// Math constants.
#define M_PI 3.14159

#define R_IDEAL_GAS_EQUATION       8.31    // kPa*L/(K*mol).
#define ONE_ATMOSPHERE             101.325 // kPa.
#define IDEAL_GAS_ENTROPY_CONSTANT 1164    // (mol^3 * s^3) / (kg^3 * L).

// Radiation constants.
#define STEFAN_BOLTZMANN_CONSTANT    5.6704e-8 // W/(m^2*K^4).
#define COSMIC_RADIATION_TEMPERATURE 3.15      // K.
#define AVERAGE_SOLAR_RADIATION      200       // W/m^2. Kind of arbitrary. Really this should depend on the sun position much like solars.
#define RADIATOR_OPTIMUM_PRESSURE    3771      // kPa at 20 C. This should be higher as gases aren't great conductors until they are dense. Used the critical pressure for air.
#define GAS_CRITICAL_TEMPERATURE     132.65    // K. The critical point temperature for air.

#define RADIATOR_EXPOSED_SURFACE_AREA_RATIO 0.04 // (3 cm + 100 cm * sin(3deg))/(2*(3+100 cm)). Unitless ratio.
#define HUMAN_EXPOSED_SURFACE_AREA          5.2 //m^2, surface area of 1.7m (H) x 0.46m (D) cylinder

#define T0C  273.15 //    0.0 degrees celcius
#define T20C 293.15 //   20.0 degrees celcius
#define TCMB 2.7    // -270.3 degrees celcius

#define QUANTIZE(variable) (round(variable,0.0001))
#define CEILING(x, y) ( -round(-(x) / (y)) * (y) )

#define INFINITY	1.#INF

// A neat little helper to convert the value X, that's between imin and imax, into a value
// that's proportionally scaled and in range of omin and omax.
#define MAP(x, imin, imax, omin, omax) ((x - imin) * (omax - omin) / (imax - imin) + omin)

#define RAND_F(LOW, HIGH) (rand()*(HIGH-LOW) + LOW)

//"fancy" math for calculating time in ms from tick_usage percentage and the length of ticks
//percent_of_tick_used * (ticklag * 100(to convert to ms)) / 100(percent ratio)
//collapsed to percent_of_tick_used * tick_lag
#define TICK_DELTA_TO_MS(percent_of_tick_used) ((percent_of_tick_used) * world.tick_lag)
#define TICK_USAGE_TO_MS(starting_tickusage) (TICK_DELTA_TO_MS(world.tick_usage-starting_tickusage))

//time of day but automatically adjusts to the server going into the next day within the same round.
//for when you need a reliable time number that doesn't depend on byond time.
#define REALTIMEOFDAY (world.timeofday + (MIDNIGHT_ROLLOVER * MIDNIGHT_ROLLOVER_CHECK))
#define MIDNIGHT_ROLLOVER_CHECK ( rollovercheck_last_timeofday != world.timeofday ? update_midnight_rollover() : midnight_rollovers )

#define round_duration_in_ticks (round_start_time ? world.time - round_start_time : 0)
#define station_time_in_ticks (roundstart_hour HOURS + round_duration_in_ticks)