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Added HSV2RGB and RGB2HSV functions for higher accuracy conversions
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- Bonus: saves over 1.2kB of flash
-also added a struct to handle HSV with 16bit hue better (including some conversions, can be extended easily)
- the functions are optimized for speed and flash use. They are faster and more accurate than what fastled offers (and use much less flash).
- replaced colorHStoRGB() with a call to the new hsv2rgb() function, saving even more flash
- the 16bit hue calculations result in an almost perfect conversion from RGB to HSV and back, the maximum error was 1/255 in the cases I tested.
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@DedeHai
DedeHai committed Sep 25, 2024
1 parent 24a424a commit a5807b5
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Showing 3 changed files with 77 additions and 41 deletions.
84 changes: 48 additions & 36 deletions wled00/colors.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -98,14 +98,14 @@ uint32_t color_fade(uint32_t c1, uint8_t amount, bool video)
*/
uint32_t adjust_color(uint32_t rgb, uint32_t hueShift, uint32_t lighten, uint32_t brighten) {
if(rgb == 0 | hueShift + lighten + brighten == 0) return rgb; // black or no change
CHSV hsv = rgb2hsv(rgb); //convert to HSV
if(hsv.v == 0) return rgb; // do not change black pixels
hsv.h += hueShift; // shift hue
CHSV32 hsv;
rgb2hsv(rgb, hsv); //convert to HSV
hsv.h += (hueShift << 8); // shift hue (hue is 16 bits)
hsv.s = max((int32_t)0, (int32_t)hsv.s - (int32_t)lighten); // desaturate
hsv.v = min((uint32_t)255, (uint32_t)hsv.v + brighten); // increase brightness
CRGB adjusted;
hsv2rgb_spectrum(hsv, adjusted); // convert back to RGB
return RGBW32(adjusted.r,adjusted.g,adjusted.b,0);
uint32_t rgb_adjusted;
hsv2rgb(hsv, rgb_adjusted); // convert back to RGB TODO: make this into 16 bit conversion
return rgb_adjusted;
}

void setRandomColor(byte* rgb)
Expand Down Expand Up @@ -223,31 +223,40 @@ CRGBPalette16 generateRandomPalette() //generate fully random palette
CHSV(random8(), random8(160, 255), random8(128, 255)));
}

void colorHStoRGB(uint16_t hue, byte sat, byte* rgb) //hue, sat to rgb
void hsv2rgb(const CHSV32& hsv, uint32_t& rgb) // convert HSV (16bit hue) to RGB (32bit with white = 0)
{
float h = ((float)hue)/10922.5f; // hue*6/65535
float s = ((float)sat)/255.0f;
int i = int(h);
float f = h - i;
int p = int(255.0f * (1.0f-s));
int q = int(255.0f * (1.0f-s*f));
int t = int(255.0f * (1.0f-s*(1.0f-f)));
p = constrain(p, 0, 255);
q = constrain(q, 0, 255);
t = constrain(t, 0, 255);
switch (i%6) {
case 0: rgb[0]=255,rgb[1]=t, rgb[2]=p; break;
case 1: rgb[0]=q, rgb[1]=255,rgb[2]=p; break;
case 2: rgb[0]=p, rgb[1]=255,rgb[2]=t; break;
case 3: rgb[0]=p, rgb[1]=q, rgb[2]=255;break;
case 4: rgb[0]=t, rgb[1]=p, rgb[2]=255;break;
case 5: rgb[0]=255,rgb[1]=p, rgb[2]=q; break;
unsigned int remainder, region, p, q, t;
unsigned int h = hsv.h;
unsigned int s = hsv.s;
unsigned int v = hsv.v;
if (s == 0) {
rgb = v << 16 | v << 8 | v;
return;
}
region = h / 10923; // 65536 / 6 = 10923
remainder = (h - (region * 10923)) * 6;
p = (v * (256 - s)) >> 8;
q = (v * (255 - ((s * remainder) >> 16))) >> 8;
t = (v * (255 - ((s * (65535 - remainder)) >> 16))) >> 8;
switch (region) {
case 0:
rgb = v << 16 | t << 8 | p; break;
case 1:
rgb = q << 16 | v << 8 | p; break;
case 2:
rgb = p << 16 | v << 8 | t; break;
case 3:
rgb = p << 16 | q << 8 | v; break;
case 4:
rgb = t << 16 | p << 8 | v; break;
default:
rgb = v << 16 | p << 8 | q; break;
}
}

CHSV rgb2hsv(const uint32_t rgb) // convert rgb to hsv, more accurate and faster than fastled version
void rgb2hsv(const uint32_t rgb, CHSV32& hsv) // convert RGB to HSV (16bit hue), much more accurate and faster than fastled version
{
CHSV hsv = CHSV(0, 0, 0);
hsv.raw = 0;
int32_t r = (rgb>>16)&0xFF;
int32_t g = (rgb>>8)&0xFF;
int32_t b = rgb&0xFF;
Expand All @@ -256,19 +265,22 @@ CHSV rgb2hsv(const uint32_t rgb) // convert rgb to hsv, more accurate and faster
minval = min(minval, b);
maxval = max(r, g);
maxval = max(maxval, b);
if (maxval == 0) return hsv; // black
if (maxval == 0) return; // black
hsv.v = maxval;
delta = maxval - minval;
hsv.s = (255 * delta) / maxval;
if (hsv.s == 0) return hsv; // gray value
int32_t h; //calculate hue
if (maxval == r)
h = (43 * (g - b)) / delta;
else if (maxval == g) h = 85 + (43 * (b - r)) / delta;
else h = 171 + (43 * (r - g)) / delta;
if(h < 0) h += 256;
hsv.h = h;
return hsv;
if (hsv.s == 0) return; // gray value
if (maxval == r) hsv.h = (10923 * (g - b)) / delta;
else if (maxval == g) hsv.h = 21845 + (10923 * (b - r)) / delta;
else hsv.h = 43690 + (10923 * (r - g)) / delta;
}

void colorHStoRGB(uint16_t hue, byte sat, byte* rgb) { //hue, sat to rgb
uint32_t crgb;
hsv2rgb(CHSV32(hue, sat, 255), crgb);
rgb[0] = byte((crgb) >> 16);
rgb[1] = byte((crgb) >> 8);
rgb[2] = byte(crgb);
}

//get RGB values from color temperature in K (https://tannerhelland.com/2012/09/18/convert-temperature-rgb-algorithm-code.html)
Expand Down
30 changes: 27 additions & 3 deletions wled00/fcn_declare.h
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Original file line number Diff line number Diff line change
Expand Up @@ -66,6 +66,29 @@ typedef struct WiFiConfig {
} wifi_config;

//colors.cpp
struct CHSV32 { // 32bit HSV color with 16bit hue for more accurate conversions
union {
struct {
uint16_t h; // hue
uint8_t s; // saturation
uint8_t v; // value
};
uint32_t raw; // 32bit access
};
inline CHSV32() __attribute__((always_inline)) = default; // default constructor

/// Allow construction from hue, saturation, and value
/// @param ih input hue
/// @param is input saturation
/// @param iv input value
inline CHSV32(uint16_t ih, uint8_t is, uint8_t iv) __attribute__((always_inline)) // constructor from 16bit h, s, v
: h(ih), s(is), v(iv) {}
inline CHSV32(uint8_t ih, uint8_t is, uint8_t iv) __attribute__((always_inline)) // constructor from 8bit h, s, v
: h((uint16_t)ih << 8), s(is), v(iv) {}
inline CHSV32(const CHSV& chsv) __attribute__((always_inline)) // constructor from CHSV
: h((uint16_t)chsv.h << 8), s(chsv.s), v(chsv.v) {}
inline operator CHSV() const { return CHSV((uint8_t)(h >> 8), s, v); } // typecast to CHSV
};
// similar to NeoPixelBus NeoGammaTableMethod but allows dynamic changes (superseded by NPB::NeoGammaDynamicTableMethod)
class NeoGammaWLEDMethod {
public:
Expand All @@ -85,9 +108,10 @@ uint32_t adjust_color(uint32_t rgb, uint32_t hueShift, uint32_t lighten, uint32_
CRGBPalette16 generateHarmonicRandomPalette(CRGBPalette16 &basepalette);
CRGBPalette16 generateRandomPalette();
inline uint32_t colorFromRgbw(byte* rgbw) { return uint32_t((byte(rgbw[3]) << 24) | (byte(rgbw[0]) << 16) | (byte(rgbw[1]) << 8) | (byte(rgbw[2]))); }
void colorHStoRGB(uint16_t hue, byte sat, byte* rgb); //hue, sat to rgb
CHSV rgb2hsv(const uint32_t rgb); // rgb to hsv
inline CHSV rgb2hsv(const CRGB c) { return rgb2hsv((uint32_t((byte(c.r) << 16) | (byte(c.g) << 8) | (byte(c.b))))); } // CRGB to hsv
void hsv2rgb(const CHSV32& hsv, uint32_t& rgb);
void colorHStoRGB(uint16_t hue, byte sat, byte* rgb);
void rgb2hsv(const uint32_t rgb, CHSV32& hsv);
inline CHSV rgb2hsv(const CRGB c) { CHSV32 hsv; rgb2hsv((uint32_t((byte(c.r) << 16) | (byte(c.g) << 8) | (byte(c.b)))), hsv); return CHSV(hsv); } // CRGB to hsv
void colorKtoRGB(uint16_t kelvin, byte* rgb);
void colorCTtoRGB(uint16_t mired, byte* rgb); //white spectrum to rgb
void colorXYtoRGB(float x, float y, byte* rgb); // only defined if huesync disabled TODO
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4 changes: 2 additions & 2 deletions wled00/ir.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -129,7 +129,7 @@ static void changeEffectSpeed(int8_t amount)
} else { // if Effect == "solid Color", change the hue of the primary color
Segment& sseg = irApplyToAllSelected ? strip.getFirstSelectedSeg() : strip.getMainSegment();
CRGB fastled_col = CRGB(sseg.colors[0]);
CHSV prim_hsv = rgb2hsv_approximate(fastled_col);
CHSV prim_hsv = rgb2hsv(fastled_col);
int16_t new_val = (int16_t)prim_hsv.h + amount;
if (new_val > 255) new_val -= 255; // roll-over if bigger than 255
if (new_val < 0) new_val += 255; // roll-over if smaller than 0
Expand Down Expand Up @@ -173,7 +173,7 @@ static void changeEffectIntensity(int8_t amount)
} else { // if Effect == "solid Color", change the saturation of the primary color
Segment& sseg = irApplyToAllSelected ? strip.getFirstSelectedSeg() : strip.getMainSegment();
CRGB fastled_col = CRGB(sseg.colors[0]);
CHSV prim_hsv = rgb2hsv_approximate(fastled_col);
CHSV prim_hsv = rgb2hsv(fastled_col);
int16_t new_val = (int16_t) prim_hsv.s + amount;
prim_hsv.s = (byte)constrain(new_val,0,255); // constrain to 0-255
hsv2rgb_rainbow(prim_hsv, fastled_col);
Expand Down

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