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Copy pathLedStrip_v2_minimal_rainbow.ino
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LedStrip_v2_minimal_rainbow.ino
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// https://github.com/Makuna/NeoPixelBus
// https://github.com/Makuna/NeoPixelBus/wiki/NeoPixelBus-object-API
// https://github.com/Makuna/NeoPixelBus/wiki/HslColor-object-API
#include <NeoPixelBus.h>
#define PIXELS 150
#define BRIGHTNESS 128
#define VELOCITY 6.0f
#define PERIODS 1.0f
#define GAMMA
#ifdef GAMMA
const uint8_t gamma_table[] PROGMEM = \
{ 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 };
#endif
const uint8_t PixelPin = 2;
uint16_t frame = 0;
float phase = 0;
uint32_t old_t = 0;
NeoPixelBus<NeoGrbFeature, Neo800KbpsMethod> strip(PIXELS, PixelPin);
void setup() {
}
#define HSV_HUE_SEXTANT 256
#define HSV_HUE_STEPS (6 * HSV_HUE_SEXTANT)
#define HSV_HUE_MIN 0
#define HSV_HUE_MAX (HSV_HUE_STEPS - 1)
#define HSV_SAT_MIN 0
#define HSV_SAT_MAX 255
#define HSV_VAL_MIN 0
#define HSV_VAL_MAX 255
void loop() {
uint16_t hue_moving = phase * HSV_HUE_MAX;
float hue_mul = HSV_HUE_MAX/(PIXELS/PERIODS);
uint8_t *ptr = strip.Pixels();
for (uint16_t i = 0; i < PIXELS; i++) {
uint16_t hue_temp = ((float)i)*hue_mul;
uint16_t hue = (hue_temp + hue_moving) % HSV_HUE_MAX;
fast_hsv2rgb_32bit(hue, 255, BRIGHTNESS, ptr++, ptr++, ptr++);
}
#ifdef GAMMA
ptr = strip.Pixels();
for (uint16_t i = 0; i < PIXELS*3; i++) {
*ptr = pgm_read_byte_near(gamma_table + *ptr);
ptr++;
}
#endif
strip.Dirty();
strip.Show();
frame++;
phase += VELOCITY/((float)(micros()-old_t));
old_t = micros();
phase = fmod(phase, 1.0f);
}
/*
* fast_hsv2rgb_32bit(uint16_t h, uint8_t s, uint8_t v, uint8_t *r, uint8_t *g , uint8_t *b)
*/
#define HSV_MONOCHROMATIC_TEST(s,v,r,g,b) \
do { \
if(!(s)) { \
*(r) = *(g) = *(b) = (v); \
return; \
} \
} while(0)
#define HSV_SWAPPTR(a,b) do { uint8_t *tmp = (a); (a) = (b); (b) = tmp; } while(0)
#define HSV_POINTER_SWAP(sextant,r,g,b) \
do { \
if((sextant) & 2) { \
HSV_SWAPPTR((r), (b)); \
} \
if((sextant) & 4) { \
HSV_SWAPPTR((g), (b)); \
} \
if(!((sextant) & 6)) { \
if(!((sextant) & 1)) { \
HSV_SWAPPTR((r), (g)); \
} \
} else { \
if((sextant) & 1) { \
HSV_SWAPPTR((r), (g)); \
} \
} \
} while(0)
void fast_hsv2rgb_32bit(uint16_t h, uint8_t s, uint8_t v, uint8_t *b, uint8_t *r , uint8_t *g) {
HSV_MONOCHROMATIC_TEST(s, v, r, g, b); // Exit with grayscale if s == 0
uint8_t sextant = h >> 8;
HSV_POINTER_SWAP(sextant, r, g, b); // Swap pointers depending which sextant we are in
*g = v; // Top level
// Perform actual calculations
/*
* Bottom level: v * (1.0 - s)
* --> (v * (255 - s) + error_corr + 1) / 256
*/
uint16_t ww; // Intermediate result
ww = v * (255 - s); // We don't use ~s to prevent size-promotion side effects
ww += 1; // Error correction
ww += ww >> 8; // Error correction
*b = ww >> 8;
uint8_t h_fraction = h & 0xff; // 0...255
uint32_t d; // Intermediate result
if(!(sextant & 1)) {
// *r = ...slope_up...;
d = v * (uint32_t)((255 << 8) - (uint16_t)(s * (256 - h_fraction)));
d += d >> 8; // Error correction
d += v; // Error correction
*r = d >> 16;
} else {
// *r = ...slope_down...;
d = v * (uint32_t)((255 << 8) - (uint16_t)(s * h_fraction));
d += d >> 8; // Error correction
d += v; // Error correction
*r = d >> 16;
}
}