const r = srcBuffer[ src ];
src ++;
const a = srcBuffer[ src ];
src ++;
byteArray[ dst ] = r;
dst ++; //r
byteArray[ dst ] = g;
dst ++; //g
byteArray[ dst ] = b;
dst ++; //b
byteArray[ dst ] = a;
dst ++; //a
}
}
return byteArray;
}
const FOURCC_DXT1 = fourCCToInt32( 'DXT1' );
const FOURCC_DXT3 = fourCCToInt32( 'DXT3' );
const FOURCC_DXT5 = fourCCToInt32( 'DXT5' );
const FOURCC_ETC1 = fourCCToInt32( 'ETC1' );
const headerLengthInt = 31; // The header length in 32 bit ints
// Offsets into the header array
const off_magic = 0;
const off_size = 1;
const off_flags = 2;
const off_height = 3;
const off_width = 4;
const off_mipmapCount = 7;
const off_pfFlags = 20;
const off_pfFourCC = 21;
const off_RGBBitCount = 22;
const off_RBitMask = 23;
const off_GBitMask = 24;
const off_BBitMask = 25;
const off_ABitMask = 26; // let off_caps = 27;
const off_caps2 = 28; // let off_caps3 = 29;
// let off_caps4 = 30;
// Parse header
const header = new Int32Array( buffer, 0, headerLengthInt );
if ( header[ off_magic ] !== DDS_MAGIC ) {
console.error( 'THREE.DDSLoader.parse: Invalid magic number in DDS header.' );
return dds;
}
if ( ! header[ off_pfFlags ] & DDPF_FOURCC ) {
console.error( 'THREE.DDSLoader.parse: Unsupported format, must contain a FourCC code.' );
return dds;
}
let blockBytes;
const fourCC = header[ off_pfFourCC ];
let isRGBAUncompressed = false;
switch ( fourCC ) {
case FOURCC_DXT1:
blockBytes = 8;
dds.format = THREE.RGB_S3TC_DXT1_Format;
break;
case FOURCC_DXT3:
blockBytes = 16;
dds.format = THREE.RGBA_S3TC_DXT3_Format;
break;
case FOURCC_DXT5:
blockBytes = 16;
dds.format = THREE.RGBA_S3TC_DXT5_Format;
break;
case FOURCC_ETC1:
blockBytes = 8;
dds.format = THREE.RGB_ETC1_Format;
break;
default:
if ( header[ off_RGBBitCount ] === 32 && header[ off_RBitMask ] & 0xff0000 && header[ off_GBitMask ] & 0xff00 && header[ off_BBitMask ] & 0xff && header[ off_ABitMask ] & 0xff000000 ) {
isRGBAUncompressed = true;
blockBytes = 64;
dds.format = THREE.RGBAFormat;
} else {
console.error( 'THREE.DDSLoader.parse: Unsupported FourCC code ', int32ToFourCC( fourCC ) );
return dds;
}
}
dds.mipmapCount = 1;
if ( header[ off_flags ] & DDSD_MIPMAPCOUNT && loadMipmaps !== false ) {
dds.mipmapCount = Math.max( 1, header[ off_mipmapCount ] );
}
const caps2 = header[ off_caps2 ];
dds.isCubemap = caps2 & DDSCAPS2_CUBEMAP ? true : false;
if ( dds.isCubemap && ( ! ( caps2 & DDSCAPS2_CUBEMAP_POSITIVEX ) || ! ( caps2 & DDSCAPS2_CUBEMAP_NEGATIVEX ) || ! ( caps2 & DDSCAPS2_CUBEMAP_POSITIVEY ) || ! ( caps2 & DDSCAPS2_CUBEMAP_NEGATIVEY ) || ! ( caps2 & DDSCAPS2_CUBEMAP_POSITIVEZ ) || ! ( caps2 & DDSCAPS2_CUBEMAP_NEGATIVEZ ) ) ) {
console.error( 'THREE.DDSLoader.parse: Incomplete cubemap faces' );
return dds;
}
dds.width = header[ off_width ];
dds.height = header[ off_height ];
let dataOffset = header[ off_size ] + 4; // Extract mipmaps buffers
const faces = dds.isCubemap ? 6 : 1;
for ( let face = 0; face < faces; face ++ ) {
let width = dds.width;
let height = dds.height;
for ( let i = 0; i < dds.mipmapCount; i ++ ) {
let byteArray, dataLength;
if ( isRGBAUncompressed ) {
byteArray = loadARGBMip( buffer, dataOffset, width, height );
dataLength = byteArray.length;
} else {
dataLength = Math.max( 4, width ) / 4 * Math.max( 4, height ) / 4 * blockBytes;
byteArray = new Uint8Array( buffer, dataOffset, dataLength );
}
const mipmap = {
'data': byteArray,
'width': width,
'height': height
};
dds.mipmaps.push( mipmap );
dataOffset += dataLength;
width = Math.max( width >> 1, 1 );
height = Math.max( height >> 1, 1 );
}
}
return dds;
}
}
THREE.DDSLoader = DDSLoader;
} )();