src/egl/main/eglcontext.c

   1 #include <assert.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include "eglconfig.h"
   5 #include "eglcontext.h"
   6 #include "egldisplay.h"
   7 #include "eglcurrent.h"
   8 #include "eglsurface.h"
   9 #include "egllog.h"
  10
  11
  12 /**
  13  * Return the API bit (one of EGL_xxx_BIT) of the context.
  14  */
  15 static EGLint
  16 _eglGetContextAPIBit(_EGLContext *ctx)
  17 {
  18    EGLint bit = 0;
  19
  20    switch (ctx->ClientAPI) {
  21    case EGL_OPENGL_ES_API:
  22       switch (ctx->ClientVersion) {
  23       case 1:
  24          bit = EGL_OPENGL_ES_BIT;
  25          break;
  26       case 2:
  27          bit = EGL_OPENGL_ES2_BIT;
  28          break;
  29       default:
  30          break;
  31       }
  32       break;
  33    case EGL_OPENVG_API:
  34       bit = EGL_OPENVG_BIT;
  35       break;
  36    case EGL_OPENGL_API:
  37       bit = EGL_OPENGL_BIT;
  38       break;
  39    default:
  40       break;
  41    }
  42
  43    return bit;
  44 }
  45
  46
  47 /**
  48  * Parse the list of context attributes and return the proper error code.
  49  */
  50 static EGLint
  51 _eglParseContextAttribList(_EGLContext *ctx, const EGLint *attrib_list)
  52 {
  53    EGLenum api = ctx->ClientAPI;
  54    EGLint i, err = EGL_SUCCESS;
  55
  56    if (!attrib_list)
  57       return EGL_SUCCESS;
  58
  59    for (i = 0; attrib_list[i] != EGL_NONE; i++) {
  60       EGLint attr = attrib_list[i++];
  61       EGLint val = attrib_list[i];
  62
  63       switch (attr) {
  64       case EGL_CONTEXT_CLIENT_VERSION:
  65          if (api != EGL_OPENGL_ES_API) {
  66             err = EGL_BAD_ATTRIBUTE;
  67             break;
  68          }
  69          if (val != 1 && val != 2) {
  70             err = EGL_BAD_ATTRIBUTE;
  71             break;
  72          }
  73          ctx->ClientVersion = val;
  74          break;
  75       default:
  76          err = EGL_BAD_ATTRIBUTE;
  77          break;
  78       }
  79
  80       if (err != EGL_SUCCESS) {
  81          _eglLog(_EGL_DEBUG, "bad context attribute 0x%04x", attr);
  82          break;
  83       }
  84    }
  85
  86    if (err == EGL_SUCCESS) {
  87       EGLint renderable_type, api_bit;
  88
  89       renderable_type = GET_CONFIG_ATTRIB(ctx->Config, EGL_RENDERABLE_TYPE);
  90       api_bit = _eglGetContextAPIBit(ctx);
  91       if (!(renderable_type & api_bit))
  92          err = EGL_BAD_CONFIG;
  93    }
  94
  95    return err;
  96 }
  97
  98
  99 /**
 100  * Initialize the given _EGLContext object to defaults and/or the values
 101  * in the attrib_list.
 102  */
 103 EGLBoolean
 104 _eglInitContext(_EGLContext *ctx, _EGLDisplay *dpy, _EGLConfig *conf,
 105                 const EGLint *attrib_list)
 106 {
 107    const EGLenum api = eglQueryAPI();
 108    EGLint err;
 109
 110    if (api == EGL_NONE) {
 111       _eglError(EGL_BAD_MATCH, "eglCreateContext(no client API)");
 112       return EGL_FALSE;
 113    }
 114
 115    memset(ctx, 0, sizeof(_EGLContext));
 116    ctx->Resource.Display = dpy;
 117    ctx->ClientAPI = api;
 118    ctx->Config = conf;
 119    ctx->WindowRenderBuffer = EGL_NONE;
 120
 121    ctx->ClientVersion = 1; /* the default, per EGL spec */
 122
 123    err = _eglParseContextAttribList(ctx, attrib_list);
 124    if (err != EGL_SUCCESS)
 125       return _eglError(err, "eglCreateContext");
 126
 127    return EGL_TRUE;
 128 }
 129
 130
 131 /**
 132  * Just a placeholder/demo function.  Real driver will never use this!
 133  */
 134 _EGLContext *
 135 _eglCreateContext(_EGLDriver *drv, _EGLDisplay *dpy, _EGLConfig *conf,
 136                   _EGLContext *share_list, const EGLint *attrib_list)
 137 {
 138    return NULL;
 139 }
 140
 141
 142 /**
 143  * Default fallback routine - drivers should usually override this.
 144  */
 145 EGLBoolean
 146 _eglDestroyContext(_EGLDriver *drv, _EGLDisplay *dpy, _EGLContext *ctx)
 147 {
 148    if (!_eglIsContextBound(ctx))
 149       free(ctx);
 150    return EGL_TRUE;
 151 }
 152
 153
 154 #ifdef EGL_VERSION_1_2
 155 static EGLint
 156 _eglQueryContextRenderBuffer(_EGLContext *ctx)
 157 {
 158    _EGLSurface *surf = ctx->DrawSurface;
 159    EGLint rb;
 160
 161    if (!surf)
 162       return EGL_NONE;
 163    if (surf->Type == EGL_WINDOW_BIT && ctx->WindowRenderBuffer != EGL_NONE)
 164       rb = ctx->WindowRenderBuffer;
 165    else
 166       rb = surf->RenderBuffer;
 167    return rb;
 168 }
 169 #endif /* EGL_VERSION_1_2 */
 170
 171
 172 EGLBoolean
 173 _eglQueryContext(_EGLDriver *drv, _EGLDisplay *dpy, _EGLContext *c,
 174                  EGLint attribute, EGLint *value)
 175 {
 176    (void) drv;
 177    (void) dpy;
 178
 179    if (!value)
 180       return _eglError(EGL_BAD_PARAMETER, "eglQueryContext");
 181
 182    switch (attribute) {
 183    case EGL_CONFIG_ID:
 184       *value = GET_CONFIG_ATTRIB(c->Config, EGL_CONFIG_ID);
 185       break;
 186    case EGL_CONTEXT_CLIENT_VERSION:
 187       *value = c->ClientVersion;
 188       break;
 189 #ifdef EGL_VERSION_1_2
 190    case EGL_CONTEXT_CLIENT_TYPE:
 191       *value = c->ClientAPI;
 192       break;
 193    case EGL_RENDER_BUFFER:
 194       *value = _eglQueryContextRenderBuffer(c);
 195       break;
 196 #endif /* EGL_VERSION_1_2 */
 197    default:
 198       return _eglError(EGL_BAD_ATTRIBUTE, "eglQueryContext");
 199    }
 200
 201    return EGL_TRUE;
 202 }
 203
 204
 205 /**
 206  * Bind the context to the surfaces.  Return the surfaces that are "orphaned".
 207  * That is, when the context is not NULL, return the surfaces it previously
 208  * bound to;  when the context is NULL, the same surfaces are returned.
 209  */
 210 static void
 211 _eglBindContextToSurfaces(_EGLContext *ctx,
 212                           _EGLSurface **draw, _EGLSurface **read)
 213 {
 214    _EGLSurface *newDraw = *draw, *newRead = *read;
 215    _EGLContext *oldCtx;
 216
 217    oldCtx = newDraw->CurrentContext;
 218    if (ctx != oldCtx) {
 219       if (oldCtx) {
 220          assert(*draw == oldCtx->DrawSurface);
 221          oldCtx->DrawSurface = NULL;
 222       }
 223       if (ctx) {
 224          *draw = ctx->DrawSurface;
 225          ctx->DrawSurface = newDraw;
 226       }
 227
 228       newDraw->CurrentContext = ctx;
 229    }
 230
 231    if (newRead != newDraw)
 232       oldCtx = newRead->CurrentContext;
 233    if (ctx != oldCtx) {
 234       if (oldCtx) {
 235          assert(*read == oldCtx->ReadSurface);
 236          oldCtx->ReadSurface = NULL;
 237       }
 238       if (ctx) {
 239          *read = ctx->ReadSurface;
 240          ctx->ReadSurface = newRead;
 241       }
 242
 243       newRead->CurrentContext = ctx;
 244    }
 245 }
 246
 247
 248 /**
 249  * Bind the context to the thread and return the previous context.
 250  *
 251  * Note that the context may be NULL.
 252  */
 253 static _EGLContext *
 254 _eglBindContextToThread(_EGLContext *ctx, _EGLThreadInfo *t)
 255 {
 256    EGLint apiIndex;
 257    _EGLContext *oldCtx;
 258
 259    apiIndex = (ctx) ?
 260       _eglConvertApiToIndex(ctx->ClientAPI) : t->CurrentAPIIndex;
 261
 262    oldCtx = t->CurrentContexts[apiIndex];
 263    if (ctx != oldCtx) {
 264       if (oldCtx)
 265          oldCtx->Binding = NULL;
 266       if (ctx)
 267          ctx->Binding = t;
 268
 269       t->CurrentContexts[apiIndex] = ctx;
 270    }
 271
 272    return oldCtx;
 273 }
 274
 275
 276 /**
 277  * Return true if the given context and surfaces can be made current.
 278  */
 279 static EGLBoolean
 280 _eglCheckMakeCurrent(_EGLContext *ctx, _EGLSurface *draw, _EGLSurface *read)
 281 {
 282    _EGLThreadInfo *t = _eglGetCurrentThread();
 283    EGLint conflict_api;
 284
 285    if (_eglIsCurrentThreadDummy())
 286       return _eglError(EGL_BAD_ALLOC, "eglMakeCurrent");
 287
 288    /* this is easy */
 289    if (!ctx) {
 290       if (draw || read)
 291          return _eglError(EGL_BAD_MATCH, "eglMakeCurrent");
 292       return EGL_TRUE;
 293    }
 294
 295    /* ctx/draw/read must be all given */
 296    if (draw == NULL || read == NULL)
 297       return _eglError(EGL_BAD_MATCH, "eglMakeCurrent");
 298
 299    /* context stealing from another thread is not allowed */
 300    if (ctx->Binding && ctx->Binding != t)
 301       return _eglError(EGL_BAD_ACCESS, "eglMakeCurrent");
 302
 303    /*
 304     * The spec says
 305     *
 306     * "If ctx is current to some other thread, or if either draw or read are
 307     * bound to contexts in another thread, an EGL_BAD_ACCESS error is
 308     * generated."
 309     *
 310     * But it also says
 311     *
 312     * "at most one context may be bound to a particular surface at a given
 313     * time"
 314     *
 315     * The latter is more restrictive so we can check only the latter case.
 316     */
 317    if ((draw->CurrentContext && draw->CurrentContext != ctx) ||
 318        (read->CurrentContext && read->CurrentContext != ctx))
 319       return _eglError(EGL_BAD_ACCESS, "eglMakeCurrent");
 320
 321    /* simply require the configs to be equal */
 322    if (draw->Config != ctx->Config || read->Config != ctx->Config)
 323       return _eglError(EGL_BAD_MATCH, "eglMakeCurrent");
 324
 325    switch (ctx->ClientAPI) {
 326 #ifdef EGL_VERSION_1_4
 327    /* OpenGL and OpenGL ES are conflicting */
 328    case EGL_OPENGL_ES_API:
 329       conflict_api = EGL_OPENGL_API;
 330       break;
 331    case EGL_OPENGL_API:
 332       conflict_api = EGL_OPENGL_ES_API;
 333       break;
 334 #endif
 335    default:
 336       conflict_api = -1;
 337       break;
 338    }
 339
 340    if (conflict_api >= 0 && _eglGetAPIContext(conflict_api))
 341       return _eglError(EGL_BAD_ACCESS, "eglMakeCurrent");
 342
 343    return EGL_TRUE;
 344 }
 345
 346
 347 /**
 348  * Bind the context to the current thread and given surfaces.  Return the
 349  * previously bound context and the surfaces it bound to.  Each argument is
 350  * both input and output.
 351  */
 352 EGLBoolean
 353 _eglBindContext(_EGLContext **ctx, _EGLSurface **draw, _EGLSurface **read)
 354 {
 355    _EGLThreadInfo *t = _eglGetCurrentThread();
 356    _EGLContext *newCtx = *ctx, *oldCtx;
 357
 358    if (!_eglCheckMakeCurrent(newCtx, *draw, *read))
 359       return EGL_FALSE;
 360
 361    /* bind the new context */
 362    oldCtx = _eglBindContextToThread(newCtx, t);
 363    *ctx = oldCtx;
 364    if (newCtx)
 365       _eglBindContextToSurfaces(newCtx, draw, read);
 366
 367    /* unbind the old context from its binding surfaces */
 368    if (oldCtx && oldCtx != newCtx) {
 369       /*
 370        * If the new context replaces some old context, the new one should not
 371        * be current before the replacement and it should not be bound to any
 372        * surface.
 373        */
 374       if (newCtx)
 375          assert(!*draw && !*read);
 376
 377       *draw = oldCtx->DrawSurface;
 378       *read = oldCtx->ReadSurface;
 379       assert(*draw && *read);
 380
 381       _eglBindContextToSurfaces(NULL, draw, read);
 382    }
 383
 384    return EGL_TRUE;
 385 }
 386
 387
 388 /**
 389  * Just a placeholder/demo function.  Drivers should override this.
 390  */
 391 EGLBoolean
 392 _eglMakeCurrent(_EGLDriver *drv, _EGLDisplay *dpy, _EGLSurface *draw,
 393                 _EGLSurface *read, _EGLContext *ctx)
 394 {
 395    return EGL_FALSE;
 396 }
 397
 398
 399 /**
 400  * This is defined by the EGL_MESA_copy_context extension.
 401  */
 402 EGLBoolean
 403 _eglCopyContextMESA(_EGLDriver *drv, EGLDisplay dpy, EGLContext source,
 404                     EGLContext dest, EGLint mask)
 405 {
 406    /* This function will always have to be overridden/implemented in the
 407     * device driver.  If the driver is based on Mesa, use _mesa_copy_context().
 408     */
 409    return EGL_FALSE;
 410 }