1 files changed, 77 insertions, 0 deletions
diff --git a/code/fe310/eos/eve/eve_track.c b/code/fe310/eos/eve/eve_track.c
new file mode 100644
index 0000000..97ef72b
--- /dev/null
+++ b/code/fe310/eos/eve/eve_track.c
@@ -0,0 +1,77 @@
+#include <stdlib.h>
+#include <math.h>
+
+#include "eve.h"
+
+void eve_track_init(void) {
+    eve_etrack_set(eve_track_inert_init, eve_track_inert_tick, NULL, NULL);
+}
+
+void eve_track_set(uint8_t type, void *param) {
+    switch (type) {
+        case EVE_TRACK_TYPE_INERT:
+            eve_etrack_set(eve_track_inert_init, eve_track_inert_tick, NULL, NULL);
+            break;
+        case EVE_TRACK_TYPE_OSC:
+            eve_etrack_set(NULL, eve_track_osc_tick, NULL, param);
+            break;
+        default:
+            break;
+    }
+}
+
+void eve_track_inert_init(EVETouchTimer *timer, EVETouch *touch) {
+    double d = sqrt(touch->vx * touch->vx + touch->vy * touch->vy);
+    int fc = (double)(EVE_RTC_FREQ) * d / EVE_TRACK_FRICTION;
+
+    timer->p = (void *)fc;
+}
+
+int eve_track_inert_tick(EVETouchTimer *timer, EVETouch *touch) {
+    int dt = eve_time_get_tick() - touch->t;
+    int fc = (int)timer->p;
+    int more = 1;
+
+    if (dt >= fc / 2) {
+        dt = fc / 2;
+        more = 0;
+    }
+    touch->x = timer->x0 + (touch->vx * dt - touch->vx * dt / fc * dt) / (int)(EVE_RTC_FREQ);
+    touch->y = timer->y0 + (touch->vy * dt - touch->vy * dt / fc * dt) / (int)(EVE_RTC_FREQ);
+    return more;
+}
+
+void eve_track_osc_init(EVETrackOsc *p, int x, int y, uint32_t T, double d, uint32_t t_max) {
+    double f0 = 2 * M_PI / (T * EVE_RTC_FREQ / 1000);
+
+    if (d < 0) d = 0;
+    if (d > 1) d = 1;
+    p->x = x;
+    p->y = y;
+    p->f = d ? f0 * sqrt(1 - d * d) : f0;
+    p->d = d;
+    p->a = -d * f0;
+    p->t_max = t_max;
+}
+
+int eve_track_osc_tick(EVETouchTimer *timer, EVETouch *touch) {
+    EVETrackOsc *p = (EVETrackOsc *)timer->p;
+    int dt = eve_time_get_tick() - touch->t;
+    int ax = timer->x0 - p->x;
+    int ay = timer->y0 - p->y;
+    int more = 1;
+
+    if (p->t_max && (dt >= p->t_max)) {
+        dt = p->t_max;
+        more = 0;
+    }
+    if (p->d) {
+        double e = exp(p->a * dt);
+        ax = ax * e;
+        ay = ay * e;
+        if ((ax == 0) && (ay == 0)) more = 0;
+    }
+    touch->x = p->x + ax * cos(p->f * dt);
+    touch->y = p->y + ay * cos(p->f * dt);
+    return more;
+}