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标题: android的eglSwapBuffers如何和SurfaceFlinger联系上的 [打印本页]

作者: zangcf 时间: 2016-5-7 13:23
标题: android的eglSwapBuffers如何和SurfaceFlinger联系上的
frameworks/native/opengl/libagl/egl.cpp:::
EGLBoolean eglSwapBuffers(EGLDisplay dpy, EGLSurface draw)
{
if (egl_display_t::is_valid(dpy) == EGL_FALSE)
      return setError(EGL_BAD_DISPLAY, EGL_FALSE);

egl_surface_t* d = static_cast<egl_surface_t*>(draw);
if (!d->isValid())
      return setError(EGL_BAD_SURFACE, EGL_FALSE);
if (d->dpy != dpy)
      return setError(EGL_BAD_DISPLAY, EGL_FALSE);

// post the surface
d->swapBuffers();

// if it's bound to a context, update the buffer
if (d->ctx != EGL_NO_CONTEXT) {
      d->bindDrawSurface((ogles_context_t*)d->ctx);
      // if this surface is also the read surface of the context
      // it is bound to, make sure to update the read buffer as well.
      // The EGL spec is a little unclear about this.
      egl_context_t* c = egl_context_t::context(d->ctx);
      if (c->read == draw) {
         d->bindReadSurface((ogles_context_t*)d->ctx);
      }
}

return EGL_TRUE;
}

作者: zangcf 时间: 2016-5-7 13:25
EGLBoolean egl_window_surface_v2_t::swapBuffers()
{
if (!buffer) {
      return setError(EGL_BAD_ACCESS, EGL_FALSE);
}

/*
   * Handle eglSetSwapRectangleANDROID()
   * We copyback from the front buffer
   */
if (!dirtyRegion.isEmpty()) {
      dirtyRegion.andSelf(Rect(buffer->width, buffer->height));
      if (previousBuffer) {
         // This was const Region copyBack, but that causes an
         // internal compile error on simulator builds
         /*const*/ Region copyBack(Region::subtract(oldDirtyRegion, dirtyRegion));
         if (!copyBack.isEmpty()) {
            void* prevBits;
            if (lock(previousBuffer,
                     GRALLOC_USAGE_SW_READ_OFTEN, &prevBits) == NO_ERROR) {
                  // copy from previousBuffer to buffer
                  copyBlt(buffer, bits, previousBuffer, prevBits, copyBack);
                  unlock(previousBuffer);
            }
         }
      }
      oldDirtyRegion = dirtyRegion;
}

if (previousBuffer) {
      previousBuffer->common.decRef(&previousBuffer->common);
      previousBuffer = 0;
}

unlock(buffer);
previousBuffer = buffer;
nativeWindow->queueBuffer(nativeWindow, buffer, -1);
buffer = 0;

// dequeue a new buffer
int fenceFd = -1;
if (nativeWindow->dequeueBuffer(nativeWindow, &buffer, &fenceFd) == NO_ERROR) {
      sp<Fence> fence(new Fence(fenceFd));
      if (fence->wait(Fence::TIMEOUT_NEVER)) {
         nativeWindow->cancelBuffer(nativeWindow, buffer, fenceFd);
         return setError(EGL_BAD_ALLOC, EGL_FALSE);
      }

      // reallocate the depth-buffer if needed
      if ((width != buffer->width) || (height != buffer->height)) {
         // TODO: we probably should reset the swap rect here
         // if the window size has changed
         width = buffer->width;
         height = buffer->height;
         if (depth.data) {
            free(depth.data);
            depth.width = width;
            depth.height  = height;
            depth.stride  = buffer->stride;
            depth.data = (GGLubyte*)malloc(depth.stride*depth.height*2);
            if (depth.data == 0) {
                  setError(EGL_BAD_ALLOC, EGL_FALSE);
                  return EGL_FALSE;
            }
         }
      }

      // keep a reference on the buffer
      buffer->common.incRef(&buffer->common);

      // finally pin the buffer down
      if (lock(buffer, GRALLOC_USAGE_SW_READ_OFTEN |
            GRALLOC_USAGE_SW_WRITE_OFTEN, &bits) != NO_ERROR) {
         ALOGE("eglSwapBuffers() failed to lock buffer %p (%ux%u)",
                  buffer, buffer->width, buffer->height);
         return setError(EGL_BAD_ACCESS, EGL_FALSE);
         // FIXME: we should make sure we're not accessing the buffer anymore
      }
} else {
      return setError(EGL_BAD_CURRENT_SURFACE, EGL_FALSE);
}

return EGL_TRUE;
}

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