Lookup tables and colormaps for scientific visualization

src/math/Lut.js

@@ -0,0 +1,118 @@
+/**
+ * @author daron1337 / http://daron1337.github.io/
+ */
+
+THREE.Lut = function ( colormap, numberofcolors ) {
+
+  this.lut = new Array();
+  this.map = THREE.ColorMapKeywords[ colormap ];
+  this.n = numberofcolors;
+  
+  var step = 1. / this.n;
+  
+  for ( var i = 0; i <= 1; i+=step ) {
+  
+    for ( var j = 0; j < this.map.length - 1; j++ ) {
+    
+      if ( i >= this.map[ j ][ 0 ] && i < this.map[ j+1 ][ 0 ] ) {
+      
+        var min = this.map[ j ][ 0 ];
+        var max = this.map[ j+1 ][ 0 ];	
+        var color = new THREE.Color( 0xffffff ); 
+        var minColor = new THREE.Color( 0xffffff ).setHex( this.map[ j ][ 1 ] );
+        var maxColor = new THREE.Color( 0xffffff ).setHex( this.map[ j+1 ][ 1 ] );	
+        			
+        color = minColor.lerp( maxColor, ( i - min ) / ( max - min ) );
+        
+        this.lut.push(color);
+        
+      }
+      
+    }
+    
+  }
+  
+  return this.set( this );
+  
+};
+
+THREE.Lut.prototype = {
+
+	constructor: THREE.Lut,
+  
+  lut: [], map: [], mapname: 'rainbow' , n: 256, minV: 0, maxV: 1,
+  
+	set: function ( value ) {
+
+		if ( value instanceof THREE.Lut ) {
+
+			this.copy( value );
+
+		} 
+
+		return this;
+
+	},
+
+	setMin: function ( min ) {
+
+		this.minV = min
+		
+		return this;
+
+	},
+
+	setMax: function ( max ) {
+
+		this.maxV = max
+		
+		return this;
+
+	},
+	
+	changeNumberOfColors: function ( numberofcolors ) {
+
+		this.n = numberofcolors
+		
+		return new THREE.Lut( this.mapname, this.n );
+
+	},
+	
+	changeColorMap: function ( colormap ) {
+    
+    this.mapname = colormap;
+		
+		return new THREE.Lut( this.mapname, this.n );
+
+	},
+  
+  copy: function ( lut ) {
+
+		this.lut = lut.lut;
+		this.mapname = lut.mapname;
+		this.map = lut.map;
+		this.n = lut.n;
+
+		return this;
+
+	},
+  
+	getColor: function ( alpha ) {
+    
+    alpha = ( alpha - this.minV ) / ( this.maxV - this.minV ); 
+  
+    var colorPosition = Math.round( alpha * this.n );
+		
+		colorPosition == this.n ? colorPosition -= 1 : colorPosition;
+		
+		return this.lut[colorPosition];
+		
+	},
+	
+};
+
+THREE.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' ] ]
+}