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#include <stdio.h>
#include <stdlib.h>
#include <SDL2/SDL.h>
#include "chip8.h"
/* references
* https://austinmorlan.com/posts/chip8_emulator/
* http://www.multigesture.net/articles/how-to-write-an-emulator-chip-8-interpreter/
* http://mattmik.com/files/chip8/mastering/chip8.html (lots of info)
* http://devernay.free.fr/hacks/chip8/C8TECH10.HTM#0.1
*/
#define VIDEO_SCALE 10
SDL_Window *window;
SDL_Renderer *renderer;
SDL_Texture *texture;
void init_video();
void update_video();
void toggle_pixel(int x, int y);
void quit();
void usage(char *);
extern uint32_t video[WIDTH*HEIGHT];
void
usage(char *program)
{
printf("usage: %s [romfile]\n", program);
}
void
quit()
{
SDL_DestroyTexture(texture);
SDL_DestroyRenderer(renderer);
SDL_DestroyWindow(window);
SDL_Quit();
}
void
init_video()
{
SDL_Init(SDL_INIT_VIDEO);
window = SDL_CreateWindow("chip8 interpreter", 0, 0, WIDTH*VIDEO_SCALE, HEIGHT*VIDEO_SCALE, SDL_WINDOW_SHOWN);
renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_STREAMING, WIDTH, HEIGHT);
}
void
update_video()
{
static int count = 0;
printf("frame %d\n", count++);
/*
for (uint32_t i = 0 ;i < WIDTH*HEIGHT; i++)
{
video[i] = (255<<16)|(255<<8)|255;
}
video[0] = (255);
video[1] = (255<<8);
video[2] = (255<<16);
*/
toggle_pixel(0, 0);
SDL_UpdateTexture(texture, NULL, video, sizeof(video[0])*WIDTH);
SDL_RenderClear(renderer);
SDL_RenderCopy(renderer, texture, NULL, NULL);
SDL_RenderPresent(renderer);
}
void
toggle_pixel(int x, int y)
{
// TODO: clean
uint32_t dos = video[WIDTH*y+x];
if (dos <= 0)
video[WIDTH*y+x] = (255<<16)|(255<<8)|255;
else
video[WIDTH*y+x] = 0;
}
int main(int argc, char *argv[])
{
if (argc < 2)
{
usage(argv[0]);
exit(EXIT_FAILURE);
}
if (!load_rom(argv[1]))
{
fprintf(stderr, "cannot start interpreter\n");
exit(EXIT_FAILURE);
}
chip8_init();
init_video();
const int fps = 60;
const int frame_delay = 1000/fps;
uint32_t frame_start;
uint32_t frame_time;
int do_quit = 0;
while(!do_quit)
{
frame_start = SDL_GetTicks();
// logic
update_video();
frame_time = SDL_GetTicks() - frame_start;
if (frame_delay > frame_time)
{
SDL_Delay(frame_delay - frame_time);
}
}
quit();
return EXIT_SUCCESS;
}
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