Color conversion scripts
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The following functions convert between LSL color in Red Green Blue (RGB) format and color in Hue Saturation Value (HSV) format. The functions are based on "c" algorithms from c color conversion but required some debugging and extensive re-working to fit them in to LSL. For a discussion of HSV color format please see the wikipedia entry at HSV Color
Contents |
RGB to HSV
// by [[Sally LaSalle]], code released to the public domain under GNU GPL version 3.0 license. // you are free to use, and you are free to donate to me if you wish!! :P // takes an RGB color as a vector, with range <float R[0,1], float G[0,1], float B[0,1]> // returns a vector with HSV ranged from <float H[0,360], float S[0,1], float V[0,1]> // H ranges smoothly from Red=0, Yellow=60, Green=120, Cyan=180, Blue=240, Violet=300 and back to Red vector RGBtoHSV( vector rgb ) { float R = rgb.x; if (R<0) // catch malformed input R=0; else if (R>1) R=1; float G = rgb.y; if (G<0) // catch malformed input G=0; else if (G>1) G=1; float B = rgb.z; if (B<0) // catch malformed input B=0; else if (B>1) B=1; float H; float S; float V; list rgbList = [R, G, B]; // list used to get min and max float min; float max; float achromatic; // =1 if R=G=B float delta; vector hsv; // the return HSV vector min = llListStatistics(LIST_STAT_MIN, rgbList); //MIN of ( R, G, B ); max = llListStatistics(LIST_STAT_MAX, rgbList); //MAX of ( R, G, B ); if (R==G && G==B) achromatic = 1; // it is a shade of grey, white or black else achromatic = 0; V = max; // V = brightness Value form 0 to 1 delta = max - min; if( max != 0 ) S = delta / max; // S = saturation from 0 to 1 else { // R = G = B = 0 // S = 0, V = 0, H = 0 S = 0; V = 0; H = 0; hsv.x = H; hsv.y = S; hsv.z = V; return hsv; //H = S = V = 0 } if (achromatic == 1) H = 0; else if( R == max ) H = 0 + ( G - B ) / delta; // between red & yellow else if( G == max ) H = 2 + ( B - R ) / delta; // between yellow & cyan else H = 4 + ( R - G ) / delta; // between cyan & red H *= 60; // H is traditionally a figure between 0 and 360 degrees if( H < 0 ) H += 360; hsv.x = H; hsv.y = S; hsv.z = V; return hsv; }
HSV to RGB
// by Sally LaSalle, code released to the public domain under GNU GPL version 3.0 license. // you are free to use, and you are free to donate to me if you wish!! :P // takes a vector encoded Hue Saturation Value (HSV) triplet // HSV should be entered with floats the ranges: <float H(0 to 360), float S(0 to 1),float V(0 to 1)> // And Returns a vector encode Red Green Blue (RGB) color triplet // RGB will be returned with floats in ranges <float R(0 to 1),float G(0 to 1),float B(0 to 1)> vector HSVtoRGB( vector hsv ) { integer i; float H = hsv.x; if (H<0) // catch malformed H input H=0; else if (H>360) H=360; float S = hsv.y; if (S<0) // catch malformed S input S=0; else if (S>1) S=1; float V = hsv.z; if (V<0) // catch malformed V input V=0; else if (V>1) V=1; float R; float G; float B; float f; // variables for calculating base color mixing around the "spectrum circle" float p; float q; float t; vector rgb; if( S == 0 ) { // achromatic (grey) simply set R,G, & B = Value R = V; G = V; B = V; rgb.x = R; rgb.y = G; rgb.z = B; return rgb; } H /= 60; // Hue factored into range 0 to 5 i = llFloor( H ); // integer floor of Hue f = H - i; // factorial part of H p = V * ( 1 - S ); q = V * ( 1 - S * f ); t = V * ( 1 - S * ( 1 - f ) ); if (i==0){ R = V; G = t; B = p; } else if (i==1){ R = q; G = V; B = p; } else if (i==2){ R = p; G = V; B = t; } else if (i==3){ R = p; G = q; B = V; } else if (i==4){ R = t; G = p; B = V; } else { R = V; G = p; B = q; } rgb.x = R; rgb.y = G; rgb.z = B; return rgb; }
HSL to RGB
//HSL to RGB conversion function. By Cobalt Arkright. Released to the public under GNU GPL version 3.0 license. //Takes a vector encoded HSL triplet and outputs a vector encoded RGB triplet. //Input values should be in the following ranges: <float H(0 to 1), float S(0 to 1), float L(0 to 1). //If you wish to use H(0 to 360), comment out the lines 6, 7, and 8, then remove the comment for lines 11, 12, and 13. vector HSLtoRGB (vector hsl) { //Catch malformed H input for H(0 to 1) if (hsl.x < 0)hsl.x = 0; else if (hsl.x > 1.0)hsl.x = 1.0; //Catch malformed H input for H(0 to 360) //if (hsl.x < 0) hsl.x = 0; //else if (hsl.x > 360) hsl.x = 360; //hsl.x = hsl.x/360; //Catch malformed S input if (hsl.y < 0)hsl.y = 0; else if (hsl.y > 1.0)hsl.y = 1.0; //Catch malformed L input if (hsl.z < 0)hsl.z = 0; else if (hsl.z > 1.0)hsl.z = 1.0; //Declare required variables vector rgb; float q; float p; float tr; float tg; float tb; //Special case: When S = 0, the result is monochromatic, and R = B = G = L. if (hsl.y == 0){ rgb.x = rgb.y = rgb.z = hsl.z; return rgb; } //Set up temporary values for conversion if (hsl.z < 0.5)q = hsl.z*(1.0+hsl.y); else if (0.5 <= hsl.z) q = hsl.z+hsl.y-(hsl.z*hsl.y); p = 2*hsl.z-q; tr = hsl.x+0.3333; tg = hsl.x; tb = hsl.x-0.3333; //Normalize temporary R value if (tr < 0 )tr = tr + 1.0; else if (tr > 1.0)tr = tr - 1.0; //Normalize temporary G value if (tg < 0 )tg = tg + 1.0; else if (tg > 1.0)tg = tg - 1.0; //Normalize temporary B value if (tb < 0 )tb = tb + 1.0; else if (tb > 1.0)tb = tb - 1.0; //Calculate R value if (tr < 0.1666)rgb.x = p+((q-p)*6*tr); else if (0.1666 <= tr < 0.5)rgb.x = q; else if (0.5 <= tr < 0.6666)rgb.x = p+((q-p)*6*(0.6666-tr)); else if (0.6666 <= tr) rgb.x = p; //Calculate G value if (tg < 0.1666)rgb.y = p+((q-p)*6*tg); else if (0.1666 <= tg < 0.5)rgb.y = q; else if (0.5 <= tg < 0.6666)rgb.y = p+((q-p)*6*(0.6666-tg)); else if (0.6666 <= tg) rgb.y = p; //Caluclate B value if (tb < 0.1666)rgb.z = p+((q-p)*6*tb); else if (0.1666 <= tb < 0.5)rgb.z = q; else if (0.5 <= tb < 0.6666)rgb.z = p+((q-p)*6*(0.6666-tb)); else if (0.6666 <= tb) rgb.z = p; //Return the result return rgb; }
HSV to HSL
For more info about the difference between HSL and HSV, see the wikipedia entry: HSL and HSV
// Convert from HSV (hue, saturation, value) to HSL (hue, saturation, luminosity) // Created by Michaelangelo David, code released to the public domain under GNU GPL version 3.0 license. vector hsv_to_hsl( vector HSV ) { vector HSL; HSL.x = HSV.x; HSL.z = (2 - HSV.y) * HSV.z; HSL.y = HSV.y * HSV.z; if (HSL.z <= 1) HSL.y /= HSL.z; else HSL.y /= (2 - HSL.z); HSL.z /= 2; return HSL; }
HSL to HSV
// Convert from HSL (hue, saturation, luminosity) to HSV (hue, saturation, value) // Created by Michaelangelo David, code released to the public domain under GNU GPL version 3.0 license. vector hsl_to_hsv( vector HSL ) { vector HSV; HSV.x = HSL.x; HSL.z *= 2; if (HSL.z <= 1) HSL.y *= HSL.z; else HSL.y *= ( 2 - HSL.z); HSV.z = (HSL.z + HSL.y) / 2; HSV.y = (2 * HSL.y) / (HSL.z + HSL.y); return HSV; }
