warzone2100/lib/gamelib/gtime.c

275 lines
6.9 KiB
C

/*
This file is part of Warzone 2100.
Copyright (C) 1999-2004 Eidos Interactive
Copyright (C) 2005-2009 Warzone Resurrection Project
Warzone 2100 is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
Warzone 2100 is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Warzone 2100; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/*
* GTime.c
*
* Provide a game clock that runs only when the game runs.
*
*/
#include <SDL_timer.h>
#include <time.h>
#include "lib/framework/frame.h"
#include "gtime.h"
#define GTIME_MINFRAME (GAME_TICKS_PER_SEC/80)
/* See header file for documentation */
UDWORD gameTime = 0, deltaGameTime = 0, graphicsTime = 0, deltaGraphicsTime = 0, realTime = 0, deltaRealTime = 0;
float gameTimeFraction = 0.0, graphicsTimeFraction = 0.0, realTimeFraction = 0.0;
/** The current clock modifier. Set to speed up the game. */
static float modifier;
/// The graphics time, the last time clock speed was set.
static UDWORD timeOffset;
/// The real time, the last time the clock speed was set.
static UDWORD baseTime;
/** When the game paused, so that gameTime can be adjusted when the game restarts. */
static SDWORD pauseStart;
/**
* Count how many times gameTimeStop has been called without a game time start.
* We use this to ensure that we can properly nest stop commands.
**/
static UDWORD stopCount;
/* Initialise the game clock */
void gameTimeInit(void)
{
/* Start the timer off at 2 so that when the scripts strip the map of objects
* for multiPlayer they will be processed as if they died. */
// Setting game and graphics time.
setGameTime(2);
// Setting real time.
realTime = baseTime;
deltaRealTime = 0;
realTimeFraction = 0.f;
modifier = 1.0f;
stopCount = 0;
}
extern void setGameTime(uint32_t newGameTime)
{
// Setting game time.
gameTime = newGameTime;
deltaGameTime = 0;
gameTimeFraction = 0.f;
// Setting graphics time to game time.
graphicsTime = gameTime;
deltaGraphicsTime = gameTime;
graphicsTimeFraction = 0.f;
timeOffset = graphicsTime;
baseTime = SDL_GetTicks();
// Not setting real time.
}
UDWORD getModularScaledGameTime(UDWORD timePeriod, UDWORD requiredRange)
{
return gameTime%timePeriod * requiredRange/timePeriod;
}
UDWORD getModularScaledGraphicsTime(UDWORD timePeriod, UDWORD requiredRange)
{
return graphicsTime%timePeriod * requiredRange/timePeriod;
}
UDWORD getModularScaledRealTime(UDWORD timePeriod, UDWORD requiredRange)
{
return realTime%timePeriod * requiredRange/timePeriod;
}
/* Call this each loop to update the game timer */
bool logicalUpdates = true;
void gameTimeUpdate()
{
uint32_t currTime = SDL_GetTicks();
bool sane = logicalUpdates;
if (currTime < realTime)
{
// Warzone 2100, the first relativistic computer game!
// Exhibit A: Time travel
// force a rebase
debug(LOG_WARNING, "Time travel is occurring! Clock went back in time a bit from %d to %d!\n", baseTime, currTime);
baseTime = currTime;
timeOffset = graphicsTime;
}
// Do not update the game time if gameTimeStop has been called
if (stopCount == 0)
{
// Calculate the new game time
uint32_t scaledCurrTime = (currTime - baseTime)*modifier + timeOffset;
if (scaledCurrTime < graphicsTime) // Make sure the clock doesn't step back at all.
{
debug(LOG_WARNING, "Rescaled clock went back in time a bit from %d to %d!\n", graphicsTime, scaledCurrTime);
scaledCurrTime = graphicsTime;
baseTime = currTime;
timeOffset = graphicsTime;
}
// Calculate the time for this frame
deltaGraphicsTime = scaledCurrTime - graphicsTime;
// Adjust deltas.
if (sane)
{
if (scaledCurrTime >= gameTime)
{
if (scaledCurrTime > gameTime + GAME_TICKS_PER_UPDATE)
{
// Game isn't updating fast enough...
uint32_t slideBack = deltaGraphicsTime - GAME_TICKS_PER_UPDATE;
baseTime += slideBack / modifier; // adjust the addition to base time
deltaGraphicsTime -= slideBack;
}
deltaGameTime = GAME_TICKS_PER_UPDATE;
}
else
{
deltaGameTime = 0;
}
}
else
{
deltaGameTime = scaledCurrTime - gameTime;
// Limit the frame time
if (deltaGraphicsTime > GTIME_MAXFRAME)
{
uint32_t slideBack = deltaGraphicsTime - GTIME_MAXFRAME;
baseTime += slideBack / modifier; // adjust the addition to base time
deltaGraphicsTime -= slideBack;
deltaGameTime -= slideBack; // If !sane, then deltaGameTime == deltaGraphicsTime.
}
}
// Store the game and graphics times
gameTime += deltaGameTime;
graphicsTime += deltaGraphicsTime;
}
// now update realTime which does not pause
// Store the real time
deltaRealTime = currTime - realTime;
realTime += deltaRealTime;
// Pre-calculate fraction used in timeAdjustedIncrement
gameTimeFraction = (float)deltaGameTime / (float)GAME_TICKS_PER_SEC;
graphicsTimeFraction = (float)deltaGraphicsTime / (float)GAME_TICKS_PER_SEC;
realTimeFraction = (float)deltaRealTime / (float)GAME_TICKS_PER_SEC;
ASSERT(graphicsTime <= gameTime, "Trying to see the future.");
}
// reset the game time modifiers
void gameTimeResetMod(void)
{
timeOffset = graphicsTime;
baseTime = SDL_GetTicks();
modifier = 1.0f;
}
// set the time modifier
void gameTimeSetMod(float mod)
{
gameTimeResetMod();
modifier = mod;
}
// get the current time modifier
void gameTimeGetMod(float *pMod)
{
*pMod = modifier;
}
BOOL gameTimeIsStopped(void)
{
return (stopCount != 0);
}
/* Call this to stop the game timer */
void gameTimeStop(void)
{
if (stopCount == 0)
{
pauseStart = SDL_GetTicks();
debug( LOG_NEVER, "Clock paused at %d\n", pauseStart);
}
stopCount += 1;
}
/* Call this to restart the game timer after a call to gameTimeStop */
void gameTimeStart(void)
{
if (stopCount == 1)
{
// shift the base time to now
timeOffset = gameTime;
baseTime = SDL_GetTicks();
}
if (stopCount > 0)
{
stopCount --;
}
}
/* Call this to reset the game timer */
void gameTimeReset(UDWORD time)
{
// reset the game timers
setGameTime(time);
gameTimeResetMod();
realTime = SDL_GetTicks();
deltaRealTime = 0;
}
void getTimeComponents(UDWORD time, UDWORD *hours, UDWORD *minutes, UDWORD *seconds)
{
UDWORD h, m, s;
UDWORD ticks_per_hour, ticks_per_minute;
/* Ticks in a minute */
ticks_per_minute = GAME_TICKS_PER_SEC * 60;
/* Ticks in an hour */
ticks_per_hour = ticks_per_minute * 60;
h = time / ticks_per_hour;
m = (time - (h * ticks_per_hour)) / ticks_per_minute;
s = (time - ((h * ticks_per_hour) + (m * ticks_per_minute))) / GAME_TICKS_PER_SEC;
*hours = h;
*minutes = m;
*seconds = s;
}