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-rw-r--r--modules/sparkler/spark.c63
1 files changed, 63 insertions, 0 deletions
diff --git a/modules/sparkler/spark.c b/modules/sparkler/spark.c
new file mode 100644
index 0000000..ea68ac2
--- /dev/null
+++ b/modules/sparkler/spark.c
@@ -0,0 +1,63 @@
+#include <stdlib.h>
+
+#include "draw.h"
+#include "particle.h"
+#include "particles.h"
+
+/* a "spark" particle type, emitted from behind rockets */
+#define SPARK_MAX_DECAY_RATE 20
+#define SPARK_MIN_DECAY_RATE 2
+#define SPARK_MAX_LIFETIME 150
+#define SPARK_MIN_LIFETIME 1
+
+typedef struct _spark_ctxt_t {
+ int decay_rate;
+ int longevity;
+ int lifetime;
+} spark_ctxt_t;
+
+
+static int spark_init(particles_t *particles, particle_t *p)
+{
+ spark_ctxt_t *ctxt = p->ctxt;
+
+ p->props->drag = 20.0;
+ p->props->mass = 0.1;
+ ctxt->decay_rate = rand_within_range(SPARK_MIN_DECAY_RATE, SPARK_MAX_DECAY_RATE);
+ ctxt->lifetime = ctxt->longevity = rand_within_range(SPARK_MIN_LIFETIME, SPARK_MAX_LIFETIME);
+
+ return 1;
+}
+
+
+static particle_status_t spark_sim(particles_t *particles, particle_t *p)
+{
+ spark_ctxt_t *ctxt = p->ctxt;
+
+ if (!ctxt->longevity || (ctxt->longevity -= ctxt->decay_rate) <= 0) {
+ ctxt->longevity = 0;
+ return PARTICLE_DEAD;
+ }
+
+ return PARTICLE_ALIVE;
+}
+
+
+static void spark_draw(particles_t *particles, particle_t *p, int x, int y, fb_fragment_t *f)
+{
+ spark_ctxt_t *ctxt = p->ctxt;
+
+ if (!draw_pixel(f, x, y, makergb(0xff, 0xa0, 0x20, ((float)ctxt->longevity / ctxt->lifetime)))) {
+ /* offscreen */
+ ctxt->longevity = 0;
+ }
+}
+
+
+particle_ops_t spark_ops = {
+ .context_size = sizeof(spark_ctxt_t),
+ .sim = spark_sim,
+ .init = spark_init,
+ .draw = spark_draw,
+ .cleanup = NULL,
+ };
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