74 lines
1.4 KiB
C
74 lines
1.4 KiB
C
#include <inttypes.h>
|
|
#include "../config.h"
|
|
#include "../random/prng.h"
|
|
#include "../pixel.h"
|
|
#include "../util.h"
|
|
|
|
//dots flying from left to right
|
|
void flyingdots()
|
|
{
|
|
uint8_t rowbuffer[NUM_ROWS], i, j;
|
|
pixel p;
|
|
|
|
clear_screen(0);
|
|
|
|
//set the pixels to the leftmost columns
|
|
p.x = NUM_COLS-1;
|
|
|
|
//clear rowbuffer
|
|
for(i = 0; i < NUM_ROWS; i++)
|
|
{
|
|
rowbuffer[i] = 0;
|
|
}
|
|
|
|
//produce 200 dots
|
|
for (i = 0; i < 200; i++)
|
|
{
|
|
//the idea is to use a buffer for one row
|
|
//first all pixels that are in the rowbuffer
|
|
//will be reduced in brightness
|
|
//(as you can assume that they were
|
|
// drawn in the last round and need to be dimmed
|
|
// to produce the trail effect)
|
|
//and then a new one will be added
|
|
//finally the rowbuffer is drawn
|
|
|
|
//loop through all pixels in our rowbuffer
|
|
for(j = 0; j < NUM_ROWS; j++)
|
|
{
|
|
//add a trail or remove the pixel, if it was bright enough
|
|
if(rowbuffer[j] > 0)
|
|
{
|
|
rowbuffer[j]--;
|
|
}
|
|
}
|
|
|
|
//choose row and brightness
|
|
p.y = random8() % NUM_ROWS;
|
|
rowbuffer[p.y] += (random8() % (NUMPLANE)) + 1;
|
|
|
|
//cap max brightness
|
|
if(rowbuffer[p.y] > NUMPLANE)
|
|
{
|
|
rowbuffer[p.y] = NUMPLANE;
|
|
}
|
|
|
|
//draw all pixels in our rowbuffer
|
|
for(j = 0; j < NUM_ROWS; j++)
|
|
{
|
|
if(rowbuffer[j] > 0)
|
|
{
|
|
p.y = j;
|
|
setpixel(p, rowbuffer[j]);
|
|
}
|
|
}
|
|
|
|
//shift the picture right
|
|
//(yes, shift_pixmap_l shifts the picture right)
|
|
shift_pixmap_l();
|
|
|
|
//wait a bit
|
|
wait(100);
|
|
}
|
|
}
|