CircleBufferGeometry

src/extras/geometries/CircleBufferGeometry.js

@@ -0,0 +1,77 @@
+/**
+ * @author benaadams / https://twitter.com/ben_a_adams
+ */
+
+THREE.CircleBufferGeometry = function ( radius, segments, thetaStart, thetaLength ) {
+
+	THREE.BufferGeometry.call( this );
+
+	this.type = 'CircleBufferGeometry';
+
+	this.parameters = {
+		radius: radius,
+		segments: segments,
+		thetaStart: thetaStart,
+		thetaLength: thetaLength
+	};
+
+	radius = radius || 50;
+	segments = segments !== undefined ? Math.max( 3, segments ) : 8;
+
+	thetaStart = thetaStart !== undefined ? thetaStart : 0;
+	thetaLength = thetaLength !== undefined ? thetaLength : Math.PI * 2;
+
+	var i;
+	
+	var stride = ( 3 + 3 + 2 );
+	var vertexData = new Float32Array( ( segments + 2 ) * stride );
+	var vertexBuffer = new THREE.InterleavedBuffer( vertexData, stride );
+
+	var positions = new THREE.InterleavedBufferAttribute( vertexBuffer, 3, 0 );
+	this.addAttribute( 'position', positions );
+	var normals = new THREE.InterleavedBufferAttribute( vertexBuffer, 3, 3 );
+	this.addAttribute( 'normal', normals );
+	var uvs = new THREE.InterleavedBufferAttribute( vertexBuffer, 2, 6 );
+	this.addAttribute( 'uv', uvs );
+
+	// center data is already zero, but need to set a few extras
+	// center normal z
+	vertexData[5] = 1.0; 
+	// center uv
+	vertexData[6] = 0.5;
+	vertexData[7] = 0.5;
+
+	for ( i = stride, s = 0, ul = ( segments + 2 ) * stride; i < ul; i += stride, s++ ) {
+
+		var segment = thetaStart + s / segments * thetaLength;
+
+		vertexData[i] = radius * Math.cos( segment ); // x
+		vertexData[i + 1] = radius * Math.sin( segment ); // y
+
+		vertexData[i + 5] = 1; // normal z
+
+		vertexData[i + 6] = ( vertexData[i] / radius + 1 ) / 2; // u
+		vertexData[i + 7] = ( vertexData[i + 1] / radius + 1 ) / 2; // v
+
+	}
+
+	var indices = [];
+
+	for ( i = 1; i <= segments; i ++ ) {
+
+		indices.push( i );
+		indices.push( i + 1 );
+		indices.push( 0 );
+
+	}
+
+	this.addAttribute( 'index', new THREE.BufferAttribute( new Uint16Array( indices ), 1 ) );
+
+	this.computeFaceNormals();
+
+	this.boundingSphere = new THREE.Sphere( new THREE.Vector3(), radius );
+
+};
+
+THREE.CircleBufferGeometry.prototype = Object.create( THREE.BufferGeometry.prototype );
+THREE.CircleBufferGeometry.prototype.constructor = THREE.CircleBufferGeometry;

utils/build/includes/extras.json

@@ -27,6 +27,7 @@
 	"src/extras/animation/MorphAnimation.js",
 	"src/extras/geometries/BoxGeometry.js",
 	"src/extras/geometries/CircleGeometry.js",
+	"src/extras/geometries/CircleBufferGeometry.js",
 	"src/extras/geometries/CylinderGeometry.js",
 	"src/extras/geometries/EdgesGeometry.js",
 	"src/extras/geometries/ExtrudeGeometry.js",