Gameboy Development Forum

Hi Kluxos,

I actually have never used GBDK, but I'll try to help.

First issue: It looks like you are using the correct functions for drawing text. Are you calling these functions after you wait for vblank? As long as you are in the vblank section of the lcd refresh cycle, you can freely edit the background and tiles. Or if the lcd is turned off, then you have all the time you want to draw on the background. I think display_off() should turn off the lcd. Drawing text on the background is usually the easiest way to go. Using sprites lets you move the text around wherever you want, but you need to write code to manage multiple sprites for a string of text. Like you said, each letter needs it's own sprite, so you would need to call set_sprite_tile() and move_sprite() for each letter. Also, you can only have 10 sprites in the same row or else some of the sprites will start to disappear. This is a limitation of the gameboy hardware.

Second issue: I would use a variable to keep track of the state of the game. When the player hits START at the menu, then you should turn off the display, load the tiles and map for the intro scene, then turn the lcd back on and change the state of the game from MENU_STATE to INTRO_STATE (or whatever you want to name your game states). In your game loop you would check what state you are in, and then call the correct functions.

For instance
if (gameState == STATE_MENU)
{
   UpdateMenu();
}
else if (gamestate == STATE_INTRO)
{
   UpdateIntro();
}

etc

So in your update Menu function you would check to see if the player has hit the start button to transition to the intro state. In the UpdateGame() function you would write code that checks if the player is pressing direction buttons and to update the location of the player.


Third Issue: For text boxes, you should probably use the gameboy's Window feature. The window will render on top of the background if it is enabled. So when you talk to an npc you should enable the window. I think      SHOW_WIN does this.  I've never used the window function yet, but I think you set an x and y position and it offsets the window to that location. I do not think you can set a width or height, but I could be wrong. So in that case you would have to put the window toward the bottom of the screen. That is usually where it is in RPGs anyway.


I hope that helped a little. Oh also, if you are using the BGB emulator it has a really awesome VRAM window that will show you the tiles you have loaded, and the background/window maps. It even updates in real time as you are playing the game. It is so helpful!