C Library Commands and How to Use Them

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This guide will eventually list almost every C Library command in the SDK, and give a detailed explanation on how to use each one.

Graphics Commands

Here you will find all of the Graphx library commands

gfx_AllocSprite and gfx_GetSprite

This command is useful to set room aside in the program for new sprites you will create with gfx_GetSprite and/or for sprites to need to decompress.

gfx_AllocSprite() In the graphx.h file:

 * Allocates room on the heap for sprite data of given size
 * Takes a pointer to the routine used for malloc as well
 * Returns NULL upon failure to allocate space, otherwise a pointer to the sprite structure
 * Note that if you use the system malloc routine, it must be used elsewhere in your program
 * otherwise it will not be linked correctly
gfx_image_t *gfx_AllocSprite(uint8_t width, uint8_t height, void *malloc_routine);
  • width - The width of the sprite you want to decompress or create
  • height - The height of the sprite you want to decompress or create
  • malloc_routine - Not exactly sure what this does, just put malloc when writing the command

gfx_GetSprite() In the graphx.h file:

 * Quickly grab the background behind a sprite (useful for transparency)
 * sprite_buffer must be pointing to a large enough buffer to hold width*height number of bytes
 * A pointer to sprite_buffer is also returned for ease of use.
 * sprite_buffer is updated with the screen coordinates given.
gfx_image_t *gfx_GetSprite_NoClip(gfx_image_t *sprite_buffer, uint24_t x, uint8_t y);
  • sprite_buffer - The name of the sprite you want to create, the one defined with AllocSprite
  • x - The x position on teh screen to display the sprite
  • y - The y position on the screen to display the sprite

Ok, so now we're going to show you how to use both commands. Check this example code out, to be explained afterwards.

//Make this a global:
gfx_image_t *spriteName
spriteName = gfx_AllocSprite(30, 40, malloc);
gfx_GetSprite(spriteName, 20, 50);
  • gfx_image_t spriteName defines the sprite variable
  • malloc(0); sets that malloc value to 0
  • spriteName = gfx_AllocSprite(30, 40, malloc); sets spriteName to the width and height of the next few values
  • gfx_GetSprite(spriteName, 20, 50); grabs a sprite the dimensions of spriteName at x-20 and y-50, and sets it to spriteName, to be called later as a sprite