chip8screen.c

//
// Created by Paltrickontpb on 30-11-2020.
//

#include "chip8screen.h"
#include <assert.h>
#include <memory.h>

static void chip8_screen_check_bounds(int x, int y){
    assert(x>=0 && x<CHIP8_WIDTH && y>=0 && y<CHIP8_HEIGHT);
}

void chip8_clear_screen(struct chip8_screen *screen){
    memset(screen->pixels, 0, sizeof(screen->pixels));
}

void chip8_screen_set(struct chip8_screen *screen, int x, int y){
    chip8_screen_check_bounds(x,y);
    screen->pixels[y][x] = true;
}

bool chip8_screen_is_set(struct chip8_screen *screen, int x, int y){
    chip8_screen_check_bounds(x,y);
    return screen->pixels[y][x];
}

bool chip8_screen_draw_sprite(struct chip8_screen *screen, int x, int y, const char *sprite, int num){
    bool pixel_collision = false;

    for(int ly=0; ly < num; ly++){
        char c = sprite[ly];
        for(int lx=0; lx<8; lx++){
            if((c & (0b10000000 >> lx)) == 0) continue;
            if(screen->pixels[(ly+y) % CHIP8_HEIGHT][(lx+x) % CHIP8_WIDTH]) pixel_collision = true;
            screen->pixels[(ly+y) % CHIP8_HEIGHT][(lx+x) % CHIP8_WIDTH] ^= true;
        }
    }

    return pixel_collision;
}