( function () {
class Lut {
constructor( colormap, count = 32 ) {
this.isLut = true;
this.lut = [];
this.map = [];
this.n = 0;
this.minV = 0;
this.maxV = 1;
this.setColorMap( colormap, count );
}
set( value ) {
if ( value.isLut === true ) {
this.copy( value );
}
return this;
}
setMin( min ) {
this.minV = min;
return this;
}
setMax( max ) {
this.maxV = max;
return this;
}
setColorMap( colormap, count = 32 ) {
this.map = ColorMapKeywords[ colormap ] || ColorMapKeywords.rainbow;
this.n = count;
const step = 1.0 / this.n;
const minColor = new THREE.Color();
const maxColor = new THREE.Color();
this.lut.length = 0; // sample at 0
this.lut.push( new THREE.Color( this.map[ 0 ][ 1 ] ) ); // sample at 1/n, ..., (n-1)/n
for ( let i = 1; i < count; i ++ ) {
const alpha = i * step;
for ( let j = 0; j < this.map.length - 1; j ++ ) {
if ( alpha > this.map[ j ][ 0 ] && alpha <= this.map[ j + 1 ][ 0 ] ) {
const min = this.map[ j ][ 0 ];
const max = this.map[ j + 1 ][ 0 ];
minColor.set( this.map[ j ][ 1 ] );
maxColor.set( this.map[ j + 1 ][ 1 ] );
const color = new THREE.Color().lerpColors( minColor, maxColor, ( alpha - min ) / ( max - min ) );
this.lut.push( color );
}
}
} // sample at 1
this.lut.push( new THREE.Color( this.map[ this.map.length - 1 ][ 1 ] ) );
return this;
}
copy( lut ) {
this.lut = lut.lut;
this.map = lut.map;
this.n = lut.n;
this.minV = lut.minV;
this.maxV = lut.maxV;
return this;
}
getColor( alpha ) {
alpha = THREE.MathUtils.clamp( alpha, this.minV, this.maxV );
alpha = ( alpha - this.minV ) / ( this.maxV - this.minV );
const colorPosition = Math.round( alpha * this.n );
return this.lut[ colorPosition ];
}
addColorMap( name, arrayOfColors ) {
ColorMapKeywords[ name ] = arrayOfColors;
return this;
}
createCanvas() {
const canvas = document.createElement( 'canvas' );
canvas.width = 1;
canvas.height = this.n;
this.updateCanvas( canvas );
return canvas;
}
updateCanvas( canvas ) {
const ctx = canvas.getContext( '2d', {
alpha: false
} );
const imageData = ctx.getImageData( 0, 0, 1, this.n );
const data = imageData.data;
let k = 0;
const step = 1.0 / this.n;
const minColor = new THREE.Color();
const maxColor = new THREE.Color();
const finalColor = new THREE.Color();
for ( let i = 1; i >= 0; i -= step ) {
for ( let j = this.map.length - 1; j >= 0; j -- ) {
if ( i < this.map[ j ][ 0 ] && i >= this.map[ j - 1 ][ 0 ] ) {
const min = this.map[ j - 1 ][ 0 ];
const max = this.map[ j ][ 0 ];
minColor.set( this.map[ j - 1 ][ 1 ] );
maxColor.set( this.map[ j ][ 1 ] );
finalColor.lerpColors( minColor, maxColor, ( i - min ) / ( max - min ) );
data[ k * 4 ] = Math.round( finalColor.r * 255 );
data[ k * 4 + 1 ] = Math.round( finalColor.g * 255 );
data[ k * 4 + 2 ] = Math.round( finalColor.b * 255 );
data[ k * 4 + 3 ] = 255;
k += 1;
}
}
}
ctx.putImageData( imageData, 0, 0 );
return canvas;
}
}
const ColorMapKeywords = {
'rainbow': [[ 0.0, 0x0000FF ], [ 0.2, 0x00FFFF ], [ 0.5, 0x00FF00 ], [ 0.8, 0xFFFF00 ], [ 1.0, 0xFF0000 ]],
'cooltowarm': [[ 0.0, 0x3C4EC2 ], [ 0.2, 0x9BBCFF ], [ 0.5, 0xDCDCDC ], [ 0.8, 0xF6A385 ], [ 1.0, 0xB40426 ]],
'blackbody': [[ 0.0, 0x000000 ], [ 0.2, 0x780000 ], [ 0.5, 0xE63200 ], [ 0.8, 0xFFFF00 ], [ 1.0, 0xFFFFFF ]],
'grayscale': [[ 0.0, 0x000000 ], [ 0.2, 0x404040 ], [ 0.5, 0x7F7F80 ], [ 0.8, 0xBFBFBF ], [ 1.0, 0xFFFFFF ]]
};
THREE.ColorMapKeywords = ColorMapKeywords;
THREE.Lut = Lut;
} )();
