ats_routine.h

#pragma once

// =============================================== ROUTINE ========================================== //
// copied and modefied from: https://gist.github.com/NoelFB/7a5fa66fc29dd7ed1c11042c30f1b00e
//
// Example:
// // Assuming you have a `routine` variable stored somewhere
// rt_begin(routine);
// {
//   // stuff that happens frame 1
// }
// rt_wait(1.0f);
// {
//   // after 1.0s, this block runs
// }
// rt_for(0.25f);
// {
//   // this block repeats for 0.25s
// }
// rt_step();
// {
//   // the following frame, this block is run
// }
// rt_label(0);
// {
//   if (something)
//     rt_repeat();
//
//   // not run if rt_repeat() was called
//   something_else();
// }
// rt_step();
// {
//   if (another) rt_goto(0); // jumps to label 0
//   if (another2) rt_restart();  // jumps to rt_begin
//   // otherwise the next block will be run next frame
// }
// rt_while(condition_is_true);
// {
//   // this is repeated until condition_is_true is false
// }
// rt_end();

typedef struct rt rt;
struct rt {
  i32 at;
  f32 timer;
};

#define RT_LABEL_OFFSET 1147483647

#define rt_hash(tag) (RT_LABEL_OFFSET + (tag))

#define rt_begin(routine, delta_time) \
  if ((routine).timer < 0) { \
    (routine).timer += (delta_time); \
    (routine).timer = clamp_max((routine).timer, 0); \
  } else { \
    rt* __rt = &(routine); \
    f32 __dt = (delta_time); \
    int __mn = 1; \
    switch (__rt->at) { \
      case 0: { \

#define rt_step() \
      } if (__mn) __rt->at = __LINE__; \
      break; \
      case __LINE__: { \

#define rt_label(name) \
      } if (__mn) __rt->at = rt_hash(name); \
      break; \
      case rt_hash(name): { \

#define rt_for(time) \
        rt_step(); \
        if (__rt->timer < time) {  \
          __rt->timer += __dt; \
          __mn = __rt->timer >= time; \
          if (__mn) __rt->timer = 0; \
        } \

#define rt_while(condition) \
      } if (__mn) __rt->at = __LINE__; \
      break; \
      case __LINE__: if (condition) { \
        __mn = 0 \

#define rt_until(condition) \
      } if (__mn) __rt->at = ((condition) ? __LINE__ : -__LINE__); \
      break; \
      case -__LINE__: \
                      if (condition) __rt->at = __LINE__; \
      break; \
      case __LINE__: { \

#define rt_wait(time) \
      } if (__mn) { \
        __rt->timer = -(time); \
        __rt->at = __LINE__; \
      } \
      break; \
      case __LINE__: { \

#define rt_end() \
      } if (__mn) __rt->at = -1; \
      break; \
    } \
  } \
  goto rt_end_of_routine;  \
  rt_end_of_routine: \

// Flow Statements:
// These can be used anywhere between rt_begin and rt_end,
// including if statements, while loops, etc.

// Repeats the block that this is contained within
// Skips the remainder of the block
#define rt_repeat() \
  goto rt_end_of_routine \

// Goes to a given block labeled with `rt_label`
#define rt_goto(name) \
  do { \
    __rt->at = rt_hash(name); \
    goto rt_end_of_routine; \
  } while(0) \

// Restarts the entire Coroutine;
// Jumps back to `rt_begin` on the next frame
#define rt_restart() \
  do { \
    __rt->at = 0; \
    __rt->timer = 0; \
    goto rt_end_of_routine; \
  } while(0) \