xiao_y 发表于 2021-1-4 11:03:09

Adafruit_NeoPixel.h库函数strip.setPixelColor(i, strip.Color(0,0,0, gamma[j...

下面是Adafruit_NeoPixel.h库里面实例程序(RGBWstrandtest),其中对void pulseWhite(uint8_t wait) 子程序颇为不解,
strip.setPixelColor(i, strip.Color(0,0,0, gamma ) );这句程序中的gamma【j】不知道作何解释,不知道哪位大神指导一下,谢谢。



void pulseWhite(uint8_t wait)
for(int j = 0; j < 256 ; j++){
      for(uint16_t i=0; i<strip.numPixels(); i++) {
          strip.setPixelColor(i, strip.Color(0,0,0, gamma ) );
      }
      delay(wait);
      strip.show();
      }


#include <Adafruit_NeoPixel.h>
#ifdef __AVR__
#include <avr/power.h>
#endif

#define PIN 6

#define NUM_LEDS 60

#define BRIGHTNESS 50

Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUM_LEDS, PIN, NEO_GRBW + NEO_KHZ800);

int gamma[] = {
    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
    0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,
    1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,
    2,3,3,3,3,3,3,3,4,4,4,4,4,5,5,5,
    5,6,6,6,6,7,7,7,7,8,8,8,9,9,9, 10,
   10, 10, 11, 11, 11, 12, 12, 13, 13, 13, 14, 14, 15, 15, 16, 16,
   17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22, 23, 24, 24, 25,
   25, 26, 27, 27, 28, 29, 29, 30, 31, 32, 32, 33, 34, 35, 35, 36,
   37, 38, 39, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 50,
   51, 52, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 66, 67, 68,
   69, 70, 72, 73, 74, 75, 77, 78, 79, 81, 82, 83, 85, 86, 87, 89,
   90, 92, 93, 95, 96, 98, 99,101,102,104,105,107,109,110,112,114,
115,117,119,120,122,124,126,127,129,131,133,135,137,138,140,142,
144,146,148,150,152,154,156,158,160,162,164,167,169,171,173,175,
177,180,182,184,186,189,191,193,196,198,200,203,205,208,210,213,
215,218,220,223,225,228,231,233,236,239,241,244,247,249,252,255 };


void setup() {
Serial.begin(115200);
// This is for Trinket 5V 16MHz, you can remove these three lines if you are not using a Trinket
#if defined (__AVR_ATtiny85__)
    if (F_CPU == 16000000) clock_prescale_set(clock_div_1);
#endif
// End of trinket special code
strip.setBrightness(BRIGHTNESS);
strip.begin();
strip.show(); // Initialize all pixels to 'off'
}

void loop() {
// Some example procedures showing how to display to the pixels:
colorWipe(strip.Color(255, 0, 0), 50); // Red
colorWipe(strip.Color(0, 255, 0), 50); // Green
colorWipe(strip.Color(0, 0, 255), 50); // Blue
colorWipe(strip.Color(0, 0, 0, 255), 50); // White

whiteOverRainbow(20,75,5);

pulseWhite(5);

// fullWhite();
// delay(2000);

rainbowFade2White(3,3,1);


}

// Fill the dots one after the other with a color
void colorWipe(uint32_t c, uint8_t wait) {
for(uint16_t i=0; i<strip.numPixels(); i++) {
    strip.setPixelColor(i, c);
    strip.show();
    delay(wait);
}
}

void pulseWhite(uint8_t wait) {
for(int j = 0; j < 256 ; j++){
      for(uint16_t i=0; i<strip.numPixels(); i++) {
          strip.setPixelColor(i, strip.Color(0,0,0, gamma ) );
      }
      delay(wait);
      strip.show();
      }

for(int j = 255; j >= 0 ; j--){
      for(uint16_t i=0; i<strip.numPixels(); i++) {
          strip.setPixelColor(i, strip.Color(0,0,0, gamma ) );
      }
      delay(wait);
      strip.show();
      }
}


void rainbowFade2White(uint8_t wait, int rainbowLoops, int whiteLoops) {
float fadeMax = 100.0;
int fadeVal = 0;
uint32_t wheelVal;
int redVal, greenVal, blueVal;

for(int k = 0 ; k < rainbowLoops ; k ++){
   
    for(int j=0; j<256; j++) { // 5 cycles of all colors on wheel

      for(int i=0; i< strip.numPixels(); i++) {

      wheelVal = Wheel(((i * 256 / strip.numPixels()) + j) & 255);

      redVal = red(wheelVal) * float(fadeVal/fadeMax);
      greenVal = green(wheelVal) * float(fadeVal/fadeMax);
      blueVal = blue(wheelVal) * float(fadeVal/fadeMax);

      strip.setPixelColor( i, strip.Color( redVal, greenVal, blueVal ) );

      }

      //First loop, fade in!
      if(k == 0 && fadeVal < fadeMax-1) {
          fadeVal++;
      }

      //Last loop, fade out!
      else if(k == rainbowLoops - 1 && j > 255 - fadeMax ){
          fadeVal--;
      }

      strip.show();
      delay(wait);
    }

}



delay(500);


for(int k = 0 ; k < whiteLoops ; k ++){

    for(int j = 0; j < 256 ; j++){

      for(uint16_t i=0; i < strip.numPixels(); i++) {
            strip.setPixelColor(i, strip.Color(0,0,0, gamma ) );
          }
          strip.show();
      }

      delay(2000);
    for(int j = 255; j >= 0 ; j--){

      for(uint16_t i=0; i < strip.numPixels(); i++) {
            strip.setPixelColor(i, strip.Color(0,0,0, gamma ) );
          }
          strip.show();
      }
}

delay(500);


}

void whiteOverRainbow(uint8_t wait, uint8_t whiteSpeed, uint8_t whiteLength ) {

if(whiteLength >= strip.numPixels()) whiteLength = strip.numPixels() - 1;

int head = whiteLength - 1;
int tail = 0;

int loops = 3;
int loopNum = 0;

static unsigned long lastTime = 0;


while(true){
    for(int j=0; j<256; j++) {
      for(uint16_t i=0; i<strip.numPixels(); i++) {
      if((i >= tail && i <= head) || (tail > head && i >= tail) || (tail > head && i <= head) ){
          strip.setPixelColor(i, strip.Color(0,0,0, 255 ) );
      }
      else{
          strip.setPixelColor(i, Wheel(((i * 256 / strip.numPixels()) + j) & 255));
      }
      
      }

      if(millis() - lastTime > whiteSpeed) {
      head++;
      tail++;
      if(head == strip.numPixels()){
          loopNum++;
      }
      lastTime = millis();
      }

      if(loopNum == loops) return;
   
      head%=strip.numPixels();
      tail%=strip.numPixels();
      strip.show();
      delay(wait);
    }
}

}
void fullWhite() {

    for(uint16_t i=0; i<strip.numPixels(); i++) {
      strip.setPixelColor(i, strip.Color(0,0,0, 255 ) );
    }
      strip.show();
}


// Slightly different, this makes the rainbow equally distributed throughout
void rainbowCycle(uint8_t wait) {
uint16_t i, j;

for(j=0; j<256 * 5; j++) { // 5 cycles of all colors on wheel
    for(i=0; i< strip.numPixels(); i++) {
      strip.setPixelColor(i, Wheel(((i * 256 / strip.numPixels()) + j) & 255));
    }
    strip.show();
    delay(wait);
}
}

void rainbow(uint8_t wait) {
uint16_t i, j;

for(j=0; j<256; j++) {
    for(i=0; i<strip.numPixels(); i++) {
      strip.setPixelColor(i, Wheel((i+j) & 255));
    }
    strip.show();
    delay(wait);
}
}

// Input a value 0 to 255 to get a color value.
// The colours are a transition r - g - b - back to r.
uint32_t Wheel(byte WheelPos) {
WheelPos = 255 - WheelPos;
if(WheelPos < 85) {
    return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3,0);
}
if(WheelPos < 170) {
    WheelPos -= 85;
    return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3,0);
}
WheelPos -= 170;
return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0,0);
}

uint8_t red(uint32_t c) {
return (c >> 8);
}
uint8_t green(uint32_t c) {
return (c >> 16);
}
uint8_t blue(uint32_t c) {
return (c);
}

xiao_y 发表于 2021-1-4 11:04:34

目标是实现纯白色灯光带呼吸灯效果,看了实例程序就是想要的呼吸效果,但是不是纯白光,不知道怎么调整。??

xiao_y 发表于 2021-1-5 10:13:18

没人啊?
换了一个思路,直接找了个sin()正弦函数来控制,发现效果还可以。

xiao_y 发表于 2021-1-12 09:38:38

已找到原因

stpanzj 发表于 2021-8-31 13:27:25

是这个吗?strip.Color(0,0,0, strip.gamma(j)),应该是取了更自然的白色。

kpj001 发表于 2021-12-7 14:06:53

本帖最后由 kpj001 于 2021-12-7 14:19 编辑

如果你学点英语就知道 gamma 的意思,没学也没关系,至少先百度一下。。。亮度 (当然,严格说 gamma不直接=亮度,这里作者为什么这么用可能是用过CRT的人的习惯罢了),函数里面不是连续变化的 gamma 值, 大概想实现一个脉冲形式的闪亮吧
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