source/graphics/Color.h

   1 /* Copyright (C) 2022 Wildfire Games.
   2  * This file is part of 0 A.D.
   3  *
   4  * 0 A.D. is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * 0 A.D. is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #ifndef INCLUDED_COLOR
  19 #define INCLUDED_COLOR
  20
  21 #include "graphics/SColor.h"
  22 #include "maths/Vector3D.h"
  23 #include "maths/Vector4D.h"
  24 #include "ps/containers/Span.h"
  25 #include "ps/CStrForward.h"
  26
  27 // Simple defines for 3 and 4 component floating point colors - just map to
  28 // corresponding vector types.
  29 typedef CVector3D RGBColor;
  30 typedef CVector4D RGBAColor;
  31
  32 // Convert float RGB(A) colors to unsigned byte.
  33 // Exposed as function pointer because it is set at init-time to
  34 // one of several implementations depending on CPU caps.
  35 extern SColor4ub (*ConvertRGBColorTo4ub)(const RGBColor& src);
  36
  37 /**
  38  * Detects CPU caps and activates the best possible codepath.
  39  */
  40 extern void ColorActivateFastImpl();
  41
  42 struct CColor
  43 {
  44         CColor() : r(-1.f), g(-1.f), b(-1.f), a(1.f) {}
  45         CColor(float cr, float cg, float cb, float ca) : r(cr), g(cg), b(cb), a(ca) {}
  46
  47         /**
  48          * Returns whether this has been set to a valid color.
  49          */
  50         operator bool() const
  51         {
  52                 return r >= 0 && g >= 0 && b >= 0 && a >= 0;
  53         }
  54
  55         /**
  56          * Try to parse @p Value as a color. Returns true on success, false otherwise.
  57          * Leaves the color unchanged if it failed.
  58          * @param value Should be "r g b" or "r g b a" where each value is an integer in [0,255].
  59          * @param defaultAlpha The alpha value that is used if the format of @p Value is "r g b".
  60          */
  61         bool ParseString(const CStr8& value, int defaultAlpha = 255);
  62
  63         bool operator==(const CColor& color) const;
  64         bool operator!=(const CColor& color) const
  65         {
  66                 return !(*this == color);
  67         }
  68
  69         // For passing to uniform as vec3/vec4.
  70         PS::span<const float> AsFloatArray() const
  71         {
  72                 // Additional check to prevent a weird compiler has a different
  73                 // alignement for an array and a class members.
  74                 static_assert(
  75                         sizeof(CColor) == sizeof(float) * 4u &&
  76                         offsetof(CColor, r) == 0 &&
  77                         offsetof(CColor, g) == sizeof(float) &&
  78                         offsetof(CColor, b) == sizeof(float) * 2u &&
  79                         offsetof(CColor, a) == sizeof(float) * 3u,
  80                         "CColor should be properly layouted to use AsFloatArray");
  81                 return PS::span(&r, 4);
  82         }
  83
  84         // For passing to CRenderer:
  85         SColor4ub AsSColor4ub() const
  86         {
  87                 return SColor4ub(
  88                         static_cast<u8>(r * 255.f),
  89                         static_cast<u8>(g * 255.f),
  90                         static_cast<u8>(b * 255.f),
  91                         static_cast<u8>(a * 255.f)
  92                 );
  93         }
  94
  95         float r, g, b, a;
  96 };
  97
  98 #endif // INCLUDED_COLOR