prosperon/source/engine/particle.c

#include "particle.h"
#include "stb_ds.h"

struct emitter make_emitter() {
  struct emitter e = {0};
  return e;
}

struct emitter set_emitter(struct emitter e) {
  arrsetlen(e.particles, e.max);

  e.first = &e.particles[0];

  for (int i = 0; i < arrlen(e.particles) - 1; i++) {
    e.particles[i].next = &e.particles[i + 1];
  }

  return e;
}

void free_emitter(struct emitter e) {
  arrfree(e.particles);
}

void start_emitter(struct emitter e) {
}

void pause_emitter(struct emitter e) {
}

void stop_emitter(struct emitter e) {
}

void emitter_step(struct emitter e, double dt) {
  for (int i = 0; i < arrlen(e.particles); i++) {
    if (e.particles[i].life <= 0)
      continue;

    e.particles[i].pos = cpvadd(e.particles[i].pos, cpvmult(e.particles[i].v, dt));
    e.particles[i].angle += e.particles[i].av * dt;
    e.particles[i].life -= dt;

    if (e.particles[i].life <= 0) {
      e.particles[i].next = e.first;
      e.first = &e.particles[i];
    }
  }
}