From bfbe9e43e108f6816c17b9b7764b75284ac78313 Mon Sep 17 00:00:00 2001 From: Tavian Barnes Date: Wed, 14 Dec 2011 19:27:22 -0500 Subject: Re-think colors. Color is a property of light, and thus doesn't include information about transparency. But canvas pixels and object pigments represent a color and a degree of transparency. The new type dmnsn_tcolor/ TColor encapsulates that information. Also, fix the transparent shadow implementation. --- libdimension/color.c | 344 --------------------------------------------------- 1 file changed, 344 deletions(-) delete mode 100644 libdimension/color.c (limited to 'libdimension/color.c') diff --git a/libdimension/color.c b/libdimension/color.c deleted file mode 100644 index 862c8ea..0000000 --- a/libdimension/color.c +++ /dev/null @@ -1,344 +0,0 @@ -/************************************************************************* - * Copyright (C) 2009-2011 Tavian Barnes * - * * - * This file is part of The Dimension Library. * - * * - * The Dimension Library is free software; you can redistribute it and/ * - * or modify it under the terms of the GNU Lesser General Public License * - * as published by the Free Software Foundation; either version 3 of the * - * License, or (at your option) any later version. * - * * - * The Dimension Library 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 * - * Lesser General Public License for more details. * - * * - * You should have received a copy of the GNU Lesser General Public * - * License along with this program. If not, see * - * . * - *************************************************************************/ - -/** - * @file - * Color handling. - */ - -#include "dimension.h" - -/* Standard colors */ -const dmnsn_color dmnsn_black = { - .R = 0.0, - .G = 0.0, - .B = 0.0, - .trans = 0.0, - .filter = 0.0, -}; -const dmnsn_color dmnsn_white = { - .R = 1.0, - .G = 1.0, - .B = 1.0, - .trans = 0.0, - .filter = 0.0, -}; -const dmnsn_color dmnsn_clear = { - .R = 0.0, - .G = 0.0, - .B = 0.0, - .trans = 1.0, - .filter = 0.0, -}; -const dmnsn_color dmnsn_red = { - .R = 1.0, - .G = 0.0, - .B = 0.0, - .trans = 0.0, - .filter = 0.0, -}; -const dmnsn_color dmnsn_green = { - .R = 0.0, - .G = 1.0, - .B = 0.0, - .trans = 0.0, - .filter = 0.0, -}; -const dmnsn_color dmnsn_blue = { - .R = 0.0, - .G = 0.0, - .B = 1.0, - .trans = 0.0, - .filter = 0.0, -}; -const dmnsn_color dmnsn_magenta = { - .R = 1.0, - .G = 0.0, - .B = 1.0, - .trans = 0.0, - .filter = 0.0, -}; -const dmnsn_color dmnsn_orange = { - .R = 1.0, - .G = 0.21404114048223255, - .B = 0.0, - .trans = 0.0, - .filter = 0.0, -}; -const dmnsn_color dmnsn_yellow = { - .R = 1.0, - .G = 1.0, - .B = 0.0, - .trans = 0.0, - .filter = 0.0, -}; -const dmnsn_color dmnsn_cyan = { - .R = 0.0, - .G = 1.0, - .B = 1.0, - .filter = 0.0, - .trans = 0.0, -}; - -/* sRGB's `C' function. */ -static inline double -dmnsn_sRGB_C(double Clinear) -{ - /* - * If C represents R, G, and B, then the sRGB values are now found as follows: - * - * { 12.92*Clinear, Clinear <= 0.0031308 - * Csrgb = { 1/2.4 - * { (1.055)*Clinear - 0.055, Clinear > 0.0031308 - */ - if (Clinear == 1.0) { - return 1.0; /* Map 1.0 to 1.0 instead of 0.9999999999999999 */ - } else if (Clinear > 0.0031308) { - return 1.055*pow(Clinear, 1.0/2.4) - 0.055; - } else { - return 12.92*Clinear; - } -} - -/* Export dmnsn_sRGB_C */ -double -dmnsn_sRGB_gamma(double Clinear) -{ - return dmnsn_sRGB_C(Clinear); -} - -/* Convert to sRGB space */ -dmnsn_color -dmnsn_color_to_sRGB(dmnsn_color color) -{ - dmnsn_color ret = { - .R = dmnsn_sRGB_C(color.R), - .G = dmnsn_sRGB_C(color.G), - .B = dmnsn_sRGB_C(color.B), - .trans = color.trans, - .filter = color.filter, - }; - return ret; -} - -/* Inverse function of sRGB's `C' function, for the reverse conversion. */ -double -dmnsn_sRGB_C_inv(double CsRGB) -{ - /* - * If C represents R, G, and B, then the Clinear values are now found as - * follows: - * - * { Csrgb/12.92, Csrgb <= 0.04045 - * Clinear = { 1/2.4 - * { ((Csrgb + 0.055)/1.055) , Csrgb > 0.04045 - */ - if (CsRGB == 1.0) { - return 1.0; /* Map 1.0 to 1.0 instead of 0.9999999999999999 */ - } else if (CsRGB <= 0.040449936) { - return CsRGB/12.92; - } else { - return pow((CsRGB + 0.055)/1.055, 2.4); - } -} - -/* Export dmnsn_sRGB_C_inv */ -double -dmnsn_sRGB_inverse_gamma(double CsRGB) -{ - return dmnsn_sRGB_C_inv(CsRGB); -} - -/* Convert from sRGB space */ -dmnsn_color -dmnsn_color_from_sRGB(dmnsn_color color) -{ - dmnsn_color ret = { - .R = dmnsn_sRGB_C_inv(color.R), - .G = dmnsn_sRGB_C_inv(color.G), - .B = dmnsn_sRGB_C_inv(color.B), - .trans = color.trans, - .filter = color.filter, - }; - return ret; -} - -/* Greyscale color intensity */ -double -dmnsn_color_intensity(dmnsn_color color) -{ - return 0.2126*color.R + 0.7152*color.G + 0.0722*color.B; -} - -/* Add two colors */ -dmnsn_color -dmnsn_color_add(dmnsn_color c1, dmnsn_color c2) -{ - dmnsn_color ret = dmnsn_new_color(c1.R + c2.R, c1.G + c2.G, c1.B + c2.B); - - /* Switch into absolute filter and transmittance space */ - double n1 = dmnsn_color_intensity(c1), n2 = dmnsn_color_intensity(c2); - double f1 = c1.filter*c1.trans, f2 = c2.filter*c2.trans; - double t1 = c1.trans - f1, t2 = c2.trans - f2; - double f = 0.0; - if (n1 + n2 >= dmnsn_epsilon) - f = (n1*f1 + n2*f2)/(n1 + n2); - double t = t1 + t2; - - /* Switch back */ - ret.trans = f + t; - if (ret.trans >= dmnsn_epsilon) - ret.filter = f/ret.trans; - - return ret; -} - -/* Subtract two colors */ -dmnsn_color -dmnsn_color_sub(dmnsn_color c1, dmnsn_color c2) -{ - dmnsn_color ret = dmnsn_new_color(c1.R - c2.R, c1.G - c2.G, c1.B - c2.B); - - /* Switch into absolute filter and transmittance space */ - double n1 = dmnsn_color_intensity(c1), n2 = dmnsn_color_intensity(c2); - double f1 = c1.filter*c1.trans, f2 = c2.filter*c2.trans; - double t1 = c1.trans - f1, t2 = c2.trans - f2; - double f = 0.0; - if (n1 - n2 >= dmnsn_epsilon) - f = (n1*f1 - n2*f2)/(n1 - n2); - double t = t1 - t2; - - /* Switch back */ - ret.trans = f + t; - if (ret.trans >= dmnsn_epsilon) - ret.filter = f/ret.trans; - - return ret; -} - -/* Multiply a color by a scalar */ -dmnsn_color -dmnsn_color_mul(double n, dmnsn_color color) -{ - color.R *= n; - color.G *= n; - color.B *= n; - color.trans *= n; - return color; -} - -/* For n in [0, 1] get the color in a gradient between c1 and c2 */ -dmnsn_color -dmnsn_color_gradient(dmnsn_color c1, dmnsn_color c2, double n) -{ - dmnsn_color ret = dmnsn_new_color( - n*(c2.R - c1.R) + c1.R, - n*(c2.G - c1.G) + c1.G, - n*(c2.B - c1.B) + c1.B - ); - - /* Switch into absolute filter and transmittance space */ - double f1 = c1.filter*c1.trans, f2 = c2.filter*c2.trans; - double t1 = c1.trans - f1, t2 = c2.trans - f2; - double f = n*(f2 - f1) + f1; - double t = n*(t2 - t1) + t1; - - /* Switch back */ - ret.trans = f + t; - ret.filter = 0.0; - if (ret.trans >= dmnsn_epsilon) - ret.filter = f/ret.trans; - - return ret; -} - -/* Filters `light' through `filter' */ -dmnsn_color -dmnsn_filter_light(dmnsn_color light, dmnsn_color filter) -{ - dmnsn_color transmitted = dmnsn_color_mul( - (1.0 - filter.filter)*filter.trans, - light - ); - dmnsn_color filtered = dmnsn_color_mul( - filter.filter*filter.trans, - dmnsn_color_illuminate(filter, light) - ); - - dmnsn_color ret = dmnsn_new_color( - transmitted.R + filtered.R, - transmitted.G + filtered.G, - transmitted.B + filtered.B - ); - - /* Switch into absolute filter and transmittance space */ - double lf = light.filter*light.trans, ff = filter.filter*filter.trans; - double lt = light.trans - lf, ft = filter.trans - ff; - double f = lf*(dmnsn_color_intensity(filtered) + ft) + lt*ff; - double t = ft*lt; - - /* Switch back */ - ret.trans = f + t; - if (ret.trans >= dmnsn_epsilon) - ret.filter = f/ret.trans; - - return ret; -} - -/* Adds the background contribution, `filtered', to `filter' */ -dmnsn_color -dmnsn_apply_transparency(dmnsn_color filtered, dmnsn_color filter) -{ - dmnsn_color ret = dmnsn_color_add( - dmnsn_color_mul(1.0 - filter.trans, filter), - filtered - ); - ret.trans = filtered.trans; - ret.filter = filtered.filter; - return ret; -} - -/* Adds the background contribution of `color' to `filter' */ -dmnsn_color -dmnsn_apply_filter(dmnsn_color color, dmnsn_color filter) -{ - return dmnsn_apply_transparency(dmnsn_filter_light(color, filter), filter); -} - -/* Remove the filter channel */ -dmnsn_color -dmnsn_remove_filter(dmnsn_color color) -{ - double intensity = dmnsn_color_intensity(color); - double newtrans = (1.0 - (1.0 - intensity)*color.filter)*color.trans; - if (1.0 - newtrans >= dmnsn_epsilon) - color = dmnsn_color_mul((1.0 - color.trans)/(1.0 - newtrans), color); - color.trans = newtrans; - color.filter = 0.0; - return color; -} - -/* Illuminates `color' with `light' */ -dmnsn_color -dmnsn_color_illuminate(dmnsn_color light, dmnsn_color color) -{ - return dmnsn_new_color5(light.R*color.R, light.G*color.G, light.B*color.B, - color.filter, color.trans); -} -- cgit v1.2.3