import { Color, MathUtils } from 'three'; 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 Color(); const maxColor = new Color(); this.lut.length = 0; // sample at 0 this.lut.push( new 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 Color().lerpColors( minColor, maxColor, ( alpha - min ) / ( max - min ) ); this.lut.push( color ); } } } // sample at 1 this.lut.push( new 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 = 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 Color(); const maxColor = new Color(); const finalColor = new 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 ]] }; export { Lut, ColorMapKeywords };