void main(void)
{
static unsigned char i,row;
static int y;
static unsigned int adr;
pal_col(1,0x30);//set while color
y=0;
update_list[0]=0x20|NT_UPD_HORZ;//horizontal update sequence, dummy address
update_list[1]=0x00;
update_list[2]=32;//update sequence is 32 tiles wide
update_list[3+32]=NT_UPD_EOF;
set_vram_update(update_list);
ppu_on_all();//enable rendering
while(1)
{
scroll(0,y);//scroll value will be applied on the next nmi
if(!(y&7))//put new row every 8 pixels
{
row=(y>>3)+59;//get row number for update, it is shifted just above the visible part of the screen
if(row>=60) row-=60;//keep the row number within the limits
adr=row<<5;//convert Y from pixels to tiles (row=y/8), then to nametable offset (offset=row*32)
if(adr<960) adr=adr|NAMETABLE_A; else adr=(adr-960)|NAMETABLE_C;//add base address of one of two nametables
update_list[0]=MSB(adr)|NT_UPD_HORZ;//set the address
update_list[1]=LSB(adr);
for(i=0;i<32;++i) update_list[3+i]=0x10+(rand8()&7);//fill row buffer with random tiles
}
--y;//next pixel
if(y<0) y=240*2-1;//keep Y within the total height of two nametables
ppu_wait_nmi();
}
void pal_fade_to(unsigned to)
{
if(!to) music_stop();
while(bright!=to)
{
delay(4);
if(bright<to) ++bright; else --bright;
pal_bright(bright);
}
if(!bright)
{
ppu_off();
set_vram_update(0,0);
scroll(0,0);
}
}
