CSCI336 – Interactive Computer Graphics

SIM Session 3 2022

Assignment 1

Task 1

Write an OpenGL program to create a simple 2D scene with an animated Ferris wheel. The image in Figure 1 shows an example of the scene (a working program will be shown in one of the lectures).

Figure 1: Ferris wheel.

 Ferris wheel

o Construct a 2D scene like the one shown in Figure 1 (does not have to be identical). The scene should consist of the following objects:

 A line for the ground

 A triangle for the base supporting the Ferris wheel

 A triangle fan for the Ferris wheel spokes

 Several carriages (Note that your program should only contain the vertex specification of a single carriage, you can reuse this with different transformations)

Note: the rendering order affects the final image. The “Painter’s Algorithm” – things drawn later will overwrite the previous content.    (4 marks)

o Implement basic animation using transformations.

 Make the Ferris wheel rotate. The carriages should rotate along with the wheel spokes.   (4 marks)

 Allow the user to toggle animation by pressing “p” on the keyboard, and to change the direction of rotation by pressing “d”.   (2 marks)

 As the Ferris wheel rotates, make the carriages sway (rotate a little clockwise, then counter-clockwise). Each carriage should have a different sway angle.   (2 marks)

Task 2

Write an OpenGL program to create a simple 3D scene of a planetary system using colour cubes to represent the “planets”. The image in Figure 2 shows an example of the scene (a working program will be shown in one of the lectures).

Figure 2: Planetary system.

 Construct the 3D scene using perspective projection.

o The scene should consist of a large “sun” in the centre and two other “planets” that orbit the sun. Note that your program should contain the vertex specification of a single colour cube. The sun and the planets are to use the same vertex specification, i.e. use transformations to alter the position, size and rotation.   (2 marks)

o Implement basic animation.

The sun and the planets rotate about their respective centres. Each planet also orbits the sun. Each planet’s rotation and orbit angle should be different. The planetary orbits and rotation only need to be in the horizontal plane, i.e. rotation about the y-axis.   (2 marks)

o Display the orbit paths, i.e. the red circles in Figure 2. You only need the vertex specification of a single line loop. Use transformations to display the orbit path at different positions and sizes.   (2 marks)

o Implement two “moons” that rotate about their own centres and orbits the outer planet. Each moon’s rotation and orbit angle should be different.    (2 marks)

Screenshots

In your submission, include screenshots demonstrating your working programs (for both tasks 1 and 2) and the features that were implemented. Save the screenshots using one of the common image formats, i.e. bmp/jpg/png.

Instructions and Assessment

Follow the instructions from your tutor.

The assignment must be your own work. If asked, you must be able to explain what you did and how you did it. Marks will be deducted if you cannot correctly explain your code. The mark allocations shown above are merely a guide. Marks will be awarded based on the overall quality of your work. Marks may be deducted for other reasons, e.g., if your code is too messy or inefficient, if you cannot correctly explain your code, etc. For code that does not compile, does not work or for programs that crash, the most you can get is half the marks (i.e. 10 marks or less). It is better to comment out sections of your code that do not work and include a note for the marker.