$24
Lab 02: Input and Collision Solution
Provided Files
main.c
myLib.c
myLib.h
Files to Edit/Add
main.c
myLib.c
myLib.h
Your Makefile
Your task.json
Instructions
In this lab, you will be completing several different TODOs, which will, piece by piece, make an interactive rectangle game.
After you download and unzip the files, add your Makefile, and then compile and run it. At this point, you should see just a blank, black screen. Complete the TODOs in order, paying close attention to the instructions.
TODO #1 - drawRect
Open myLib.c and complete the drawRect function.
In main.c, find and uncomment UNCOMMENT#1 to see the fruits of your labor. You should see 5 rectangles in total. There should be 4 green rectangles, one on the top, bottom, left, and right of the screen. There should also be a blue rectangle in the center of the screen.
TODO #2
Head back to myLib.c, find fillScreen (right beneath drawRect) and complete it.
You may only use a single loop (one for-loop) to complete this one.
Hint: the index of the top-right pixel is 239, and the index of the leftmost pixel in the next row is 240. Use this concept to your advantage.
Enter main.c and uncomment UNCOMMENT#2. The background of your game should now be a lovely shade of cyan.
TODO #3
This one requires a lot of moving parts to work, so it is broken into three parts.
TODO #3.0
Open myLib.h, find the button macros, and complete them.
For BUTTON_PRESSED, assume that buttons and oldButtons have been set up appropriately.
TODO #3.1
Since buttons and oldButtons haven’t been set up correctly, head on back to main.c and initialize them in the initialize function.
They have already been declared in main.c (and in myLib.h as extern), so you don’t have to worry about that part this time, but you will when you code things yourself for your homework.
TODO #3.2
The buttons still won’t do anything unless you update them each frame, so do that in the main while-loop.
After you have completed these tasks, find UNCOMMENT#3 in the update function and do the thing.
Run it, and now you can press Start to toggle the background between cyan and a fabulous bright yellow.
Holding down the Start button for a long time should have the same effect as just tapping it a single time. If not, you did one of these three TODOs incorrectly.
TODO #4
Now that you can take button input, find this TODO in the update function and make it so that the blue rectangle can move up, down, left, and right if you press the corresponding arrow key.
This time, it should move for as long as the key is held, meaning that if you tap it once quickly, it will barely move, but if you press it for several seconds, it will move a lot. If not, fix that.
Compile and run, and you should be able to move the blue rectangle around as you please.
TODO #5
This one will likely take you the longest, but is also the most important.
TODO #5.0
At the bottom of myLib.c, implement the collision function. It takes in the positions and dimensions of two rectangles, and returns a 1 if they are colliding, or a 0 if not.
Hint: draw lots of pictures. Using graph paper, or drawing a grid yourself, is extremely useful. This function should work regardless of the size or velocity of the rectangle (if one is moving).
TODO #5.1
Now that you have the collision function implemented, use it in the update function. If the blue rectangle collides with any of the four stationary green rectangles, reset the blue rectangle’s position to the center of the screen (this is where the blue rectangle was first initialized).
Hint: since there are four separate green rectangles for which you need to detect a collision, you’ll need to use the collision function four separate times.
Compile and run this, verify that it runs correctly, and then you are done.
Submission Instructions
Zip up your entire project folder, including all source files, the Makefile, and everything produced during compilation (including the .gba file). Submit this zip on Canvas. Name your submission Lab02_FirstameLastname, for example:“Lab02_GeorgeBurdell.zip”.
