OpenCL Programming by Example

Reading and writing buffers

Till now we discussed how to create an image. The OpenCL provides APIs to transfer image data to device image buffer before the kernel is launched. Similarly, there is a function which transfers the image computed data back to the host memory. The clEnqueueWriteImage function copies the data from host to device memory as follows:

cl_int clEnqueueWriteImage (cl_command_queue command_queue,
  cl_mem image,cl_bool blocking_write,const size_t *origin,const size_t *region,size_t row_pitch,size_t slice_pitch,const void * ptr,cl_uint num_events_in_wait_list,const cl_event *event_wait_list,cl_event *event)

The clEnqueueReadImage function copies the data back from device to host memory as follows:

cl_int clEnqueueReadImage (cl_command_queue ...