musiclight2/main.c

/*
 * vim: sw=2 ts=2 expandtab
 *
 * THE PIZZA-WARE LICENSE" (derived from "THE BEER-WARE LICENCE"):
 * <cfr34k@tkolb.de> wrote this file. As long as you retain this notice you can
 * do whatever you want with this stuff. If we meet some day, and you think
 * this stuff is worth it, you can buy me a pizza in return. - Thomas Kolb
 */

#include <pthread.h>
#include <semaphore.h>

#include <stdio.h>
#include <math.h>
#include <string.h>
#include <stdint.h>
#include <malloc.h>

#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>

#include "lua_utils.h"
#include "lua_wrappers.h"

#include "fft.h"
#include "utils.h"
#include "ws2801.h"

#include "config.h"

// Frames per second
#define FPS ((double)BUFFER_PARTS * SAMPLE_RATE / BLOCK_LEN)

// Number of new samples put into the buffer each frame
#define READ_SAMPLES (BLOCK_LEN / BUFFER_PARTS)

double fft[BLOCK_LEN];
sample signal[BLOCK_LEN];
double rms;
double lastUpdateTime = 0;

sem_t  fftSemaphore;

int running = 1;

void* fft_thread(void *param) {
	sample       buffer[BLOCK_LEN];
	sample       block[BLOCK_LEN];
	double       fftOutReal[BLOCK_LEN], fftOutImag[BLOCK_LEN];
	double       tmpFFT[BLOCK_LEN];
  double       tmpRMS;

	double       nextFrame = get_hires_time() + 0.05;
	double       curTime;

	int i;

	init_fft();

	while(running) {
		// shift the buffer left
		memmove(buffer, buffer + READ_SAMPLES,
		        (BLOCK_LEN - READ_SAMPLES) * sizeof(sample));

		size_t ret = fread(buffer + (BLOCK_LEN - READ_SAMPLES),
		                   sizeof(sample), READ_SAMPLES, stdin);
		if(ret != READ_SAMPLES) {
			break;
		}

		memcpy(block, buffer, BLOCK_LEN * sizeof(sample));

		apply_hanning(block);
		fft_transform(block, fftOutReal, fftOutImag);
		complex_to_absolute(fftOutReal, fftOutImag, tmpFFT);

    tmpRMS = 0;
    for(i = 0; i < BLOCK_LEN; i++) {
      tmpRMS += buffer[i]*buffer[i];
    }
    tmpRMS = sqrt(tmpRMS/BLOCK_LEN);

    // --- SAFE SECTION ---
    sem_wait(&fftSemaphore);

    memcpy(fft, tmpFFT, sizeof(fft));
    memcpy(signal, buffer, sizeof(signal));
    rms = tmpRMS;

		curTime = get_hires_time();
    lastUpdateTime = curTime;

		sem_post(&fftSemaphore);
    // --- END SAFE SECTION ---

		if(curTime > nextFrame + 0.05) {
			printf("Frame too late! Skipping.\n");
			nextFrame = -1;
		}

		if(curTime < nextFrame - 0.05) {
			printf("Frame too early.\n");
			nextFrame = -1;
		}

		if(nextFrame < 0) {
			printf("Frame time reset.\n");
			nextFrame = curTime;
		}

		nextFrame += 1.000/FPS;
		sleep_until(nextFrame);
	}

	return NULL;
}

double gamma_correct(double d, double gamma) {
  return pow(d, gamma);
}

int main(int argc, char **argv) {
  double nextFrame = get_hires_time() + LED_INTERVAL;

	int i;
	pthread_t fftThread;

  int active = 1;

  double *red;
  double *green;
  double *blue;

  int useFading, fadeStep;

  if(argc < 2) {
    fprintf(stderr, "LUA script file must be given as command line argument!\n");
    return 1;
  }

  // initialize lua
  lua_State *L = lua_open();

  // load the lua libraries
  luaL_openlibs(L);

  // register local functions
  lua_register_funcs(L);

  // load the configuration from "config.lua"
  if(luaL_dofile(L, "config.lua")) {
    lua_showerror(L, "luaL_dofile(config.lua) failed.");
    return 1;
  }

  lua_getglobal(L, "WS2801_HOST");
  if(!lua_isstring(L, -1)) return 2;
  const char *host = lua_tostring(L, -1);

  lua_getglobal(L, "WS2801_PORT");
  if(!lua_isnumber(L, -1)) return 2;
  unsigned short port = lua_tointeger(L, -1);

  lua_getglobal(L, "GAMMA");
  if(!lua_isnumber(L, -1)) return 2;
  double gamma = lua_tonumber(L, -1);

  lua_getglobal(L, "NUM_MODULES");
  if(!lua_isnumber(L, -1)) return 2;
  int num_modules = lua_tointeger(L, -1);

  lua_getglobal(L, "CENTER_MODULE");
  if(!lua_isnumber(L, -1)) return 2;
  int center_module = lua_tointeger(L, -1);

  // allocate arrays
  red = malloc(num_modules * sizeof(double));
  green = malloc(num_modules * sizeof(double));
  blue = malloc(num_modules * sizeof(double));

  // load and initialize the script
  if(luaL_loadfile(L, argv[1])) {
    lua_showerror(L, "luaL_loadfile(cmdline_argument) failed.");
  }

  // priming call: read the lua file to make functions known
  if(lua_pcall(L, 0, 0, 0)) {
    lua_showerror(L, "lua_pcall failed.");
  }

  // call the init function
  lua_getglobal(L, "init");
  lua_pushnumber(L, num_modules);
  lua_pushnumber(L, center_module);
  if(lua_pcall(L, 2, 1, 0)) {
    lua_showerror(L, "lua_pcall(init) failed.");
  }

  fadeStep = lua_tointeger(L, -1);
  useFading = fadeStep > 0;
  if(useFading) {
    ws2801_set_fadestep(fadeStep);
    printf("Fading enabled with fadestep %i.\n", fadeStep);
  }

  // initialize the WS2801 library
  printf("Connecting to %s:%i\n", host, port);
  ws2801_init(host, port);

	// create semaphores
	sem_init(&fftSemaphore, 0, 1);

	// run the fft thread
	pthread_create(&fftThread, NULL, fft_thread, NULL);

	while(running) {
    if(active) {
      // call the periodic() function from LUA
      lua_getglobal(L, "periodic");
      if(lua_pcall(L, 0, 3, 0)) { // no arguments, 3 return values
        lua_showerror(L, "lua_pcall(periodic) failed.");
      }

      // read the return values (reverse order, as lua uses a stack)
      lua_readdoublearray(L, blue, num_modules);
      lua_readdoublearray(L, green, num_modules);
      lua_readdoublearray(L, red, num_modules);

      if(useFading) {
        for(i = 0; i < num_modules; i++) {
          ws2801_fade_color(i,
              255 * gamma_correct(red[i], gamma),
              255 * gamma_correct(green[i], gamma),
              255 * gamma_correct(blue[i], gamma));
        }
        ws2801_commit();
      } else {
        for(i = 0; i < num_modules; i++) {
          ws2801_set_color(i,
              255 * gamma_correct(red[i], gamma),
              255 * gamma_correct(green[i], gamma),
              255 * gamma_correct(blue[i], gamma));
        }
        ws2801_commit();
      }

      if(lastUpdateTime < nextFrame - 1) {
        printf("Idle for 1 second -> stopping updates.\n");

        for(i = 0; i < num_modules; i++) {
          ws2801_fade_color(i, 20, 20, 20);
        }
        ws2801_commit();

        active = 0;
      }
    } else if(lastUpdateTime > nextFrame - 1) {
      printf("Resuming updates.\n");
      active = 1;
    }

    nextFrame += LED_INTERVAL;
    sleep_until(nextFrame);
	}

  ws2801_shutdown();

  // free arrays
  free(red);
  free(green);
  free(blue);

	pthread_join(fftThread, NULL);

  lua_close(L);

	return 0;
}