控制 RGB LED 的开/关 - 比使用“if”更智能的方法？ （阿杜诺，C++）

Question

I want to control three RGB LEDs in color (eff. 9 LEDs in total) and whether to be on or off. I am using Arduino with PlatformIO and the FastLED library to turn them on using FastLED.show(); .

There are six buttons on my display: LED1 , LED2 , LED3 , RED , GREEN , BLUE (dual state buttons) which give me

true when pressed and

false when released

void bt0PopCallback(void *ptr){uint32_t dual_state; NexDSButton *btn = (NexDSButton *)ptr; bt0.getValue(&dual_state); if(dual_state){ LED1 = true; } else{ LED1 = false; } }
void bt1PopCallback(void *ptr){uint32_t dual_state; NexDSButton *btn = (NexDSButton *)ptr; bt1.getValue(&dual_state); if(dual_state){ LED2 = true; } else{ LED2 = false; } }
void bt2PopCallback(void *ptr){uint32_t dual_state; NexDSButton *btn = (NexDSButton *)ptr; bt2.getValue(&dual_state); if(dual_state){ LED3 = true; } else{ LED3 = false; } }

Eg: LED1 = true when LED1 button is pressed, LED1 = false when button is released.

If LED1 = true and RED = true, this led shall turn red. When RED is released and GREEN is pressed the LED1 is now green. If LED1 is released and LED2 is pressed LED1 goes off and LED2 turns on GREEN.

I came up with this one:

if(BLUE == true){BLUEV = 255;} else { BLUEV = 0;}
if(RED == true){REDV = 255;} else { REDV = 0;}
if(GREEN == true){GREENV = 255;} else { GREENV = 0;}

if(LED1 == true){leds[0] = CRGB(REDV, GREENV, BLUEV); } else { leds[0] = CRGB(0, 0, 0); }
if(LED2 == true){leds[1] = CRGB(REDV, GREENV, BLUEV); } else { leds[1] = CRGB(0, 0, 0); }
if(LED3 == true){leds[2] = CRGB(REDV, GREENV, BLUEV); } else { leds[2] = CRGB(0, 0, 0); }
FastLED.show();

but it's obviously imperfect, I reckon.

Anyone has suggestions how to code it better? Maybe using a switch case?

Cheers!

Answer 1

For starters, you can assign dual_state to the corresponding LED without if-else in your callbacks.

Here's an example:

void bt0PopCallback( void* ptr )
{
    uint32_t dual_state;
    NexDSButton* btn = (NexDSButton*) ptr;
    bt0.getValue( &dual_state );
    LED1 = dual_state;                          // direct assignment
}

For other if-else variants in your code for colors, you can use the ternary operator ?: to clean things up like this:

BLUEV  = BLUE  ? 255 : 0;
REDV   = RED   ? 255 : 0;
GREENV = GREEN ? 255 : 0;

And, for setting the values of leds array, use a for loop. The LED1 , LED2 , and LED3 may be grouped using an std::array to be used in the loop for the corresponding values of leds .

Here's an example with std::array :

#include <array>

const std::array<decltype(LED1), NUM_LEDS> LED { LED1, LED2, LED3 };

for ( int i = 0; i < NUM_LEDS; ++i )            // loop to set the colors of LEDs
{
    leds[i] = LED[i] ? CRGB(REDV, GREENV, BLUEV) : CRGB(0, 0, 0);
}

NUM_LEDS represents the size of the leds array ie:

#define NUM_LEADS 3

CRGB leds[NUM_LEADS];