0
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1 /*
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2 SDL - Simple DirectMedia Layer
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3 Copyright (C) 1997, 1998, 1999, 2000, 2001 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 Library General Public
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7 License as published by the Free Software Foundation; either
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8 version 2 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 Library 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 Library General Public
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16 License along with this library; if not, write to the Free
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17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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18
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19 Sam Lantinga
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20 slouken@devolution.com
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21 */
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22
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23 #ifdef SAVE_RCSID
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24 static char rcsid =
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25 "@(#) $Id$";
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26 #endif
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27
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28 #ifndef DISABLE_FILE
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29
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30 /*
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31 Code to load and save surfaces in Windows BMP format.
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32
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33 Why support BMP format? Well, it's a native format for Windows, and
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34 most image processing programs can read and write it. It would be nice
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35 to be able to have at least one image format that we can natively load
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36 and save, and since PNG is so complex that it would bloat the library,
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37 BMP is a good alternative.
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38
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39 This code currently supports Win32 DIBs in uncompressed 8 and 24 bpp.
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40 */
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41
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42 #include <string.h>
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43
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44 #include "SDL_error.h"
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45 #include "SDL_video.h"
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46 #include "SDL_endian.h"
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47
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48 /* Compression encodings for BMP files */
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49 #ifndef BI_RGB
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50 #define BI_RGB 0
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51 #define BI_RLE8 1
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52 #define BI_RLE4 2
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53 #define BI_BITFIELDS 3
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54 #endif
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55
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56
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57 SDL_Surface * SDL_LoadBMP_RW (SDL_RWops *src, int freesrc)
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58 {
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59 int was_error;
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60 long fp_offset;
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61 int bmpPitch;
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62 int i, pad;
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63 SDL_Surface *surface;
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64 Uint32 Rmask;
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65 Uint32 Gmask;
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66 Uint32 Bmask;
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67 SDL_Palette *palette;
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68 Uint8 *bits;
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69 int ExpandBMP;
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70
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71 /* The Win32 BMP file header (14 bytes) */
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72 char magic[2];
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73 Uint32 bfSize;
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74 Uint16 bfReserved1;
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75 Uint16 bfReserved2;
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76 Uint32 bfOffBits;
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77
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78 /* The Win32 BITMAPINFOHEADER struct (40 bytes) */
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79 Uint32 biSize;
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80 Sint32 biWidth;
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81 Sint32 biHeight;
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82 Uint16 biPlanes;
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83 Uint16 biBitCount;
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84 Uint32 biCompression;
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85 Uint32 biSizeImage;
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86 Sint32 biXPelsPerMeter;
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87 Sint32 biYPelsPerMeter;
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88 Uint32 biClrUsed;
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89 Uint32 biClrImportant;
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90
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91 /* Make sure we are passed a valid data source */
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92 surface = NULL;
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93 was_error = 0;
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94 if ( src == NULL ) {
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95 was_error = 1;
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96 goto done;
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97 }
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98
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99 /* Read in the BMP file header */
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100 fp_offset = SDL_RWtell(src);
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101 SDL_ClearError();
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102 if ( SDL_RWread(src, magic, 1, 2) != 2 ) {
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103 SDL_Error(SDL_EFREAD);
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104 was_error = 1;
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105 goto done;
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106 }
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107 if ( strncmp(magic, "BM", 2) != 0 ) {
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108 SDL_SetError("File is not a Windows BMP file");
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109 was_error = 1;
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110 goto done;
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111 }
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112 bfSize = SDL_ReadLE32(src);
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113 bfReserved1 = SDL_ReadLE16(src);
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114 bfReserved2 = SDL_ReadLE16(src);
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115 bfOffBits = SDL_ReadLE32(src);
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116
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117 /* Read the Win32 BITMAPINFOHEADER */
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118 biSize = SDL_ReadLE32(src);
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119 if ( biSize == 12 ) {
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120 biWidth = (Uint32)SDL_ReadLE16(src);
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121 biHeight = (Uint32)SDL_ReadLE16(src);
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122 biPlanes = SDL_ReadLE16(src);
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123 biBitCount = SDL_ReadLE16(src);
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124 biCompression = BI_RGB;
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125 biSizeImage = 0;
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126 biXPelsPerMeter = 0;
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127 biYPelsPerMeter = 0;
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128 biClrUsed = 0;
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129 biClrImportant = 0;
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130 } else {
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131 biWidth = SDL_ReadLE32(src);
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132 biHeight = SDL_ReadLE32(src);
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133 biPlanes = SDL_ReadLE16(src);
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134 biBitCount = SDL_ReadLE16(src);
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135 biCompression = SDL_ReadLE32(src);
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136 biSizeImage = SDL_ReadLE32(src);
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137 biXPelsPerMeter = SDL_ReadLE32(src);
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138 biYPelsPerMeter = SDL_ReadLE32(src);
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139 biClrUsed = SDL_ReadLE32(src);
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140 biClrImportant = SDL_ReadLE32(src);
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141 }
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142
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143 /* Check for read error */
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144 if ( strcmp(SDL_GetError(), "") != 0 ) {
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145 was_error = 1;
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146 goto done;
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147 }
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148
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149 /* Expand 1 and 4 bit bitmaps to 8 bits per pixel */
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150 switch (biBitCount) {
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151 case 1:
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152 case 4:
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153 ExpandBMP = biBitCount;
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154 biBitCount = 8;
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155 break;
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156 default:
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157 ExpandBMP = 0;
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158 break;
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159 }
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160
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161 /* We don't support any BMP compression right now */
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162 Rmask = Gmask = Bmask = 0;
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163 switch (biCompression) {
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164 case BI_RGB:
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165 /* If there are no masks, use the defaults */
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166 if ( bfOffBits == (14+biSize) ) {
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167 /* Default values for the BMP format */
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168 switch (biBitCount) {
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169 case 15:
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170 case 16:
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171 Rmask = 0x7C00;
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172 Gmask = 0x03E0;
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173 Bmask = 0x001F;
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174 break;
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175 case 24:
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176 #if SDL_BYTEORDER == SDL_BIG_ENDIAN
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177 Rmask = 0x000000FF;
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178 Gmask = 0x0000FF00;
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179 Bmask = 0x00FF0000;
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180 break;
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181 #endif
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182 case 32:
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183 Rmask = 0x00FF0000;
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184 Gmask = 0x0000FF00;
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185 Bmask = 0x000000FF;
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186 break;
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187 default:
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188 break;
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189 }
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190 break;
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191 }
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192 /* Fall through -- read the RGB masks */
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193
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194 case BI_BITFIELDS:
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195 switch (biBitCount) {
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196 case 15:
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197 case 16:
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198 case 32:
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199 Rmask = SDL_ReadLE32(src);
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200 Gmask = SDL_ReadLE32(src);
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201 Bmask = SDL_ReadLE32(src);
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202 break;
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203 default:
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204 break;
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205 }
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206 break;
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207 default:
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208 SDL_SetError("Compressed BMP files not supported");
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209 was_error = 1;
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210 goto done;
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211 }
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212
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213 /* Create a compatible surface, note that the colors are RGB ordered */
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214 surface = SDL_CreateRGBSurface(SDL_SWSURFACE,
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215 biWidth, biHeight, biBitCount, Rmask, Gmask, Bmask, 0);
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216 if ( surface == NULL ) {
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217 was_error = 1;
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218 goto done;
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219 }
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220
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221 /* Load the palette, if any */
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222 palette = (surface->format)->palette;
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223 if ( palette ) {
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224 if ( biClrUsed == 0 ) {
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225 biClrUsed = 1 << biBitCount;
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226 }
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227 if ( biSize == 12 ) {
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228 for ( i = 0; i < (int)biClrUsed; ++i ) {
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229 SDL_RWread(src, &palette->colors[i].b, 1, 1);
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230 SDL_RWread(src, &palette->colors[i].g, 1, 1);
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231 SDL_RWread(src, &palette->colors[i].r, 1, 1);
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232 palette->colors[i].unused = 0;
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233 }
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234 } else {
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235 for ( i = 0; i < (int)biClrUsed; ++i ) {
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236 SDL_RWread(src, &palette->colors[i].b, 1, 1);
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237 SDL_RWread(src, &palette->colors[i].g, 1, 1);
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238 SDL_RWread(src, &palette->colors[i].r, 1, 1);
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239 SDL_RWread(src, &palette->colors[i].unused, 1, 1);
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240 }
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241 }
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242 palette->ncolors = biClrUsed;
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243 }
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244
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245 /* Read the surface pixels. Note that the bmp image is upside down */
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246 if ( SDL_RWseek(src, fp_offset+bfOffBits, SEEK_SET) < 0 ) {
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247 SDL_Error(SDL_EFSEEK);
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248 was_error = 1;
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249 goto done;
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250 }
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251 bits = (Uint8 *)surface->pixels+(surface->h*surface->pitch);
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252 switch (ExpandBMP) {
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253 case 1:
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254 bmpPitch = (biWidth + 7) >> 3;
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255 pad = (((bmpPitch)%4) ? (4-((bmpPitch)%4)) : 0);
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256 break;
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257 case 4:
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258 bmpPitch = (biWidth + 1) >> 1;
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259 pad = (((bmpPitch)%4) ? (4-((bmpPitch)%4)) : 0);
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260 break;
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261 default:
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262 pad = ((surface->pitch%4) ?
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263 (4-(surface->pitch%4)) : 0);
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264 break;
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265 }
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266 while ( bits > (Uint8 *)surface->pixels ) {
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267 bits -= surface->pitch;
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268 switch (ExpandBMP) {
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269 case 1:
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270 case 4: {
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271 Uint8 pixel = 0;
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272 int shift = (8-ExpandBMP);
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273 for ( i=0; i<surface->w; ++i ) {
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274 if ( i%(8/ExpandBMP) == 0 ) {
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275 if ( !SDL_RWread(src, &pixel, 1, 1) ) {
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276 SDL_SetError(
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277 "Error reading from BMP");
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278 was_error = 1;
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279 goto done;
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280 }
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281 }
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282 *(bits+i) = (pixel>>shift);
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283 pixel <<= ExpandBMP;
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284 } }
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285 break;
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286
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287 default:
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288 if ( SDL_RWread(src, bits, 1, surface->pitch)
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289 != surface->pitch ) {
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290 SDL_Error(SDL_EFREAD);
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291 was_error = 1;
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292 goto done;
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293 }
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294 #if SDL_BYTEORDER == SDL_BIG_ENDIAN
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295 /* Byte-swap the pixels if needed. Note that the 24bpp
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296 case has already been taken care of above. */
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297 switch(biBitCount) {
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298 case 15:
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299 case 16: {
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300 Uint16 *pix = (Uint16 *)bits;
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301 for(i = 0; i < surface->w; i++)
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302 pix[i] = SDL_Swap16(pix[i]);
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303 break;
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304 }
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305
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306 case 32: {
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307 Uint32 *pix = (Uint32 *)bits;
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308 for(i = 0; i < surface->w; i++)
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309 pix[i] = SDL_Swap32(pix[i]);
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310 break;
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311 }
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312 }
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313 #endif
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314 break;
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315 }
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316 /* Skip padding bytes, ugh */
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317 if ( pad ) {
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318 Uint8 padbyte;
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319 for ( i=0; i<pad; ++i ) {
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320 SDL_RWread(src, &padbyte, 1, 1);
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321 }
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322 }
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323 }
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324 done:
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325 if ( was_error ) {
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326 if ( surface ) {
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327 SDL_FreeSurface(surface);
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328 }
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329 surface = NULL;
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330 }
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331 if ( freesrc && src ) {
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332 SDL_RWclose(src);
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333 }
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334 return(surface);
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335 }
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336
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337 int SDL_SaveBMP_RW (SDL_Surface *saveme, SDL_RWops *dst, int freedst)
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338 {
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339 long fp_offset;
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340 int i, pad;
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341 SDL_Surface *surface;
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342 Uint8 *bits;
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343
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344 /* The Win32 BMP file header (14 bytes) */
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345 char magic[2] = { 'B', 'M' };
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346 Uint32 bfSize;
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347 Uint16 bfReserved1;
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348 Uint16 bfReserved2;
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349 Uint32 bfOffBits;
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350
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351 /* The Win32 BITMAPINFOHEADER struct (40 bytes) */
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352 Uint32 biSize;
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353 Sint32 biWidth;
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354 Sint32 biHeight;
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355 Uint16 biPlanes;
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356 Uint16 biBitCount;
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357 Uint32 biCompression;
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358 Uint32 biSizeImage;
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359 Sint32 biXPelsPerMeter;
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360 Sint32 biYPelsPerMeter;
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361 Uint32 biClrUsed;
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362 Uint32 biClrImportant;
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363
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364 /* Make sure we have somewhere to save */
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365 surface = NULL;
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366 if ( dst ) {
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367 if ( saveme->format->palette ) {
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368 if ( saveme->format->BitsPerPixel == 8 ) {
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369 surface = saveme;
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370 } else {
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371 SDL_SetError("%d bpp BMP files not supported",
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372 saveme->format->BitsPerPixel);
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373 }
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374 }
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375 else if ( (saveme->format->BitsPerPixel == 24) &&
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376 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
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377 (saveme->format->Rmask == 0x00FF0000) &&
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378 (saveme->format->Gmask == 0x0000FF00) &&
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379 (saveme->format->Bmask == 0x000000FF)
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380 #else
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381 (saveme->format->Rmask == 0x000000FF) &&
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382 (saveme->format->Gmask == 0x0000FF00) &&
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383 (saveme->format->Bmask == 0x00FF0000)
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384 #endif
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385 ) {
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386 surface = saveme;
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387 } else {
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388 SDL_Rect bounds;
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389
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390 /* Convert to 24 bits per pixel */
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391 surface = SDL_CreateRGBSurface(SDL_SWSURFACE,
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392 saveme->w, saveme->h, 24,
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393 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
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394 0x00FF0000, 0x0000FF00, 0x000000FF,
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395 #else
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396 0x000000FF, 0x0000FF00, 0x00FF0000,
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397 #endif
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398 0);
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399 if ( surface != NULL ) {
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400 bounds.x = 0;
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401 bounds.y = 0;
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402 bounds.w = saveme->w;
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403 bounds.h = saveme->h;
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404 if ( SDL_LowerBlit(saveme, &bounds, surface,
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405 &bounds) < 0 ) {
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406 SDL_FreeSurface(surface);
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407 SDL_SetError(
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408 "Couldn't convert image to 24 bpp");
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409 surface = NULL;
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410 }
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411 }
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412 }
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413 }
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414
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415 if ( surface && (SDL_LockSurface(surface) == 0) ) {
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416 /* Set the BMP file header values */
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417 bfSize = 0; /* We'll write this when we're done */
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418 bfReserved1 = 0;
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419 bfReserved2 = 0;
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420 bfOffBits = 0; /* We'll write this when we're done */
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421
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422 /* Write the BMP file header values */
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423 fp_offset = SDL_RWtell(dst);
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424 SDL_ClearError();
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425 SDL_RWwrite(dst, magic, 2, 1);
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426 SDL_WriteLE32(dst, bfSize);
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427 SDL_WriteLE16(dst, bfReserved1);
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428 SDL_WriteLE16(dst, bfReserved2);
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429 SDL_WriteLE32(dst, bfOffBits);
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430
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431 /* Set the BMP info values */
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432 biSize = 40;
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433 biWidth = surface->w;
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434 biHeight = surface->h;
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435 biPlanes = 1;
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436 biBitCount = surface->format->BitsPerPixel;
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437 biCompression = BI_RGB;
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438 biSizeImage = surface->h*surface->pitch;
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439 biXPelsPerMeter = 0;
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440 biYPelsPerMeter = 0;
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441 if ( surface->format->palette ) {
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442 biClrUsed = surface->format->palette->ncolors;
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443 } else {
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444 biClrUsed = 0;
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445 }
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446 biClrImportant = 0;
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447
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448 /* Write the BMP info values */
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449 SDL_WriteLE32(dst, biSize);
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450 SDL_WriteLE32(dst, biWidth);
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451 SDL_WriteLE32(dst, biHeight);
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452 SDL_WriteLE16(dst, biPlanes);
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453 SDL_WriteLE16(dst, biBitCount);
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454 SDL_WriteLE32(dst, biCompression);
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455 SDL_WriteLE32(dst, biSizeImage);
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456 SDL_WriteLE32(dst, biXPelsPerMeter);
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457 SDL_WriteLE32(dst, biYPelsPerMeter);
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458 SDL_WriteLE32(dst, biClrUsed);
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459 SDL_WriteLE32(dst, biClrImportant);
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460
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461 /* Write the palette (in BGR color order) */
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462 if ( surface->format->palette ) {
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463 SDL_Color *colors;
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464 int ncolors;
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465
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466 colors = surface->format->palette->colors;
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467 ncolors = surface->format->palette->ncolors;
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468 for ( i=0; i<ncolors; ++i ) {
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469 SDL_RWwrite(dst, &colors[i].b, 1, 1);
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470 SDL_RWwrite(dst, &colors[i].g, 1, 1);
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471 SDL_RWwrite(dst, &colors[i].r, 1, 1);
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472 SDL_RWwrite(dst, &colors[i].unused, 1, 1);
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473 }
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474 }
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475
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476 /* Write the bitmap offset */
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477 bfOffBits = SDL_RWtell(dst)-fp_offset;
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478 if ( SDL_RWseek(dst, fp_offset+10, SEEK_SET) < 0 ) {
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479 SDL_Error(SDL_EFSEEK);
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480 }
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481 SDL_WriteLE32(dst, bfOffBits);
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482 if ( SDL_RWseek(dst, fp_offset+bfOffBits, SEEK_SET) < 0 ) {
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483 SDL_Error(SDL_EFSEEK);
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484 }
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485
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486 /* Write the bitmap image upside down */
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487 bits = (Uint8 *)surface->pixels+(surface->h*surface->pitch);
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488 pad = ((surface->pitch%4) ? (4-(surface->pitch%4)) : 0);
|
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489 while ( bits > (Uint8 *)surface->pixels ) {
|
|
490 bits -= surface->pitch;
|
|
491 if ( SDL_RWwrite(dst, bits, 1, surface->pitch)
|
|
492 != surface->pitch) {
|
|
493 SDL_Error(SDL_EFWRITE);
|
|
494 break;
|
|
495 }
|
|
496 if ( pad ) {
|
|
497 const Uint8 padbyte = 0;
|
|
498 for ( i=0; i<pad; ++i ) {
|
|
499 SDL_RWwrite(dst, &padbyte, 1, 1);
|
|
500 }
|
|
501 }
|
|
502 }
|
|
503
|
|
504 /* Write the BMP file size */
|
|
505 bfSize = SDL_RWtell(dst)-fp_offset;
|
|
506 if ( SDL_RWseek(dst, fp_offset+2, SEEK_SET) < 0 ) {
|
|
507 SDL_Error(SDL_EFSEEK);
|
|
508 }
|
|
509 SDL_WriteLE32(dst, bfSize);
|
|
510 if ( SDL_RWseek(dst, fp_offset+bfSize, SEEK_SET) < 0 ) {
|
|
511 SDL_Error(SDL_EFSEEK);
|
|
512 }
|
|
513
|
|
514 /* Close it up.. */
|
|
515 SDL_UnlockSurface(surface);
|
|
516 if ( surface != saveme ) {
|
|
517 SDL_FreeSurface(surface);
|
|
518 }
|
|
519 }
|
|
520
|
|
521 if ( freedst && dst ) {
|
|
522 SDL_RWclose(dst);
|
|
523 }
|
|
524 return((strcmp(SDL_GetError(), "") == 0) ? 0 : -1);
|
|
525 }
|
|
526
|
|
527 #endif /* ENABLE_FILE */
|