time step fixed

[physics.git] / src / main.cpp

/*
 *  Copyright (C) 2008 Patrik Gornicz, Gornicz_P (at) hotmail (dot) com.
 *
 *  This program 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 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <GL/gl.h>
#include <GL/glu.h>
#include <SDL/SDL.h>

#include "debug.h"
#include "handleSignal.h"

#include "game.h"
#include "ticks.h"

#include "graphics/graphics.h"
#include "input/inputManager.h"
#include "config/config.h"

/// ***** Private Method Headers *****

void init();

void sighandler( int sig );

void run();
void clean();

void blockUpdate();
void updateFPSCounters();

void handleInput();
void update(float);
void draw();

/// ***** Private Variables *****

// variable used to determine if it is time to shutdown
bool is_Running;

/* Values for the main game loop
 * target_UPS := the amount of updates that is wanted in one second
 * last_Update := stores the time of the last update
 * update_Sum := used to determine the updates needs for this run

 * ups := updates per second for the last second
 * fps := frames per second for the last second
 * update_Count := counts this seconds updates
 * draw_Count  := counts this seconds draws
 * last_Second := stores the time of the last second, used for ups and fps
 */
int target_UPS = 100;
long int last_Block_Update;
float update_Sum = 0;

int ups =100, fps=100;
int update_Count, draw_Count;
long int last_Second;


float target_time_steps_per_second = 1000;
float times;
float time_steps_Count;


// experiment with rolling averages
float rUpdate = 100;
float rDraw = 100;
float rInput = 100;
float rRun = 100;

float num = 10;


/// ***** MAIN Method *****
int main()
{
    init();
    run();
    clean();
    return 0;
}

/// ***** Initializers/Cleaners *****

void init()
{
    installSignal();

    graphics::init();

    game::init();

    input::init();

    cfg::init();

#ifdef DEBUGGING
    cout << "Initialization Complete" << endl;
#endif
}

void clean()
{
#ifdef DEBUGGING
    cout << "Cleaning up" << endl;
#endif

    cfg::clean();

    input::clean();

    game::clean();

    graphics::clean();
}

/// ***** Private Methods *****

float total = 0;

void run()
{
    is_Running = true;
    last_Block_Update = tickCountMicro();
    last_Second = tickCountMicro();

    while(is_Running)
    {
        long int time;

        time = tickCountMicro();
            blockUpdate();
            updateFPSCounters();
            draw();
        time = tickCountMicro() - time;

        rRun = (rRun * (num-1) + time) / num;

        //cout << "total:\t" << total << endl;
        //cout << "rR:\t" << rRun << endl;
        //total = 0;
    }
}

void blockUpdate()
{
    long int start = tickCountMicro();
    long int diff = start - last_Block_Update;

    //cout << "Block" << endl;

    // Calculate the updates that should be run for the next draw
    update_Sum += diff / (1000000 / (float)target_UPS);

    // insures the float to int cast is done once.
    int iupdate_sum = (int)update_Sum;

    // TODO the main run loop needs to be tested and pruned
    if (iupdate_sum > 0)
    {
        // Calculate a time step that spreads the updates out as much as possible
        // used because really quick updates are nearly wasted

        //float time_step = ((float)diff) / iupdate_sum / 1000;
        //float time_step = 1000 / (100000 / rUpdate) / iupdate_sum;
        float time_step = 10;

        // run the updates
        for (int i = 0; i < iupdate_sum; i++)
        {
            handleInput();
            update(time_step);
        }
        // remove the updates that where run from the sum
        update_Sum -= iupdate_sum;
        last_Block_Update = tickCountMicro();
    }
}

void updateFPSCounters()
{
    // Check if a second has passed to recalculate UPS and FPS
    if (tickCountMicro() - last_Second >= 1000000)
    {
        ups = update_Count;
        fps = draw_Count;
        times = time_steps_Count;
        update_Count = 0;
        draw_Count = 0;
        time_steps_Count = 0;

        last_Second = tickCountMicro();

#ifdef FPSUPS
        cout << "ups:\t" << ups << endl;
        cout << "fps:\t" << fps << endl;
        cout << "times:\t" << times << endl;
#endif
    }
}

void handleInput()
{
    long int time;

    time = tickCountMicro();
        input::update();

        game::handleInput();

        if(cfg::endGame())
            is_Running = false;
    time = tickCountMicro() - time;

    rInput = (rInput*(num-1) + time) /num;

    total += rInput;
}

void update(float time_step)
{
    long int time;

    update_Count++;
    time_steps_Count += time_step;

    time = tickCountMicro();
        game::update(time_step);
    time = tickCountMicro() - time;

    rUpdate = (rUpdate * (num-1) + time) / num;

    //cout << "ts:\t" << time_step << endl;
    //cout << "ru:\t" << rUpdate << endl;

    total += rUpdate;
}

void draw()
{
    long int time;

    draw_Count++;

    time = tickCountMicro();
        game::draw();

        SDL_GL_SwapBuffers();

        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

//        SDL_Delay(10);
    time = tickCountMicro() - time;

    rDraw = (rDraw*(num-1) + time) /num;

    //cout << "rd:\t" << rDraw << endl;

    total += rDraw;
}