big_sprite

Big Sprite

Renders a big sprite of 16x16. Since the Game Boy hardware does not directly support sprites that large

Source

Start by including gb/gb.h this file defines most important functions you are going to need when develop Game Boy games.

#include <gb/gb.h>

The sprite.c file defines the sprite data in the form of an unsigned char array. Most of the time you want to generate this file using tools such as GBTD.

#include "sprite.c"

void main() {

Set the sprite size to 8x16 pixels, two tiles one above the other. Internally sets bit 2 of the LCDC register to 1.

    SPRITES_8x16;

Loads the tile patterns stored in sprite into the Sprite Tile Pattern table.

• first parameter 0 determines at which position we should start loading.
• second parameter 4 determines how many tiles we want to loading
• third parameter sprite sets the variable to load from

This means that we are loading 4 tiles starting at 0 from the variable sprite.

    set_sprite_data(0, 4, sprite);

Tell sprite 0 to display sprite 0. Since we are loading 8x16 tiles this will make sprite 0 show tile 0 and tile 1.

    set_sprite_tile(0, 0);

Finally move a sprite to a position that we can see.

    move_sprite(0, 75, 75);

We want to display a 16x16 sprite. Unfortunately the Game Boy hardware does not directly support a sprite that large. So in order to have a sprite of that size we are simply displaying two 8x16 tiles next to each other!

Since we've already loaded our entire sprite in line 16 we can now simply tell sprite 1 to display our second sprite. Again, since we are displaying 8x16 tiles this statement will display tile 2 and tile 3.

    set_sprite_tile(1, 2);

In order to form the illusion of a bigger sprite we display the second tile directly next to the other simply by offsetting the position 8 pixels to the right.

    move_sprite(1, 75 + 8, 75);

As always, in order for the sprites to display we need to call SHOW_SPRITES once.

    SHOW_SPRITES;
}