Particle ALPHA 透明度
----------------

The script in this example is:

default {
    state_entry() {    
        llParticleSystem( [
            PSYS_PART_START_ALPHA, 1.0,    
            PSYS_PART_END_ALPHA, 0.0,
           
            PSYS_PART_START_SCALE,< 3.0, 3.0, 0 >,
            PSYS_SRC_BURST_PART_COUNT,3, 
            PSYS_SRC_BURST_RATE,4.0, 
            PSYS_PART_MAX_AGE,3.9,  
            PSYS_SRC_PATTERN,PSYS_SRC_PATTERN_DROP,
           
            PSYS_PART_FLAGS,PSYS_PART_INTERP_COLOR_MASK
        ] );
    }
}

(Ignore the middle section with COUNT, RATE, AGE and PATTERN until later.)

ALPHA:
        maximum:  1.0 (opaque, the default)
        minimum:   0.0 (fully transparent)

The option to fade particles, is off by default but enabled when
you enable the ability to change particle color.  (See the previous example).