Question:  what is the simplest way to call the HSV to rgb conversion that is

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Question: what is the simplest way to call the HSV to rgb conversion that is built into the fastspi library? I have a sketch that uses static byte vales for r, g , and b .

2

leds[i] = CHSV(h, s, v) is nice

3

And if you want to extract the individual values into your own “r, g, b” variables:

CRGB rgb( CHSV( hue, sat, val ) );
r = rgb.r;
g = rgb.g;
b = rgb.b;

There’s no API for calling hsv2rgb with six scalar variables (H,S,V inputs and &R,&G,&B outputs). However, both Zeke’s example and this one (above) compile down into code that’s approximately as efficient as it would be passing in six separate variables – and sometimes it’s actually smaller/faster than that.

This code work for you?

4

for the first suggestion from Zeke:
my code works with:
leds[iLed] = CRGB(red,blue,green);

But when I add:

setup()
int h = 300;
int s = 100;
int v = 100;

and
add one line in
loop()

      leds[iLed] = CHSV(h, s, v);

I get error messages:
In function ‘void choosearray(int)’:
no match for ‘operator=’ in ‘leds[((int)iLed)] = CHSV(((uint8_t)h), ((uint8_t)s), ((uint8_t)v))’
C:\Users\hib\Documents\Arduino\libraries\FastSPI_LED2/pixeltypes.h:118: note: candidates are: CRGB& CRGB::operator=(const CRGB&)
C:\Users\hib\Documents\Arduino\libraries\FastSPI_LED2/pixeltypes.h:127: note: CRGB& CRGB::operator=(uint32_t)

5

when I try Mark’s suggestion and
use:

CRGB rgb( CHSV( hue, sat, val ) );
r = rgb.r;
g = rgb.g;
b = rgb.b;

instead of

I get many errors dealing with not declaring a class or struct (which I am not that familiar with;

mario_1.ino: In function ‘void choosearray(int)’:
mario_1:98: error: expected primary-expression before ‘rgb’
mario_1:98: error: expected ;' before 'rgb' mario_1:99: error: 'r' was not declared in this scope mario_1:99: error: request for member 'r' in 'rgb', which is of non-class type 'int [3][3][3]' mario_1:100: error: 'g' was not declared in this scope mario_1:100: error: request for member 'g' in 'rgb', which is of non-class type 'int [3][3][3]' mario_1:101: error: 'b' was not declared in this scope mario_1:101: error: request for member 'b' in 'rgb', which is of non-class type 'int [3][3][3]' mario_1:107: error: expected primary-expression before 'rgb' mario_1:107: error: expected;’ before ‘rgb’
mario_1:108: error: ‘r’ was not declared in this scope
mario_1:108: error: request for member ‘r’ in ‘rgb’, which is of non-class type ‘int [3][3][3]’
mario_1:109: error: ‘g’ was not declared in this scope
mario_1:109: error: request for member ‘g’ in ‘rgb’, which is of non-class type ‘int [3][3][3]’
mario_1:110: error: ‘b’ was not declared in this scope
mario_1:110: error: request for member ‘b’ in ‘rgb’, which is of non-class type ‘int [3][3][3]’
mario_1:114: error: expected primary-expression before ‘rgb’
mario_1:114: error: expected ;' before 'rgb' mario_1:115: error: 'r' was not declared in this scope mario_1:115: error: request for member 'r' in 'rgb', which is of non-class type 'int [3][3][3]' mario_1:116: error: 'g' was not declared in this scope mario_1:116: error: request for member 'g' in 'rgb', which is of non-class type 'int [3][3][3]' mario_1:117: error: 'b' was not declared in this scope mario_1:117: error: request for member 'b' in 'rgb', which is of non-class type 'int [3][3][3]' mario_1:121: error: expected primary-expression before 'rgb' mario_1:121: error: expected;’ before ‘rgb’
mario_1:122: error: ‘r’ was not declared in this scope
mario_1:122: error: request for member ‘r’ in ‘rgb’, which is of non-class type ‘int [3][3][3]’
mario_1:123: error: ‘g’ was not declared in this scope
mario_1:123: error: request for member ‘g’ in ‘rgb’, which is of non-class type ‘int [3][3][3]’
mario_1:124: error: ‘b’ was not declared in this scope
mario_1:124: error: request for member ‘b’ in ‘rgb’, which is of non-class type ‘int [3][3][3]’

6

What version of the library are you using? RC5 is the latest. https://code.google.com/p/fastspi/downloads/list I just want to make sure we’re on the same page before digging in to the details here.

7

Also just FYI, something to think about once we get the compilation issues under control here: in the FastLED library, hue, saturation, and brightness are defined here as 8-bit values from 0-255; they should be declared as “uint8_t” or simply just “byte” instead of “int” (which is a 16-bit data type). There’s some discussion of that here: https://code.google.com/p/fastspi/wiki/CRGBreference#Introduction_to_HSV

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I just tested with RC5 and this program compiles and works. This is the entire program; you might want to try compiling this and see what you get.

#include “FastLED.h”

#define OUTPUT_PIN 13
#define NUM_LEDS 10
CRGB leds[NUM_LEDS];

byte h = 200;
byte s = 100;
byte v = 100;

void setup() {
FastLED.addLeds< WS2811, OUTPUT_PIN, GRB>(leds, NUM_LEDS);
}

void loop() {

for( int i = 0; i < NUM_LEDS; i++) {
leds[i] = CHSV(h, s, v); // HSV to RGB assignment
}

FastLED.show();
}

9

@Mark_Kriegsman
I uninstalled prior FastSPI library an installed RC5.

I tried your code but it calls for a missing library in the first line
#include “FastLED.h”

Since there is no such file in RC5, I substituted “FastSPI_LED2.h” and it compiled.

tomorrow I will HSV with my sketch.

thanks

10

Ah…ooops, sorry about the “FastLED.h” name problem! You did the right thing switching to FastSPI_LED2.
I bet that with the old version removed you’ll have success.

11

I ran the sketch with my LPD8806 strip and I get no control over color with H.

H and S together affect color sometimes, but not in any known manner. V controls brightness

Do you have any suggestions?

12

If you keep S and V both at 255, and just change Hue, do you get sensible results?

And just to make sure the basics are working: when you use RGB values directly instead of HSV, do you get the expected results?

13

that did the trick,

thanks

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Great! Can’t wait to see the results!
Happy to help.