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91 regels
2.3 KiB

  1. /*
  2. * libee ASCII-Art library
  3. * Copyright (c) 2002, 2003 Sam Hocevar <sam@zoy.org>
  4. * All Rights Reserved
  5. *
  6. * $Id$
  7. *
  8. * This program is free software; you can redistribute it and/or modify
  9. * it under the terms of the GNU General Public License as published by
  10. * the Free Software Foundation; either version 2 of the License, or
  11. * (at your option) any later version.
  12. *
  13. * This program is distributed in the hope that it will be useful,
  14. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16. * GNU General Public License for more details.
  17. *
  18. * You should have received a copy of the GNU General Public License
  19. * along with this program; if not, write to the Free Software
  20. * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21. */
  22. #include "config.h"
  23. #include <stdlib.h>
  24. #include "ee.h"
  25. void ee_fill_triangle(int x1, int y1, int x2, int y2, int x3, int y3, char c)
  26. {
  27. int x, y, xa, xb, xmax, ymax;
  28. /* Bubble-sort y1 <= y2 <= y3 */
  29. if(y1 > y2)
  30. {
  31. ee_fill_triangle(x2, y2, x1, y1, x3, y3, c);
  32. return;
  33. }
  34. if(y2 > y3)
  35. {
  36. ee_fill_triangle(x1, y1, x3, y3, x2, y2, c);
  37. return;
  38. }
  39. /* Promote precision */
  40. x1 *= 4;
  41. x2 *= 4;
  42. x3 *= 4;
  43. xmax = ee_get_width() - 1;
  44. ymax = ee_get_height() - 1;
  45. /* Rasterize our triangle */
  46. for(y = y1 < 0 ? 0 : y1; y <= y3 && y <= ymax; y++)
  47. {
  48. if(y <= y2)
  49. {
  50. xa = (y1 == y2) ? x2 : x1 + (x2 - x1) * (y - y1) / (y2 - y1);
  51. xb = (y1 == y3) ? x3 : x1 + (x3 - x1) * (y - y1) / (y3 - y1);
  52. }
  53. else
  54. {
  55. xa = (y3 == y2) ? x2 : x3 + (x2 - x3) * (y - y3) / (y2 - y3);
  56. xb = (y3 == y1) ? x1 : x3 + (x1 - x3) * (y - y3) / (y1 - y3);
  57. }
  58. if(xb < xa)
  59. {
  60. int tmp = xb;
  61. xb = xa; xa = tmp;
  62. }
  63. /* Rescale xa and xb, slightly cropping */
  64. xa = (xa + 2) / 4;
  65. xb = (xb - 2) / 4;
  66. if(xb < 0) continue;
  67. if(xa > xmax) continue;
  68. if(xa < 0) xa = 0;
  69. if(xb > xmax) xb = xmax;
  70. for(x = xa; x <= xb; x++)
  71. {
  72. ee_goto(x, y);
  73. ee_putchar(c);
  74. }
  75. }
  76. }