Mercurial > sdl-ios-xcode
annotate src/video/SDL_drawline.c @ 2896:1ef2f1e75ff7
Date: Sat, 20 Dec 2008 23:25:19 +0100
From: Couriersud
Subject: 32 & 16 bit versions of blendrect and blendline
attached are 32, 16 and 15 bit versions of the blendrect and blendline
functionality. There was an issue with the bresenham alg. in drawline
which I also fixed.
author | Sam Lantinga <slouken@libsdl.org> |
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date | Sat, 20 Dec 2008 23:19:20 +0000 |
parents | 1863c8b59658 |
children | e40448bc7727 |
rev | line source |
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1 /* |
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2 SDL - Simple DirectMedia Layer |
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3 Copyright (C) 1997-2009 Sam Lantinga |
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4 |
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5 This library is free software; you can redistribute it and/or |
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6 modify it under the terms of the GNU Lesser General Public |
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7 License as published by the Free Software Foundation; either |
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8 version 2.1 of the License, or (at your option) any later version. |
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9 |
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10 This library is distributed in the hope that it will be useful, |
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 Lesser General Public License for more details. |
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14 |
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15 You should have received a copy of the GNU Lesser General Public |
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16 License along with this library; if not, write to the Free Software |
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17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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18 |
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19 Sam Lantinga |
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20 slouken@libsdl.org |
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21 */ |
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22 #include "SDL_config.h" |
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23 |
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24 #include "SDL_video.h" |
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25 #include "SDL_blit.h" |
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26 |
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27 #define ABS(_x) ((_x) < 0 ? -(_x) : (_x)) |
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28 |
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29 #define SWAP(_x, _y) do { int tmp; tmp = _x; _x = _y; _y = tmp; } while (0) |
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30 |
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31 #define BRESENHAM(x0, y0, x1, y1, op, color) \ |
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32 { \ |
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33 int deltax, deltay, steep, error, xstep, ystep, x, y; \ |
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34 \ |
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35 deltax = ABS(x1 - x0); \ |
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36 deltay = ABS(y1 - y0); \ |
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37 steep = (deltay > deltax); \ |
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38 if (steep) { \ |
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39 SWAP(x0, y0); \ |
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40 SWAP(x1, y1); \ |
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41 SWAP(deltax, deltay); \ |
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42 } \ |
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43 error = (x1 - x0) / 2; \ |
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44 y = y0; \ |
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45 if (x0 > x1) { \ |
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46 xstep = -1; \ |
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47 } else { \ |
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48 xstep = 1; \ |
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49 } \ |
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50 if (y0 < y1) { \ |
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51 ystep = 1; \ |
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52 } else { \ |
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53 ystep = -1; \ |
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54 } \ |
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55 if (!steep) { \ |
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56 for (x = x0; x != x1; x += xstep) { \ |
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57 op(x, y, color); \ |
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58 error -= deltay; \ |
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59 if (error < 0) { \ |
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60 y += ystep; \ |
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61 error += deltax; \ |
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62 } \ |
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63 } \ |
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64 } else { \ |
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65 for (x = x0; x != x1; x += xstep) { \ |
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66 op(y, x, color); \ |
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67 error -= deltay; \ |
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68 if (error < 0) { \ |
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69 y += ystep; \ |
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70 error += deltax; \ |
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71 } \ |
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72 } \ |
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73 } \ |
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74 } |
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75 |
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76 #define SETPIXEL(x, y, type, bpp, color) \ |
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77 *(type *)(dst->pixels + y * dst->pitch + x * bpp) = (type) color |
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78 |
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79 #define SETPIXEL1(x, y, color) SETPIXEL(x, y, Uint8, 1, color); |
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80 #define SETPIXEL2(x, y, color) SETPIXEL(x, y, Uint16, 2, color); |
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81 #define SETPIXEL4(x, y, color) SETPIXEL(x, y, Uint32, 4, color); |
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82 |
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83 SDL_DrawLine(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color) |
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84 { |
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85 /* This function doesn't work on surfaces < 8 bpp */ |
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86 if (dst->format->BitsPerPixel < 8) { |
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87 SDL_SetError("SDL_DrawLine(): Unsupported surface format"); |
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88 return (-1); |
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89 } |
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90 |
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91 /* Perform clipping */ |
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92 /* FIXME |
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93 if (!SDL_IntersectRect(dstrect, &dst->clip_rect, dstrect)) { |
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94 return (0); |
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95 } |
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96 */ |
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97 |
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98 switch (dst->format->BytesPerPixel) { |
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99 case 1: |
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100 BRESENHAM(x1, y1, x2, y2, SETPIXEL1, color); |
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101 break; |
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102 case 2: |
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103 BRESENHAM(x1, y1, x2, y2, SETPIXEL2, color); |
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104 break; |
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105 case 3: |
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106 SDL_Unsupported(); |
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107 return -1; |
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108 case 4: |
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109 BRESENHAM(x1, y1, x2, y2, SETPIXEL4, color); |
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110 break; |
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111 } |
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112 return 0; |
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113 } |
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114 |
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Added stubs for software implementations of blending fills and line drawing
Sam Lantinga <slouken@libsdl.org>
parents:
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