borgware-2d/animations/plasma.c

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#include <math.h> // Floating point math is dog slow on AVR, but I don't care.
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#include <stdint.h>
#include "../config.h"
#include "../pixel.h"
#include "../util.h"
#include "plasma.h"
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#ifndef __AVR__
#define FRAME_TICK 80
#define FRAME_COUNT 750
#else
#define FRAME_TICK 1
#define FRAME_COUNT 600
#endif
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#define PLASMA_X (1.0 / (NUM_COLS / (2.0 * M_PI)))
/**
* calculates the distance between two points
* @param x1 x coordinate of the first point
* @param y1 y coordinate of the first point
* @param x2 x coordinate of the second point
* @param y2 y coordinate of the second point
* @return distance between the points
*/
static double dist(double x1, double y1, double x2, double y2)
{
return sqrt(((x1 - x2) * (x1 - x2)) + ((y1 - y2) * (y1 - y2)));
}
/**
* draws a simple plasma effect
*/
void plasma(void)
{
for (double t = 0; t < (FRAME_COUNT / 10.0); t = t + 0.1) {
for (unsigned char x = 0; x < NUM_COLS; ++x)
{
for (unsigned char y = 0; y < NUM_ROWS; ++y)
{
double nColor1 = sin(x * PLASMA_X + t) + 1;
double nColor2 = sin(dist(x, y, NUM_COLS * sin(t) + NUM_COLS,
NUM_ROWS * cos(t) + NUM_ROWS) * PLASMA_X) + 1;
unsigned char nColor =
((nColor1 + nColor2) * (NUMPLANE - 1)) / 2;
setpixel((pixel){x, y}, nColor);
}
}
wait(FRAME_TICK);
}
}