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)
Particles in this example start opaque and fade away.
例子中从不透明到消失。
The option to fade particles, is off by default but enabled when
you enable the ability to change particle color. (See the previous example).
Particles can only fade away, they can't fade "in", unfortunately.
只能消失，不是出现。（这句好象不太对，如果倒过来呢？等一下试一次）
So keep values for START_ALPHA greater than END_ALPHA. Maybe someday LL will let particles fade in.
所以，保持值，开始比结束值高，估计ll以后会改进成允许fade in
