Dogcows Code - chaz/yoink/blob - src/texture.cc

   1
   2 /*******************************************************************************
   3
   4  Copyright (c) 2009, Charles McGarvey
   5  All rights reserved.
   6
   7  Redistribution   and   use  in  source  and  binary  forms,  with  or  without
   8  modification, are permitted provided that the following conditions are met:
   9
  10    * Redistributions  of  source  code  must retain the above copyright notice,
  11      this list of conditions and the following disclaimer.
  12    * Redistributions  in binary form must reproduce the above copyright notice,
  13      this  list of conditions and the following disclaimer in the documentation
  14      and/or other materials provided with the distribution.
  15
  16  THIS  SOFTWARE  IS  PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  17  AND  ANY  EXPRESS  OR  IMPLIED  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  19  DISCLAIMED.  IN  NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  20  FOR  ANY  DIRECT,  INDIRECT,  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  DAMAGES  (INCLUDING,  BUT  NOT  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  22  SERVICES;  LOSS  OF  USE,  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  23  CAUSED  AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  24  OR  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  25  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26
  27 *******************************************************************************/
  28
  29 #include <cstdlib>
  30
  31 #include <boost/bind.hpp>
  32
  33 #include <SDL/SDL.h>
  34 #include <SDL/SDL_image.h>
  35
  36 #include "dispatcher.hh"
  37 #include "opengl.hh"
  38
  39 #include "texture.hh"
  40
  41
  42 namespace dc {
  43
  44
  45 class texture_impl
  46 {
  47         void unloadFromGL()
  48         {
  49                 if (object)
  50                 {
  51                         glDeleteTextures(1, &object);
  52                         object = 0;
  53                 }
  54         }
  55
  56         void contextRecreated(const notification& note)
  57         {
  58                 unloadFromGL();
  59                 uploadToGL();
  60         }
  61
  62 public:
  63         texture_impl(texture* outside, bool keepInMemory)
  64                 : interface(outside), keepData(keepInMemory), object(0), imageData(0)
  65         {
  66                 dispatcher::instance().addHandler("video.context_recreated",
  67                                 boost::bind(&texture_impl::contextRecreated, this, _1),
  68                                 this);
  69         }
  70
  71         ~texture_impl()
  72         {
  73                 dispatcher::instance().removeHandler(this);
  74
  75                 if (imageData)
  76                 {
  77                         SDL_FreeSurface(imageData);
  78                 }
  79                 unloadFromGL();
  80         }
  81
  82
  83         static int powerOfTwo(int input)
  84         {
  85                 int value = 1;
  86
  87                 while (value < input)
  88                 {
  89                         value <<= 1;
  90                 }
  91                 return value;
  92         }
  93
  94         static SDL_Surface* prepareImageForGL(SDL_Surface* surface)
  95         {
  96                 // Adapted from some public domain code.  This stuff is common enough
  97                 // that it really should be included in SDL_image...  We need this
  98                 // because images loaded with SDL_image aren't exactly OpenGL-ready
  99                 // right out of the box.
 100
 101                 int w = powerOfTwo(surface->w);
 102                 int h = powerOfTwo(surface->h);
 103
 104                 // 1. OpenGL images must (generally) have dimensions of a power-of-two.
 105
 106                 SDL_Surface* image = SDL_CreateRGBSurface
 107                 (
 108                         SDL_SWSURFACE,
 109                         w, h,
 110                         32,
 111 #if SDL_BYTEORDER == SDL_LIL_ENDIAN
 112                         0x000000FF,
 113                         0x0000FF00,
 114                         0x00FF0000,
 115                         0xFF000000
 116 #else
 117                         0xFF000000,
 118                         0x00FF0000,
 119                         0x0000FF00,
 120                         0x000000FF
 121 #endif
 122                 );
 123
 124                 if (!image)
 125                 {
 126                         return 0;
 127                 }
 128
 129                 Uint32 savedFlags = surface->flags&(SDL_SRCALPHA|SDL_RLEACCELOK);
 130                 Uint8  savedAlpha = surface->format->alpha;
 131                 if (savedFlags & SDL_SRCALPHA)
 132                 {
 133                         SDL_SetAlpha(surface, 0, 0);
 134                 }
 135
 136                 SDL_Rect srcArea, destArea;
 137                 srcArea.x = 0; destArea.x = 0;
 138                 srcArea.y = 0; destArea.y = h - surface->h;
 139                 srcArea.w = surface->w;
 140                 srcArea.h = surface->h;
 141                 SDL_BlitSurface(surface, &srcArea, image, &destArea);
 142
 143                 if (savedFlags & SDL_SRCALPHA)
 144                 {
 145                         SDL_SetAlpha(surface, savedFlags, savedAlpha);
 146                 }
 147
 148                 // 2. OpenGL textures make more sense when they are "upside down."
 149
 150                 Uint8 line[image->pitch];
 151
 152                 Uint8 *pixels = static_cast<Uint8*>(image->pixels);
 153                 Uint16 pitch = image->pitch;
 154                 int ybegin = 0;
 155                 int yend = image->h - 1;
 156
 157                 if (SDL_MUSTLOCK(image)) SDL_LockSurface(image);
 158                 while (ybegin < yend)
 159                 {
 160                         memcpy(line, pixels + pitch * ybegin, pitch);
 161                         memcpy(pixels + pitch * ybegin, pixels + pitch * yend, pitch);
 162                         memcpy(pixels + pitch * yend, line, pitch);
 163                         ybegin++;
 164                         yend--;
 165                 }
 166                 if (SDL_MUSTLOCK(image)) SDL_UnlockSurface(image);
 167
 168                 return image;
 169         }
 170
 171
 172         void loadImageData()
 173         {
 174                 SDL_Surface* surface;
 175
 176                 surface = IMG_Load(interface->getPathToFile().c_str());
 177
 178                 if (!surface)
 179                 {
 180                         throw texture::exception("loading failed");
 181                 }
 182
 183                 imageData = prepareImageForGL(surface);
 184                 SDL_FreeSurface(surface);
 185
 186                 if (!imageData)
 187                 {
 188                         throw texture::exception("");
 189                 }
 190
 191                 if (imageData->format->BytesPerPixel == 3)
 192                 {
 193                         mode = GL_RGB;
 194                 }
 195                 else if (imageData->format->BytesPerPixel == 4)
 196                 {
 197                         mode = GL_RGBA;
 198                 }
 199                 else
 200                 {
 201                         SDL_FreeSurface(imageData);
 202                         throw texture::exception("image is not the required 24 or 32 bpp");
 203                 }
 204
 205                 width = imageData->w;
 206                 height = imageData->h;
 207         }
 208
 209
 210         void uploadToGL()
 211         {
 212                 if (object)
 213                 {
 214                         // Already loaded.
 215                         return;
 216                 }
 217
 218                 if (!imageData)
 219                 {
 220                         loadImageData();
 221                 }
 222
 223                 glGenTextures(1, &object);
 224
 225                 glBindTexture(GL_TEXTURE_2D, object);
 226
 227                 glTexImage2D
 228                 (
 229                         GL_TEXTURE_2D,
 230                         0,
 231                         mode,
 232                         imageData->w,
 233                         imageData->h,
 234                         0,
 235                         mode,
 236                         GL_UNSIGNED_BYTE,
 237                         imageData->pixels
 238                 );
 239
 240                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 241                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 242
 243                 if (!keepData)
 244                 {
 245                         SDL_FreeSurface(imageData);
 246                         imageData = 0;
 247                 }
 248         }
 249
 250
 251         unsigned width;
 252         unsigned height;
 253         int mode;
 254         GLuint object;
 255
 256         bool keepData;
 257         SDL_Surface* imageData;
 258
 259         texture* interface;
 260 };
 261
 262
 263 texture::texture(const std::string& name, bool keepInMemory)
 264         : resource(name), impl(new texture_impl(this, keepInMemory)) {}
 265
 266
 267 void texture::bind()
 268 {
 269         glBindTexture(GL_TEXTURE_2D, getObject());
 270 }
 271
 272 GLuint texture::getObject()
 273 {
 274         if (!impl->object)
 275         {
 276                 impl->uploadToGL();
 277         }
 278
 279         return impl->object;
 280 }
 281
 282
 283 unsigned texture::getWidth()
 284 {
 285         if (!impl->object)
 286         {
 287                 impl->uploadToGL();
 288         }
 289
 290         return impl->width;
 291 }
 292
 293 unsigned texture::getHeight()
 294 {
 295         if (!impl->object)
 296         {
 297                 impl->uploadToGL();
 298         }
 299
 300         return impl->height;
 301 }
 302
 303
 304 } // namespace dc
 305