Fall 2021 CSCB07 – Software Design Assignment Logistics  This assignment is worth 8% of the course grade and it is due on Nov 2, 2021  It should be done individually Instructions In computer graphics, an object is usually represented by dividing its surface into a set of polygons (also called faces). Such set is called a mesh. Graphical elements such as vertices, polygons, and meshes can be transformed (e.g. translated, rotated, etc.) using transformation matrices. For example, to rotate a vertex = (, , ) about the x-axis with angle θ, we can multiply the following matrix by the column vector representing : () = [ 1 0 0 0 − 0 ] That is, would be transformed into ′ = [ 1 0 0 0 − 0 ] [ ] = [ − + ] Similarly, the following matrices can be used to rotate about the y-axis and the z-axis respectively: () = [ 0 0 1 0 − 0 ] () = [ − 0 0 0 0 1 ] Fall 2021 Several file formats can be used to represent meshes: OBJ, PLY, STL, FBX, etc. In this assignment, we will only target the OBJ and PLY formats. OBJ format The OBJ files to be considered consist of two consecutive sets of lines: the first set (lines starting with a “v”) represents the unique vertices contained in the mesh and the second set (lines starting with an “f”) represents the faces of the mesh. For example, the mesh below contains two polygons: the first includes the vertices defined at lines 1, 2, and 3 and the second includes the vertices defined at lines 2, 3, and 4. PLY format The PLY format is similar to OBJ except for the following: - It has a header that specifies different aspects including the number of vertices and the number of faces. You can assume that the highlighted parts are fixed. - The lines representing the vertices do not start with a “v”. - The lines representing the faces do not start with an “f”. Instead, they start with the number of vertices included in the corresponding face. - Vertex indexing starts at 0 instead of 1. That is, the first line containing a vertex is labelled 0. v 5.1 1.2 0.3 v 4.9 1.5 0.3 v 3.8 1.4 0.5 v 4.1 1.6 0.6 f 1 2 3 f 2 3 4 ply format ascii 1.0 element vertex 4 property float32 x property float32 y property float32 z element face 2 property list uint8 int32 vertex_indices end_header 5.1 1.2 0.3 4.9 1.5 0.3 3.8 1.4 0.5 4.1 1.6 0.6 3 0 1 2 3 1 2 3 Fall 2021 1. Create a new java project and add to it a package named assignment 2. Define a class named GraphicalObject representing graphical objects that could be transformed using a matrix. It has the following void methods: a. transform: an abstract method that takes a two-dimensional matrix of double representing the transformation matrix. b. rotateXAxis: a concrete method that rotates the graphical object about the x-axis. It takes one argument of type double representing θ. c. rotateYAxis: a concrete method that rotates the graphical object about the y-axis. It takes one argument of type double representing θ. d. rotateZAxis: a concrete method that rotates the graphical object about the z-axis. It takes one argument of type double representing θ. 3. Define class Vertex as follows: a. It has three fields of type double representing the coordinates of the vertex. b. It has a constructor that takes three arguments of type double and initializes the coordinates accordingly. c. It inherits from GraphicalObject. d. It overrides hashCode and equals. e. It overrides toString by returning a string containing the three coordinates separated by spaces. 4. Define class Polygon as follows: a. It has one field of type LinkedHashSet named vertices b. It has a constructor that takes one argument of type LinkedHashSet and initializes vertices accordingly. c. It inherits from GraphicalObject. Transforming a polygon is done by transforming all of its vertices. d. It overrides hashCode and equals. 5. Define interfaces MeshReader and MeshWriter, as well as classes OBJMeshReader, PLYMeshReader, OBJMeshWriter, and PLYMeshWriter according to the following UML class diagram. Each of the classes is supposed to provide an implementation that reads/writes polygons as per the corresponding format. Fall 2021 6. Define class Mesh as follows: a. It has a field of type HashSet named polygons b. It has a field of type MeshReader named reader c. It has a field of type MeshWriter named writer d. It has a void method named setReader that takes an argument of type MeshReader and sets reader accordingly. e. It has a void method named setWriter that takes an argument of type MeshWriter and sets writer accordingly. f. It has a void method named readFromFile that takes a file name as an argument and uses reader to read the polygons from the file. g. It has a void method named writeToFile that takes a file name as an argument and uses writer to write the mesh to the file. h. It inherits from GraphicalObject. Transforming a mesh is done by transforming all of its polygons. i. It overrides hashCode and equals. 7. Write enough JUnit tests to test your code properly and maximize coverage. Test methods that aim at increasing coverage by adding code that is not relevant to the assertion are not allowed. 8. Kindly take note of the following: a. Adding extra fields or methods to the aforementioned interfaces and classes is not allowed. b. You can test your code using the files “car.obj” and “car.ply” provided with this assignment. c. You can visualize OBJ and PLY files online (e.g. https://3dviewer.net/) if you do not have an appropriate viewer installed. d. You might want to use the following methods when reading OBJ and PLY files i. Method split of class String Fall 2021 ii. Method parseDouble of class Double e. The following code reads a mesh from an OBJ file, rotates it about the y-axis by π/3, and saves the rotated mesh to OBJ and PLY files: public static void main(String [] args) { Mesh mesh = new Mesh(); mesh.setReader(new OBJMeshReader()); mesh.readFromFile("/Users/rawad/car.obj"); mesh.rotateYAxis(Math.PI/3); mesh.setWriter(new OBJMeshWriter()); mesh.writeToFile("/Users/rawad/car_rotated.obj"); mesh.setWriter(new PLYMeshWriter()); mesh.writeToFile("/Users/rawad/car_rotated.ply"); } Submission Upload the java files as a single archive file to “Assignment” on Quercus by Nov 2nd at the latest. 学霸联盟