| Sprite8 | Function (tigcc.a)

sprites.h

void Sprite8 (short x, short y, short height, const unsigned char *sprite, void *vm_addr, short mode);

Draws a sprite with a width of 8 pixels or less on the screen.

Sprite8 draws a sprite with a width of 8 pixels or less on the screen. Use Sprite16 or Sprite32 for wider sprites. This routine is many times faster than TIOS routines like DrawIcon, BitmapPut, etc. x and y are the coordinates of the upper left corner of the sprite. height is the height of the sprite. sprite is a pointer to the array of unsigned characters which define the shape of the sprite (line by line). vm_addr is the pointer to the video plane; it should be LCD_MEM if you are not using grayscale or the PortSet function. mode is the drawing mode, and it may have one of the following values (these constants are defined in the enum SprtModes):

SPRT_XOR | XOR the sprite into a background. This is used only for non-masked sprites. XOR mode switches every pixel with a corresponding '1' bit in the sprite array from white to black and verse vica.
SPRT_OR | OR the sprite into a background. This is mainly used for masked sprites together with SPRT_AND. OR means that every pixel with a corresponding '1' bit in the sprite array will be set to black, but all other pixels stay the same. If you want to turn all other pixels to white instead, one way to achieve this would be to AND the sprite as well.
SPRT_AND | AND the sprite into a background. This is used for masked sprites together with SPRT_OR. AND turns off every pixel with a corresponding '0' bit in the sprite array, but all other pixels remain untouched.

In fact, you can use one of two techniques to draw sprites:

- Non-masked sprites. Using this method, the sprites are simply XORed into the background. This technique was popular in many games on old 8-bit computers. To erase the sprite, it is enough to call the routine again on the same position.
- Masked sprites. This is the more advanced method, which needs more programming practice, but produces much better results. Using this method, you first need to erase a part of the background which occupies a space where the sprite need to be displayed, then to draw the actual sprite shape. To do this, AND the inverse of the sprite mask to the background, then OR the sprite at the same location. However, it is not so easy to restore the background later. For solving this problem, a lot of advanced methods are developed (like "double-buffering", etc.). These methods are quite common in advanced ASM games, and they are explained in many ASM tutorials.

Here is a simple example (called "Masked Sprite"), which first draws a simple "background", then draws a "masked" sprite (which is a simple 8x8 square with solid edges and blank interior) at (30,30):

    // Display a masked sprite over an arbitrary background

    #define USE_TI89              // Compile for TI-89
    #define USE_TI92PLUS          // Compile for TI-92 Plus
    #define USE_V200              // Compile for V200

    #define OPTIMIZE_ROM_CALLS    // Use ROM Call Optimization
    #define MIN_AMS 100           // Compile for AMS 1.00 or higher
    #define SAVE_SCREEN           // Save/Restore LCD Contents

    #include <tigcclib.h>         // Include All Header Files

    // Main Function
    void _main(void)
    {
      static const unsigned char sprite[] = {0xFF,0x81,0x81,0x81,0x81,0x81,0x81,0xFF};
      static const unsigned char imask[] = {(unsigned char)~0xFF,(unsigned char)~0xFF,
        (unsigned char)~0xFF,(unsigned char)~0xFF,(unsigned char)~0xFF,
        (unsigned char)~0xFF,(unsigned char)~0xFF,(unsigned char)~0xFF};
      int i;
      ClrScr ();
      for (i = 0; i <= LCD_WIDTH; i++)
        DrawLine (i, 0, i, LCD_HEIGHT, A_SHADE_NS);  // A simple background
      Sprite8 (30, 30, 8, imask, LCD_MEM, SPRT_AND);
      Sprite8 (30, 30, 8, sprite, LCD_MEM, SPRT_OR);
      ngetchx ();
    }

Here the sprite mask is `{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}`, but it needs to be inverted before passing it to the Sprite8 function. For this purpose, the operator '~' may be very useful. Note that '~' is "bitwise NOT". Of course, ~0xFF is the same as 0x00, but this notation makes the program more clear (and it does not increase the code size, because the inverting will be performed at compilation time). And if you want to use Sprite16 or Sprite32, the notation ~0xFF will still be valid in a short int array, or in a long int array if you add the 'L' suffix (see the respective info about Sprite32). Without this notation, you must use 0x00 in Sprite8, but 0xFF00 in Sprite16, and 0xFFFFFF00 in Sprite32. This is why a notation like ~0xFF is more universal.
Starting from TIGCC v0.91, you can use binary numbers to define your sprites. On the one hand, it makes the program incompatible with other C dialects as well as previous (ancient) versions of TIGCC. On the other hand, it makes designing a sprite much easier and also allows for editing the sprite at a later time without having to reconvert it. The binary representation of the sprite presented above would look like this:

    static const unsigned char sprite[]={
    0b11111111,
    0b10000001,
    0b10000001,
    0b10000001,
    0b10000001,
    0b10000001,
    0b10000001,
    0b11111111};