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8bitworkshop/presets/nes/vrambuffer.c
2019-03-11 12:55:29 -04:00

60 lines
1.3 KiB
C

#include "neslib.h"
#include <string.h>
#include <stdio.h>
// VRAM buffer module
#include "vrambuf.h"
//#link "vrambuf.c"
// link the pattern table into CHR ROM
//#link "chr_generic.s"
// function to scroll window up and down until end
void scroll_demo() {
int x = 0; // x scroll position
int y = 0; // y scroll position
int dy = 1; // y scroll direction
// 32-character array for string-building
char str[32];
// clear string array
memset(str, 0, sizeof(str));
// infinite loop
while (1) {
// write message to string array
sprintf(str, "%6x %6d", y, y);
// write string array into VRAM buffer
putbytes(NTADR_A(2,y%30), str, 32);
// wait for next frame
// and flush VRAM buffer
cflushnow();
// set scroll (shadow) registers
scroll(x, y);
// update y variable
y += dy;
// change direction when hitting either edge of scroll area
if (y >= 479) dy = -1;
if (y == 0) dy = 1;
}
}
// main function, run after console reset
void main(void) {
// set palette colors
pal_col(1,0x04);
pal_col(2,0x20);
pal_col(3,0x30);
// clear vram buffer
cclearbuf();
// set NMI handler
set_vram_update(updbuf);
// enable PPU rendering (turn on screen)
ppu_on_all();
// scroll window back and forth
scroll_demo();
}