sparkler: parameterize particles

Having everything in fixed defines severely constrains the
diversity of particle behaviors and appearances.

This commit has been sitting around bitrotting since 2017, but
now that there's all this settings infra. and randomizing via
rtv, it seems worth landing, so I've rebased and am merging to
prevent a bitrot->rebase recurrence.

As-is, this commit ~minimally establishes a somewhat streamlined
parameterizing mechanism w/X-Macro patterns, while wiring up a
few of the obvious use cases surrounding xplode/burst, colorizing
the default sparkler explosions while at it.

It appears that when I first hacked this up I did some
experimentation with parameters as well, so there are some tweaks
to the behavior as opposed to a strict conversion of the fixed
defines to parameters.  They seem minor enough to just leave be.

Plus a few minor optimizations like converting divides to
multiplies were in there.

Future commits can now wire up settings to choose from parameter
presets for different sparklers...

1 files changed, 35 insertions, 21 deletions

diff --git a/src/modules/sparkler/rocket.c b/src/modules/sparkler/rocket.c
index 8afceb4..e0b17a2 100644
--- a/src/modules/sparkler/rocket.c
+++ b/src/modules/sparkler/rocket.c
@@ -1,10 +1,13 @@
+#include <stdarg.h>
 #include <stdlib.h>
 
 #include "til_fb.h"
 
+#include "burst.h"
 #include "helpers.h"
 #include "particle.h"
 #include "particles.h"
+#include "xplode.h"
 
 /* a "rocket" particle type */
 #define ROCKET_MAX_DECAY_RATE	20
@@ -28,8 +31,16 @@ typedef struct rocket_ctxt_t {
 	float		last_velocity;	/* cache velocity to sense violent accelerations and explode when they happen */
 } rocket_ctxt_t;
 
+static unsigned xplode_colors[] = {
+	0xffff00,
+	0xff0000,
+	0xff00ff,
+	0x00ffff,
+	0x0000ff,
+	0x00ff00,
+};
 
-static int rocket_init(particles_t *particles, const particles_conf_t *conf, particle_t *p)
+static int rocket_init(particles_t *particles, const particles_conf_t *conf, particle_t *p, unsigned n_params, va_list params)
 {
 	rocket_ctxt_t	*ctxt = p->ctxt;
 
@@ -41,9 +52,9 @@ static int rocket_init(particles_t *particles, const particles_conf_t *conf, par
 	ctxt->decay_rate = rand_within_range(conf->seedp, ROCKET_MIN_DECAY_RATE, ROCKET_MAX_DECAY_RATE);
 	ctxt->longevity = rand_within_range(conf->seedp, ROCKET_MIN_LIFETIME, ROCKET_MAX_LIFETIME);
 
-	ctxt->wander.x = (float)(rand_within_range(conf->seedp, 0, 628) - 314) / 10000.0f;
-	ctxt->wander.y = (float)(rand_within_range(conf->seedp, 0, 628) - 314) / 10000.0f;
-	ctxt->wander.z = (float)(rand_within_range(conf->seedp, 0, 628) - 314) / 10000.0f;
+	ctxt->wander.x = (float)(rand_within_range(conf->seedp, 0, 628) - 314) * .0001;
+	ctxt->wander.y = (float)(rand_within_range(conf->seedp, 0, 628) - 314) * .0001;
+	ctxt->wander.z = (float)(rand_within_range(conf->seedp, 0, 628) - 314) * .0001;
 	ctxt->wander = v3f_normalize(&ctxt->wander);
 
 	ctxt->last_velocity = p->props->velocity;
@@ -63,31 +74,34 @@ static particle_status_t rocket_sim(particles_t *particles, const particles_conf
 	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;
+		int		n_xplode;
+		unsigned	color = xplode_colors[rand_within_range(conf->seedp, 0, nelems(xplode_colors))];
 		/* 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. */
+		/* how many explosion particles? */
 		n_xplode = rand_within_range(conf->seedp, ROCKETS_XPLODE_MIN_SIZE, ROCKETS_XPLODE_MAX_SIZE);
+
+		/* add a burst shockwave particle at our location, scale force
+		 * and radius according to explosion size.
+		 */
+		particles_spawn_particle(particles, p, NULL, &burst_ops, 1, BURST_PARAM_FORCE_FLOAT, (float)n_xplode * 0.00001f);
+
+		/* add the explosion particles */
 		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(conf->seedp, 0, 314159 * 2) - 314159) / 100000.0);
-			props.direction.y = ((float)(rand_within_range(conf->seedp, 0, 314159 * 2) - 314159) / 100000.0);
-			props.direction.z = ((float)(rand_within_range(conf->seedp, 0, 314159 * 2) - 314159) / 100000.0);
+			props.direction.x = ((float)(rand_within_range(conf->seedp, 0, 31415900 * 2) - 31415900) * .0000001);
+			props.direction.y = ((float)(rand_within_range(conf->seedp, 0, 31415900 * 2) - 31415900) * .0000001);
+			props.direction.z = ((float)(rand_within_range(conf->seedp, 0, 31415900 * 2) - 31415900) * .0000001);
 			props.direction = v3f_normalize(&props.direction);
 
 			//props->velocity = ((float)rand_within_range(100, 200) / 100000.0);
-			props.velocity = ((float)rand_within_range(conf->seedp, 100, 300) / 100000.0);
-			particles_spawn_particle(particles, p, &props, ops);
+			props.velocity = ((float)rand_within_range(conf->seedp, 100, 400) * .00001);
+			particles_spawn_particle(particles, p, &props, ops, 1, XPLODE_PARAM_COLOR_UINT, color);
 		}
 		return PARTICLE_DEAD;
 	}
@@ -106,13 +120,13 @@ static particle_status_t rocket_sim(particles_t *particles, const particles_conf
 
 		props.direction = v3f_negate(&props.direction);
 
-		props.direction.x += (float)(rand_within_range(conf->seedp, 0, 40) - 20) / 100.0;
-		props.direction.y += (float)(rand_within_range(conf->seedp, 0, 40) - 20) / 100.0;
-		props.direction.z += (float)(rand_within_range(conf->seedp, 0, 40) - 20) / 100.0;
+		props.direction.x += (float)(rand_within_range(conf->seedp, 0, 40) - 20) * .01;
+		props.direction.y += (float)(rand_within_range(conf->seedp, 0, 40) - 20) * .01;
+		props.direction.z += (float)(rand_within_range(conf->seedp, 0, 40) - 20) * .01;
 		props.direction = v3f_normalize(&props.direction);
 
-		props.velocity = (float)rand_within_range(conf->seedp, 10, 50) / 100000.0;
-		particles_spawn_particle(particles, p, &props, &spark_ops);
+		props.velocity = (float)rand_within_range(conf->seedp, 10, 50) * .00001;
+		particles_spawn_particle(particles, p, &props, &spark_ops, 0);
 	}
 
 	ctxt->last_velocity = p->props->velocity;