From ea9492b882316ec261069a6700e52c4543672f2b Mon Sep 17 00:00:00 2001
From: astrodud <astrodud@gmail.com>
Date: Fri, 7 Jan 2011 21:46:45 -0800
Subject: [PATCH] added LathedObject which creates a geometry by rotating a set
 of Vertices around the z axis. UV mapping is supported. See
 http://astrodud.isgreat.org/asteroids for an example.

---
 src/extras/primitives/LathedObject.js | 45 +++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 src/extras/primitives/LathedObject.js

diff --git a/src/extras/primitives/LathedObject.js b/src/extras/primitives/LathedObject.js
new file mode 100644
index 00000000..4f6debf4
--- /dev/null
+++ b/src/extras/primitives/LathedObject.js
@@ -0,0 +1,45 @@
+/**
+ * @author astrodud / http://astrodud.isgreat.org/
+ */
+
+function LathedObject( verts, nsteps, latheAngle ) {
+   THREE.Geometry.call( this );
+   nsteps = nsteps || 12;
+   latheAngle = latheAngle || 2 * Math.PI;
+   var stepSize = latheAngle / nsteps;
+   var newV = [], oldInds = [], newInds = [], startInds = [];
+   for ( var j = 0; j < verts.length; j ++ ) {
+      this.vertices.push( new THREE.Vertex( verts[ j ] ) );
+      oldInds[ j ] = this.vertices.length - 1;
+      newV[ j ] = new THREE.Vector3( verts[ j ].x, verts[ j ].y, verts[ j ].z );
+   }
+   var m = THREE.Matrix4.rotationZMatrix( stepSize );
+   for ( var r = 0; r <= latheAngle + 0.001; r += stepSize ) { // need the +0.001 to it go up to latheAngle
+      for ( var j = 0; j < newV.length; j ++ ) {
+	 if ( r < latheAngle ) {
+	    newV[ j ] = transformVector3( newV[ j ], m );
+	    this.vertices.push( new THREE.Vertex( newV[ j ] ) );
+	    newInds[ j ] = this.vertices.length - 1;
+	 } else {
+	    newInds = startInds; // wrap it up!
+	 }
+      }
+      if ( r == 0 ) startInds = oldInds;
+      for ( var j = 0; j < oldInds.length - 1; j ++ ) {
+	 this.faces.push( new THREE.Face4( newInds[ j ], newInds[ j + 1 ], oldInds[ j + 1 ], oldInds[ j ] ) );
+	 this.uvs.push( [ new THREE.UV( r / latheAngle, j / verts.length ),
+			  new THREE.UV( r / latheAngle, ( j + 1 ) / verts.length ),
+			  new THREE.UV( ( r - stepSize ) / latheAngle, ( j + 1 ) / verts.length ),
+			  new THREE.UV( ( r - stepSize ) / latheAngle, j / verts.length ) ] );
+      }
+      oldInds = newInds;
+      newInds = [];
+   }
+   this.computeCentroids();
+   this.computeFaceNormals();
+   this.computeVertexNormals();
+   this.sortFacesByMaterial();
+};
+
+LathedObject.prototype = new THREE.Geometry();
+LathedObject.prototype.constructor = LathedObject;