$25
CS2261-LAB 5 Mode 4 Solved
In this lab, you’ll be completing several different TODOs, which will piece by piece add Mode 4 drawing to a simple game. Each TODO represents a component of this improvement, and is broken down into sub-TODOs. Your code may not compile until you complete an entire TODO block, at which point the game should compile with the new drawing function working as expected.
After downloading and unzipping the files, if you take a look at the code, what you see should be familiar. It’s a completed Lab04 with a bit of a fun spin! It has a few new features to highlight and test some Mode 4 functionality. If you were to build it right now, however, it will be a blank screen. Complete the TODOs in order, paying close attention to the instructions.
Note: Make sure to copy over your Makefile and .vscode/tasks.json from one of your previous assignments.
TODO 1.0 - SetPixel4
For us to be able to set pixels in Mode 4, we need to account for the additional cases that Mode 4 requires, so we’re making a new function.
● In myLib.c , complete setPixel4()
● Build and run. If you press START, you should be able to travel to the game state and see that the text is drawing correctly (drawChar4 and drawString4 have already been written for you). If not, fix this before going further.
○ The states will be black screens besides the game state (where you should see text drawn)
TODO 2.0 - fillScreen4
We want to be able to see the rest of the states, so we need to fill the screen next.
● TODO 2.0
○ In myLib.c , complete fillScreen4()
● TODO 2.1
○ At this point, if you compile and run, you won’t see anything. That’s because our goTo state functions are only filling the screen once (on the hidden page), then doing nothing. To fix this, we need to flip the page with flipPage() after doing our drawing and after we wait for VBlank.
○ In main.c , in the goToStart function, wait for VBlank, then flip the page.
● TODO 2.2
○ Do the same for goToPause
● TODO 2.3:
○ Do the same for goToWin
● TODO 2.4:
○ Do the same for goToLose
● Build and run your lab thus far. You should be able to travel through all the states you just edited and see their titles printed on them (except for Start because drawFullScreenImage is still blank). If not, fix this before going further.
TODO 3.0 - drawFullscreenImage4
We want to actually be able to see the start screen. Let’s make it so we can draw fullscreen images!
● TODO 3.0
○ In myLib.c, complete drawFullScreenImage4()
● TODO 3.1
○ This isn’t worth anything if we don’t have an image to draw. Open start.png in Usenti.
○ No need to resize this image, as it is already 240x160px (the size of the screen).
● TODO 3.2
○ We are in Mode 4, so the image can only use a MAX of 256 colors. Usenti has a tool to reduce the number of colors.
○ Go to Palette Requantize. Type 256 and hit OK
● TODO 3.3
○ Export your image (Image Export).
○ You will save it as a GBA source file in the Lab05 folder.
○ In the export settings, select bitmap(GBA) and “8bpp” (8 bits per pixel means that it’s a char for each pixel, like Mode 4 wants).
○ Also make sure that Pal (top right) is checked. This will include the palette in the .c file as an array of 256 shorts.
● TODO 3.4
○ #include start.h at the top of main.c
○ We need to be able to load the image’s palette (located in start.c) in the game so that the hardware knows what colors to use.
○ In main.c, in the goToStart function, write a single call to DMANow() that will copy the entire start image palette into the game’s PALETTE
■ You can find the necessary image information declared in start.h
● TODO 3.5
○ Uncomment the call to drawFullScreenImage4 in the goToStart function.
● Build and run your lab. You should be able to see all the states now (except for the moving elements in Game). If not, fix this before going further.
TODO 4.0 - drawImage4
We want to be able to draw smaller images as well.
● TODO 4.0
○ In myLib.c, complete drawImage4()
● TODO 4.1
○ Open kirby.png in Usenti. This one was drawn using a small enough palette and size, so there is no need to resize or requantize.
● TODO 4.2
○ Export this image the same way you did the last one, making sure that Pal is checked.
○ In initGame(), write the same DMANow() call you wrote to load in the palette last time, this time loading in kirbyPal.
○ Note: this time, after we load in the palette, we also put some of our own colors in there (you can view this in game.c. It looks super complicated, and you don’t have to do it this way when you are making your games). It has already been done for you.
● TODO 4.3
○ Include kirby.h at the top of game.c
○ Uncomment the rest of drawBall()
● Build and run. When you reach the game state, you should see one kirby ball bouncing around. If not, fix this before going further.
TODO 5.0 - drawRect4
For our last touch, we need to be able to draw Rectangles ● In myLib.c, complete drawRect4()
○ This will be by far the longest function you code in this lab. You need to account for ALL cases where you have to set pixels in front or behind each row.
■ HINT: draw lots of pictures. There are 4 col/width cases, so make sure you identify and account for all of them.
○ You also need to make sure it still works if you draw a rectangle of small width (1 or 2) ● Build and run.
○ If you shoot, the bullets are now of different widths, and they don’t fly straight up when you are moving; they lean in the direction you were moving when you shot. If any of your homeworks are like this, we will assume you copied code, and penalize heavily. These additions are to help you test drawRect.
○ The rectangles should all be correctly sized, and they should not wiggle when they move diagonally (they should move smoothly in that direction).
○ When you shoot the rectangles, they should turn into kirby images
