// Leaping fish for the tidepool: hides under the water, and every 20-60 s (or on touch) arcs out of the pool with a
// splash, flips over the top, and dives back in. One small mesh-free prim set: root = body (squashed sphere, coral),
// link "tail" (flattened cone). For a friend, 2026-10-11. Claude Opus 5.5 (Tessel).
vector HOME;                 // resting spot under the water (region coords), set at start
float T0; integer LEAPING;
float DUR = 1.4; float H = 0.9; float SPAN = 0.9;
integer TAIL;

integer link_named(string n)
{
    integer i = llGetNumberOfPrims();
    for (; i > 1; --i) if (llGetLinkName(i) == n) return i;
    return 0;
}

splash()
{
    llParticleSystem([PSYS_PART_FLAGS, PSYS_PART_INTERP_SCALE_MASK | PSYS_PART_INTERP_COLOR_MASK,
        PSYS_SRC_PATTERN, PSYS_SRC_PATTERN_ANGLE_CONE, PSYS_SRC_ANGLE_BEGIN, 0.0, PSYS_SRC_ANGLE_END, 0.5,
        PSYS_SRC_BURST_PART_COUNT, 16, PSYS_SRC_BURST_RATE, 0.05, PSYS_SRC_MAX_AGE, 0.15,
        PSYS_SRC_BURST_SPEED_MIN, 1.0, PSYS_SRC_BURST_SPEED_MAX, 1.8, PSYS_SRC_ACCEL, <0, 0, -4.0>,
        PSYS_PART_MAX_AGE, 0.7, PSYS_PART_START_SCALE, <0.05, 0.05, 0>, PSYS_PART_END_SCALE, <0.02, 0.02, 0>,
        PSYS_PART_START_COLOR, <0.8, 0.95, 1.0>, PSYS_PART_END_COLOR, <0.6, 0.85, 1.0>,
        PSYS_PART_START_ALPHA, 0.9, PSYS_PART_END_ALPHA, 0.0]);
}

place(vector p, rotation r) { llSetLinkPrimitiveParamsFast(LINK_ROOT, [PRIM_POSITION, p, PRIM_ROTATION, r]); }

leap()
{
    if (LEAPING) return;
    LEAPING = TRUE; T0 = llGetTime();
    splash();
    llSetTimerEvent(0.05);
}

default
{
    state_entry()
    {
        TAIL = link_named("tail");
        HOME = llGetPos();
        if (TAIL) llSetLinkPrimitiveParamsFast(TAIL, [PRIM_POS_LOCAL, <-0.11, 0, 0>, PRIM_ROT_LOCAL, llEuler2Rot(<0, -PI_BY_TWO, 0>)]);
        llSetTimerEvent(20 + llFrand(40));
    }
    on_rez(integer n) { llResetScript(); }
    touch_start(integer n) { leap(); }
    timer()
    {
        if (!LEAPING) { leap(); return; }
        float s = (llGetTime() - T0) / DUR;
        if (s >= 1)
        {
            LEAPING = FALSE; splash();
            place(HOME, ZERO_ROTATION);
            llSetTimerEvent(20 + llFrand(40));
            return;
        }
        // arc along local x of the pool: up, over, and down, nose following the curve
        vector p = HOME + <(s - 0.5) * SPAN, 0, 0.08 + H * 4 * s * (1 - s)>;
        float slope = H * 4 * (1 - 2 * s) / SPAN;
        place(p, llEuler2Rot(<0, -llAtan2(slope, 1), 0>));
        if (TAIL) llSetLinkPrimitiveParamsFast(TAIL, [PRIM_ROT_LOCAL,
            llEuler2Rot(<0, -PI_BY_TWO, 0>) * llEuler2Rot(<0, 0, 0.5 * llSin(llGetTime() * 30)>)]);
    }
}