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#include <stdlib.h>
#include "draw.h"
#include "particle.h"
#include "particles.h"
/* a "rocket" particle type */
#define ROCKET_MAX_DECAY_RATE 20
#define ROCKET_MIN_DECAY_RATE 2
#define ROCKET_MAX_LIFETIME 500
#define ROCKET_MIN_LIFETIME 300
#define ROCKETS_MAX 20
#define ROCKETS_XPLODE_MIN_SIZE 2000
#define ROCKETS_XPLODE_MAX_SIZE 8000
extern particle_ops_t burst_ops;
extern particle_ops_t spark_ops;
extern particle_ops_t xplode_ops;
static unsigned rockets_cnt;
typedef struct rocket_ctxt_t {
int decay_rate;
int longevity;
v3f_t wander;
float last_velocity; /* cache velocity to sense violent accelerations and explode when they happen */
} rocket_ctxt_t;
static int rocket_init(particles_t *particles, particle_t *p)
{
rocket_ctxt_t *ctxt = p->ctxt;
if (rockets_cnt >= ROCKETS_MAX) {
return 0;
}
rockets_cnt++;
ctxt->decay_rate = rand_within_range(ROCKET_MIN_DECAY_RATE, ROCKET_MAX_DECAY_RATE);
ctxt->longevity = rand_within_range(ROCKET_MIN_LIFETIME, ROCKET_MAX_LIFETIME);
ctxt->wander.x = (float)(rand_within_range(0, 628) - 314) / 10000.0f;
ctxt->wander.y = (float)(rand_within_range(0, 628) - 314) / 10000.0f;
ctxt->wander.z = (float)(rand_within_range(0, 628) - 314) / 10000.0f;
ctxt->wander = v3f_normalize(&ctxt->wander);
ctxt->last_velocity = p->props->velocity;
p->props->drag = 0.4;
p->props->mass = 0.8;
return 1;
}
static particle_status_t rocket_sim(particles_t *particles, particle_t *p)
{
rocket_ctxt_t *ctxt = p->ctxt;
int i, n_sparks;
if (!ctxt->longevity ||
(ctxt->longevity -= ctxt->decay_rate) <= 0 ||
p->props->velocity - ctxt->last_velocity > p->props->velocity * .05) { /* explode if accelerated too hard (burst) */
int n_xplode;
/* on death we explode */
ctxt->longevity = 0;
/* add a burst shockwave particle at our location
* TODO: need way to supply particle-type-specific parameters at spawn (burst size should derive from n_xplode)
*/
particles_spawn_particle(particles, p, NULL, &burst_ops);
/* add a bunch of new explosion particles */
/* TODO: also particle-type-specific parameters, colors! rocket bursts should be able to vary the color. */
n_xplode = rand_within_range(ROCKETS_XPLODE_MIN_SIZE, ROCKETS_XPLODE_MAX_SIZE);
for (i = 0; i < n_xplode; i++) {
particle_props_t props = *p->props;
particle_ops_t *ops = &xplode_ops;
props.direction.x = ((float)(rand_within_range(0, 314159 * 2) - 314159) / 100000.0);
props.direction.y = ((float)(rand_within_range(0, 314159 * 2) - 314159) / 100000.0);
props.direction.z = ((float)(rand_within_range(0, 314159 * 2) - 314159) / 100000.0);
props.direction = v3f_normalize(&props.direction);
//props->velocity = ((float)rand_within_range(100, 200) / 100000.0);
props.velocity = ((float)rand_within_range(100, 300) / 100000.0);
particles_spawn_particle(particles, p, &props, ops);
}
return PARTICLE_DEAD;
}
#if 1
/* FIXME: this isn't behaving as intended */
p->props->direction = v3f_add(&p->props->direction, &ctxt->wander);
p->props->direction = v3f_normalize(&p->props->direction);
#endif
p->props->velocity += .00003;
/* spray some sparks behind the rocket */
n_sparks = rand_within_range(10, 40);
for (i = 0; i < n_sparks; i++) {
particle_props_t props = *p->props;
props.direction = v3f_negate(&props.direction);
props.direction.x += (float)(rand_within_range(0, 40) - 20) / 100.0;
props.direction.y += (float)(rand_within_range(0, 40) - 20) / 100.0;
props.direction.z += (float)(rand_within_range(0, 40) - 20) / 100.0;
props.direction = v3f_normalize(&props.direction);
props.velocity = (float)rand_within_range(10, 50) / 100000.0;
particles_spawn_particle(particles, p, &props, &spark_ops);
}
ctxt->last_velocity = p->props->velocity;
return PARTICLE_ALIVE;
}
static void rocket_draw(particles_t *particles, particle_t *p, int x, int y, fb_fragment_t *f)
{
rocket_ctxt_t *ctxt = p->ctxt;
if (!draw_pixel(f, x, y, 0xff0000)) {
/* kill off parts that wander off screen */
ctxt->longevity = 0;
}
}
static void rocket_cleanup(particles_t *particles, particle_t *p)
{
rockets_cnt--;
}
particle_ops_t rocket_ops = {
.context_size = sizeof(rocket_ctxt_t),
.sim = rocket_sim,
.init = rocket_init,
.draw = rocket_draw,
.cleanup = rocket_cleanup,
};
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