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 *newCtx,
 212                           _EGLSurface **draw, _EGLSurface **read)
 213 {
 214    _EGLSurface *newDraw = *draw, *newRead = *read;
 215    _EGLContext *oldCtx;
 216
 217    /*
 218     * The goal is to bind a newCtx to newDraw.  Since newDraw may already have
 219     * a binding context (oldCtx), and newCtx may already be bound to another
 220     * surface (oldDraw), the old bindings are broken first and the new one is
 221     * created.
 222     */
 223    oldCtx = newDraw->CurrentContext;
 224    if (newCtx != oldCtx) {
 225       if (oldCtx) {
 226          assert(oldCtx->DrawSurface == newDraw);
 227          oldCtx->DrawSurface = NULL;
 228       }
 229
 230       if (newCtx) {
 231          _EGLSurface *oldDraw = newCtx->DrawSurface;
 232          if (oldDraw)
 233             oldDraw->CurrentContext = NULL;
 234
 235          newCtx->DrawSurface = newDraw;
 236          *draw = oldDraw;
 237       }
 238
 239       newDraw->CurrentContext = newCtx;
 240    }
 241
 242    /* likewise */
 243    if (newRead != newDraw)
 244       oldCtx = newRead->CurrentContext;
 245    if (newCtx != oldCtx) {
 246       if (oldCtx) {
 247          assert(oldCtx->ReadSurface == newRead);
 248          oldCtx->ReadSurface = NULL;
 249       }
 250
 251       if (newCtx) {
 252          _EGLSurface *oldRead = newCtx->ReadSurface;
 253          if (oldRead)
 254             oldRead->CurrentContext = NULL;
 255
 256          newCtx->ReadSurface = newRead;
 257          *read = oldRead;
 258       }
 259
 260       newRead->CurrentContext = newCtx;
 261    }
 262 }
 263
 264
 265 /**
 266  * Bind the context to the thread and return the previous context.
 267  *
 268  * Note that the context may be NULL.
 269  */
 270 static _EGLContext *
 271 _eglBindContextToThread(_EGLContext *ctx, _EGLThreadInfo *t)
 272 {
 273    EGLint apiIndex;
 274    _EGLContext *oldCtx;
 275
 276    apiIndex = (ctx) ?
 277       _eglConvertApiToIndex(ctx->ClientAPI) : t->CurrentAPIIndex;
 278
 279    oldCtx = t->CurrentContexts[apiIndex];
 280    if (ctx != oldCtx) {
 281       if (oldCtx)
 282          oldCtx->Binding = NULL;
 283       if (ctx)
 284          ctx->Binding = t;
 285
 286       t->CurrentContexts[apiIndex] = ctx;
 287    }
 288
 289    return oldCtx;
 290 }
 291
 292
 293 /**
 294  * Return true if the given context and surfaces can be made current.
 295  */
 296 static EGLBoolean
 297 _eglCheckMakeCurrent(_EGLContext *ctx, _EGLSurface *draw, _EGLSurface *read)
 298 {
 299    _EGLThreadInfo *t = _eglGetCurrentThread();
 300    EGLint conflict_api;
 301
 302    if (_eglIsCurrentThreadDummy())
 303       return _eglError(EGL_BAD_ALLOC, "eglMakeCurrent");
 304
 305    /* this is easy */
 306    if (!ctx) {
 307       if (draw || read)
 308          return _eglError(EGL_BAD_MATCH, "eglMakeCurrent");
 309       return EGL_TRUE;
 310    }
 311
 312    /* ctx/draw/read must be all given */
 313    if (draw == NULL || read == NULL)
 314       return _eglError(EGL_BAD_MATCH, "eglMakeCurrent");
 315
 316    /* context stealing from another thread is not allowed */
 317    if (ctx->Binding && ctx->Binding != t)
 318       return _eglError(EGL_BAD_ACCESS, "eglMakeCurrent");
 319
 320    /*
 321     * The spec says
 322     *
 323     * "If ctx is current to some other thread, or if either draw or read are
 324     * bound to contexts in another thread, an EGL_BAD_ACCESS error is
 325     * generated."
 326     *
 327     * But it also says
 328     *
 329     * "at most one context may be bound to a particular surface at a given
 330     * time"
 331     *
 332     * The latter is more restrictive so we can check only the latter case.
 333     */
 334    if ((draw->CurrentContext && draw->CurrentContext != ctx) ||
 335        (read->CurrentContext && read->CurrentContext != ctx))
 336       return _eglError(EGL_BAD_ACCESS, "eglMakeCurrent");
 337
 338    /* simply require the configs to be equal */
 339    if (draw->Config != ctx->Config || read->Config != ctx->Config)
 340       return _eglError(EGL_BAD_MATCH, "eglMakeCurrent");
 341
 342    switch (ctx->ClientAPI) {
 343 #ifdef EGL_VERSION_1_4
 344    /* OpenGL and OpenGL ES are conflicting */
 345    case EGL_OPENGL_ES_API:
 346       conflict_api = EGL_OPENGL_API;
 347       break;
 348    case EGL_OPENGL_API:
 349       conflict_api = EGL_OPENGL_ES_API;
 350       break;
 351 #endif
 352    default:
 353       conflict_api = -1;
 354       break;
 355    }
 356
 357    if (conflict_api >= 0 && _eglGetAPIContext(conflict_api))
 358       return _eglError(EGL_BAD_ACCESS, "eglMakeCurrent");
 359
 360    return EGL_TRUE;
 361 }
 362
 363
 364 /**
 365  * Bind the context to the current thread and given surfaces.  Return the
 366  * previously bound context and the surfaces it bound to.  Each argument is
 367  * both input and output.
 368  */
 369 EGLBoolean
 370 _eglBindContext(_EGLContext **ctx, _EGLSurface **draw, _EGLSurface **read)
 371 {
 372    _EGLThreadInfo *t = _eglGetCurrentThread();
 373    _EGLContext *newCtx = *ctx, *oldCtx;
 374
 375    if (!_eglCheckMakeCurrent(newCtx, *draw, *read))
 376       return EGL_FALSE;
 377
 378    /* bind the new context */
 379    oldCtx = _eglBindContextToThread(newCtx, t);
 380
 381    if (newCtx)
 382       _eglBindContextToSurfaces(newCtx, draw, read);
 383
 384    /* unbind the old context from its binding surfaces */
 385    if (oldCtx && oldCtx != newCtx) {
 386       assert(!*draw && !*read);
 387
 388       *draw = oldCtx->DrawSurface;
 389       *read = oldCtx->ReadSurface;
 390       assert(*draw && *read);
 391
 392       _eglBindContextToSurfaces(NULL, draw, read);
 393    }
 394
 395    *ctx = oldCtx;
 396    /* draw and read have been updated in _eglBindContextToSurfaces */
 397
 398    return EGL_TRUE;
 399 }
 400
 401
 402 /**
 403  * Just a placeholder/demo function.  Drivers should override this.
 404  */
 405 EGLBoolean
 406 _eglMakeCurrent(_EGLDriver *drv, _EGLDisplay *dpy, _EGLSurface *draw,
 407                 _EGLSurface *read, _EGLContext *ctx)
 408 {
 409    return EGL_FALSE;
 410 }
 411
 412
 413 /**
 414  * This is defined by the EGL_MESA_copy_context extension.
 415  */
 416 EGLBoolean
 417 _eglCopyContextMESA(_EGLDriver *drv, EGLDisplay dpy, EGLContext source,
 418                     EGLContext dest, EGLint mask)
 419 {
 420    /* This function will always have to be overridden/implemented in the
 421     * device driver.  If the driver is based on Mesa, use _mesa_copy_context().
 422     */
 423    return EGL_FALSE;
 424 }