CSC 220 Object-Oriented Multimedia Programming, Spring 2017

Transcription

1 CSC 220 Object-Oriented Multimedia Programming, Spring 2017 Dr. Dale E. Parson, Assignment 2, Working with 3D shapes and geometric transforms. This assignment is due via D2L Dropbox Assignment 2 ShapePaint3DIntro by 11:59 PM on Sunday March 5. I have added a weekend to compensate for the snow day. 10% penalty for each day it is late. When using Processing on the Kutztown campus Windows computers, make sure to start out every time by setting your Processing Preferences -> Sketchbook Location to U:\Processing. The U:\ drive is a networked drive that will save your work and make it accessible across campus. If you save it to your desktop or the lab PC you are using, you will lose your work when you log out. You must save it to the U:\ drive. If you do not have a folder called Processing under U:\, you must create one using the Windows Explorer. Processing Preferences is under the File menu on Windows. If you will be downloading Processing 3.X and running it using an off-campus computer (do not use version 2.X for assignments), you can copy your project sketch named ShapePaint3DIntro to a flash drive on one machine, and then copy it from the flash drive to another Processing sketch folder. PREPARATORY STEP A: Open your assignment 1 ShapePaint2DMinimal sketch and SAVE AS ShapePaint3DIntro. You must remove most of my code to get a clean start. After replacing my name with yours at the top of the sketch, replace the global variables and the following global functions with these definitions: page 1

2 /************************************************************ /* Author: Dr. Parson (Replace with STUDENT name.) /* Due Date: Sunday 11:59 PM, 10% penalty per day late /* Course: CSC120 Intro. to Creative Graphical Coding /* Professor Name: Dr. Parson /* Assignment: 2. /* Sketch name: ShapePaint3DIntro (Introductory version of 3D). *********************************************************/ ShapeObjectTemplate [] visible = new ShapeObjectTemplate[10]; // Initially visible[0] == null, etc. int visiblecount = 0 ; // incr on '+', decr on '-', clear on '_' // visible.length gives the full length of the array (the number // of elements it can hold). Use visiblecount to record how many // non-null object references are in the array. boolean tomove = true ; // toggle to false to avoid moving the objects, toggle on 'm' boolean isortho = false ; // false for perspective(), true for ortho(), change in 'o' vs 'p' void setup() { void draw() { The above is the entire starting point for the top of the sketch. Below are detailed instructions on what to do in each global function. We will not be using any Java HashMaps in this assignment. The 10-element array visible declared above is the only collection of objects. Also hollow out the keypressed() function near the bottom of the sketch in preparation: void keypressed() { PREPARATORY STEP B: Delete all code for class b and class c from assignment 1. KEEP interface ShapeObjectTemplate and class a implements ShapeObjectTemplate in your sketch, but eliminate method getboundingbox() from both of them, since we won t be using it. KEEP class a s other methods unchanged for now. You will be changing class a to use 3D shapes and transforms, but you also need to rewrite setup(), draw(), and keypressed(). Keeping 2D class a unchanged for now allows you to test those global method changes. You will have to change these lines of code in move(): if (x < -domewidthheight/2 x > domewidthheight/2) { speedx = -speedx ; to this: if (x < -width/2 x > width/2) { speedx = -speedx ; if (x < -width/2) { x = (-width/2) + 1 ; // Bring it back into range. else { x = width/2-1 ; // Bring it back into range page 2

3 Make similar changes to the if (y < -domewidthheight/2 y > domewidthheight/2) block of code, using height instead of width. Also, in shuffle() replace domewidthheight with width for x and height for y. This code will work with a rectangular display, and we need not need to tailor it for a planetarium. At this point your sketch should compile correctly, although with empty setup(), draw(), and keypressed() global functions, it does not do anything. There are only 4 global variables above. You may add more later if you like. I didn t need more. Here is what they provide: ShapeObjectTemplate [] visible = new ShapeObjectTemplate[10]; // Initially visible[0] == null, etc. int visiblecount = 0 ; // incr on '+', decr on '-', clear on '_' // visible.length gives the full length of the array (the number // of elements it can hold). Use visiblecount to record how many // non-null object references are in the array. Array visible can hold up to 10 object references for object classes derived from interface ShapeObjectTemplate. Initially, array elements visible[0] through visible[visible.length-1] contain the null value (lower case), where visible.length-1 == 9 for this array. Note that unlike C++, a Java array stores its length in its.length field; an array is an object that includes a.length field. Variable visiblecount records the number of consecutive elements in visible that are non-null, starting at visible[0]. At this point there are no object references in the array. boolean tomove = true ; // toggle to false to avoid moving the objects, toggle on 'm' boolean isortho = false ; // false for perspective(), true for ortho(), change in 'o' vs 'p' Variable tomove is a boolean that is set to default true when a loop within draw() is to call move() after display() for each non-null object. My draw() code for assignment 1 uses variable tomove in this way. Variable isortho is a boolean that indicates perspective() projection when false, and ortho() (orthographic) projection when true. We will go over these two forms of projection in class. REQUIREMENT 1 (5%): This is the only step in my setup() function. Add more if you like. Set the size() of the window, using P3D as the third argument so that we can use 3D shapes. The window does not need to be a square. An alternative would be fullscreen(p3d). Do not use both. REQUIREMENT 2 (15%): Start the draw() function with this code: void draw() { if (isortho) { ortho(); // Use orthographic projection else { perspective(); // Use perspective projection. spheredetail(15); // Limit detail on spheres to reduce CPU load. Here are the instructions for the rest of draw(): page 3

4 Set a background() color, a contrasting stroke() color, and a strokeweight() greater than 0. Draw a set of widely spaced lines across the display. You may draw horizontal or vertical lines in a for loop or while loop. My screen dump below shows widely spaced diagonal lines. You may draw diagonal lines if you want, but vertical or horizontal are fine. Use only 2D coordinates for the line endpoints, allowing the z coordinate to default to 0. Complete the draw() function with this code: pushmatrix(); translate(width/2, height/2, 0); LOOP to display and optionally move objects in array visible. popmatrix(); For the above LOOP you can use a for loop or while loop with C++-like syntax, iterating from visible[0] through visible[visiblecount-1]. Those elements should be!= null if your code updates visiblecount correctly, although, feel free to check visible[i]!= null before using any array element visible[i]. Within the LOOP, call the display() method for any non-null element. Immediately after calling display(), call move() on that same object if and only if global variable tomove is true. My assignment 1 code has similar calls to move(). An example 3D screen dump for my solution. Note my lines for REQUIREMENT 2. page 4

5 REQUIREMENT 3 (20%): Rewrite the keypressed() function from scratch as follows: A key == '+' constructs a new a() object and adds it to array visible, adjusting visiblecount appropriately. If visiblecount == visible.length, then there are no null elements the array is full. In that case, use random() to randomly select one of the array elements 0 through visible.length-1, and store the reference to the new a() in that location, replacing the previous reference, without changing visiblecount. A key == '-' assigns null into the topmost element of visible and decrements visiblecount by 1. A key == '_' (underline) resets all visible elements to null and visiblecount to 0. A key == 'm' (lower case m) toggles the value in global variable tomove between true and false. See key == 'M' (uppercase M) in assignment 1 s keypressed(). A key == 'o' (the lower case letter) sets global variable isortho to true. A key == 'p' sets global variable isortho to false. A key == '~' (tilde) loops through array visible and calls shuffle() on every non-null element. A key == 's' calls library function saveframe("screen3d-######.png") to take a screen shot of your sketch s window and store it in a file in your sketch. Make sure to clean these out with a file explorer to recover space; DO NOT accidentally remove your.pde source file by mistake. Document these key commands in a comment block near the top of your sketch. At this point your sketch should work correctly with your previous 2D implementation of class a. Make sure to test all key commands thoroughly. REQUIREMENT 4 (20%): Rewrite method display() in class a to create some kind of stick figure or other mobile entity with multiple body parts, where most of the body parts are 3D shapes. The Processing reference lists the following 3D library functions: 3D Primitives: box(), sphere(), and spheredetail(). It is also possible to create custom 3D PShape obejcts via createshape() with 3-dimensional vertices or groups of 2D objects in a 3D arrangement. I will show examples in class for the adventurous. Creating and using a custom 3D PShape earns 5% bonus points, but is not required. If you create such a PShape, tell me in a comment near the top. I used only 3D sphere() in my solution illustrated on the previous page, except for the mouth, which is a 2D arc. Here are my data fields for class a. You can add others, and eliminate any you decide not to use. You do need to keep x, y, z, speedx, speedy, and speedz. The shape needs to move in all 3 dimensions. class a implements ShapeObjectTemplate { // 3D shapes for assignment 2 float x ; float y ; float z ; float speedx ; float speedy ; float speedz ; float rotatex, rotatey, rotatez ; // degrees page 5

6 float rotatexspeed, rotateyspeed, rotatezspeed ; // in degrees int red ; int green ; int blue ; a() { shuffle(); Class a s display() function must start with the lines of code: void display() { pushmatrix(); translate(x, y, z); and end with this matching line: popmatrix(); As in assignment 1, the opening pushmatrix() saves the incoming coordinate transforms (with location 0,0 at the center of the window), and the closing popmatrix() restores them. Then, for each body part, do the following steps: a. pushmatrix() b. translate in 3D to the center of the body part, relative to the center of the body. The center of my stick figure s body on the previous page is the center of its head. c. scale if you need to grow or shrink in one or more of the 3D dimensions. d. rotate the body part if you wish, using rotatex, rotatey, and/or rotatez. You may also need an additional translate or other transform for exact positioning. e. Display the sphere(), box(), 2D shape, or PShape. f. popmatrix() For example, here is my code for the torso that connects to the head of my stick figure: // TORSO: pushmatrix(); translate(0,width/5,0); scale(.5, 2.0,.5); fill((red+51)%256, (green+71)%256, (blue+91)%256); sphere(width/10); popmatrix(); My code builds my figure facing forward and standing right-side-up. I will add the code requirements to make the entire figure rotate in a step below. The translate for the TORSO places it centered below the HEAD (x and z offsets of 0), with a Y displacement of width/5; you can hard code numbers here if you like; they do not need to be a function of width or height. I found satisfactory values through trial and error. The scale() call with 3 distinct scale factors for X, Y, and Z elongates the sphere into an ellipsoid page 6

7 TORSO. Note that the TORSO is elongated in the vertical direction (scale == 2.0), and shrunk in the X and Z directions (scale ==.5). Use a scale factor of 1.0 for any dimension that you do not wish to change. Please look at the TORSO in the illustration. I used similar steps for the other body parts. Each LEG required a 3D rotate and an additional translate to slide the LEG into position. Also, I added the two EYEs, the NOSE, and the MOUTH within the scope of the HEAD s pushmatrix()-popmatrix() delimiters. Each of those has its own nested pushmatrix()- popmatrix(), translating its location relative to the center of the HEAD. I used nostroke() for the NOSE and 2D MOUTH. Feel free to experiment. Test your initial stick figure by running and adding objects to the display via the + key. REQUIREMENT 5 (5%): Add one or two of rotatex, rotatey, and/or rotatez for the entire figure, immediately after the initial translate within display(). Do not use all three, because it becomes too hard to see what is going on. REQUIREMENT 6 (20%): Rewrite the move() function to update the location and other fields inside class a, similar to assignment 1, but now in 3D. I kept x within the range width/2 TO width/2, y within the range height/2 TO height/2, and z within the range TO 100. Use some trial & error for the z limits, noting that a positive z comes toward the viewer, and a negative z goes away. Also, you MUST move the figure towards location (mousex, mousey, 0) when the mousepressed library variable is true. Here is my initial code within move() that achieves this effect; feel free to use it: void move() { if (mousepressed) { float msx = mousex-width/2 ; float msy = mousey-height/2 ; x = ((msx)+99.0*x) / 100.0; y = ((msy)+99.0*y) / 100.0; z = z / 2.0 ; else { x = x + speedx ; y = y + speedy ; z = z + speedz ; The reason for subtracting width/2 from mousex and height/2 for mousey is because mousex and mousey are in screen coordinates, with 0,0 at the upper left. The subtraction adjusts for 0,0 at the center of the display. The multiplication of the current location by 99.0, and then division by 100.0, makes movement towards the mouse location occur slowly. NOTE that while my move() is very random, your can have a highly organized move() method if you like, for example, walking in only one x, y or z direction at a time, and changing direction periodically. REQUIREMENT 7 (10%): Rewrite the shuffle() function to randomize the location and other fields inside class a, similar to assignment 1, but now in 3D. Use limits similar to those for REQUIREMENT 6. REQUIREMENT 8 (5%): Use one of rotatex, rotatey, or rotatez that you did NOT use in REQUIREMENT 5 to rotate a body part within the display() method. For example, when tomove is false in my solution, the head continues to rotate about the Y axis because I added a rotatey call within the HEAD s pushmatrix()-popmatrix() block of code in display(). page 7