Contents:

• Collaboration Policy
• Overview
• An Example
• Technical Requirements
• Grading Standards
• Submitting Your Assignment

Collaboration Policy

For this assignment, you must work individually in regard to the design and implementation of your project.

Please make sure you adhere to the policies on academic integrity in this regard.

Overview

You are to design an interactive sketch depicting the horizon. The top half of the sketch will represent the sky and the bottom half the ground. The exact y-coordinate of the horizon should be a variable in your code. This will be a horizon line at which all objects appear to vanish in the distance. Color and decorate the top and bottom of your sketch appropriately. You are welcome to have distant aspects of the ground, such as a mountain, cross the horizon if you choose.

Your sketch must be interactive, as follows. When the user clicks on the sketch, you are to draw one of two types of objects. If the click occurs in the sky (i.e., above the horizon line), draw an object that belongs in the sky at that point (e.g., a cloud, bird, plane, hot-air baloon, ...). Alternatively, if the click is below the horizon, draw something that belongs on the land (i.e., an animal, flower, building, ...). The size of the added objects should depend linearly upon the distance from the mouse click and the horizon, such that items shrink to near zero size as they approach the horizon.

For the sake of creativity, your objects and landscape for this project should be different from anything you may have created for the first project.

An Example

Here is my own interactive example, inspired by the annual balloon glow (even though its actually held in Forest Park, not by the Arch). You may reset the sketch by pressing the 'r' key.

For full disclosure, I will note that I used rather advanced techniques to achieve the effect of the arch being in front of some objects and behind others; I would not expect you to create such an effect with the techniques we've learned thus far. A still frame created with my software is as follows.

Note well the vanishing effect, in that the size of objects gets infinitesimally small as they get closer to the horizon.

If you would like a little more inspiration, feel free to check out last year's students' projects (but please note that not all of them implemented the perspective properly).

Technical Requirements

Your sketch must meet the following technical requirements:

• The canvas must be at least 500 pixels by 500 pixels.
• The y-coordinate of the horizon must be defined as a variable horizon such that your entire sketch still works if we were to change the horizon value.
• If the mouse is clicked above the horizon, an object that belongs in the sky should be drawn; if the mouse is clicked below the horizon, and object that belongs in the foreground should be drawn.
• Your objects can be simple (but not too simple). For example, a single cloud might be made of multiple ellipses, a flower might be made with nested colored ellipses and a green rectangle as a stem.
• You must use separate functions to define each type of object (see suggestion below).
• You must use a loop to achieve repetition somewhere in your drawing. For example, you could use it to draw petals on a flower or stripes on a hot-air baloon.
• You should use the random() function to add some unpredictable variance to the shapes that are drawn (e.g., color, size, orientation).
• You must properly define the size of your objects based upon the relative distance from the mouse to the horizon. Effectively, you should compute a scale factor so that the scale is 0 at the horizon and 1 at either the top or bottom edge of the sketch, and then linearly interpolate the scale for the rest of the area.
• The user should be able to reset your sketch by pressing the 'r' key, and should be able to save a screenshot of the current canvas by pressing the 's' key.

We suggest you use the following structure for your program.

// Header comments
// Declare global variables

void setup() {
  // Set up the drawing.
  // Draw the sky and the ground and any other default scenery
}

void draw() { /* remains empty */ }

void mousePressed() {
  // Use the mouseY position to decide whether drawing on sky or on ground
  // Compute scale factor and call appropriate drawing function.
}

// You may rename this function, depending on what you choose as your sky object
void drawBalloon( int x, int y, float scale) {
  // Draw a balloon at the given coordinates using the scale factor.
}

// You may rename this function, depending on what you choose as your sky object
void drawPerson( int x, int y, float scale) {
  // Draw a person at the given coordinates using scale factor.
}

Submitting Your Assignment

Please see details regarding the submission process from the general programming web page, as well as a discussion of the late policy.

For this project, we ask that you submit the following three files:

• The .pde file that contains the actual Processing source code you've written
• A separate 'readme' text file, as outlined in the general webpage on programming projects.
• A .jpg image of an example sketch. You might create this from within Processing by using the command

        save("filename.jpg");   // or any other such filename
        

  when a particular key is pressed, so that you can wait to generate the image until after you add several examples of your objects.

Grading Standards

The assignment is worth 70 points, which will be assessed as follows:

• (10 points) Drawing of original sky and ground, with horizon line well-defined at variable y-coordinate.
• (10 points) Objects are drawn at the mouse location when pressed, with the appropriate type of object, depending on whether the mouse was pressed above or below the horizon.
• (10 points) Proper function definitions for drawing the objects, with appropriate use of parameters to describe the position and size of each object.
• (10 points) Use of parameters to achieve appropriate illusion of perspective, such that the size of objects approach zero as their positions approach the horizon.
• (10 points) Meaningful use of loops.
• (5 points) Meaningful use of the random() function to vary the appearance of drawn objects.
• (5 points) Sketch allows for both reset with 'r' and screenshot with 's'.
• (5 points) Source code includes a proper header and adequate comments, and appropriate variables.
• (5 points) Proper adherence to submission procedures, including submission of readme file and sample jpg image.

An unspecified number of bonus points are available for anyone who clearly goes above and beyond the set of requirements in terms of difficulty, artistry, or creativity.