elinux-tcl / rainbows.c

/*
 * blink_test.c
 *
 * Copyright 2012 Christopher De Vries
 * This program is distributed under the Artistic License 2.0, a copy of which
 * is included in the file LICENSE.txt
 */
#include "tclled.h"
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>
#include <math.h>

static const char *device = "/dev/spidev2.0";
static const int leds = 500;
static int continue_looping;

void stop_program(int sig);
void HSVtoRGB(double h, double s, double v, double *r, double *g, double *b);

int main(int argc, char *argv[]) {
  tcl_buffer buf;
  int fd;
  int return_value;
  tcl_color *p;
  int i;
  double h, r, g, b;

  /* Open the device file using Low-Level IO */
  fd = open(device,O_WRONLY);
  if(fd<0) {
    fprintf(stderr,"Error %d: %s\n",errno,strerror(errno));
    exit(1);
  }

  /* Initialize the SPI bus for Total Control Lighting */
  return_value = spi_init(fd);
  if(return_value==-1) {
    fprintf(stderr,"SPI initialization error %d: %s\n",errno, strerror(errno));
    exit(1);
  }

  /* Initialize pixel buffer */
  if(tcl_init(&buf,leds)<0) {
    fprintf(stderr,"Pixel buffer initialization error: Not enough memory.\n");
    exit(1);
  }

  /* Set the gamma correction factors for each color */
  set_gamma(2.2,2.2,2.2);

  /* Blank the pixels */
  for(i=0;i<leds;i++) {
    write_gamma_color(&buf.pixels[i],0x00,0x00,0x00);
  }

  send_buffer(fd,&buf);

  /* Prepare to receive ctrl-c to stop looping */
  continue_looping = 1;
  signal(SIGINT,stop_program);
  h = 0.0;

  /* Loop while continue_looping is true */
  while(continue_looping) {
    h+=2.0;
    if(h>=360.0) h=0.0;
    memmove(buf.pixels+1,buf.pixels,sizeof(tcl_pixel)*(leds-2));
    HSVtoRGB(h,1.0,1.0,&r,&g,&b);
    write_gamma_color(p,(int)(r*255.0),(int)(g*255.0),(int)floor(b*255.0));
    send_buffer(fd,&buf);
    usleep(10000);
  }

  tcl_free(&buf);
  close(fd);
  printf("Program Terminated.\n");

  return 0;
}

void stop_program(int sig) {
  /* Ignore the signal */
  signal(sig,SIG_IGN);

  /* stop the looping */
  continue_looping = 0;

  /* Put the ctrl-c to default action in case something goes wrong */
  signal(sig,SIG_DFL);
}

/* Convert hsv values (0<=h<360, 0<=s<=1, 0<=v<=1) to rgb values (0<=r<=1, etc) */
void HSVtoRGB(double h, double s, double v, double *r, double *g, double *b) {
  int i;
	double f, p, q, t;

	if( s < 1.0e-6 ) {
		/* grey */
		*r = *g = *b = v;
		return;
	}

	h /= 60.0;			        /* Divide into 6 regions (0-5) */
	i = (int)floor( h );
	f = h - (double)i;			/* fractional part of h */
	p = v * ( 1.0 - s );
	q = v * ( 1.0 - s * f );
	t = v * ( 1.0 - s * ( 1.0 - f ) );

	switch( i ) {
		case 0:
		  *r = v;
			*g = t;
			*b = p;
			break;
		case 1:
			*r = q;
			*g = v;
			*b = p;
			break;
		case 2:
			*r = p;
			*g = v;
			*b = t;
			break;
		case 3:
			*r = p;
			*g = q;
			*b = v;
			break;
		case 4:
			*r = t;
			*g = p;
			*b = v;
			break;
		default:		// case 5:
			*r = v;
			*g = p;
			*b = q;
			break;
	}
}
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