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annotate src/video/SDL_rect.c @ 3381:c4d6458121db

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author Sam Lantinga <slouken@libsdl.org>
date Sun, 11 Oct 2009 10:30:47 +0000
parents 47965eacde88
children 0267b8b1595c
rev   line source
1895
c121d94672cb SDL 1.2 is moving to a branch, and SDL 1.3 is becoming the head.
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1 /*
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2 SDL - Simple DirectMedia Layer
2859
99210400e8b9 Updated copyright date
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3 Copyright (C) 1997-2009 Sam Lantinga
1895
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4
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5 This library is free software; you can redistribute it and/or
c121d94672cb SDL 1.2 is moving to a branch, and SDL 1.3 is becoming the head.
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6 modify it under the terms of the GNU Lesser General Public
c121d94672cb SDL 1.2 is moving to a branch, and SDL 1.3 is becoming the head.
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7 License as published by the Free Software Foundation; either
c121d94672cb SDL 1.2 is moving to a branch, and SDL 1.3 is becoming the head.
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8 version 2.1 of the License, or (at your option) any later version.
c121d94672cb SDL 1.2 is moving to a branch, and SDL 1.3 is becoming the head.
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9
c121d94672cb SDL 1.2 is moving to a branch, and SDL 1.3 is becoming the head.
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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
c121d94672cb SDL 1.2 is moving to a branch, and SDL 1.3 is becoming the head.
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
c121d94672cb SDL 1.2 is moving to a branch, and SDL 1.3 is becoming the head.
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13 Lesser General Public License for more details.
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14
c121d94672cb SDL 1.2 is moving to a branch, and SDL 1.3 is becoming the head.
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15 You should have received a copy of the GNU Lesser General Public
c121d94672cb SDL 1.2 is moving to a branch, and SDL 1.3 is becoming the head.
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16 License along with this library; if not, write to the Free Software
c121d94672cb SDL 1.2 is moving to a branch, and SDL 1.3 is becoming the head.
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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
c121d94672cb SDL 1.2 is moving to a branch, and SDL 1.3 is becoming the head.
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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_rect_c.h"
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26
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27 SDL_bool
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28 SDL_HasIntersection(const SDL_Rect * A, const SDL_Rect * B)
c121d94672cb SDL 1.2 is moving to a branch, and SDL 1.3 is becoming the head.
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29 {
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30 int Amin, Amax, Bmin, Bmax;
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31
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32 /* Horizontal intersection */
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33 Amin = A->x;
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34 Amax = Amin + A->w;
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35 Bmin = B->x;
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36 Bmax = Bmin + B->w;
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37 if (Bmin > Amin)
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38 Amin = Bmin;
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39 if (Bmax < Amax)
c121d94672cb SDL 1.2 is moving to a branch, and SDL 1.3 is becoming the head.
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40 Amax = Bmax;
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41 if (Amax <= Amin)
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42 return SDL_FALSE;
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43
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44 /* Vertical intersection */
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45 Amin = A->y;
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46 Amax = Amin + A->h;
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47 Bmin = B->y;
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48 Bmax = Bmin + B->h;
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49 if (Bmin > Amin)
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50 Amin = Bmin;
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51 if (Bmax < Amax)
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52 Amax = Bmax;
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53 if (Amax <= Amin)
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54 return SDL_FALSE;
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55
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56 return SDL_TRUE;
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57 }
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58
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59 SDL_bool
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60 SDL_IntersectRect(const SDL_Rect * A, const SDL_Rect * B, SDL_Rect * result)
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61 {
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62 int Amin, Amax, Bmin, Bmax;
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63
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64 /* Horizontal intersection */
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65 Amin = A->x;
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66 Amax = Amin + A->w;
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67 Bmin = B->x;
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68 Bmax = Bmin + B->w;
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69 if (Bmin > Amin)
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70 Amin = Bmin;
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71 result->x = Amin;
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72 if (Bmax < Amax)
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73 Amax = Bmax;
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74 result->w = Amax - Amin;
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75
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76 /* Vertical intersection */
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77 Amin = A->y;
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78 Amax = Amin + A->h;
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79 Bmin = B->y;
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80 Bmax = Bmin + B->h;
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81 if (Bmin > Amin)
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82 Amin = Bmin;
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83 result->y = Amin;
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84 if (Bmax < Amax)
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85 Amax = Bmax;
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86 result->h = Amax - Amin;
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87
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88 return !SDL_RectEmpty(result);
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89 }
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90
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91 void
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92 SDL_UnionRect(const SDL_Rect * A, const SDL_Rect * B, SDL_Rect * result)
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93 {
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94 int Amin, Amax, Bmin, Bmax;
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95
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96 /* Horizontal union */
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97 Amin = A->x;
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98 Amax = Amin + A->w;
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99 Bmin = B->x;
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100 Bmax = Bmin + B->w;
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101 if (Bmin < Amin)
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102 Amin = Bmin;
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103 result->x = Amin;
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104 if (Bmax > Amax)
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105 Amax = Bmax;
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106 result->w = Amax - Amin;
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107
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108 /* Vertical intersection */
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109 Amin = A->y;
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110 Amax = Amin + A->h;
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111 Bmin = B->y;
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112 Bmax = Bmin + B->h;
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113 if (Bmin < Amin)
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114 Amin = Bmin;
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115 result->y = Amin;
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116 if (Bmax > Amax)
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117 Amax = Bmax;
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118 result->h = Amax - Amin;
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119 }
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120
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121 SDL_bool
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122 SDL_IntersectRectAndLine(const SDL_Rect * rect, int *X1, int *Y1, int *X2,
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123 int *Y2)
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124 {
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125 int x1, y1;
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126 int x2, y2;
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127 int rectx1;
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128 int recty1;
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129 int rectx2;
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130 int recty2;
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131
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Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
132 if (!rect || !X1 || !Y1 || !X2 || !Y2) {
3046
47965eacde88 Fix recommended by Eddy L O Jansson
Sam Lantinga <slouken@libsdl.org>
parents: 3004
diff changeset
133 return SDL_FALSE;
2909
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
134 }
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
135
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
136 x1 = *X1;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
137 y1 = *Y1;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
138 x2 = *X2;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
139 y2 = *Y2;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
140 rectx1 = rect->x;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
141 recty1 = rect->y;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
142 rectx2 = rect->x + rect->w - 1;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
143 recty2 = rect->y + rect->h - 1;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
144
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
145 /* Check to see if entire line is inside rect */
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
146 if (x1 >= rectx1 && x1 <= rectx2 && x2 >= rectx1 && x2 <= rectx2 &&
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
147 y1 >= recty1 && y1 <= recty2 && y2 >= recty1 && y2 <= recty2) {
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
148 return SDL_TRUE;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
149 }
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
150
2994
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Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
151 /* Check to see if entire line is to one side of rect */
2909
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
152 if ((x1 < rectx1 && x2 < rectx1) || (x1 > rectx2 && x2 > rectx2) ||
3004
f3d7226a8dfd Fixed lines intersecting the top corners of a rectangle
Sam Lantinga <slouken@libsdl.org>
parents: 2997
diff changeset
153 (y1 < recty1 && y2 < recty1) || (y1 > recty2 && y2 > recty2)) {
2909
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
154 return SDL_FALSE;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
155 }
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
156
2994
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
157 if (y1 == y2) {
2909
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
158 /* Horizontal line, easy to clip */
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
159 if (x1 < rectx1) {
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
160 *X1 = rectx1;
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Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
161 } else if (x1 > rectx2) {
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
162 *X1 = rectx2;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
163 }
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
164 if (x2 < rectx1) {
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
165 *X2 = rectx1;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
166 } else if (x2 > rectx2) {
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
167 *X2 = rectx2;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
168 }
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
169 return SDL_TRUE;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
170 }
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
171
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
172 if (x1 == x2) {
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
173 /* Vertical line, easy to clip */
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
174 if (y1 < recty1) {
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
175 *Y1 = recty1;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
176 } else if (y1 > recty2) {
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
177 *Y1 = recty2;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
178 }
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
179 if (y2 < recty1) {
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
180 *Y2 = recty1;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
181 } else if (y2 > recty2) {
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
182 *Y2 = recty2;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
183 }
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
184 return SDL_TRUE;
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
185 }
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
186
2997
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
187 else {
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
188 /* The task of clipping a line with finite slope ratios in a fixed-
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
189 * precision coordinate space is not as immediately simple as it is
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
190 * with coordinates of arbitrary precision. If the ratio of slopes
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
191 * between the input line segment and the result line segment is not
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
192 * a whole number, you have in fact *moved* the line segment a bit,
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
193 * and there can be no avoiding it without more precision
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
194 */
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
195 int *x_result_[] = { X1, X2, NULL }, **x_result = x_result_;
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
196 int *y_result_[] = { Y1, Y2, NULL }, **y_result = y_result_;
2994
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
197 SDL_bool intersection = SDL_FALSE;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
198 double b, m, left, right, bottom, top;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
199 int xl, xh, yl, yh;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
200
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
201 /* solve mx+b line formula */
2997
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
202 m = (double) (y1 - y2) / (double) (x1 - x2);
2994
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
203 b = y2 - m * (double) x2;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
204
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
205 /* find some linear intersections */
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
206 left = (m * (double) rectx1) + b;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
207 right = (m * (double) rectx2) + b;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
208 top = (recty1 - b) / m;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
209 bottom = (recty2 - b) / m;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
210
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
211 /* sort end-points' x and y components individually */
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
212 if (x1 < x2) {
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
213 xl = x1;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
214 xh = x2;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
215 } else {
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
216 xl = x2;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
217 xh = x1;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
218 }
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
219 if (y1 < y2) {
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
220 yl = y1;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
221 yh = y2;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
222 } else {
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
223 yl = y2;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
224 yh = y1;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
225 }
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
226
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
227 #define RISING(a, b, c) (((a)<=(b))&&((b)<=(c)))
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
228
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
229 /* check for a point that's entirely inside the rect */
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
230 if (RISING(rectx1, x1, rectx2) && RISING(recty1, y1, recty2)) {
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
231 x_result++;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
232 y_result++;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
233 intersection = SDL_TRUE;
2997
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
234 } else
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
235 /* it was determined earlier that *both* end-points are not contained */
2994
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
236 if (RISING(rectx1, x2, rectx2) && RISING(recty1, y2, recty2)) {
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
237 **(x_result++) = x2;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
238 **(y_result++) = y2;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
239 intersection = SDL_TRUE;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
240 }
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
241
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
242 if (RISING(recty1, left, recty2) && RISING(xl, rectx1, xh)) {
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
243 **(x_result++) = rectx1;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
244 **(y_result++) = (int) left;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
245 intersection = SDL_TRUE;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
246 }
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
247
2997
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
248 if (*x_result == NULL)
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
249 return intersection;
2994
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
250 if (RISING(recty1, right, recty2) && RISING(xl, rectx2, xh)) {
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
251 **(x_result++) = rectx2;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
252 **(y_result++) = (int) right;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
253 intersection = SDL_TRUE;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
254 }
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
255
2997
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
256 if (*x_result == NULL)
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
257 return intersection;
2994
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
258 if (RISING(rectx1, top, rectx2) && RISING(yl, recty1, yh)) {
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
259 **(x_result++) = (int) top;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
260 **(y_result++) = recty1;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
261 intersection = SDL_TRUE;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
262 }
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
263
2997
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
264 if (*x_result == NULL)
Sam Lantinga <slouken@libsdl.org>
parents: 2994
diff changeset
265 return intersection;
2994
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
266 if (RISING(rectx1, bottom, rectx2) && RISING(yl, recty2, yh)) {
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
267 **(x_result++) = (int) bottom;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
268 **(y_result++) = recty2;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
269 intersection = SDL_TRUE;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
270 }
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
271
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
272 return intersection;
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
273 }
7563b99e9a49 Date: Sat, 3 Jan 2009 22:11:18 -0500
Sam Lantinga <slouken@libsdl.org>
parents: 2920
diff changeset
274
2909
3da0bb421d83 Added line clipping
Sam Lantinga <slouken@libsdl.org>
parents: 2859
diff changeset
275 return SDL_FALSE;
3da0bb421d83 Added line clipping
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276 }
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277
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278 void
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279 SDL_AddDirtyRect(SDL_DirtyRectList * list, const SDL_Rect * rect)
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280 {
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281 SDL_DirtyRect *dirty;
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282
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283 /* FIXME: At what point is this optimization too expensive? */
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284 for (dirty = list->list; dirty; dirty = dirty->next) {
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285 if (SDL_HasIntersection(&dirty->rect, rect)) {
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286 SDL_UnionRect(&dirty->rect, rect, &dirty->rect);
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287 return;
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288 }
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289 }
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290
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291 if (list->free) {
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292 dirty = list->free;
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293 list->free = dirty->next;
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294 } else {
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295 dirty = (SDL_DirtyRect *) SDL_malloc(sizeof(*dirty));
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296 if (!dirty) {
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297 return;
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298 }
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299 }
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300 dirty->rect = *rect;
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301 dirty->next = list->list;
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302 list->list = dirty;
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303 }
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304
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305 void
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306 SDL_ClearDirtyRects(SDL_DirtyRectList * list)
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307 {
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308 SDL_DirtyRect *prev, *curr;
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309
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310 /* Skip to the end of the free list */
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311 prev = NULL;
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312 for (curr = list->free; curr; curr = curr->next) {
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313 prev = curr;
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314 }
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315
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316 /* Add the list entries to the end */
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317 if (prev) {
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318 prev->next = list->list;
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319 } else {
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320 list->free = list->list;
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321 }
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322 list->list = NULL;
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323 }
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324
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325 void
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326 SDL_FreeDirtyRects(SDL_DirtyRectList * list)
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327 {
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328 while (list->list) {
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329 SDL_DirtyRect *elem = list->list;
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330 list->list = elem->next;
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331 SDL_free(elem);
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332 }
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333 while (list->free) {
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334 SDL_DirtyRect *elem = list->free;
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335 list->free = elem->next;
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336 SDL_free(elem);
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337 }
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338 }
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339
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340 /* vi: set ts=4 sw=4 expandtab: */