HW04SMF

CS430 - Homework Assignment 4

Programming Problem:

1. Understand the Simple Model Format SMF (*.smf)

    SMF is a standard file format for specifying meshes. You do not have to implement a complete specification in SMF, just the v and f rules.
    Make sure that you ignore any other commands in the input. A v denotes a vertex, and a f denotes a face. Three floating point numbers follow a v that define the x, y, z positions of the vertex. Integer references to the vertices follow an f. The references assume the order of the vertices specified in the file. The vertices for a face are defined in counter-clockwise order. The numbering of the vertices begins at 1.

    Here is a small example of the format:

    v -1.0 -1.0 -1.0
    v -2.0 -3.0 -4.0
    ...
    f 1 2 3
    f 3 4 1

    Several example smf files can be found and here.

2. Write a program, named CG_hw4 and in your language of choice, to draw the edges of an smf model to the specified viewport. Additionally:
    1. Accept smf file as an input. Examples can be found here.
    2. [-f] The next argument is the input SMF file
    3. The output image (screen/page) will be [501, 501]
    4. The view plane window should be placed within the viewport.
    5. Clipping should occur along the outer boundaries of the viewport if necessary.
    6. You should be able to process any subset of the command-line arguments in any arbitrary order.
    7. [-j] The next argument is an integer lower bound in the x dimension of the view port in screen coordinates (0)
    8. [-k] The next argument is an integer in lower bound in the y dimension of the view port in screen coordinates (0)
    9. [-o] The next argument is an integer in upper bound in the x dimension of the view port in screen coordinates (500)
    10. [-p] The next argument is an integer in upper bound in the y dimension of the view port in screen coordinates (500)
    11. You can assume that the viewport will always be specified within the image/page, and that j & k will be less than o and p.
    12. 3D view volume defined as follows:
        i. [-x] floating point x of Projection Reference Point (PRP) in VRC coordinates (0.0)
        ii. [-y] floating point y of Projection Reference Point (PRP) in VRC coordinates (0.0)
        iii. [-z] floating point z of Projection Reference Point (PRP) in VRC coordinates (1.0)
        iv. [-X] floating point x of View Reference Point (VRP) in world coordinates (0.0)
        v. [-Y] floating point y of View Reference Point (VRP) in world coordinates (0.0)
        vi. [-Z] floating point z of View Reference Point (VRP) in world coordinates (0.0)
        vii. [-q] floating point x of View Plane Normal vector (VPN) in world coordinates (0.0)
        viii. [-r] floating point y of View Plane Normal vector (VPN) in world coordinates (0.0) NOTE: This is redefining a previous command line option!!!
        ix. [-w] floating point z of View Plane Normal vector (VPN) in world coordinates (-1.0)
        x. [-Q] floating point x of View Up Vector (VUP) in world coordinates (0.0)
        xi. [-R] floating point y of View Up Vector (VUP) in world coordinates (1.0)
        xii. [-W] floating point z of View UP Vector (VUP) in world coordinates (0.0)
           You may assume that the VUP is not parallel to VPN
        xiii. [-u] floating point u min of the VRC window in VRC coordinates (-0.7)
        xiv. [-v] floating point v min of the VRC window in VRC coordinates (-0.7)
        xv. [-U] floating point u max of the VRC window in VRC coordinates (0.7)
        xvi. [-V] floating point v max of the VRC window in VRC coordinates (0.7)
        xvii. [-P] Use parallel projection. If this flag is not present, use perspective projection.
    13. The are no limitations on the values of PRP, VRP, VPN and VUP.
    14. You can assume that u and v will always be less than U and V.
    15. Print the projected 2D lines to standard out in the output Postscript format.

The command-line options correspond to the values in Figure 1.

Figure 1: View Frustum

14½. Extra Credit (2 points). Add backface culling with the [-b] option. Due date is the last day of classes.

15. While you won't be doing front and back face clipping in this assignment you will need values for the near and far plane. You can use the default values for these parameter from HW5, front (-F) equal 0.6, and back (-B) equal -0.6.

16. The default values that should be assumed if none are entered are equivalent to the following command line option set:
./CG_hw4 -f bound-lo-sphere.smf -j 0 -k 0 -o 500 -p 500 -x 0.0 -y 0.0 -z 1.0 -X 0.0 -Y 0.0 -Z 0.0 -q 0.0 -r 0.0 -w -1.0 -Q 0.0 -R 1.0 -W 0.0 -u -0.7 -v -0.7 -U 0.7 -V 0.7 > out.ps