gistfile1.txt

typedef struct TimeInfo
{
    uint32_t accum;
    uint32_t delta_error_accum;
    uint32_t previous_tick;
    uint32_t globaltime;
    uint32_t frequency; //like 1/60 in 15.16 fixedpoint
} TimeInfo;


void UpdateTimeAccum(TimeInfo* tinfo)
{
    uint32_t delta, delta_error, tick;
    uint32_t current_tick = SDL_GetTicks();

    if(current_tick < tinfo->previous_tick)
        tick = ((UINT_MAX - tinfo->previous_tick) + current_tick + 1) * 65536;
    else
        tick = (current_tick - tinfo->previous_tick) * 65536;
    delta = tick / 1000;
    delta_error = tick % 1000;
    tinfo->delta_error_accum += delta_error;
    while(tinfo->delta_error_accum >= 1000){
        ++delta;
        tinfo->delta_error_accum -= 1000;
    }
    tinfo->accum += delta;
    tinfo->previous_tick = current_tick;
}

void WorldThink(Object* objs, int count, TimeInfo* tinfo)
{
    while(tinfo->accum >= tinfo->frequency){
        tinfo->globaltime += tinfo->frequency;
        for(int i=0; i<count; ++i)
            UpdateObject(&objs[i], (float)globaltime / 65536.0f);
        tinfo->accum -= tinfo->frequency;
    }
}

void WorldDraw(Object* objs, int count, TimeInfo* tinfo)
{
    for(int i=0; i<count; ++i){
        ObjectState* s0 = objs[i].state[0]; //current state
        ObjectState* s1 = objs[i].state[1]; //next state
        float t = (float)tinfo->accum / tinfo->frequency; //leftover after the integration
        ObjectState* drawstate = Interpolate(s0, s1, t);
        DrawObject(objs[i], drawstate);
    }
}

int main(int argc, const char* argv[])
{
Object objects[128];
TimeInfo tinfo;

/* initialize everything
 ...
*/
    while(running)
    {
        UpdateTimeAccum(&tinfo);
        WorldThink(objects, 128, &tinfo);
        WorldDraw (objects, 128, &tinfo);
    }
    return 0;
}