/* ** Command & Conquer Generals Zero Hour(tm) ** Copyright 2025 Electronic Arts Inc. ** ** This program is free software: you can redistribute it and/or modify ** it under the terms of the GNU General Public License as published by ** the Free Software Foundation, either version 3 of the License, or ** (at your option) any later version. ** ** This program is distributed in the hope that it will be useful, ** but WITHOUT ANY WARRANTY; without even the implied warranty of ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ** GNU General Public License for more details. ** ** You should have received a copy of the GNU General Public License ** along with this program. If not, see . */ /*********************************************************************************************** *** C O N F I D E N T I A L --- W E S T W O O D S T U D I O S *** *********************************************************************************************** * * * Project Name : Command & Conquer * * * * $Archive:: /Commando/Library/RGB.CPP $* * * * $Author:: Greg_h $* * * * $Modtime:: 7/22/97 11:37a $* * * * $Revision:: 1 $* * * *---------------------------------------------------------------------------------------------* * Functions: * * RGBClass::Adjust -- Adjust one RGB value toward another. * * RGBClass::Difference -- Determines the "distance" between two colors. * * RGBClass::operator HSVClass -- Conversion operator for RGB to HSV object. * * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ #include "always.h" #include "hsv.h" #include "palette.h" #include "rgb.h" RGBClass const BlackColor(0, 0, 0); /*********************************************************************************************** * RGBClass::Adjust -- Adjust one RGB value toward another. * * * * This routine is used to modify an RGB value to proportionately match another RGB value * * according to the ratio parameter specified. Typical use of this routine is in palette * * fading from one palette to another or to black. * * * * INPUT: ratio -- The ration of transformation. This value is in the form of 0 to 255, * * with 0 being no change, and 255 being 100% transformed into the * * destination color. * * * * rgb -- Reference to the destination RGB color to transform this color into. * * * * OUTPUT: none * * * * WARNINGS: none * * * * HISTORY: * * 12/02/1995 JLB : Created. * *=============================================================================================*/ void RGBClass::Adjust(int ratio, RGBClass const & rgb) { /* ** Ratio conversion is limited to 0 through 100%. This is ** the range of 0 to 255. */ ratio &= 0x00FF; /* ** Adjust the color guns by the ratio specified toward the ** destination color. */ int value = (int)rgb.Red - (int)Red; Red = (unsigned char)((int)Red + (value * ratio) / 256); value = (int)rgb.Green - (int)Green; Green = (unsigned char)((int)Green + (value * ratio) / 256); value = (int)rgb.Blue - (int)Blue; Blue = (unsigned char)((int)Blue + (value * ratio) / 256); } /*********************************************************************************************** * RGBClass::Difference -- Determines the "distance" between two colors. * * * * This routine is used to calculate a relative distance between two colors. The value is * * relative only to itself and thus is useful only for determining the magnitude of * * color difference rather than the nature of the color difference. Palette remapping * * code uses this routine to find closest matches for colors. * * * * INPUT: rgb -- Reference to the color to be compared to this color. * * * * OUTPUT: Returns the difference between the two colors. The value returned is zero if the * * colors exactly match. The greater the positive value the greater the difference * * between the colors. * * * * WARNINGS: none * * * * HISTORY: * * 12/02/1995 JLB : Created. * *=============================================================================================*/ int RGBClass::Difference(RGBClass const & rgb) const { int r = (int)Red - (int)rgb.Red; if (r < 0) r = -r; int g = (int)Green - (int)rgb.Green; if (g < 0) g = -g; int b = (int)Blue - (int)rgb.Blue; if (b < 0) b = -b; /* ** At first crack, the difference algorithm might be coded as the sum of the color differences ** (or sum of the square of the color distances). However, this would not take advantage of the ** fact that the human eye is most sensative to green, followed by the color blue. With this ** thought in mind, the following difference algorithm is used. */ return(4*g + 3*b + 2*r); } /*********************************************************************************************** * RGBClass::operator HSVClass -- Conversion operator for RGB to HSV object. * * * * This conversion operator will convert an RGBClass object into an HSVClass object. * * * * INPUT: none * * * * OUTPUT: Returns with a reference (implicit) to the HSVClass object that most closely * * represents the RGBClass object. * * * * WARNINGS: none * * * * HISTORY: * * 02/20/1996 JLB : Created. * *=============================================================================================*/ RGBClass::operator HSVClass (void) const { int hue; int saturation; int value; /* ** Fetch working component values for the color guns. */ int red = Get_Red(); int green = Get_Green(); int blue = Get_Blue(); /* ** The hue defaults to none. Only if there is a saturation value will the ** hue be calculated. */ hue = 0; /* ** Set the value (brightness) to match the brightest color gun. */ value = (red > green) ? red : green; if (blue > value) value = blue; /* ** Determine the amount of true white present in the color. This is the ** minimum color gun value. The white component is used to determine ** color saturation. */ int white = (red < green) ? red : green; if (blue < white) white = blue; /* ** Determine the saturation (intensity) of the color by comparing the ** ratio of true white as a component of the overall color. The more ** white component, the less saturation. */ saturation = 0; if (value) { saturation = ((value - white) * 255) / value; } /* ** If there is any saturation at all, then the hue must be calculated. The ** hue is based on a six sided color wheel. */ if (saturation != 0) { unsigned int tmp = value - white; unsigned int r1 = ((value - red) * 255) / tmp; unsigned int g1 = ((value - green) * 255) / tmp; unsigned int b1 = ((value - blue) * 255) / tmp; // Find effect of second most predominant color. // In which section of the hexagon of colors does the color lie? if (value == red) { if (white == green) { tmp = 5 * 256 + b1; } else { tmp = 1 * 256 - g1; } } else { if (value == green) { if (white == blue) { tmp = 1 * 256 + r1; } else { tmp = 3 * 256 - b1; } } else { if (white == red) { tmp = 3 * 256 + g1; } else { tmp = 5 * 256 - r1; } } } // Divide by six and round. hue = tmp / 6; } HSVClass hsv((unsigned char)hue, (unsigned char)saturation, (unsigned char)value); return(hsv); }