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