libvo/gl_common.c

   1 /**
   2  * \file gl_common.c
   3  * \brief OpenGL helper functions used by vo_gl.c and vo_gl2.c
   4  *
   5  * Common OpenGL routines.
   6  * Copyleft (C) Reimar Döffinger <Reimar.Doeffinger@stud.uni-karlsruhe.de>, 2005
   7  * Licensend under the GNU GPL v2.
   8  * Special thanks go to the xine team and Matthias Hopf, whose video_out_opengl.c
   9  * gave me lots of good ideas.
  10  */
  11 #include <stdlib.h>
  12 #include <stdio.h>
  13 #include <string.h>
  14 #include <ctype.h>
  15 #include <math.h>
  16 #include "gl_common.h"
  17
  18 /**
  19  * \defgroup glextfunctions OpenGL extension functions
  20  *
  21  * the pointers to these functions are acquired when the OpenGL
  22  * context is created
  23  * \{
  24  */
  25 void (APIENTRY *GenBuffers)(GLsizei, GLuint *);
  26 void (APIENTRY *DeleteBuffers)(GLsizei, const GLuint *);
  27 void (APIENTRY *BindBuffer)(GLenum, GLuint);
  28 GLvoid* (APIENTRY *MapBuffer)(GLenum, GLenum);
  29 GLboolean (APIENTRY *UnmapBuffer)(GLenum);
  30 void (APIENTRY *BufferData)(GLenum, intptr_t, const GLvoid *, GLenum);
  31 void (APIENTRY *CombinerParameterfv)(GLenum, const GLfloat *);
  32 void (APIENTRY *CombinerParameteri)(GLenum, GLint);
  33 void (APIENTRY *CombinerInput)(GLenum, GLenum, GLenum, GLenum, GLenum,
  34                                GLenum);
  35 void (APIENTRY *CombinerOutput)(GLenum, GLenum, GLenum, GLenum, GLenum,
  36                                 GLenum, GLenum, GLboolean, GLboolean,
  37                                 GLboolean);
  38 void (APIENTRY *BeginFragmentShader)(void);
  39 void (APIENTRY *EndFragmentShader)(void);
  40 void (APIENTRY *SampleMap)(GLuint, GLuint, GLenum);
  41 void (APIENTRY *ColorFragmentOp2)(GLenum, GLuint, GLuint, GLuint, GLuint,
  42                                   GLuint, GLuint, GLuint, GLuint, GLuint);
  43 void (APIENTRY *ColorFragmentOp3)(GLenum, GLuint, GLuint, GLuint, GLuint,
  44                                   GLuint, GLuint, GLuint, GLuint, GLuint,
  45                                   GLuint, GLuint, GLuint);
  46 void (APIENTRY *SetFragmentShaderConstant)(GLuint, const GLfloat *);
  47 void (APIENTRY *ActiveTexture)(GLenum);
  48 void (APIENTRY *BindTexture)(GLenum, GLuint);
  49 void (APIENTRY *MultiTexCoord2f)(GLenum, GLfloat, GLfloat);
  50 void (APIENTRY *GenPrograms)(GLsizei, GLuint *);
  51 void (APIENTRY *DeletePrograms)(GLsizei, const GLuint *);
  52 void (APIENTRY *BindProgram)(GLenum, GLuint);
  53 void (APIENTRY *ProgramString)(GLenum, GLenum, GLsizei, const GLvoid *);
  54 void (APIENTRY *ProgramEnvParameter4f)(GLenum, GLuint, GLfloat, GLfloat,
  55                                        GLfloat, GLfloat);
  56 int (APIENTRY *SwapInterval)(int);
  57 /** \} */ // end of glextfunctions group
  58
  59 //! \defgroup glgeneral OpenGL general helper functions
  60
  61 //! \defgroup glcontext OpenGL context management helper functions
  62
  63 //! \defgroup gltexture OpenGL texture handling helper functions
  64
  65 //! \defgroup glconversion OpenGL conversion helper functions
  66
  67 /**
  68  * \brief adjusts the GL_UNPACK_ALIGNMENT to fit the stride.
  69  * \param stride number of bytes per line for which alignment should fit.
  70  * \ingroup glgeneral
  71  */
  72 void glAdjustAlignment(int stride) {
  73   GLint gl_alignment;
  74   if (stride % 8 == 0)
  75     gl_alignment=8;
  76   else if (stride % 4 == 0)
  77     gl_alignment=4;
  78   else if (stride % 2 == 0)
  79     gl_alignment=2;
  80   else
  81     gl_alignment=1;
  82   glPixelStorei (GL_UNPACK_ALIGNMENT, gl_alignment);
  83 }
  84
  85 struct gl_name_map_struct {
  86   GLint value;
  87   char *name;
  88 };
  89
  90 #undef MAP
  91 #define MAP(a) {a, #a}
  92 //! mapping table for the glValName function
  93 static const struct gl_name_map_struct gl_name_map[] = {
  94   // internal format
  95   MAP(GL_R3_G3_B2), MAP(GL_RGB4), MAP(GL_RGB5), MAP(GL_RGB8),
  96   MAP(GL_RGB10), MAP(GL_RGB12), MAP(GL_RGB16), MAP(GL_RGBA2),
  97   MAP(GL_RGBA4), MAP(GL_RGB5_A1), MAP(GL_RGBA8), MAP(GL_RGB10_A2),
  98   MAP(GL_RGBA12), MAP(GL_RGBA16), MAP(GL_LUMINANCE8),
  99
 100   // format
 101   MAP(GL_RGB), MAP(GL_RGBA), MAP(GL_RED), MAP(GL_GREEN), MAP(GL_BLUE),
 102   MAP(GL_ALPHA), MAP(GL_LUMINANCE), MAP(GL_LUMINANCE_ALPHA),
 103   MAP(GL_COLOR_INDEX),
 104   // rest 1.2 only
 105   MAP(GL_BGR), MAP(GL_BGRA),
 106
 107   //type
 108   MAP(GL_BYTE), MAP(GL_UNSIGNED_BYTE), MAP(GL_SHORT), MAP(GL_UNSIGNED_SHORT),
 109   MAP(GL_INT), MAP(GL_UNSIGNED_INT), MAP(GL_FLOAT), MAP(GL_DOUBLE),
 110   MAP(GL_2_BYTES), MAP(GL_3_BYTES), MAP(GL_4_BYTES),
 111   // rest 1.2 only
 112   MAP(GL_UNSIGNED_BYTE_3_3_2), MAP(GL_UNSIGNED_BYTE_2_3_3_REV),
 113   MAP(GL_UNSIGNED_SHORT_5_6_5), MAP(GL_UNSIGNED_SHORT_5_6_5_REV),
 114   MAP(GL_UNSIGNED_SHORT_4_4_4_4), MAP(GL_UNSIGNED_SHORT_4_4_4_4_REV),
 115   MAP(GL_UNSIGNED_SHORT_5_5_5_1), MAP(GL_UNSIGNED_SHORT_1_5_5_5_REV),
 116   MAP(GL_UNSIGNED_INT_8_8_8_8), MAP(GL_UNSIGNED_INT_8_8_8_8_REV),
 117   MAP(GL_UNSIGNED_INT_10_10_10_2), MAP(GL_UNSIGNED_INT_2_10_10_10_REV),
 118   {0, 0}
 119 };
 120 #undef MAP
 121
 122 /**
 123  * \brief return the name of an OpenGL constant
 124  * \param value the constant
 125  * \return name of the constant or "Unknown format!"
 126  * \ingroup glgeneral
 127  */
 128 const char *glValName(GLint value)
 129 {
 130   int i = 0;
 131
 132   while (gl_name_map[i].name) {
 133     if (gl_name_map[i].value == value)
 134       return gl_name_map[i].name;
 135     i++;
 136   }
 137   return "Unknown format!";
 138 }
 139
 140 //! always return this format as internal texture format in glFindFormat
 141 #define TEXTUREFORMAT_ALWAYS GL_RGB8
 142 #undef TEXTUREFORMAT_ALWAYS
 143
 144 /**
 145  * \brief find the OpenGL settings coresponding to format.
 146  *
 147  * All parameters may be NULL.
 148  * \param fmt MPlayer format to analyze.
 149  * \param bpp [OUT] bits per pixel of that format.
 150  * \param gl_texfmt [OUT] internal texture format that fits the
 151  * image format, not necessarily the best for performance.
 152  * \param gl_format [OUT] OpenGL format for this image format.
 153  * \param gl_type [OUT] OpenGL type for this image format.
 154  * \return 1 if format is supported by OpenGL, 0 if not.
 155  * \ingroup gltexture
 156  */
 157 int glFindFormat(uint32_t fmt, int *bpp, GLint *gl_texfmt,
 158                   GLenum *gl_format, GLenum *gl_type)
 159 {
 160   int supported = 1;
 161   int dummy1;
 162   GLenum dummy2;
 163   GLint dummy3;
 164   if (bpp == NULL) bpp = &dummy1;
 165   if (gl_texfmt == NULL) gl_texfmt = &dummy3;
 166   if (gl_format == NULL) gl_format = &dummy2;
 167   if (gl_type == NULL) gl_type = &dummy2;
 168
 169   *bpp = IMGFMT_IS_BGR(fmt)?IMGFMT_BGR_DEPTH(fmt):IMGFMT_RGB_DEPTH(fmt);
 170   *gl_texfmt = 3;
 171   switch (fmt) {
 172     case IMGFMT_RGB24:
 173       *gl_format = GL_RGB;
 174       *gl_type = GL_UNSIGNED_BYTE;
 175       break;
 176     case IMGFMT_RGBA:
 177       *gl_texfmt = 4;
 178       *gl_format = GL_RGBA;
 179       *gl_type = GL_UNSIGNED_BYTE;
 180       break;
 181     case IMGFMT_YV12:
 182       supported = 0; // no native YV12 support
 183     case IMGFMT_Y800:
 184     case IMGFMT_Y8:
 185       *gl_texfmt = 1;
 186       *bpp = 8;
 187       *gl_format = GL_LUMINANCE;
 188       *gl_type = GL_UNSIGNED_BYTE;
 189       break;
 190 #if 0
 191     // we do not support palettized formats, although the format the
 192     // swscale produces works
 193     case IMGFMT_RGB8:
 194       gl_format = GL_RGB;
 195       gl_type = GL_UNSIGNED_BYTE_2_3_3_REV;
 196       break;
 197 #endif
 198     case IMGFMT_RGB15:
 199       *gl_format = GL_RGBA;
 200       *gl_type = GL_UNSIGNED_SHORT_1_5_5_5_REV;
 201       break;
 202     case IMGFMT_RGB16:
 203       *gl_format = GL_RGB;
 204       *gl_type = GL_UNSIGNED_SHORT_5_6_5_REV;
 205       break;
 206 #if 0
 207     case IMGFMT_BGR8:
 208       // special case as red and blue have a differen number of bits.
 209       // GL_BGR and GL_UNSIGNED_BYTE_3_3_2 isn't supported at least
 210       // by nVidia drivers, and in addition would give more bits to
 211       // blue than to red, which isn't wanted
 212       gl_format = GL_RGB;
 213       gl_type = GL_UNSIGNED_BYTE_3_3_2;
 214       break;
 215 #endif
 216     case IMGFMT_BGR15:
 217       *gl_format = GL_BGRA;
 218       *gl_type = GL_UNSIGNED_SHORT_1_5_5_5_REV;
 219       break;
 220     case IMGFMT_BGR16:
 221       *gl_format = GL_RGB;
 222       *gl_type = GL_UNSIGNED_SHORT_5_6_5;
 223       break;
 224     case IMGFMT_BGR24:
 225       *gl_format = GL_BGR;
 226       *gl_type = GL_UNSIGNED_BYTE;
 227       break;
 228     case IMGFMT_BGRA:
 229       *gl_texfmt = 4;
 230       *gl_format = GL_BGRA;
 231       *gl_type = GL_UNSIGNED_BYTE;
 232       break;
 233     default:
 234       *gl_texfmt = 4;
 235       *gl_format = GL_RGBA;
 236       *gl_type = GL_UNSIGNED_BYTE;
 237       supported = 0;
 238   }
 239 #ifdef TEXTUREFORMAT_ALWAYS
 240   *gl_texfmt = TEXTUREFORMAT_ALWAYS;
 241 #endif
 242   return supported;
 243 }
 244
 245 static void *setNull(const GLubyte *s) {
 246   return NULL;
 247 }
 248
 249 typedef struct {
 250   void **funcptr;
 251   char *extstr;
 252   char *funcnames[7];
 253 } extfunc_desc_t;
 254
 255 static const extfunc_desc_t extfuncs[] = {
 256   {(void **)&GenBuffers, NULL, {"glGenBuffers", "glGenBuffersARB", NULL}},
 257   {(void **)&DeleteBuffers, NULL, {"glDeleteBuffers", "glDeleteBuffersARB", NULL}},
 258   {(void **)&BindBuffer, NULL, {"glBindBuffer", "glBindBufferARB", NULL}},
 259   {(void **)&MapBuffer, NULL, {"glMapBuffer", "glMapBufferARB", NULL}},
 260   {(void **)&UnmapBuffer, NULL, {"glUnmapBuffer", "glUnmapBufferARB", NULL}},
 261   {(void **)&BufferData, NULL, {"glBufferData", "glBufferDataARB", NULL}},
 262   {(void **)&CombinerParameterfv, NULL, {"glCombinerParameterfv", "glCombinerParameterfvNV", NULL}},
 263   {(void **)&CombinerParameteri, NULL, {"glCombinerParameteri", "glCombinerParameteriNV", NULL}},
 264   {(void **)&CombinerInput, NULL, {"glCombinerInput", "glCombinerInputNV", NULL}},
 265   {(void **)&CombinerOutput, NULL, {"glCombinerOutput", "glCombinerOutputNV", NULL}},
 266   {(void **)&BeginFragmentShader, NULL, {"glBeginFragmentShaderATI", NULL}},
 267   {(void **)&EndFragmentShader, NULL, {"glEndFragmentShaderATI", NULL}},
 268   {(void **)&SampleMap, NULL, {"glSampleMapATI", NULL}},
 269   {(void **)&ColorFragmentOp2, NULL, {"glColorFragmentOp2ATI", NULL}},
 270   {(void **)&ColorFragmentOp3, NULL, {"glColorFragmentOp3ATI", NULL}},
 271   {(void **)&SetFragmentShaderConstant, NULL, {"glSetFragmentShaderConstantATI", NULL}},
 272   {(void **)&ActiveTexture, NULL, {"glActiveTexture", "glActiveTextureARB", NULL}},
 273   {(void **)&BindTexture, NULL, {"glBindTexture", "glBindTextureARB", "glBindTextureEXT", NULL}},
 274   {(void **)&MultiTexCoord2f, NULL, {"glMultiTexCoord2f", "glMultiTexCoord2fARB", NULL}},
 275   {(void **)&GenPrograms, NULL, {"glGenPrograms", "glGenProgramsARB", "glGenProgramsNV", NULL}},
 276   {(void **)&DeletePrograms, NULL, {"glDeletePrograms", "glDeleteProgramsARB", "glDeleteProgramsNV", NULL}},
 277   {(void **)&BindProgram, NULL, {"glBindProgram", "glBindProgramARB", "glBindProgramNV", NULL}},
 278   {(void **)&ProgramString, NULL, {"glProgramString", "glProgramStringARB", "glProgramStringNV", NULL}},
 279   {(void **)&ProgramEnvParameter4f, NULL, {"glProgramEnvParameter4f", "glProgramEnvParameter4fARB", "glProgramEnvParameter4fNV", NULL}},
 280   {(void **)&SwapInterval, "_swap_control", {"glXSwapInterval", "glXSwapIntervalEXT", "glXSwapIntervalSGI", "wglSwapInterval", "wglSwapIntervalEXT", "wglSwapIntervalSGI", NULL}},
 281   {NULL}
 282 };
 283
 284 /**
 285  * \brief find the function pointers of some useful OpenGL extensions
 286  * \param getProcAddress function to resolve function names, may be NULL
 287  * \param ext2 an extra extension string
 288  */
 289 static void getFunctions(void *(*getProcAddress)(const GLubyte *),
 290                          const char *ext2) {
 291   const extfunc_desc_t *dsc;
 292   const char *extensions = (const char *)glGetString(GL_EXTENSIONS);
 293   char *allexts;
 294   if (!extensions) extensions = "";
 295   if (!ext2) ext2 = "";
 296   allexts = (char *)malloc(strlen(extensions) + strlen(ext2) + 2);
 297   strcpy(allexts, extensions);
 298   strcat(allexts, " ");
 299   strcat(allexts, ext2);
 300   mp_msg(MSGT_VO, MSGL_V, "OpenGL extensions string:\n%s\n", allexts);
 301   if (!getProcAddress)
 302     getProcAddress = setNull;
 303   for (dsc = extfuncs; dsc->funcptr; dsc++) {
 304     void *ptr = NULL;
 305     int i;
 306     if (!dsc->extstr || strstr(allexts, dsc->extstr)) {
 307       for (i = 0; !ptr && dsc->funcnames[i]; i++)
 308         ptr = getProcAddress((const GLubyte *)dsc->funcnames[i]);
 309     }
 310     *(dsc->funcptr) = ptr;
 311   }
 312   free(allexts);
 313 }
 314
 315 /**
 316  * \brief create a texture and set some defaults
 317  * \param target texture taget, usually GL_TEXTURE_2D
 318  * \param fmt internal texture format
 319  * \param filter filter used for scaling, e.g. GL_LINEAR
 320  * \param w texture width
 321  * \param h texture height
 322  * \param val luminance value to fill texture with
 323  * \ingroup gltexture
 324  */
 325 void glCreateClearTex(GLenum target, GLenum fmt, GLint filter,
 326                       int w, int h, unsigned char val) {
 327   GLfloat fval = (GLfloat)val / 255.0;
 328   GLfloat border[4] = {fval, fval, fval, fval};
 329   GLenum clrfmt = (fmt == GL_ALPHA) ? GL_ALPHA : GL_LUMINANCE;
 330   char *init = (char *)malloc(w * h);
 331   memset(init, val, w * h);
 332   glAdjustAlignment(w);
 333   glPixelStorei(GL_UNPACK_ROW_LENGTH, w);
 334   glTexImage2D(target, 0, fmt, w, h, 0, clrfmt, GL_UNSIGNED_BYTE, init);
 335   glTexParameterf(target, GL_TEXTURE_PRIORITY, 1.0);
 336   glTexParameteri(target, GL_TEXTURE_MIN_FILTER, filter);
 337   glTexParameteri(target, GL_TEXTURE_MAG_FILTER, filter);
 338   glTexParameteri(target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 339   glTexParameteri(target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 340   // Border texels should not be used with CLAMP_TO_EDGE
 341   // We set a sane default anyway.
 342   glTexParameterfv(target, GL_TEXTURE_BORDER_COLOR, border);
 343   free(init);
 344 }
 345
 346 /**
 347  * \brief skips whitespace and comments
 348  * \param f file to read from
 349  */
 350 static void ppm_skip(FILE *f) {
 351   int c, comment = 0;
 352   do {
 353     c = fgetc(f);
 354     if (c == '#')
 355       comment = 1;
 356     if (c == '\n')
 357       comment = 0;
 358   } while (c != EOF && (isspace(c) || comment));
 359   if (c != EOF)
 360     ungetc(c, f);
 361 }
 362
 363 #define MAXDIM (16 * 1024)
 364
 365 /**
 366  * \brief creates a texture from a PPM file
 367  * \param target texture taget, usually GL_TEXTURE_2D
 368  * \param fmt internal texture format
 369  * \param filter filter used for scaling, e.g. GL_LINEAR
 370  * \param f file to read PPM from
 371  * \param width [out] width of texture
 372  * \param height [out] height of texture
 373  * \param maxval [out] maxval value from PPM file
 374  * \return 0 on error, 1 otherwise
 375  * \ingroup gltexture
 376  */
 377 int glCreatePPMTex(GLenum target, GLenum fmt, GLint filter,
 378                    FILE *f, int *width, int *height, int *maxval) {
 379   unsigned w, h, m, val;
 380   char *data;
 381   ppm_skip(f);
 382   if (fgetc(f) != 'P' || fgetc(f) != '6')
 383     return 0;
 384   ppm_skip(f);
 385   if (fscanf(f, "%u", &w) != 1)
 386     return 0;
 387   ppm_skip(f);
 388   if (fscanf(f, "%u", &h) != 1)
 389     return 0;
 390   ppm_skip(f);
 391   if (fscanf(f, "%u", &m) != 1)
 392     return 0;
 393   val = fgetc(f);
 394   if (!isspace(val))
 395     return 0;
 396   if (w > MAXDIM || h > MAXDIM)
 397     return 0;
 398   data = (char *)malloc(w * h * 3);
 399   if (fread(data, w * 3, h, f) != h)
 400     return 0;
 401   glCreateClearTex(target, fmt, filter, w, h, 0);
 402   glUploadTex(target, GL_RGB, GL_UNSIGNED_BYTE, data, w * 3, 0, 0, w, h, 0);
 403   free(data);
 404   if (width) *width = w;
 405   if (height) *height = h;
 406   if (maxval) *maxval = m;
 407   return 1;
 408 }
 409
 410 /**
 411  * \brief return the number of bytes per pixel for the given format
 412  * \param format OpenGL format
 413  * \param type OpenGL type
 414  * \return bytes per pixel
 415  * \ingroup glgeneral
 416  *
 417  * Does not handle all possible variants, just those used by MPlayer
 418  */
 419 int glFmt2bpp(GLenum format, GLenum type) {
 420   switch (type) {
 421     case GL_UNSIGNED_BYTE_3_3_2:
 422     case GL_UNSIGNED_BYTE_2_3_3_REV:
 423       return 1;
 424     case GL_UNSIGNED_SHORT_5_5_5_1:
 425     case GL_UNSIGNED_SHORT_1_5_5_5_REV:
 426     case GL_UNSIGNED_SHORT_5_6_5:
 427     case GL_UNSIGNED_SHORT_5_6_5_REV:
 428       return 2;
 429   }
 430   if (type != GL_UNSIGNED_BYTE)
 431     return 0; //not implemented
 432   switch (format) {
 433     case GL_LUMINANCE:
 434     case GL_ALPHA:
 435       return 1;
 436     case GL_RGB:
 437     case GL_BGR:
 438       return 3;
 439     case GL_RGBA:
 440     case GL_BGRA:
 441       return 4;
 442   }
 443   return 0; // unknown
 444 }
 445
 446 /**
 447  * \brief upload a texture, handling things like stride and slices
 448  * \param target texture target, usually GL_TEXTURE_2D
 449  * \param format OpenGL format of data
 450  * \param type OpenGL type of data
 451  * \param data data to upload
 452  * \param stride data stride
 453  * \param x x offset in texture
 454  * \param y y offset in texture
 455  * \param w width of the texture part to upload
 456  * \param h height of the texture part to upload
 457  * \param slice height of an upload slice, 0 for all at once
 458  * \ingroup gltexture
 459  */
 460 void glUploadTex(GLenum target, GLenum format, GLenum type,
 461                  const void *data, int stride,
 462                  int x, int y, int w, int h, int slice) {
 463   int y_max = y + h;
 464   if (w <= 0 || h <= 0) return;
 465   if (slice <= 0)
 466     slice = h;
 467   if (stride < 0) {
 468     data += h * stride;
 469     stride = -stride;
 470   }
 471   // this is not always correct, but should work for MPlayer
 472   glAdjustAlignment(stride);
 473   glPixelStorei(GL_UNPACK_ROW_LENGTH, stride / glFmt2bpp(format, type));
 474   for (; y + slice <= y_max; y += slice) {
 475     glTexSubImage2D(target, 0, x, y, w, slice, format, type, data);
 476     data += stride * slice;
 477   }
 478   if (y < y_max)
 479     glTexSubImage2D(target, 0, x, y, w, y_max - y, format, type, data);
 480 }
 481
 482 static void fillUVcoeff(GLfloat *ucoef, GLfloat *vcoef,
 483                         float uvcos, float uvsin) {
 484   int i;
 485   ucoef[0] = 0 * uvcos + 1.403 * uvsin;
 486   vcoef[0] = 0 * uvsin + 1.403 * uvcos;
 487   ucoef[1] = -0.344 * uvcos + -0.714 * uvsin;
 488   vcoef[1] = -0.344 * uvsin + -0.714 * uvcos;
 489   ucoef[2] = 1.770 * uvcos + 0 * uvsin;
 490   vcoef[2] = 1.770 * uvsin + 0 * uvcos;
 491   ucoef[3] = 0;
 492   vcoef[3] = 0;
 493   // Coefficients (probably) must be in [0, 1] range, whereas they originally
 494   // are in [-2, 2] range, so here comes the trick:
 495   // First put them in the [-0.5, 0.5] range, then add 0.5.
 496   // This can be undone with the HALF_BIAS and SCALE_BY_FOUR arguments
 497   // for CombinerInput and CombinerOutput (or the respective ATI variants)
 498   for (i = 0; i < 4; i++) {
 499     ucoef[i] = ucoef[i] * 0.25 + 0.5;
 500     vcoef[i] = vcoef[i] * 0.25 + 0.5;
 501   }
 502 }
 503
 504 /**
 505  * \brief Setup register combiners for YUV to RGB conversion.
 506  * \param uvcos used for saturation and hue adjustment
 507  * \param uvsin used for saturation and hue adjustment
 508  */
 509 static void glSetupYUVCombiners(float uvcos, float uvsin) {
 510   GLfloat ucoef[4];
 511   GLfloat vcoef[4];
 512   GLint i;
 513   glGetIntegerv(GL_MAX_GENERAL_COMBINERS_NV, &i);
 514   if (i < 2)
 515     mp_msg(MSGT_VO, MSGL_ERR,
 516            "[gl] 2 general combiners needed for YUV combiner support (found %i)\n", i);
 517   glGetIntegerv (GL_MAX_TEXTURE_UNITS, &i);
 518   if (i < 3)
 519     mp_msg(MSGT_VO, MSGL_ERR,
 520            "[gl] 3 texture units needed for YUV combiner support (found %i)\n", i);
 521   if (!CombinerInput || !CombinerOutput ||
 522       !CombinerParameterfv || !CombinerParameteri) {
 523     mp_msg(MSGT_VO, MSGL_FATAL, "[gl] Combiner functions missing!\n");
 524     return;
 525   }
 526   fillUVcoeff(ucoef, vcoef, uvcos, uvsin);
 527   CombinerParameterfv(GL_CONSTANT_COLOR0_NV, ucoef);
 528   CombinerParameterfv(GL_CONSTANT_COLOR1_NV, vcoef);
 529
 530   // UV first, like this green component cannot overflow
 531   CombinerInput(GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_A_NV,
 532                 GL_TEXTURE1, GL_HALF_BIAS_NORMAL_NV, GL_RGB);
 533   CombinerInput(GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_B_NV,
 534                 GL_CONSTANT_COLOR0_NV, GL_HALF_BIAS_NORMAL_NV, GL_RGB);
 535   CombinerInput(GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_C_NV,
 536                 GL_TEXTURE2, GL_HALF_BIAS_NORMAL_NV, GL_RGB);
 537   CombinerInput(GL_COMBINER0_NV, GL_RGB, GL_VARIABLE_D_NV,
 538                 GL_CONSTANT_COLOR1_NV, GL_HALF_BIAS_NORMAL_NV, GL_RGB);
 539   CombinerOutput(GL_COMBINER0_NV, GL_RGB, GL_DISCARD_NV, GL_DISCARD_NV,
 540                  GL_SPARE0_NV, GL_SCALE_BY_FOUR_NV, GL_NONE, GL_FALSE,
 541                  GL_FALSE, GL_FALSE);
 542
 543   // stage 2
 544   CombinerInput(GL_COMBINER1_NV, GL_RGB, GL_VARIABLE_A_NV, GL_SPARE0_NV,
 545                 GL_SIGNED_IDENTITY_NV, GL_RGB);
 546   CombinerInput(GL_COMBINER1_NV, GL_RGB, GL_VARIABLE_B_NV, GL_ZERO,
 547                  GL_UNSIGNED_INVERT_NV, GL_RGB);
 548   CombinerInput(GL_COMBINER1_NV, GL_RGB, GL_VARIABLE_C_NV,
 549                 GL_TEXTURE0, GL_SIGNED_IDENTITY_NV, GL_RGB);
 550   CombinerInput(GL_COMBINER1_NV, GL_RGB, GL_VARIABLE_D_NV, GL_ZERO,
 551                 GL_UNSIGNED_INVERT_NV, GL_RGB);
 552   CombinerOutput(GL_COMBINER1_NV, GL_RGB, GL_DISCARD_NV, GL_DISCARD_NV,
 553                  GL_SPARE0_NV, GL_NONE, GL_NONE, GL_FALSE,
 554                  GL_FALSE, GL_FALSE);
 555
 556   // leave final combiner stage in default mode
 557   CombinerParameteri(GL_NUM_GENERAL_COMBINERS_NV, 2);
 558 }
 559
 560 /**
 561  * \brief Setup ATI version of register combiners for YUV to RGB conversion.
 562  * \param uvcos used for saturation and hue adjustment
 563  * \param uvsin used for saturation and hue adjustment
 564  *
 565  * ATI called this fragment shader, but the name is confusing in the
 566  * light of a very different OpenGL 2.0 extension with the same name
 567  */
 568 static void glSetupYUVCombinersATI(float uvcos, float uvsin) {
 569   GLfloat ucoef[4];
 570   GLfloat vcoef[4];
 571   GLint i;
 572   glGetIntegerv(GL_NUM_FRAGMENT_REGISTERS_ATI, &i);
 573   if (i < 3)
 574     mp_msg(MSGT_VO, MSGL_ERR,
 575            "[gl] 3 registers needed for YUV combiner (ATI) support (found %i)\n", i);
 576   glGetIntegerv (GL_MAX_TEXTURE_UNITS, &i);
 577   if (i < 3)
 578     mp_msg(MSGT_VO, MSGL_ERR,
 579            "[gl] 3 texture units needed for YUV combiner (ATI) support (found %i)\n", i);
 580   if (!BeginFragmentShader || !EndFragmentShader ||
 581       !SetFragmentShaderConstant || !SampleMap ||
 582       !ColorFragmentOp2 || !ColorFragmentOp3) {
 583     mp_msg(MSGT_VO, MSGL_FATAL, "[gl] Combiner (ATI) functions missing!\n");
 584     return;
 585   }
 586   fillUVcoeff(ucoef, vcoef, uvcos, uvsin);
 587   BeginFragmentShader();
 588   SetFragmentShaderConstant(GL_CON_0_ATI, ucoef);
 589   SetFragmentShaderConstant(GL_CON_1_ATI, vcoef);
 590   SampleMap(GL_REG_0_ATI, GL_TEXTURE0, GL_SWIZZLE_STR_ATI);
 591   SampleMap(GL_REG_1_ATI, GL_TEXTURE1, GL_SWIZZLE_STR_ATI);
 592   SampleMap(GL_REG_2_ATI, GL_TEXTURE2, GL_SWIZZLE_STR_ATI);
 593   // UV first, like this green component cannot overflow
 594   ColorFragmentOp2(GL_MUL_ATI, GL_REG_1_ATI, GL_NONE, GL_NONE,
 595                    GL_REG_1_ATI, GL_NONE, GL_BIAS_BIT_ATI,
 596                    GL_CON_0_ATI, GL_NONE, GL_BIAS_BIT_ATI);
 597   ColorFragmentOp3(GL_MAD_ATI, GL_REG_2_ATI, GL_NONE, GL_4X_BIT_ATI,
 598                    GL_REG_2_ATI, GL_NONE, GL_BIAS_BIT_ATI,
 599                    GL_CON_1_ATI, GL_NONE, GL_BIAS_BIT_ATI,
 600                    GL_REG_1_ATI, GL_NONE, GL_NONE);
 601   ColorFragmentOp2(GL_ADD_ATI, GL_REG_0_ATI, GL_NONE, GL_NONE,
 602                    GL_REG_0_ATI, GL_NONE, GL_NONE,
 603                    GL_REG_2_ATI, GL_NONE, GL_NONE);
 604   EndFragmentShader();
 605 }
 606
 607 static const char *yuv_prog_template =
 608   "!!ARBfp1.0\n"
 609   "OPTION ARB_precision_hint_fastest;"
 610   "PARAM ycoef = {%.4f, %.4f, %.4f};"
 611   "PARAM ucoef = {%.4f, %.4f, %.4f};"
 612   "PARAM vcoef = {%.4f, %.4f, %.4f};"
 613   "PARAM offsets = {%.4f, %.4f, %.4f};"
 614   "PARAM gamma = {%.4f, %.4f, %.4f};"
 615   "TEMP res, y, u, v;"
 616   "TEX y, fragment.texcoord[0], texture[0], %s;"
 617   "MAD res, y, ycoef, offsets;"
 618   "TEX u, fragment.texcoord[1], texture[1], %s;"
 619   "MAD res, u, ucoef, res;"
 620   "TEX v, fragment.texcoord[2], texture[2], %s;"
 621   "MAD result.color, v, vcoef, res;"
 622   "END";
 623
 624 static const char *yuv_pow_prog_template =
 625   "!!ARBfp1.0\n"
 626   "OPTION ARB_precision_hint_fastest;"
 627   "PARAM ycoef = {%.4f, %.4f, %.4f};"
 628   "PARAM ucoef = {%.4f, %.4f, %.4f};"
 629   "PARAM vcoef = {%.4f, %.4f, %.4f};"
 630   "PARAM offsets = {%.4f, %.4f, %.4f};"
 631   "PARAM gamma = {%.4f, %.4f, %.4f};"
 632   "TEMP res, y, u, v;"
 633   "TEX y, fragment.texcoord[0], texture[0], %s;"
 634   "MAD res, y, ycoef, offsets;"
 635   "TEX u, fragment.texcoord[1], texture[1], %s;"
 636   "MAD res, u, ucoef, res;"
 637   "TEX v, fragment.texcoord[2], texture[2], %s;"
 638   "MAD_SAT res, v, vcoef, res;"
 639   "POW result.color.r, res.r, gamma.r;"
 640   "POW result.color.g, res.g, gamma.g;"
 641   "POW result.color.b, res.b, gamma.b;"
 642   "END";
 643
 644 static const char *yuv_lookup_prog_template =
 645   "!!ARBfp1.0\n"
 646   "OPTION ARB_precision_hint_fastest;"
 647   "PARAM ycoef = {%.4f, %.4f, %.4f, 0};"
 648   "PARAM ucoef = {%.4f, %.4f, %.4f, 0};"
 649   "PARAM vcoef = {%.4f, %.4f, %.4f, 0};"
 650   "PARAM offsets = {%.4f, %.4f, %.4f, 0.125};"
 651   "PARAM gamma = {%.4f, %.4f, %.4f};"
 652   "TEMP res, y, u, v;"
 653   "TEX y, fragment.texcoord[0], texture[0], %s;"
 654   "MAD res, y, ycoef, offsets;"
 655   "TEX u, fragment.texcoord[1], texture[1], %s;"
 656   "MAD res, u, ucoef, res;"
 657   "TEX v, fragment.texcoord[2], texture[2], %s;"
 658   "MAD res, v, vcoef, res;"
 659   "TEX result.color.r, res.raaa, texture[3], 2D;"
 660   "ADD res.a, res.a, 0.25;"
 661   "TEX result.color.g, res.gaaa, texture[3], 2D;"
 662   "ADD res.a, res.a, 0.25;"
 663   "TEX result.color.b, res.baaa, texture[3], 2D;"
 664   "END";
 665
 666 /**
 667  * \brief setup a fragment program that will do YUV->RGB conversion
 668  * \param brightness brightness adjustment offset
 669  * \param contrast contrast adjustment factor
 670  * \param uvcos used for saturation and hue adjustment
 671  * \param uvsin used for saturation and hue adjustment
 672  * \param lookup use fragment program that uses texture unit 4 to
 673  *               do additional conversion via lookup.
 674  */
 675 static void glSetupYUVFragprog(float brightness, float contrast,
 676                         float uvcos, float uvsin, float rgamma,
 677                         float ggamma, float bgamma, int type, int rect) {
 678   char yuv_prog[1000];
 679   const char *prog_template = yuv_prog_template;
 680   char *tex_type = rect ? "RECT" : "2D";
 681   int lookup = 0;
 682   GLint i;
 683   // this is the conversion matrix, with y, u, v factors
 684   // for red, green, blue and the constant offsets
 685   float ry, ru, rv, rc;
 686   float gy, gu, gv, gc;
 687   float by, bu, bv, bc;
 688   switch (type) {
 689     case YUV_CONVERSION_FRAGMENT_POW:
 690       prog_template = yuv_pow_prog_template;
 691       break;
 692     case YUV_CONVERSION_FRAGMENT_LOOKUP:
 693       prog_template = yuv_lookup_prog_template;
 694       lookup = 1;
 695       break;
 696   }
 697   glGetIntegerv (GL_MAX_TEXTURE_UNITS, &i);
 698   if (i < 3)
 699     mp_msg(MSGT_VO, MSGL_ERR,
 700            "[gl] 3 texture units needed for YUV fragment support (found %i)\n", i);
 701   if (lookup && i < 4)
 702     mp_msg(MSGT_VO, MSGL_ERR,
 703            "[gl] 4 texture units needed for YUV fragment support with lookup (found %i)\n", i);
 704   if (!ProgramString) {
 705     mp_msg(MSGT_VO, MSGL_FATAL, "[gl] ProgramString function missing!\n");
 706     return;
 707   }
 708   ry = 1.164 * contrast;
 709   gy = 1.164 * contrast;
 710   by = 1.164 * contrast;
 711   ru = 0 * uvcos + 1.596 * uvsin;
 712   rv = 0 * uvsin + 1.596 * uvcos;
 713   gu = -0.391 * uvcos + -0.813 * uvsin;
 714   gv = -0.391 * uvsin + -0.813 * uvcos;
 715   bu = 2.018 * uvcos + 0 * uvsin;
 716   bv = 2.018 * uvsin + 0 * uvcos;
 717   rc = (-16 * ry + (-128) * ru + (-128) * rv) / 255.0 + brightness;
 718   gc = (-16 * gy + (-128) * gu + (-128) * gv) / 255.0 + brightness;
 719   bc = (-16 * by + (-128) * bu + (-128) * bv) / 255.0 + brightness;
 720   // these "center" contrast control so that e.g. a contrast of 0
 721   // leads to a grey image, not a black one
 722   rc += 0.5 - contrast / 2.0;
 723   gc += 0.5 - contrast / 2.0;
 724   bc += 0.5 - contrast / 2.0;
 725   rgamma = 1.0 / rgamma;
 726   ggamma = 1.0 / ggamma;
 727   bgamma = 1.0 / bgamma;
 728   snprintf(yuv_prog, 1000, prog_template, ry, gy, by, ru, gu, bu, rv, gv, bv,
 729            rc, gc, bc, rgamma, bgamma, bgamma, tex_type, tex_type, tex_type);
 730   ProgramString(GL_FRAGMENT_PROGRAM, GL_PROGRAM_FORMAT_ASCII,
 731                 strlen(yuv_prog), yuv_prog);
 732   glGetIntegerv(GL_PROGRAM_ERROR_POSITION, &i);
 733   if (i != -1)
 734     mp_msg(MSGT_VO, MSGL_ERR,
 735       "[gl] Error compiling fragment program, make sure your card supports\n"
 736       "GL_ARB_fragment_program (use glxinfo to check).%.10s\n", &yuv_prog[i]);
 737 }
 738
 739 /**
 740  * \brief little helper function to create a lookup table for gamma
 741  * \param map buffer to create map into
 742  * \param size size of buffer
 743  * \param gamma gamma value
 744  */
 745 static void gen_gamma_map(unsigned char *map, int size, float gamma) {
 746   int i;
 747   gamma = 1.0 / gamma;
 748   for (i = 0; i < size; i++) {
 749     float tmp = (float)i / (size - 1.0);
 750     tmp = pow(tmp, gamma);
 751     if (tmp > 1.0) tmp = 1.0;
 752     if (tmp < 0.0) tmp = 0.0;
 753     map[i] = 255 * tmp;
 754   }
 755 }
 756
 757 //! resolution of texture for gamma lookup table
 758 #define LOOKUP_RES 512
 759
 760 /**
 761  * \brief setup YUV->RGB conversion
 762  * \param target texture target for Y, U and V textures (e.g. GL_TEXTURE_2D)
 763  * \param type YUV conversion type
 764  * \param brightness brightness adjustment offset
 765  * \param contrast contrast adjustment factor
 766  * \param hue hue adjustment angle
 767  * \param saturation saturation adjustment factor
 768  * \param rgamma gamma value for red channel
 769  * \param ggamma gamma value for green channel
 770  * \param bgamma gamma value for blue channel
 771  * \ingroup glconversion
 772  */
 773 void glSetupYUVConversion(GLenum target, int type,
 774                           float brightness, float contrast,
 775                           float hue, float saturation,
 776                           float rgamma, float ggamma, float bgamma) {
 777   float uvcos = saturation * cos(hue);
 778   float uvsin = saturation * sin(hue);
 779   switch (type) {
 780     case YUV_CONVERSION_COMBINERS:
 781       glSetupYUVCombiners(uvcos, uvsin);
 782       break;
 783     case YUV_CONVERSION_COMBINERS_ATI:
 784       glSetupYUVCombinersATI(uvcos, uvsin);
 785       break;
 786     case YUV_CONVERSION_FRAGMENT_LOOKUP:
 787       {
 788         unsigned char lookup_data[4 * LOOKUP_RES];
 789         gen_gamma_map(lookup_data, LOOKUP_RES, rgamma);
 790         gen_gamma_map(&lookup_data[LOOKUP_RES], LOOKUP_RES, ggamma);
 791         gen_gamma_map(&lookup_data[2 * LOOKUP_RES], LOOKUP_RES, bgamma);
 792         ActiveTexture(GL_TEXTURE3);
 793         glCreateClearTex(GL_TEXTURE_2D, GL_LUMINANCE8, GL_LINEAR,
 794                          LOOKUP_RES, 4, 0);
 795         glUploadTex(GL_TEXTURE_2D, GL_LUMINANCE, GL_UNSIGNED_BYTE, lookup_data,
 796                     LOOKUP_RES, 0, 0, LOOKUP_RES, 4, 0);
 797         ActiveTexture(GL_TEXTURE0);
 798       }
 799     case YUV_CONVERSION_FRAGMENT:
 800     case YUV_CONVERSION_FRAGMENT_POW:
 801       glSetupYUVFragprog(brightness, contrast, uvcos, uvsin,
 802                          rgamma, ggamma, bgamma, type,
 803                          target == GL_TEXTURE_RECTANGLE);
 804       break;
 805   }
 806 }
 807
 808 /**
 809  * \brief enable the specified YUV conversion
 810  * \param target texture target for Y, U and V textures (e.g. GL_TEXTURE_2D)
 811  * \param type type of YUV conversion
 812  * \ingroup glconversion
 813  */
 814 void glEnableYUVConversion(GLenum target, int type) {
 815   if (type <= 0) return;
 816   switch (type) {
 817     case YUV_CONVERSION_COMBINERS:
 818       ActiveTexture(GL_TEXTURE1);
 819       glEnable(target);
 820       ActiveTexture(GL_TEXTURE2);
 821       glEnable(target);
 822       ActiveTexture(GL_TEXTURE0);
 823       glEnable(GL_REGISTER_COMBINERS_NV);
 824       break;
 825     case YUV_CONVERSION_COMBINERS_ATI:
 826       ActiveTexture(GL_TEXTURE1);
 827       glEnable(target);
 828       ActiveTexture(GL_TEXTURE2);
 829       glEnable(target);
 830       ActiveTexture(GL_TEXTURE0);
 831       glEnable(GL_FRAGMENT_SHADER_ATI);
 832       break;
 833     case YUV_CONVERSION_FRAGMENT_LOOKUP:
 834     case YUV_CONVERSION_FRAGMENT_POW:
 835     case YUV_CONVERSION_FRAGMENT:
 836       glEnable(GL_FRAGMENT_PROGRAM);
 837       break;
 838   }
 839 }
 840
 841 /**
 842  * \brief disable the specified YUV conversion
 843  * \param target texture target for Y, U and V textures (e.g. GL_TEXTURE_2D)
 844  * \param type type of YUV conversion
 845  * \ingroup glconversion
 846  */
 847 void glDisableYUVConversion(GLenum target, int type) {
 848   if (type <= 0) return;
 849   switch (type) {
 850     case YUV_CONVERSION_COMBINERS:
 851       ActiveTexture(GL_TEXTURE1);
 852       glDisable(target);
 853       ActiveTexture(GL_TEXTURE2);
 854       glDisable(target);
 855       ActiveTexture(GL_TEXTURE0);
 856       glDisable(GL_REGISTER_COMBINERS_NV);
 857       break;
 858     case YUV_CONVERSION_COMBINERS_ATI:
 859       ActiveTexture(GL_TEXTURE1);
 860       glDisable(target);
 861       ActiveTexture(GL_TEXTURE2);
 862       glDisable(target);
 863       ActiveTexture(GL_TEXTURE0);
 864       glDisable(GL_FRAGMENT_SHADER_ATI);
 865       break;
 866     case YUV_CONVERSION_FRAGMENT_LOOKUP:
 867     case YUV_CONVERSION_FRAGMENT_POW:
 868     case YUV_CONVERSION_FRAGMENT:
 869       glDisable(GL_FRAGMENT_PROGRAM);
 870       break;
 871   }
 872 }
 873
 874 /**
 875  * \brief draw a texture part at given 2D coordinates
 876  * \param x screen top coordinate
 877  * \param y screen left coordinate
 878  * \param w screen width coordinate
 879  * \param h screen height coordinate
 880  * \param tx texture top coordinate in pixels
 881  * \param ty texture left coordinate in pixels
 882  * \param tw texture part width in pixels
 883  * \param th texture part height in pixels
 884  * \param sx width of texture in pixels
 885  * \param sy height of texture in pixels
 886  * \param rect_tex whether this texture uses texture_rectangle extension
 887  * \param is_yv12 if set, also draw the textures from units 1 and 2
 888  * \param flip flip the texture upside down
 889  * \ingroup gltexture
 890  */
 891 void glDrawTex(GLfloat x, GLfloat y, GLfloat w, GLfloat h,
 892                GLfloat tx, GLfloat ty, GLfloat tw, GLfloat th,
 893                int sx, int sy, int rect_tex, int is_yv12, int flip) {
 894   GLfloat tx2 = tx / 2, ty2 = ty / 2, tw2 = tw / 2, th2 = th / 2;
 895   if (!rect_tex) {
 896     tx /= sx; ty /= sy; tw /= sx; th /= sy;
 897     tx2 = tx, ty2 = ty, tw2 = tw, th2 = th;
 898   }
 899   if (flip) {
 900     y += h;
 901     h = -h;
 902   }
 903   glBegin(GL_QUADS);
 904   glTexCoord2f(tx, ty);
 905   if (is_yv12) {
 906     MultiTexCoord2f(GL_TEXTURE1, tx2, ty2);
 907     MultiTexCoord2f(GL_TEXTURE2, tx2, ty2);
 908   }
 909   glVertex2f(x, y);
 910   glTexCoord2f(tx, ty + th);
 911   if (is_yv12) {
 912     MultiTexCoord2f(GL_TEXTURE1, tx2, ty2 + th2);
 913     MultiTexCoord2f(GL_TEXTURE2, tx2, ty2 + th2);
 914   }
 915   glVertex2f(x, y + h);
 916   glTexCoord2f(tx + tw, ty + th);
 917   if (is_yv12) {
 918     MultiTexCoord2f(GL_TEXTURE1, tx2 + tw2, ty2 + th2);
 919     MultiTexCoord2f(GL_TEXTURE2, tx2 + tw2, ty2 + th2);
 920   }
 921   glVertex2f(x + w, y + h);
 922   glTexCoord2f(tx + tw, ty);
 923   if (is_yv12) {
 924     MultiTexCoord2f(GL_TEXTURE1, tx2 + tw2, ty2);
 925     MultiTexCoord2f(GL_TEXTURE2, tx2 + tw2, ty2);
 926   }
 927   glVertex2f(x + w, y);
 928   glEnd();
 929 }
 930
 931 #ifdef GL_WIN32
 932 #include "w32_common.h"
 933 /**
 934  * \brief little helper since wglGetProcAddress definition does not fit our
 935  *        getProcAddress
 936  * \param procName name of function to look up
 937  * \return function pointer returned by wglGetProcAddress
 938  */
 939 static void *w32gpa(const GLubyte *procName) {
 940   return wglGetProcAddress(procName);
 941 }
 942
 943 int setGlWindow(int *vinfo, HGLRC *context, HWND win)
 944 {
 945   int new_vinfo;
 946   HDC windc = GetDC(win);
 947   HGLRC new_context = 0;
 948   int keep_context = 0;
 949
 950   // should only be needed when keeping context, but not doing glFinish
 951   // can cause flickering even when we do not keep it.
 952   if (*context)
 953   glFinish();
 954   new_vinfo = GetPixelFormat(windc);
 955   if (*context && *vinfo && new_vinfo && *vinfo == new_vinfo) {
 956       // we can keep the wglContext
 957       new_context = *context;
 958       keep_context = 1;
 959   } else {
 960     // create a context
 961     new_context = wglCreateContext(windc);
 962     if (!new_context) {
 963       mp_msg(MSGT_VO, MSGL_FATAL, "[gl] Could not create GL context!\n");
 964       return SET_WINDOW_FAILED;
 965     }
 966   }
 967
 968   // set context
 969   if (!wglMakeCurrent(windc, new_context)) {
 970     mp_msg (MSGT_VO, MSGL_FATAL, "[gl] Could not set GL context!\n");
 971     if (!keep_context) {
 972       wglDeleteContext(new_context);
 973     }
 974     return SET_WINDOW_FAILED;
 975   }
 976
 977   // set new values
 978   vo_window = win;
 979   vo_hdc = windc;
 980   {
 981     RECT rect;
 982     GetClientRect(win, &rect);
 983     vo_dwidth = rect.right;
 984     vo_dheight = rect.bottom;
 985   }
 986   if (!keep_context) {
 987     if (*context)
 988       wglDeleteContext(*context);
 989     *context = new_context;
 990     *vinfo = new_vinfo;
 991     getFunctions(w32gpa, NULL);
 992
 993     // and inform that reinit is neccessary
 994     return SET_WINDOW_REINIT;
 995   }
 996   return SET_WINDOW_OK;
 997 }
 998
 999 void releaseGlContext(int *vinfo, HGLRC *context) {
1000   *vinfo = 0;
1001   if (*context) {
1002     wglMakeCurrent(0, 0);
1003     wglDeleteContext(*context);
1004   }
1005   *context = 0;
1006 }
1007
1008 void swapGlBuffers() {
1009   SwapBuffers(vo_hdc);
1010 }
1011 #else
1012 #ifdef HAVE_LIBDL
1013 #include <dlfcn.h>
1014 #endif
1015 #include "x11_common.h"
1016 /**
1017  * \brief find address of a linked function
1018  * \param s name of function to find
1019  * \return address of function or NULL if not found
1020  *
1021  * Copied from xine
1022  */
1023 static void *getdladdr(const char *s) {
1024 #ifdef HAVE_LIBDL
1025 #if defined(__sun) || defined(__sgi)
1026   static void *handle = NULL;
1027   if (!handle)
1028     handle = dlopen(NULL, RTLD_LAZY);
1029   return dlsym(handle, s);
1030 #else
1031   return dlsym(0, s);
1032 #endif
1033 #else
1034   return NULL;
1035 #endif
1036 }
1037
1038 /**
1039  * \brief Returns the XVisualInfo associated with Window win.
1040  * \param win Window whose XVisualInfo is returne.
1041  * \return XVisualInfo of the window. Caller must use XFree to free it.
1042  */
1043 static XVisualInfo *getWindowVisualInfo(Window win) {
1044   XWindowAttributes xw_attr;
1045   XVisualInfo vinfo_template;
1046   int tmp;
1047   XGetWindowAttributes(mDisplay, win, &xw_attr);
1048   vinfo_template.visualid = XVisualIDFromVisual(xw_attr.visual);
1049   return XGetVisualInfo(mDisplay, VisualIDMask, &vinfo_template, &tmp);
1050 }
1051
1052 /**
1053  * \brief Changes the window in which video is displayed.
1054  * If possible only transfers the context to the new window, otherwise
1055  * creates a new one, which must be initialized by the caller.
1056  * \param vinfo Currently used visual.
1057  * \param context Currently used context.
1058  * \param win window that should be used for drawing.
1059  * \return one of SET_WINDOW_FAILED, SET_WINDOW_OK or SET_WINDOW_REINIT.
1060  * In case of SET_WINDOW_REINIT the context could not be transfered
1061  * and the caller must initialize it correctly.
1062  * \ingroup glcontext
1063  */
1064 int setGlWindow(XVisualInfo **vinfo, GLXContext *context, Window win)
1065 {
1066   XVisualInfo *new_vinfo;
1067   GLXContext new_context = NULL;
1068   int keep_context = 0;
1069
1070   // should only be needed when keeping context, but not doing glFinish
1071   // can cause flickering even when we do not keep it.
1072   if (*context)
1073   glFinish();
1074   new_vinfo = getWindowVisualInfo(win);
1075   if (*context && *vinfo && new_vinfo &&
1076       (*vinfo)->visualid == new_vinfo->visualid) {
1077       // we can keep the GLXContext
1078       new_context = *context;
1079       XFree(new_vinfo);
1080       new_vinfo = *vinfo;
1081       keep_context = 1;
1082   } else {
1083     // create a context
1084     new_context = glXCreateContext(mDisplay, new_vinfo, NULL, True);
1085     if (!new_context) {
1086       mp_msg(MSGT_VO, MSGL_FATAL, "[gl] Could not create GLX context!\n");
1087       XFree(new_vinfo);
1088       return SET_WINDOW_FAILED;
1089     }
1090   }
1091
1092   // set context
1093   if (!glXMakeCurrent(mDisplay, vo_window, new_context)) {
1094     mp_msg (MSGT_VO, MSGL_FATAL, "[gl] Could not set GLX context!\n");
1095     if (!keep_context) {
1096       glXDestroyContext (mDisplay, new_context);
1097       XFree(new_vinfo);
1098     }
1099     return SET_WINDOW_FAILED;
1100   }
1101
1102   // set new values
1103   vo_window = win;
1104   {
1105     Window root;
1106     int tmp;
1107     unsigned utmp;
1108     XGetGeometry(mDisplay, vo_window, &root, &tmp, &tmp,
1109         (unsigned *)&vo_dwidth, (unsigned *)&vo_dheight, &utmp, &utmp);
1110   }
1111   if (!keep_context) {
1112     void *(*getProcAddress)(const GLubyte *);
1113     const char *(*glXExtStr)(Display *, int);
1114     if (*context)
1115       glXDestroyContext(mDisplay, *context);
1116     *context = new_context;
1117     if (*vinfo)
1118       XFree(*vinfo);
1119     *vinfo = new_vinfo;
1120       getProcAddress = getdladdr("glXGetProcAddress");
1121     if (!getProcAddress)
1122       getProcAddress = getdladdr("glXGetProcAddressARB");
1123     if (!getProcAddress)
1124       getProcAddress = (void *)getdladdr;
1125     glXExtStr = getdladdr("glXQueryExtensionsString");
1126     getFunctions(getProcAddress, !glXExtStr ? NULL :
1127                  glXExtStr(mDisplay, DefaultScreen(mDisplay)));
1128
1129     // and inform that reinit is neccessary
1130     return SET_WINDOW_REINIT;
1131   }
1132   return SET_WINDOW_OK;
1133 }
1134
1135 /**
1136  * \brief free the VisualInfo and GLXContext of an OpenGL context.
1137  * \ingroup glcontext
1138  */
1139 void releaseGlContext(XVisualInfo **vinfo, GLXContext *context) {
1140   if (*vinfo)
1141     XFree(*vinfo);
1142   *vinfo = NULL;
1143   if (*context)
1144   {
1145     glFinish();
1146     glXMakeCurrent(mDisplay, None, NULL);
1147     glXDestroyContext(mDisplay, *context);
1148   }
1149   *context = 0;
1150 }
1151
1152 void swapGlBuffers(void) {
1153   glXSwapBuffers(mDisplay, vo_window);
1154 }
1155 #endif
1156