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Assignment 2: Kinect Controlled Monkey Cannon

Hurray, a Video Game!

Your task: Using JMonkey, create a Cannon that can rotate on its base around the y and x axis (that is: pitch and yaw, that is: what you would expect from an old style artillery weapon). This cannon is controlled by your left and right arm:

· The cannon's pitch takes the angle of your right arm vs. the ground (i.e. if you hold your right hand out straight to the right, the cannon points horizontally)

· The cannon rotates around its Y axis (changing the N,S,E,W direction, so to say) depending on your relative position of hand and shoulderline: hand > 10cm in front: cannon rotates +, >10cm behind: cannon rotates - .

· Your left arm controls a firing mechanism: if you move your left hand from above your shoulders below your shoulders, the cannon fires.

We then let the cannon-ball fly and see if it hits a target-box, which is placed somewhere.

Oh, the cannon and the target will be replaced randomly after each shot.

The goal of the game is to shoot the box 5 times, as fast as possible.

What is assignment about?

· Starting with JMonkey

· Thinking about coordinate systems and transforms

· impressing other students

(you can easily extend this game: two cannons are placed into a fractal environment with targets behind the mountains, two player game with TCP connection, ...ideas welcome!)

For those who panic easily:

· The TA will explain a lot during the lab

· We will talk very detailed about this assignment in class

· it's a group assignment

· The example codes example1, example2 are at least a start with JMonkey (see class website)

· We will NOT use any JMonkey physics in here! (that will come later and add a lot of joy to the project!)

· You have an entire week! :-)

· I do help, if you come to my office hours/office any time

The task in steps:

1. setup a ground area, which is a box of 20 x 0.1 x 20 meters (Box b = new Box(10,0.05,10))

2. create the cannon. The cannon should just consist of a Cylinder, as the cannon itself (excuse my lack of military terminology, as I am a convinced pacifist, only firing virtual cannons), and its base, e.g. a box.

3. Think about the Geometry and Node objects. You need to organize your cannon into an appropriate scene graph structure. When rotating the cylinder up/down, the base does not change. When rotating around the y-axis, the base AND the cylinder rotate!

4. Connect to the Kinect input. Determine the angle between right wrist and right shoulder (simple approach: just assuming an arm length of 1 meter (1000 millimeter), and defining the height difference between wrist and shoulder by "dy", the horizontal angle is atan2(dy, 1000.0)). Determine the z-distance between right wrist and shoulder.

5. Animation: animations in JMonkey are very easily achieved: the graphic output is automatically updated (usually with something like 100fps). Before the update, the method "public void simpleUpdate(float tpf)" is called. This is a method of SimpleApplication, which you inherit your own class from. Hence, overriding this method gives you your own animation thread. Please read about the tpf ("time per frame") parameter in there to adjust your game's speed to your computer's abilities.

6. When all this works, you should see a cannon, which rotates depending on your right arm position.

7. The firing mechanism: each time your left hand moves from above to below your shoulder, you create a Sphere inside of the cannon (coordinate system? transformations?), and with it, you create variables for its position and speed (3D!). The initial speed is given by the cylinder's axis direction (how do you compute that?)

8. some self made physics: update your cannon-balls position based on its speed (i'll talk about that in class), and its speed based on gravity.

9. create the game logic around your system: add a box, test collision of sphere and box (your own collision test, not JMonkey physics)

10. play.

It's a group project. Help each other.

Bonus:

are you able to connect two computers via TCP to play against each other? the target would then be the enemy cannon.