graphics/Effects/ParallaxScrolling/ParallaxScrolling.c

/*---------------------------------------------------------------------------------
 
 
    Simple parallax scrolling effect demo
    -- alekmaul
 
 
---------------------------------------------------------------------------------*/
#include <snes.h>
 
extern char back, back_end;
extern char palette;
extern char map;
 
//---------------------------------------------------------------------------------
int main(void)
{
    // Read tiles to VRAM
    bgInitTileSet(0, &back, &palette, 0, (&back_end - &back), 16 * 2 * 2, BG_16COLORS, 0x1000);
 
    // Copy Map to VRAM
    bgInitMapSet(0, &map, 64 * 32 * 2, SC_64x32, 0x0000);
 
    // Now Put in 16 color mode and disable other BGs except 1st one
    setMode(BG_MODE1, 0);
    bgSetDisable(1);
    bgSetDisable(2);
    setScreenOn();
 
    // Init HDMA table
    // 72 lines with 1 scrolling effect (top of screen)
    // Next 88 lines with 2 scrolling effect (middle of screen)
    // Next 64 lines with 4 scrolling effect (end of screen)
    HDMATable16[0] = 72;
    *(u16 *)&(HDMATable16 + 1) = 1;
    HDMATable16[3] = 88;
    *(u16 *)&(HDMATable16 + 4) = 2;
    HDMATable16[6] = 64;
    *(u16 *)&(HDMATable16 + 7) = 4;
    HDMATable16[9] = 0x00; // end of hdma table
 
    // Wait for key to change gradient
    while (1)
    {
        // Update scrolling
        setParallaxScrolling(0);
 
        // Change scrolling inside HDMA table
        *(u16 *)&(HDMATable16 + 1) += 1;
        *(u16 *)&(HDMATable16 + 4) += 2;
        *(u16 *)&(HDMATable16 + 7) += 4;
        WaitForVBlank();
    }
    return 0;
}