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 #include <stdio.h>
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29
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30 #include "SDL_types.h"
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31 #include "SDL_video.h"
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32 #include "SDL_blit.h"
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33
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34 /* Functions to perform alpha blended blitting */
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35
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36 /* N->1 blending with per-surface alpha */
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37 static void BlitNto1SurfaceAlpha(SDL_BlitInfo *info)
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38 {
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39 int width = info->d_width;
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40 int height = info->d_height;
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41 Uint8 *src = info->s_pixels;
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42 int srcskip = info->s_skip;
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43 Uint8 *dst = info->d_pixels;
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44 int dstskip = info->d_skip;
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45 Uint8 *palmap = info->table;
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46 SDL_PixelFormat *srcfmt = info->src;
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47 SDL_PixelFormat *dstfmt = info->dst;
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48 int srcbpp = srcfmt->BytesPerPixel;
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49
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50 const unsigned A = srcfmt->alpha;
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51
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52 while ( height-- ) {
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53 DUFFS_LOOP4(
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54 {
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55 Uint32 pixel;
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56 unsigned sR;
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57 unsigned sG;
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58 unsigned sB;
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59 unsigned dR;
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60 unsigned dG;
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61 unsigned dB;
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62 DISEMBLE_RGB(src, srcbpp, srcfmt, pixel, sR, sG, sB);
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63 dR = dstfmt->palette->colors[*dst].r;
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64 dG = dstfmt->palette->colors[*dst].g;
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65 dB = dstfmt->palette->colors[*dst].b;
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66 ALPHA_BLEND(sR, sG, sB, A, dR, dG, dB);
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67 dR &= 0xff;
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68 dG &= 0xff;
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69 dB &= 0xff;
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70 /* Pack RGB into 8bit pixel */
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71 if ( palmap == NULL ) {
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72 *dst =((dR>>5)<<(3+2))|
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73 ((dG>>5)<<(2))|
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74 ((dB>>6)<<(0));
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75 } else {
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76 *dst = palmap[((dR>>5)<<(3+2))|
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77 ((dG>>5)<<(2)) |
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78 ((dB>>6)<<(0))];
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79 }
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80 dst++;
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81 src += srcbpp;
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82 },
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83 width);
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84 src += srcskip;
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85 dst += dstskip;
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86 }
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87 }
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88
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89 /* N->1 blending with pixel alpha */
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90 static void BlitNto1PixelAlpha(SDL_BlitInfo *info)
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91 {
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92 int width = info->d_width;
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93 int height = info->d_height;
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94 Uint8 *src = info->s_pixels;
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95 int srcskip = info->s_skip;
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96 Uint8 *dst = info->d_pixels;
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97 int dstskip = info->d_skip;
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98 Uint8 *palmap = info->table;
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99 SDL_PixelFormat *srcfmt = info->src;
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100 SDL_PixelFormat *dstfmt = info->dst;
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101 int srcbpp = srcfmt->BytesPerPixel;
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102
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103 /* FIXME: fix alpha bit field expansion here too? */
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104 while ( height-- ) {
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105 DUFFS_LOOP4(
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106 {
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107 Uint32 pixel;
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108 unsigned sR;
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109 unsigned sG;
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110 unsigned sB;
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111 unsigned sA;
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112 unsigned dR;
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113 unsigned dG;
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114 unsigned dB;
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115 DISEMBLE_RGBA(src,srcbpp,srcfmt,pixel,sR,sG,sB,sA);
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116 dR = dstfmt->palette->colors[*dst].r;
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117 dG = dstfmt->palette->colors[*dst].g;
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118 dB = dstfmt->palette->colors[*dst].b;
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119 ALPHA_BLEND(sR, sG, sB, sA, dR, dG, dB);
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120 dR &= 0xff;
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121 dG &= 0xff;
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122 dB &= 0xff;
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123 /* Pack RGB into 8bit pixel */
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124 if ( palmap == NULL ) {
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125 *dst =((dR>>5)<<(3+2))|
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126 ((dG>>5)<<(2))|
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127 ((dB>>6)<<(0));
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128 } else {
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129 *dst = palmap[((dR>>5)<<(3+2))|
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130 ((dG>>5)<<(2)) |
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131 ((dB>>6)<<(0)) ];
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132 }
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133 dst++;
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134 src += srcbpp;
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135 },
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136 width);
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137 src += srcskip;
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138 dst += dstskip;
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139 }
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140 }
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141
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142 /* colorkeyed N->1 blending with per-surface alpha */
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143 static void BlitNto1SurfaceAlphaKey(SDL_BlitInfo *info)
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144 {
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145 int width = info->d_width;
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146 int height = info->d_height;
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147 Uint8 *src = info->s_pixels;
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148 int srcskip = info->s_skip;
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149 Uint8 *dst = info->d_pixels;
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150 int dstskip = info->d_skip;
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151 Uint8 *palmap = info->table;
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152 SDL_PixelFormat *srcfmt = info->src;
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153 SDL_PixelFormat *dstfmt = info->dst;
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154 int srcbpp = srcfmt->BytesPerPixel;
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155 Uint32 ckey = srcfmt->colorkey;
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156
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157 const int A = srcfmt->alpha;
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158
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159 while ( height-- ) {
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160 DUFFS_LOOP(
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161 {
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162 Uint32 pixel;
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163 unsigned sR;
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164 unsigned sG;
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165 unsigned sB;
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166 unsigned dR;
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167 unsigned dG;
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168 unsigned dB;
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169 DISEMBLE_RGB(src, srcbpp, srcfmt, pixel, sR, sG, sB);
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170 if ( pixel != ckey ) {
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171 dR = dstfmt->palette->colors[*dst].r;
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172 dG = dstfmt->palette->colors[*dst].g;
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173 dB = dstfmt->palette->colors[*dst].b;
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174 ALPHA_BLEND(sR, sG, sB, A, dR, dG, dB);
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175 dR &= 0xff;
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176 dG &= 0xff;
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177 dB &= 0xff;
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178 /* Pack RGB into 8bit pixel */
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179 if ( palmap == NULL ) {
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180 *dst =((dR>>5)<<(3+2))|
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181 ((dG>>5)<<(2)) |
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182 ((dB>>6)<<(0));
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183 } else {
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184 *dst = palmap[((dR>>5)<<(3+2))|
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185 ((dG>>5)<<(2)) |
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186 ((dB>>6)<<(0)) ];
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187 }
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188 }
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189 dst++;
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190 src += srcbpp;
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191 },
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192 width);
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193 src += srcskip;
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194 dst += dstskip;
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195 }
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196 }
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197
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198 /* fast RGB888->(A)RGB888 blending with surface alpha */
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199 static void BlitRGBtoRGBSurfaceAlpha(SDL_BlitInfo *info)
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200 {
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201 int width = info->d_width;
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202 int height = info->d_height;
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203 Uint32 *srcp = (Uint32 *)info->s_pixels;
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204 int srcskip = info->s_skip >> 2;
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205 Uint32 *dstp = (Uint32 *)info->d_pixels;
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206 int dstskip = info->d_skip >> 2;
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207 SDL_PixelFormat *srcfmt = info->src;
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208 unsigned alpha = srcfmt->alpha;
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209
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210 while(height--) {
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211 DUFFS_LOOP4({
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212 Uint32 s;
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213 Uint32 d;
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214 Uint32 s1;
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215 Uint32 d1;
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216 s = *srcp;
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217 d = *dstp;
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218 s1 = s & 0xff00ff;
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219 d1 = d & 0xff00ff;
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220 d1 = (d1 + ((s1 - d1) * alpha >> 8)) & 0xff00ff;
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221 s &= 0xff00;
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222 d &= 0xff00;
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223 d = (d + ((s - d) * alpha >> 8)) & 0xff00;
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224 *dstp = d1 | d | 0xff000000;
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225 ++srcp;
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226 ++dstp;
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227 }, width);
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228 srcp += srcskip;
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229 dstp += dstskip;
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230 }
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231 }
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232
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233 /* fast ARGB888->(A)RGB888 blending with pixel alpha */
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234 static void BlitRGBtoRGBPixelAlpha(SDL_BlitInfo *info)
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235 {
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236 int width = info->d_width;
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237 int height = info->d_height;
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238 Uint32 *srcp = (Uint32 *)info->s_pixels;
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239 int srcskip = info->s_skip >> 2;
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240 Uint32 *dstp = (Uint32 *)info->d_pixels;
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241 int dstskip = info->d_skip >> 2;
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242
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243 while(height--) {
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244 DUFFS_LOOP4({
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245 Uint32 dalpha;
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246 Uint32 d;
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247 Uint32 s1;
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248 Uint32 d1;
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249 Uint32 s = *srcp;
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250 Uint32 alpha = s >> 24;
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251 /* FIXME: Here we special-case opaque alpha since the
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252 compositioning used (>>8 instead of /255) doesn't handle
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253 it correctly. Also special-case alpha=0 for speed?
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254 Benchmark this! */
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255 if(alpha == SDL_ALPHA_OPAQUE) {
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256 *dstp = (s & 0x00ffffff) | (*dstp & 0xff000000);
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257 } else {
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258 /*
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259 * take out the middle component (green), and process
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260 * the other two in parallel. One multiply less.
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261 */
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262 d = *dstp;
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263 dalpha = d & 0xff000000;
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264 s1 = s & 0xff00ff;
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265 d1 = d & 0xff00ff;
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266 d1 = (d1 + ((s1 - d1) * alpha >> 8)) & 0xff00ff;
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267 s &= 0xff00;
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268 d &= 0xff00;
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269 d = (d + ((s - d) * alpha >> 8)) & 0xff00;
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270 *dstp = d1 | d | dalpha;
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271 }
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272 ++srcp;
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273 ++dstp;
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274 }, width);
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275 srcp += srcskip;
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276 dstp += dstskip;
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277 }
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278 }
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279
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280 /* fast RGB565->RGB565 blending with surface alpha */
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281 static void Blit565to565SurfaceAlpha(SDL_BlitInfo *info)
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282 {
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283 int width = info->d_width;
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284 int height = info->d_height;
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285 Uint16 *srcp = (Uint16 *)info->s_pixels;
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286 int srcskip = info->s_skip >> 1;
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287 Uint16 *dstp = (Uint16 *)info->d_pixels;
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288 int dstskip = info->d_skip >> 1;
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289 unsigned alpha = info->src->alpha >> 3; /* downscale alpha to 5 bits */
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290
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291 while(height--) {
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292 DUFFS_LOOP4({
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293 Uint32 s = *srcp++;
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294 Uint32 d = *dstp;
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295 /*
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296 * shift out the middle component (green) to the high 16
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297 * bits, and process all three RGB components at the same
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298 * time.
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299 */
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300 s = (s | s << 16) & 0x07e0f81f;
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301 d = (d | d << 16) & 0x07e0f81f;
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302 d += (s - d) * alpha >> 5;
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303 d &= 0x07e0f81f;
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304 *dstp++ = d | d >> 16;
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305 }, width);
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306 srcp += srcskip;
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307 dstp += dstskip;
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308 }
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309 }
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310
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311 /* fast RGB555->RGB555 blending with surface alpha */
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312 static void Blit555to555SurfaceAlpha(SDL_BlitInfo *info)
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313 {
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314 int width = info->d_width;
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315 int height = info->d_height;
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316 Uint16 *srcp = (Uint16 *)info->s_pixels;
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317 int srcskip = info->s_skip >> 1;
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318 Uint16 *dstp = (Uint16 *)info->d_pixels;
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319 int dstskip = info->d_skip >> 1;
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320 unsigned alpha = info->src->alpha >> 3; /* downscale alpha to 5 bits */
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321
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322 while(height--) {
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323 DUFFS_LOOP4({
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324 Uint32 s = *srcp++;
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325 Uint32 d = *dstp;
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326 /*
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327 * shift out the middle component (green) to the high 16
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328 * bits, and process all three RGB components at the same
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329 * time.
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330 */
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331 s = (s | s << 16) & 0x03e07c1f;
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332 d = (d | d << 16) & 0x03e07c1f;
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333 d += (s - d) * alpha >> 5;
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334 d &= 0x03e07c1f;
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335 *dstp++ = d | d >> 16;
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336 }, width);
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337 srcp += srcskip;
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338 dstp += dstskip;
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339 }
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340 }
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341
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342 /* fast ARGB8888->RGB565 blending with pixel alpha */
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343 static void BlitARGBto565PixelAlpha(SDL_BlitInfo *info)
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344 {
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345 int width = info->d_width;
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346 int height = info->d_height;
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347 Uint32 *srcp = (Uint32 *)info->s_pixels;
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348 int srcskip = info->s_skip >> 2;
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349 Uint16 *dstp = (Uint16 *)info->d_pixels;
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350 int dstskip = info->d_skip >> 1;
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351
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352 while(height--) {
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353 DUFFS_LOOP4({
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354 Uint32 s = *srcp;
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355 unsigned alpha = s >> 27; /* downscale alpha to 5 bits */
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356 /* FIXME: Here we special-case opaque alpha since the
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357 compositioning used (>>8 instead of /255) doesn't handle
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358 it correctly. Also special-case alpha=0 for speed?
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359 Benchmark this! */
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360 if(alpha == (SDL_ALPHA_OPAQUE >> 3)) {
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361 *dstp = (s >> 8 & 0xf800) + (s >> 5 & 0x7e0)
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362 + (s >> 3 & 0x1f);
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363 } else {
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364 Uint32 d = *dstp;
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365 /*
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366 * convert source and destination to G0RAB65565
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367 * and blend all components at the same time
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368 */
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369 s = ((s & 0xfc00) << 11) + (s >> 8 & 0xf800)
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370 + (s >> 3 & 0x1f);
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371 d = (d | d << 16) & 0x07e0f81f;
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372 d += (s - d) * alpha >> 5;
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373 d &= 0x07e0f81f;
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374 *dstp = d | d >> 16;
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375 }
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376 srcp++;
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377 dstp++;
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378 }, width);
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379 srcp += srcskip;
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380 dstp += dstskip;
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381 }
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382 }
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383
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384 /* fast ARGB8888->RGB555 blending with pixel alpha */
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385 static void BlitARGBto555PixelAlpha(SDL_BlitInfo *info)
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386 {
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387 int width = info->d_width;
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388 int height = info->d_height;
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389 Uint32 *srcp = (Uint32 *)info->s_pixels;
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390 int srcskip = info->s_skip >> 2;
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391 Uint16 *dstp = (Uint16 *)info->d_pixels;
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392 int dstskip = info->d_skip >> 1;
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393
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394 while(height--) {
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395 DUFFS_LOOP4({
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396 unsigned alpha;
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397 Uint32 s = *srcp;
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398 alpha = s >> 27; /* downscale alpha to 5 bits */
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399 /* FIXME: Here we special-case opaque alpha since the
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400 compositioning used (>>8 instead of /255) doesn't handle
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401 it correctly. Also special-case alpha=0 for speed?
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402 Benchmark this! */
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403 if(alpha == (SDL_ALPHA_OPAQUE >> 3)) {
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404 *dstp = (s >> 9 & 0x7c00) + (s >> 6 & 0x3e0)
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405 + (s >> 3 & 0x1f);
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406 } else {
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407 Uint32 d = *dstp;
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408 /*
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409 * convert source and destination to G0RAB65565
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410 * and blend all components at the same time
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411 */
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412 s = ((s & 0xf800) << 10) + (s >> 9 & 0x7c00)
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413 + (s >> 3 & 0x1f);
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414 d = (d | d << 16) & 0x03e07c1f;
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415 d += (s - d) * alpha >> 5;
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416 d &= 0x03e07c1f;
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417 *dstp = d | d >> 16;
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418 }
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419 srcp++;
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420 dstp++;
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421 }, width);
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422 srcp += srcskip;
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423 dstp += dstskip;
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424 }
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425 }
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426
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427 /* General (slow) N->N blending with per-surface alpha */
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428 static void BlitNtoNSurfaceAlpha(SDL_BlitInfo *info)
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429 {
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430 int width = info->d_width;
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431 int height = info->d_height;
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432 Uint8 *src = info->s_pixels;
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433 int srcskip = info->s_skip;
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434 Uint8 *dst = info->d_pixels;
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435 int dstskip = info->d_skip;
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436 SDL_PixelFormat *srcfmt = info->src;
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437 SDL_PixelFormat *dstfmt = info->dst;
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438 int srcbpp = srcfmt->BytesPerPixel;
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439 int dstbpp = dstfmt->BytesPerPixel;
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440 unsigned sA = srcfmt->alpha;
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441 unsigned dA = dstfmt->Amask ? SDL_ALPHA_OPAQUE : 0;
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442
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443 while ( height-- ) {
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444 DUFFS_LOOP4(
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445 {
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446 Uint32 pixel;
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447 unsigned sR;
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448 unsigned sG;
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449 unsigned sB;
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450 unsigned dR;
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451 unsigned dG;
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452 unsigned dB;
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453 DISEMBLE_RGB(src, srcbpp, srcfmt, pixel, sR, sG, sB);
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454 DISEMBLE_RGB(dst, dstbpp, dstfmt, pixel, dR, dG, dB);
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455 ALPHA_BLEND(sR, sG, sB, sA, dR, dG, dB);
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456 ASSEMBLE_RGBA(dst, dstbpp, dstfmt, dR, dG, dB, dA);
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457 src += srcbpp;
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458 dst += dstbpp;
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459 },
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460 width);
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461 src += srcskip;
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462 dst += dstskip;
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463 }
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464 }
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465
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466 /* General (slow) colorkeyed N->N blending with per-surface alpha */
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467 static void BlitNtoNSurfaceAlphaKey(SDL_BlitInfo *info)
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468 {
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469 int width = info->d_width;
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470 int height = info->d_height;
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471 Uint8 *src = info->s_pixels;
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472 int srcskip = info->s_skip;
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473 Uint8 *dst = info->d_pixels;
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474 int dstskip = info->d_skip;
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475 SDL_PixelFormat *srcfmt = info->src;
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476 SDL_PixelFormat *dstfmt = info->dst;
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477 Uint32 ckey = srcfmt->colorkey;
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478 int srcbpp = srcfmt->BytesPerPixel;
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479 int dstbpp = dstfmt->BytesPerPixel;
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480 unsigned sA = srcfmt->alpha;
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481 unsigned dA = dstfmt->Amask ? SDL_ALPHA_OPAQUE : 0;
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482
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483 while ( height-- ) {
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484 DUFFS_LOOP4(
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485 {
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486 Uint32 pixel;
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487 unsigned sR;
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488 unsigned sG;
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489 unsigned sB;
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490 unsigned dR;
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491 unsigned dG;
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492 unsigned dB;
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493 RETRIEVE_RGB_PIXEL(src, srcbpp, pixel);
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494 if(pixel != ckey) {
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495 RGB_FROM_PIXEL(pixel, srcfmt, sR, sG, sB);
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496 DISEMBLE_RGB(dst, dstbpp, dstfmt, pixel, dR, dG, dB);
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497 ALPHA_BLEND(sR, sG, sB, sA, dR, dG, dB);
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498 ASSEMBLE_RGBA(dst, dstbpp, dstfmt, dR, dG, dB, dA);
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499 }
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500 src += srcbpp;
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501 dst += dstbpp;
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502 },
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503 width);
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504 src += srcskip;
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505 dst += dstskip;
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506 }
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507 }
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508
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509 /* General (slow) N->N blending with pixel alpha */
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510 static void BlitNtoNPixelAlpha(SDL_BlitInfo *info)
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511 {
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512 int width = info->d_width;
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513 int height = info->d_height;
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514 Uint8 *src = info->s_pixels;
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515 int srcskip = info->s_skip;
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516 Uint8 *dst = info->d_pixels;
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517 int dstskip = info->d_skip;
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518 SDL_PixelFormat *srcfmt = info->src;
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519 SDL_PixelFormat *dstfmt = info->dst;
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520
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521 int srcbpp;
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522 int dstbpp;
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523
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524 /* Set up some basic variables */
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525 srcbpp = srcfmt->BytesPerPixel;
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526 dstbpp = dstfmt->BytesPerPixel;
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527
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528 /* FIXME: for 8bpp source alpha, this doesn't get opaque values
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529 quite right. for <8bpp source alpha, it gets them very wrong
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530 (check all macros!)
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531 It is unclear whether there is a good general solution that doesn't
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532 need a branch (or a divide). */
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533 while ( height-- ) {
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534 DUFFS_LOOP4(
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535 {
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536 Uint32 pixel;
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537 unsigned sR;
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538 unsigned sG;
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539 unsigned sB;
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540 unsigned dR;
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541 unsigned dG;
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542 unsigned dB;
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543 unsigned sA;
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544 unsigned dA;
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545 DISEMBLE_RGBA(src, srcbpp, srcfmt, pixel, sR, sG, sB, sA);
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546 DISEMBLE_RGBA(dst, dstbpp, dstfmt, pixel, dR, dG, dB, dA);
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547 ALPHA_BLEND(sR, sG, sB, sA, dR, dG, dB);
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548 ASSEMBLE_RGBA(dst, dstbpp, dstfmt, dR, dG, dB, dA);
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549 src += srcbpp;
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550 dst += dstbpp;
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551 },
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552 width);
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553 src += srcskip;
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554 dst += dstskip;
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555 }
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556 }
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557
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558
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559 SDL_loblit SDL_CalculateAlphaBlit(SDL_Surface *surface, int blit_index)
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560 {
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561 SDL_PixelFormat *sf = surface->format;
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562 SDL_PixelFormat *df = surface->map->dst->format;
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563
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564 if(sf->Amask == 0) {
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565 if((surface->flags & SDL_SRCCOLORKEY) == SDL_SRCCOLORKEY) {
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566 if(df->BytesPerPixel == 1)
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567 return BlitNto1SurfaceAlphaKey;
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568 else
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569 return BlitNtoNSurfaceAlphaKey;
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570 } else {
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571 /* Per-surface alpha blits */
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572 switch(df->BytesPerPixel) {
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573 case 1:
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574 return BlitNto1SurfaceAlpha;
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575
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576 case 2:
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577 if(surface->map->identity) {
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578 if(df->Gmask == 0x7e0)
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579 return Blit565to565SurfaceAlpha;
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580 else if(df->Gmask == 0x3e0)
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581 return Blit555to555SurfaceAlpha;
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582 }
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583 return BlitNtoNSurfaceAlpha;
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584
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585 case 4:
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586 if(sf->Rmask == df->Rmask
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587 && sf->Gmask == df->Gmask
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588 && sf->Bmask == df->Bmask
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589 && (sf->Rmask | sf->Gmask | sf->Bmask) == 0xffffff
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590 && sf->BytesPerPixel == 4)
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591 return BlitRGBtoRGBSurfaceAlpha;
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592 else
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593 return BlitNtoNSurfaceAlpha;
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594
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595 case 3:
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596 default:
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597 return BlitNtoNSurfaceAlpha;
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598 }
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599 }
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600 } else {
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601 /* Per-pixel alpha blits */
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602 switch(df->BytesPerPixel) {
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603 case 1:
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604 return BlitNto1PixelAlpha;
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605
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606 case 2:
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607 if(sf->BytesPerPixel == 4 && sf->Amask == 0xff000000
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608 && sf->Gmask == 0xff00
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609 && ((sf->Rmask == 0xff && df->Rmask == 0x1f)
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610 || (sf->Bmask == 0xff && df->Bmask == 0x1f))) {
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611 if(df->Gmask == 0x7e0)
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612 return BlitARGBto565PixelAlpha;
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613 else if(df->Gmask == 0x3e0)
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614 return BlitARGBto555PixelAlpha;
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615 }
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616 return BlitNtoNPixelAlpha;
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617
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618 case 4:
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619 if(sf->Amask == 0xff000000
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620 && sf->Rmask == df->Rmask
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621 && sf->Gmask == df->Gmask
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622 && sf->Bmask == df->Bmask
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623 && sf->BytesPerPixel == 4)
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624 return BlitRGBtoRGBPixelAlpha;
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625 return BlitNtoNPixelAlpha;
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626
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627 case 3:
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628 default:
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629 return BlitNtoNPixelAlpha;
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630 }
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631 }
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632 }
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633
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