Starting from:
$25
CS2261- Lab 03 Solved
Arrays and Swap
Provided Files
• main.c
• myLib.c
• myLib.h
• coords.c
• coords.h
Files to Edit/Add
• main.c
• Your Makefile
Instructions
In this lab, you will be completing several different TODOs, which will, piece by piece, complete a simple cactus jumping game (although the term “game” only loosely applies to this one). Your code may not compile until you complete an entire TODO block, at which point the game should compile with a new component of the final outcome (unless otherwise specified).
• TODO 1 – Cacti
Ø First, we want to create the cacti. They will sit on the top of the sand, and will move to the write (the movement has already been written).
o TODO 1.0: Find the cactusCols and oldCactusCols arrays in main.c. These will be the locations of the cacti. Notice that we don’t have variables for the lengths of these, so we’re going to find a way to calculate the length when we need it. o TODO 1.1: Find the drawCacti function. Complete this by calling the already-written eraseCactus function with each column in your oldCactusCols array (to erase them) and the drawCactus function for each column in your cactusCols array (to draw them).
§ Hint: you will need to calculate (not hard code) the length of the arrays. Since they are preallocated globally, what tool can we use to find the length? o TODO 1.2: Call the drawCacti function in the main while loop to draw your cacti each frame of the game.
Ø Compile and run. If you did everything correctly, you should see two equally-spaced cacti moving to the right, and, when they hit the right side of the screen, reset to the left.
• TODO 2 – Player
Ø The game wouldn’t be much fun without a player, so let’s draw one.
o TODO 2.0: Open coords.c and examine the contents. For this lab (and this lab only), we have opted to draw the player by having arrays of coordinates (row arrays that match up to column arrays), and setting a pixel at each of those row-column pairs. Note that there is a macro defining the length of the coordinate arrays, which we may need later.
o TODO 2.1: In main.c, find the drawPerson function. It takes an array of rows and a same-length array of columns, along with the length of those arrays (remember: there would otherwise be no way to determine this), as well as a color. Complete this function so that it sets a pixel at each corresponding row-column pair in the arrays to the specified color.
§ Hint: don’t overthink this. All you’re doing is iterating over the length of the arrays and calling setPixel for each i. o TODO 2.2: In the main while loop, after waitForVBlank, call drawPerson with the invisiblePerson arrays using the SKYCOLOR to erase the person’s previous location (this will make sense later).
o TODO 2.3: A few lines later, call drawPerson with the visiblePerson arrays using WHITE to draw the person’s current location.
Ø Compile and run. You should see our new player character on top of the sand, getting repeatedly smacked by cacti.
• TODO 3 – Swap
Ø For the purposes of this lab, we’re going to have our player jump by swapping the coordinates of the visiblePerson with those of the invisiblePerson (who is currently safely above the cacti). o TODO 3.0: In main.c, write a new function called swap that returns void and swaps the value of two integers passed in as parameters. Don’t forget to write a prototype at the top of main.c.
§ Note: this function may NOT exploit the fact that the things we will be swapping (in later TODOs) are statically allocated and/or in arrays. It must work for any two integers.
§ Hint: think about what you will need to actually take in as arguments to make this work
o TODO 3.1: In our main while loop, if the Start button is pressed, utilize your new swap function so that each element of invisiblePersonRows is swapped with each corresponding element of visiblePersonRows, and then the same for invisiblePersonCols and visiblePersonCols.
Ø Compile and run. If everything is working right, every time you press the Start button, the player character alternates between a place of safety above the cacti and back to where they started, standing on the sand.
• TODO 4 – More Cacti
Ø Now that everything is working, let’s make it more exciting by adding more cacti.
o TODO 4.0: Change the initialization of the cactusCols and the oldCactusCols arrays so that the starting locations are 0, 73, and 147.
Ø Compile and run. If you coded TODO 1.1 correctly, this should be all it took to add a third cactus in the cycle. If you don’t see this, revisit TODO 1.1 to make sure it works for any length of the arrays. If it does all work, submit your lab.
Provided Files
• main.c
• myLib.c
• myLib.h
• coords.c
• coords.h
Files to Edit/Add
• main.c
• Your Makefile
Instructions
In this lab, you will be completing several different TODOs, which will, piece by piece, complete a simple cactus jumping game (although the term “game” only loosely applies to this one). Your code may not compile until you complete an entire TODO block, at which point the game should compile with a new component of the final outcome (unless otherwise specified).
• TODO 1 – Cacti
Ø First, we want to create the cacti. They will sit on the top of the sand, and will move to the write (the movement has already been written).
o TODO 1.0: Find the cactusCols and oldCactusCols arrays in main.c. These will be the locations of the cacti. Notice that we don’t have variables for the lengths of these, so we’re going to find a way to calculate the length when we need it. o TODO 1.1: Find the drawCacti function. Complete this by calling the already-written eraseCactus function with each column in your oldCactusCols array (to erase them) and the drawCactus function for each column in your cactusCols array (to draw them).
§ Hint: you will need to calculate (not hard code) the length of the arrays. Since they are preallocated globally, what tool can we use to find the length? o TODO 1.2: Call the drawCacti function in the main while loop to draw your cacti each frame of the game.
Ø Compile and run. If you did everything correctly, you should see two equally-spaced cacti moving to the right, and, when they hit the right side of the screen, reset to the left.
• TODO 2 – Player
Ø The game wouldn’t be much fun without a player, so let’s draw one.
o TODO 2.0: Open coords.c and examine the contents. For this lab (and this lab only), we have opted to draw the player by having arrays of coordinates (row arrays that match up to column arrays), and setting a pixel at each of those row-column pairs. Note that there is a macro defining the length of the coordinate arrays, which we may need later.
o TODO 2.1: In main.c, find the drawPerson function. It takes an array of rows and a same-length array of columns, along with the length of those arrays (remember: there would otherwise be no way to determine this), as well as a color. Complete this function so that it sets a pixel at each corresponding row-column pair in the arrays to the specified color.
§ Hint: don’t overthink this. All you’re doing is iterating over the length of the arrays and calling setPixel for each i. o TODO 2.2: In the main while loop, after waitForVBlank, call drawPerson with the invisiblePerson arrays using the SKYCOLOR to erase the person’s previous location (this will make sense later).
o TODO 2.3: A few lines later, call drawPerson with the visiblePerson arrays using WHITE to draw the person’s current location.
Ø Compile and run. You should see our new player character on top of the sand, getting repeatedly smacked by cacti.
• TODO 3 – Swap
Ø For the purposes of this lab, we’re going to have our player jump by swapping the coordinates of the visiblePerson with those of the invisiblePerson (who is currently safely above the cacti). o TODO 3.0: In main.c, write a new function called swap that returns void and swaps the value of two integers passed in as parameters. Don’t forget to write a prototype at the top of main.c.
§ Note: this function may NOT exploit the fact that the things we will be swapping (in later TODOs) are statically allocated and/or in arrays. It must work for any two integers.
§ Hint: think about what you will need to actually take in as arguments to make this work
o TODO 3.1: In our main while loop, if the Start button is pressed, utilize your new swap function so that each element of invisiblePersonRows is swapped with each corresponding element of visiblePersonRows, and then the same for invisiblePersonCols and visiblePersonCols.
Ø Compile and run. If everything is working right, every time you press the Start button, the player character alternates between a place of safety above the cacti and back to where they started, standing on the sand.
• TODO 4 – More Cacti
Ø Now that everything is working, let’s make it more exciting by adding more cacti.
o TODO 4.0: Change the initialization of the cactusCols and the oldCactusCols arrays so that the starting locations are 0, 73, and 147.
Ø Compile and run. If you coded TODO 1.1 correctly, this should be all it took to add a third cactus in the cycle. If you don’t see this, revisit TODO 1.1 to make sure it works for any length of the arrays. If it does all work, submit your lab.
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