HSV.h

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#pragma once
 
#include "lua_include.h"
#include "global.h"
#include <cmath>

 
int HSV(lua_State* L_)
{
    double h = luaL_checknumber(L_, 1);
    double s = luaL_checknumber(L_, 2);
    double v = luaL_checknumber(L_, 3);
 
    if (s < 0) s = 0; else if (s > 1) s = 1;
    if (v < 0) v = 0; else if (v > 1) v = 1;
    while (h < 0) h += 360;
    while (h >= 360) h -= 360;
 
    double c = v * s;
    double x = c * (1 - fabs(fmod(h / 60.0, 2) - 1));
    double m = v - c;
 
    double r1, g1, b1;
    if (h < 60)       { r1 = c; g1 = x; b1 = 0; }
    else if (h < 120) { r1 = x; g1 = c; b1 = 0; }
    else if (h < 180) { r1 = 0; g1 = c; b1 = x; }
    else if (h < 240) { r1 = 0; g1 = x; b1 = c; }
    else if (h < 300) { r1 = x; g1 = 0; b1 = c; }
    else              { r1 = c; g1 = 0; b1 = x; }
 
    int r = (int)((r1 + m) * 31);
    int g = (int)((g1 + m) * 63);
    int b = (int)((b1 + m) * 31);
 
    uint16_t color = (r << 11) | (g << 5) | b;
    lua_pushinteger(L_, color);
 
    return 1;
}