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Move stars1 to stars2 and change stars1 to create twinkling

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This commit is contained in:
Michael Hayes
2013-09-25 22:30:12 +12:00
parent 264608fc16
commit ff4c55c03b
6 changed files with 337 additions and 25 deletions
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apps/stars1/stars1.c
+26 -25
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@@ -19,11 +19,11 @@
A lower value (say 5) is useful for flashing pixels. */
#define PWM_RATE 40
/* This is the rate (Hz) that new stars are created. */
#define CREATE_RATE 2
/* Number of twinkling stars. */
#define NUM_STARS 10
/* This is the rate (Hz) of luminance changes. */
#define FADE_RATE 2
#define TWINKLE_RATE 5
#define UPDATE_RATE (LUMINANCE_STEPS * PWM_RATE)
@@ -31,17 +31,17 @@
int main (void)
{
uint16_t fade_tick = 0;
uint16_t twinkle_tick = 0;
uint16_t create_tick = 0;
uint8_t pwm_tick = 0;
uint8_t i;
uint8_t x;
uint8_t y;
uint8_t col;
/* This stores the current luminance level for each pixel. */
uint8_t display[TINYGL_HEIGHT][TINYGL_WIDTH] = {0, };
/* This controls the luminance levels. The maximum value
of LUMINANCE_STEPS gives 100 percent duty cycle.
The first value must be zero to turn star off when it dies. */
of LUMINANCE_STEPS gives 100 percent duty cycle. */
const uint8_t levels[] = {0, 1, 2, 4, 8, 15, 25, 15, 8, 4, 2, 1};
system_init ();
@@ -49,6 +49,19 @@ int main (void)
tinygl_init (LOOP_RATE);
pacer_init (LOOP_RATE);
for (i = 0; i < NUM_STARS; i++)
{
/* Create new star, but not over a live one. */
do
{
x = rand () % TINYGL_WIDTH;
y = rand () % TINYGL_HEIGHT;
} while (display[y][x]);
display[y][x] = rand () % ARRAY_SIZE (levels);
}
while (1)
{
@@ -60,10 +73,10 @@ int main (void)
tinygl_update ();
}
fade_tick++;
if (fade_tick >= UPDATE_RATE / FADE_RATE)
twinkle_tick++;
if (twinkle_tick >= UPDATE_RATE / TWINKLE_RATE)
{
fade_tick = 0;
twinkle_tick = 0;
/* Change luminance of stars until they die. */
for (x = 0; x < TINYGL_WIDTH; x++)
@@ -71,27 +84,15 @@ int main (void)
for (y = 0; y < TINYGL_HEIGHT; y++)
{
if (display[y][x] > 0)
{
display[y][x]--;
if (display[y][x] == 0)
display[y][x] = ARRAY_SIZE (levels) - 1;
}
}
}
}
create_tick++;
if (create_tick >= UPDATE_RATE / CREATE_RATE)
{
create_tick = 0;
/* Create new star, but not over a live one. */
do
{
x = rand () % TINYGL_WIDTH;
y = rand () % TINYGL_HEIGHT;
} while (display[y][x]);
display[y][x] = ARRAY_SIZE (levels) - 1;
}
/* Pulse width modulate pixels to control luminance. */
for (x = 0; x < TINYGL_WIDTH; x++)
{