Looking for script that can change textures via avatar proximity

default {
    state_entry() {
        llSensorRepeat(
            "", // Name of avatar (if you want a specific one)
            NULL_KEY, // Key of avatar (if you want a specific one)
            AGENT, // Type of object to sense
            24.0, // Range
            PI, // Scan all around (PI_BY_TWO gives a semi-sphere)
            1.0 // Repeat every 1 second, decrease this for faster responses
        );
    }

    sensor(integer x) {
        vector closestPos = llDetectedPos(0); // Index 0 is always closest
        vector myPos = llGetPos();

        float distance = llVecDist(closestPos, myPos);
        distance -= 5.0; // The distance to become 100% transparent
        float alpha = distance / 20.0; // The distance to become 100% opaque

        llSetAlpha(alpha, ALL_SIDES);
    }
    no_sensor() {
        llSetAlpha(1.0, ALL_SIDES);
    }
}