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title-screen.md

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Title Screen

The title screen shows a basic title image using the background and draws text asking the player to press A. Once the user presses A, it will go to the story screen.

Our title screen has 3 pieces of data:

  • The "Press A to play" text
  • The title screen tile data
  • The title screen tilemap
{{#include ../../galactic-armada/src/main/states/title-screen/title-screen-state.asm:title-screen-start}}

Initiating the Title Screen

In our title screen's "InitTitleScreen" function, we'll do the following:

  • draw the title screen graphic
  • draw our "Press A to play"
  • turn on the LCD.

Here is what our "InitTitleScreenState" function looks like

{{#include ../../galactic-armada/src/main/states/title-screen/title-screen-state.asm:title-screen-init}}

In order to draw text in our game, we've created a function called "DrawTextTilesLoop". We'll pass this function which tile to start on in de, and the address of our text in hl.

{{#include ../../galactic-armada/src/main/utils/text-utils.asm:draw-text-tiles}}

The "DrawTitleScreen" function puts the tiles for our title screen graphic in VRAM, and draws its tilemap to the background:

NOTE: Because of the text font, we'll add an offset of 52 to our tilemap tiles. We've created a function that adds the 52 offset, since we'll need to do so more than once.

{{#include ../../galactic-armada/src/main/states/title-screen/title-screen-state.asm:draw-title-screen}}

The "CopyDEintoMemoryAtHL" and "CopyDEintoMemoryAtHL_With52Offset" functions are defined in "src/main/utils/memory-utils.asm":

{{#include ../../galactic-armada/src/main/utils/memory-utils.asm:memory-utils}}

Updating the Title Screen

The title screen's update logic is the simplest of the 3. All we are going to do is wait until the A button is pressed. Afterwards, we'll go to the story screen game state.

{{#include ../../galactic-armada/src/main/states/title-screen/title-screen-state.asm:update-title-screen}}

Our "WaitForKeyFunction" is defined in "src/main/utils/input-utils.asm". We'll poll for input and infinitely loop until the specified button is pressed down.

{{#include ../../galactic-armada/src/main/utils/input-utils.asm:input-utils}}

That's it for our title screen. Next up is our story screen.