graphics/primitives.cpp

   1 /* ScummVM - Graphic Adventure Engine
   2  *
   3  * ScummVM is the legal property of its developers, whose names
   4  * are too numerous to list here. Please refer to the COPYRIGHT
   5  * file distributed with this source distribution.
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version 2
  10  * of the License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  *
  21  * $URL$
  22  * $Id$
  23  */
  24
  25 #include "common/util.h"
  26
  27 namespace Graphics {
  28
  29 void drawLine(int x0, int y0, int x1, int y1, int color, void (*plotProc)(int, int, int, void *), void *data) {
  30         // Bresenham's line algorithm, as described by Wikipedia
  31         const bool steep = ABS(y1 - y0) > ABS(x1 - x0);
  32
  33         if (steep) {
  34                 SWAP(x0, y0);
  35                 SWAP(x1, y1);
  36         }
  37
  38         const int delta_x = ABS(x1 - x0);
  39         const int delta_y = ABS(y1 - y0);
  40         const int delta_err = delta_y;
  41         int x = x0;
  42         int y = y0;
  43         int err = 0;
  44
  45         const int x_step = (x0 < x1) ? 1 : -1;
  46         const int y_step = (y0 < y1) ? 1 : -1;
  47
  48         if (steep)
  49                 (*plotProc)(y, x, color, data);
  50         else
  51                 (*plotProc)(x, y, color, data);
  52
  53         while (x != x1) {
  54                 x += x_step;
  55                 err += delta_err;
  56                 if (2 * err > delta_x) {
  57                         y += y_step;
  58                         err -= delta_x;
  59                 }
  60                 if (steep)
  61                         (*plotProc)(y, x, color, data);
  62                 else
  63                         (*plotProc)(x, y, color, data);
  64         }
  65 }
  66
  67
  68 // FIXME: This is a limited version of thick line drawing
  69 // it draws striped lines at some angles. Better algorithm could
  70 // be found here:
  71 //
  72 //   http://homepages.enterprise.net/murphy/thickline/index.html
  73 //
  74 // Feel free to replace it with better implementation
  75 void drawThickLine(int x0, int y0, int x1, int y1, int thickness, int color, void (*plotProc)(int, int, int, void *), void *data) {
  76         const bool steep = ABS(y1 - y0) > ABS(x1 - x0);
  77
  78         if (steep) {
  79                 SWAP(x0, y0);
  80                 SWAP(x1, y1);
  81         }
  82
  83         float dx = x1 - x0;
  84         float dy = y1 - y0;
  85         float d = (float)sqrt(dx * dx + dy * dy);
  86
  87         if (!d)
  88                 return;
  89
  90         int thickX = (int)((float)thickness * dy / d / 2);
  91         int thickY = (int)((float)thickness * dx / d / 2);
  92
  93         const int delta_x = ABS(x1 - x0);
  94         const int delta_y = ABS(y1 - y0);
  95         const int delta_err = delta_y;
  96         int x = x0;
  97         int y = y0;
  98         int err = 0;
  99
 100         const int x_step = (x0 < x1) ? 1 : -1;
 101         const int y_step = (y0 < y1) ? 1 : -1;
 102
 103         if (steep)
 104                 drawLine(y - thickY, x + thickX, y + thickY, x - thickX, color, plotProc, data);
 105         else
 106                 drawLine(x - thickX, y + thickY, x + thickX, y - thickY, color, plotProc, data);
 107
 108         while (x != x1) {
 109                 x += x_step;
 110                 err += delta_err;
 111                 if (2 * err > delta_x) {
 112                         y += y_step;
 113                         err -= delta_x;
 114                 }
 115                 if (steep)
 116                         drawLine(y - thickY, x + thickX, y + thickY, x - thickX, color, plotProc, data);
 117                 else
 118                         drawLine(x - thickX, y + thickY, x + thickX, y - thickY, color, plotProc, data);
 119         }
 120 }
 121
 122 }       // End of namespace Graphics