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8bitworkshop/presets/coleco/stars.c

82 lines
1.4 KiB
C

#include <stdlib.h>
#include <string.h>
#include <cv.h>
#include <cvu.h>
#define PATTERN ((const cv_vmemp)0x0000)
#define COLOR ((const cv_vmemp)0x2000)
#define IMAGE ((const cv_vmemp)0x1c00)
volatile bool vint;
volatile uint_fast8_t vint_counter;
uint_fast8_t oldcounter;
void vint_handler(void)
{
vint = true;
vint_counter++;
}
void update_stars(void)
{
uint_fast8_t j;
uint_fast8_t tmp = vint_counter;
tmp %= (16 * 8);
for(j = 0; j < 3; j++)
{
cvu_voutb(0x00, PATTERN + j * 256 * 8 + oldcounter);
cvu_voutb(0x10, PATTERN + j * 256 * 8 + tmp);
}
oldcounter = tmp;
}
void init_stars(void)
{
uint_fast8_t i, j, r;
for(j = 0; j < 32; j += rand() % 2)
{
r = rand() % 16;
for(i = 0; i < 24; i++)
{
cvu_voutb(r++, IMAGE + j + i * 32);
r %= 16;
}
}
for(j = 0; j < 3; j++)
cvu_vmemset(COLOR + j * 256 * 8, (CV_COLOR_WHITE << 4) | CV_COLOR_BLACK, 16 * 8);
cvu_voutb(0x10, PATTERN);
oldcounter = 0;
vint_counter = 0;
}
void main(void)
{
cv_set_screen_active(false);
cv_set_image_table(IMAGE);
cv_set_color_table(0x3fff);
cv_set_character_pattern_t(0x1fff);
cv_set_screen_mode(CV_SCREENMODE_BITMAP);
cv_set_vint_handler(&vint_handler);
cvu_vmemset(PATTERN, 0, 8 * 256 * 3);
cvu_vmemset(COLOR, 0, 8 * 256 * 3);
cvu_vmemset(IMAGE, 0xff, 32 * 24);
init_stars();
cv_set_screen_active(true);
for(;;)
{
while(!vint);
update_stars();
vint = false;
}
}