src/blitter/32bpp_base.hpp

   1 /* $Id$ */
   2
   3 /*
   4  * This file is part of OpenTTD.
   5  * OpenTTD 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, version 2.
   6  * OpenTTD 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.
   7  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   8  */
   9
  10 /** @file 32bpp_base.hpp Base for all 32 bits blitters. */
  11
  12 #ifndef BLITTER_32BPP_BASE_HPP
  13 #define BLITTER_32BPP_BASE_HPP
  14
  15 #include "base.hpp"
  16 #include "../core/bitmath_func.hpp"
  17 #include "../core/math_func.hpp"
  18 #include "../gfx_func.h"
  19
  20 /** Base for all 32bpp blitters. */
  21 class Blitter_32bppBase : public Blitter {
  22 public:
  23         /* virtual */ uint8 GetScreenDepth() { return 32; }
  24         /* virtual */ void *MoveTo(void *video, int x, int y);
  25         /* virtual */ void SetPixel(void *video, int x, int y, uint8 colour);
  26         /* virtual */ void DrawRect(void *video, int width, int height, uint8 colour);
  27         /* virtual */ void CopyFromBuffer(void *video, const void *src, int width, int height);
  28         /* virtual */ void CopyToBuffer(const void *video, void *dst, int width, int height);
  29         /* virtual */ void CopyImageToBuffer(const void *video, void *dst, int width, int height, int dst_pitch);
  30         /* virtual */ void ScrollBuffer(void *video, int &left, int &top, int &width, int &height, int scroll_x, int scroll_y);
  31         /* virtual */ int BufferSize(int width, int height);
  32         /* virtual */ void PaletteAnimate(const Palette &palette);
  33         /* virtual */ Blitter::PaletteAnimation UsePaletteAnimation();
  34         /* virtual */ int GetBytesPerPixel() { return 4; }
  35
  36         /**
  37          * Look up the colour in the current palette.
  38          */
  39         static inline Colour LookupColourInPalette(uint index)
  40         {
  41                 return _cur_palette.palette[index];
  42         }
  43
  44         /**
  45          * Compose a colour based on RGBA values and the current pixel value.
  46          */
  47         static inline Colour ComposeColourRGBANoCheck(uint r, uint g, uint b, uint a, Colour current)
  48         {
  49                 uint cr = current.r;
  50                 uint cg = current.g;
  51                 uint cb = current.b;
  52
  53                 /* The 256 is wrong, it should be 255, but 256 is much faster... */
  54                 return Colour(
  55                                                         ((int)(r - cr) * a) / 256 + cr,
  56                                                         ((int)(g - cg) * a) / 256 + cg,
  57                                                         ((int)(b - cb) * a) / 256 + cb);
  58         }
  59
  60         /**
  61          * Compose a colour based on RGBA values and the current pixel value.
  62          * Handles fully transparent and solid pixels in a special (faster) way.
  63          */
  64         static inline Colour ComposeColourRGBA(uint r, uint g, uint b, uint a, Colour current)
  65         {
  66                 if (a == 0) return current;
  67                 if (a >= 255) return Colour(r, g, b);
  68
  69                 return ComposeColourRGBANoCheck(r, g, b, a, current);
  70         }
  71
  72         /**
  73          * Compose a colour based on Pixel value, alpha value, and the current pixel value.
  74          */
  75         static inline Colour ComposeColourPANoCheck(Colour colour, uint a, Colour current)
  76         {
  77                 uint r  = colour.r;
  78                 uint g  = colour.g;
  79                 uint b  = colour.b;
  80
  81                 return ComposeColourRGBANoCheck(r, g, b, a, current);
  82         }
  83
  84         /**
  85          * Compose a colour based on Pixel value, alpha value, and the current pixel value.
  86          * Handles fully transparent and solid pixels in a special (faster) way.
  87          */
  88         static inline Colour ComposeColourPA(Colour colour, uint a, Colour current)
  89         {
  90                 if (a == 0) return current;
  91                 if (a >= 255) {
  92                         colour.a = 255;
  93                         return colour;
  94                 }
  95
  96                 return ComposeColourPANoCheck(colour, a, current);
  97         }
  98
  99         /**
 100          * Make a pixel looks like it is transparent.
 101          * @param colour the colour already on the screen.
 102          * @param nom the amount of transparency, nominator, makes colour lighter.
 103          * @param denom denominator, makes colour darker.
 104          * @return the new colour for the screen.
 105          */
 106         static inline Colour MakeTransparent(Colour colour, uint nom, uint denom = 256)
 107         {
 108                 uint r = colour.r;
 109                 uint g = colour.g;
 110                 uint b = colour.b;
 111
 112                 return Colour(r * nom / denom, g * nom / denom, b * nom / denom);
 113         }
 114
 115         /**
 116          * Make a colour dark grey, for specialized 32bpp remapping.
 117          * @param r red component
 118          * @param g green component
 119          * @param b blue component
 120          * @return the brightness value of the new colour, now dark grey.
 121          */
 122         static inline uint8 MakeDark(uint8 r, uint8 g, uint8 b)
 123         {
 124                 /* Magic-numbers are ~66% of those used in MakeGrey() */
 125                 return ((r * 13063) + (g * 25647) + (b * 4981)) / 65536;
 126         }
 127
 128         /**
 129          * Make a colour grey - based.
 130          * @param colour the colour to make grey.
 131          * @return the new colour, now grey.
 132          */
 133         static inline Colour MakeGrey(Colour colour)
 134         {
 135                 uint r = colour.r;
 136                 uint g = colour.g;
 137                 uint b = colour.b;
 138
 139                 /* To avoid doubles and stuff, multiple it with a total of 65536 (16bits), then
 140                  *  divide by it to normalize the value to a byte again. See heightmap.cpp for
 141                  *  information about the formula. */
 142                 uint grey = ((r * 19595) + (g * 38470) + (b * 7471)) / 65536;
 143
 144                 return Colour(grey, grey, grey);
 145         }
 146
 147         static const int DEFAULT_BRIGHTNESS = 128;
 148
 149         static inline Colour AdjustBrightness(Colour colour, uint8 brightness)
 150         {
 151                 /* Shortcut for normal brightness */
 152                 if (brightness == DEFAULT_BRIGHTNESS) return colour;
 153
 154                 uint16 ob = 0;
 155                 uint16 r = colour.r * brightness / DEFAULT_BRIGHTNESS;
 156                 uint16 g = colour.g * brightness / DEFAULT_BRIGHTNESS;
 157                 uint16 b = colour.b * brightness / DEFAULT_BRIGHTNESS;
 158
 159                 /* Sum overbright */
 160                 if (r > 255) ob += r - 255;
 161                 if (g > 255) ob += g - 255;
 162                 if (b > 255) ob += b - 255;
 163
 164                 if (ob == 0) return Colour(r, g, b, colour.a);
 165
 166                 /* Reduce overbright strength */
 167                 ob /= 2;
 168                 return Colour(
 169                                      r >= 255 ? 255 : min(r + ob * (255 - r) / 256, 255),
 170                                      g >= 255 ? 255 : min(g + ob * (255 - g) / 256, 255),
 171                                      b >= 255 ? 255 : min(b + ob * (255 - b) / 256, 255),
 172                                      colour.a);
 173         }
 174 };
 175
 176 #endif /* BLITTER_32BPP_BASE_HPP */