Function subdivide

MathBox/mathbox-bundle.js:32995–33059

( face, detail )

	// Analytically subdivide a face to the required detail level.

	function subdivide( face, detail ) {

		var cols = Math.pow(2, detail);
		var a = prepare( that.vertices[ face.a ] );
		var b = prepare( that.vertices[ face.b ] );
		var c = prepare( that.vertices[ face.c ] );
		var v = [];

		// Construct all of the vertices for this subdivision.

		for ( var i = 0 ; i <= cols; i ++ ) {

			v[ i ] = [];

			var aj = prepare( a.clone().lerp( c, i / cols ) );
			var bj = prepare( b.clone().lerp( c, i / cols ) );
			var rows = cols - i;

			for ( var j = 0; j <= rows; j ++) {

				if ( j == 0 && i == cols ) {

					v[ i ][ j ] = aj;

				} else {

					v[ i ][ j ] = prepare( aj.clone().lerp( bj, j / rows ) );

				}

			}

		}

		// Construct all of the faces.

		for ( var i = 0; i < cols ; i ++ ) {

			for ( var j = 0; j < 2 * (cols - i) - 1; j ++ ) {

				var k = Math.floor( j / 2 );

				if ( j % 2 == 0 ) {

					make(
						v[ i ][ k + 1],
						v[ i + 1 ][ k ],
						v[ i ][ k ]
					);

				} else {

					make(
						v[ i ][ k + 1 ],
						v[ i + 1][ k + 1],
						v[ i + 1 ][ k ]
					);