modify static method

BufferGeometry modify(BufferGeometry bufferGeometry, int count)

Implementation

static BufferGeometry modify(BufferGeometry bufferGeometry, int count) {
	BufferGeometry geometry = bufferGeometry.clone();

	// currently morphAttributes are not supported
	geometry.morphAttributes.remove('position');
	geometry.morphAttributes.remove('normal');
	final attributes = geometry.attributes;

	// this modifier can only process indexed and non-indexed geomtries with at least a position attribute

	for ( final name in attributes.keys) {
		if ( name != 'position' && name != 'uv' && name != 'normal' && name != 'tangent' && name != 'color' ) geometry.deleteAttributeFromString( name );
	}

	geometry = BufferGeometryUtils.mergeVertices( geometry );

	final List<Vertex> vertices = [];
	final List<Triangle> faces = [];

	// add vertices

	final BufferAttribute positionAttribute = geometry.getAttributeFromString( 'position' );
	final BufferAttribute? uvAttribute = geometry.getAttributeFromString( 'uv' );
	final BufferAttribute? normalAttribute = geometry.getAttributeFromString( 'normal' );
	final BufferAttribute? tangentAttribute = geometry.getAttributeFromString( 'tangent' );
	final BufferAttribute? colorAttribute = geometry.getAttributeFromString( 'color' );

	Vector4? t;
	Vector3? v2;
	Vector3? nor;
	Color? col;

	for (int i = 0; i < positionAttribute.count; i ++ ) {

		final v = Vector3.zero().fromBuffer( positionAttribute, i );
		if ( uvAttribute != null) {
			v2 = Vector3.zero().fromBuffer( uvAttribute, i );
		}

		if ( normalAttribute != null) {
			nor = Vector3.zero().fromBuffer( normalAttribute, i );
		}

		if ( tangentAttribute != null) {
			t = Vector4.zero().fromBuffer( tangentAttribute, i );
		}

		if ( colorAttribute != null) {
			col = Color().fromBuffer( colorAttribute, i );

		}

		final vertex = Vertex(v, v2, nor, t, col );
		vertices.add( vertex );
	}

	// add faces

	BufferAttribute<NativeArray<num>>? index = geometry.getIndex();

	if ( index != null ) {
		for (int i = 0; i < index.count; i += 3 ) {
			final a = index.getX( i )!.toInt();
			final b = index.getX( i + 1 )!.toInt();
			final c = index.getX( i + 2 )!.toInt();

			final triangle = Triangle( vertices[ a ], vertices[ b ], vertices[ c ], a, b, c );
			faces.add( triangle );
		}
	}
    else {
		for (int i = 0; i < positionAttribute.count; i += 3 ) {
			final a = i;
			final b = i + 1;
			final c = i + 2;

			final triangle = Triangle( vertices[ a ], vertices[ b ], vertices[ c ], a, b, c );
			faces.add( triangle );
		}
	}

	// compute all edge collapse costs

	for (int i = 0, il = vertices.length; i < il; i ++ ) {
		_computeEdgeCostAtVertex(vertices[ i ]);
	}

    Vertex? nextVertex;
	int z = count;
	while (z-- != -1) {
		nextVertex = _minimumCostEdge( vertices );

		if (nextVertex == null) {
			console.info( 'SimplifyModifier: No next vertex' );
			break;
		}

		_collapse( vertices, faces, nextVertex, nextVertex.collapseNeighbor );

	}

	final simplifiedGeometry = BufferGeometry();
	final List<double> position = [];
	final List<double> uv = [];
	final List<double> normal = [];
	final List<double> tangent = [];
	final List<double> color = [];
	final List<int> indx = [];

	for (int i = 0; i < vertices.length; i ++ ) {
		final vertex = vertices[ i ];

		position.addAll([ vertex.position.x, vertex.position.y, vertex.position.z ]);
		if ( vertex.uv != null) {
			uv.addAll([ vertex.uv!.x, vertex.uv!.y ]);
		}

		if ( vertex.normal != null) {
			normal.addAll([ vertex.normal!.x, vertex.normal!.y, vertex.normal!.z ]);
		}

		if ( vertex.tangent != null) {
			tangent.addAll([ vertex.tangent!.x, vertex.tangent!.y, vertex.tangent!.z, vertex.tangent!.w ]);
		}

		if ( vertex.color != null) {
			color.addAll( [vertex.color!.red, vertex.color!.green, vertex.color!.blue] );
		}

		// cache final index to GREATLY speed up faces refinalruction
		vertex.id = i;
	}

	//

	for (int i = 0; i < faces.length; i ++ ) {
		final face = faces[ i ];
		indx.addAll([ face.v1!.id, face.v2!.id, face.v3!.id ]);
	}

	simplifiedGeometry.setAttributeFromString( 'position', Float32BufferAttribute.fromList( position, 3 ) );
	if ( uv.isNotEmpty) simplifiedGeometry.setAttributeFromString( 'uv', Float32BufferAttribute.fromList( uv, 2 ) );
	if ( normal.isNotEmpty ) simplifiedGeometry.setAttributeFromString( 'normal', Float32BufferAttribute.fromList( normal, 3 ) );
	if ( tangent.isNotEmpty ) simplifiedGeometry.setAttributeFromString( 'tangent', Float32BufferAttribute.fromList( tangent, 4 ) );
	if ( color.isNotEmpty ) simplifiedGeometry.setAttributeFromString( 'color', Float32BufferAttribute.fromList( color, 3 ) );

	simplifiedGeometry.setIndex( indx );

	return simplifiedGeometry;
}