prosperon/source/engine/warp.c

#include "warp.h"
#include "stb_ds.h"
#include "log.h"

static warp_gravity **warps = NULL;

warp_damp *warp_damp_make()
{
  warp_damp *d = calloc(sizeof(*d),1);
  return d;
}

void warp_damp_free(warp_damp *d) { free(d); }

warp_gravity *warp_gravity_make()
{
  warp_gravity *n = calloc(sizeof(*n),1);
  n->strength = 9.8;
  n->t.scale = (HMM_Vec3){0,-1,0};
  n->planar_force = (HMM_Vec3){0,-1,0};
  arrput(warps, n);
  return n;
}

void warp_gravity_free(warp_gravity *n) {
  for (int i = 0; i < arrlen(warps); i++) {
    if (warps[i] == n) {
      arrdelswap(warps, i);
      break;
    }
  }
  free(n);
}

HMM_Vec3 warp_damp_force(warp_damp *d, HMM_Vec3 pos, HMM_Vec3 vel)
{
  return HMM_MulV3(vel, d->damp);
}

HMM_Vec3 warp_gravity_force(warp_gravity *g, HMM_Vec3 pos)
{
  HMM_Vec3 f = (HMM_Vec3){0,0,0};
  if (g->strength == 0) return f;
  if (g->spherical) {
    HMM_Vec3 dir = HMM_SubV3(g->t.pos, pos);
    float len = HMM_LenV3(dir);
    if (len == 0) return f;
    HMM_Vec3 norm = HMM_NormV3(HMM_SubV3(g->t.pos, pos));
    return HMM_MulV3F(norm,g->strength);
  } else {
    return HMM_MulV3F(g->planar_force, g->strength);
  }
}

HMM_Vec3 warp_force(HMM_Vec3 pos, warpmask mask)
{
  HMM_Vec3 f = (HMM_Vec3){0,0,0};
  for (int i = 0; i < arrlen(warps); i++) {
    if (!(mask & warps[i]->mask)) continue;
    f = HMM_AddV3(f, warp_gravity_force(warps[i], pos));
  }
  return f;
}